taxonID	type	description	language	source
80735A2DFFB9FF9916D3A43FFBBBAB73.taxon	type_taxon	Type genus: Haplotaxis Hoffmeister, 1843	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFB9FF9916D3A43FFBBBAB73.taxon	diagnosis	Diagnosis [modified from the Haplotaxis description in Brinkhurst (1988)]	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFB9FF9916D3A43FFBBBAB73.taxon	description	Body form narrow and elongate, body wall with well-developed cuticular layer, brain anterior to mouth within elongate peristomium, the latter usually biannulate with a distinct transverse groove, although not in all species (Brinkhurst and Marchese 1987, Brinkhurst and McKey-Fender 1991) (Figs 2 A – C, 3 C). Ventral chaetae large, single, usually straight in basal part and curved to strongly hooked distally (Fig. 3 I – J); simple-pointed, but may have distal ornamentation or keel; modified genital chaetae in at least two species. Dorsal chaetae smaller than ventrals, single, sigmoid to nearly straight; may be absent in many or all segments. Foregut without a dorsal, pharyngeal pad; mouth opens into a capacious, thin-walled oral cavity (possibly eversible) (Fig. 3 B – C); mouth and oral cavity with strongly developed radial muscle bands extending to the body wall, interspersed with diagonal muscle bands (Figs 2 A – C, 3 A); conspicuous pharyngeal glands absent. Oral cavity terminates in a thick-walled, muscular pharynx (or ‘ gizzard’, a disputed term here — see ‘ Gizzard vs. muscular pharynx in Haplotaxis ’ in the discussion), consisting of transverse-circular muscle bands, interspersed with radial muscle, usually in IV – V (Fig. 3 B – D). Nephridia present in all middle and posterior segments; ducts with large, irregular cells, forming a compact mass filling much of the segment (Fig. 3 G). Conspicuous coelomocytes absent. Dorsal and ventral blood vessels connected by simple commissural vessels, often in each segment; those in anterior segments long and convoluted. Small clusters of glandular cells (‘ Timm’s glands’) may be present midventrally in some segments, approaching or surrounding the ventral nerve cord (Fig. 3 H). Clitellum one cell thick. Spermathecae in 2 – 4 segments, in front of gonadal segments, typically petiolate, with pores anterior and lateral or dorsolateral. Usually with two pairs of testes (typically in X – XI), followed by one or two pairs of ovaries with the second pair rather than the first being lost where reduction has occurred; eggs mesolecithal. Gonoducts simple, without attached prostate glands, but there may be glands around the pores; male ducts tubular, plesioporous.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFB9FF92155BA2C7FDE7AAD6.taxon	materials_examined	Material examined: Vouchers of the European Haplotaxis specimens (from Sweden, France, Italy, and Greece; see details in Table 1 and Supporting information, Table S 1) used in this analysis are all sexually immature, but they agree with the general descriptions of Haplotaxis gordioides (e. g. in Brinkhurst and Jamieson 1971) in non-genital characters. Moreover, we have no access to material from the type locality of the generic type (Haplotaxis gordioides), and we cannot conclude that the latter species is present among our samples. The African specimens (Table 1; Supporting information, Table S 1), although conforming to Haplotaxidae as defined above, will be described in a future contribution. Morphological vouchers were examined for most of the Japanese and North American Haplotaxis material. Haplotaxis spJP 1: NSMT An- 1915 – 1917: Japan, Shizuoka Prefecture, Kakida River, Doniwa, Shimizu-cho, Sunto-gun, 8 Jan 2010, collected by T. Torii; anterior end and slide mounted, part of tail analysed for DNA (CE 30885); two additional topotypic specimens from same date, whole mounted. Haplotaxis spJP 2: NSMT An 1918 – 1922: Japan, Aomori Prefecture, Gudari-numa stream, Hakkoda Mountains, 17 Mar 2017, collected by A. Ohtaka; five topotypic specimens, whole mounted, part of tail from one specimen (CE 31629) analysed for DNA. Haplotaxis spUS 1: USNM 1716294: USA, Washington, Jefferson Co., Bull Creek near Clearwater River, 2 Apr 2016, collected by S. Fend; anterior end and slide mounted, part of tail analysed for DNA (CE 30796). Haplotaxis spUS 2: USNM 1716295 – 1716298: USA, Idaho, Blaine Co., Corral Creek 1 km above Trail Creek, 1 Jun 2016, collected by S. Fend; anterior end and slide mounted, part of tail analysed for DNA (CE 30863); same collection data, three topotypic, whole mounted anterior ends (CE 30864 - 66). S. Fend collection: 2 Jun 2008, seven whole mounted and five dissected specimens. Haplotaxis spUS 3: SMNH 224406: USA, California, Guadalupe Creek above reservoir, 27 Mar 2007, collected by S. Fend, one of seven collected specimens, slide mounted, but part of tail analysed for DNA (CE 5231); other slides in S. Fend collection. Haplotaxis spUS 4: USNM 1716299 – 1716306: USA, Oregon, Jefferson Co., Metolius River above Camp Sherman, 4 Dec 2019, collected by S. Fend; anterior and posterior segments slide mounted, middle segments analysed for DNA (CE 36035); same collection date, four topotypic, whole mounted anterior ends, (CE 36036 – 39); 4 Jun 2018, three topotypic, whole mounted anterior ends (CE 36014 – 16). Additional Haplotaxis specimens were examined here for morphology and shown in Figure 3, but were not analysed for DNA: USA, Montana, Broadwater Co., spring near Brewer, 17 Mar 2007, collected by D. L. Gustafson; two sagittally sectioned specimens. California, Colusa Co., Stony Creek at Stonyford, 4 Nov 2002, collected by S. Fend; one whole mounted specimen. This material remains in S. Fend’s personal collection.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFB9FF92155BA2C7FDE7AAD6.taxon	discussion	Remarks This family (clade 1 in the present molecular analysis) is now defined by a unique combination of characters that have been associated with a predatory habit, and used to define the genus Haplotaxis by Brinkhurst (1988) (in italics, characters that are new in comparison with the Brinkhurst (1988) diagnosis, and are possible apomorphies): replacement of eversible pharynx and pharyngeal glands by a massive muscular pharynx in 1 / 2 IV – V (VI); capacious, thin-walled oral cavity (possibly eversible); ventral chaetae large, single, sickle-shaped, dorsals small, straight, simple, often lost in many or all segments. Taxa with paired chaetae are no longer included in the family. However, as we have not been able to study more than a few of the included species, and as the available sexually mature worms are indeed few, our diagnosis, as well as the species list, should be seen merely as a hypothesis of monophyly of the family. The true identity of the type species of Haplotaxis, Haplotaxis gordioides, is not resolved in this study; see Discussion for more details. Allspecimensattributedto Haplotaxis andtotheHaplotaxidae s. s. in the present analysis have the very elongate habitus of the type species, Haplotaxis gordioides. Other diagnostic characters also appear consistent with Haplotaxis s. s. descriptions, and can be easily seen in the available whole mounted specimens (Fig. 2 A – C). All of these characters are unique to the family, or unusual among other oligochaete families. The peristomium is elongate, most often biannulate, with the first annulus anterior to the mouth, containing the brain; the posterior annulus surrounds the buccal region. Segments beginning in V also may be biannulate, with a narrow anterior annulus. Mouth gives into a thin-walled, capacious oral cavity with folded epithelium, joined to the body wall with numerous muscle bands. Foregut continues as a muscular pharynx whose walls contain radial and circular muscles; the latter may form anterior or median sphincters (cf. Benham 1905: fig. 1, Smith 1918: fig. 7, Yamaguchi 1937: fig. 2, Brinkhurst and Marchese 1987: fig. 9). Length of the pharynx, as well as thickness and orientation of musculature varies among populations. A thin cuticular layer is visible at the beginning of the mouth, then becomes gradually thinner but remains visible within the pharynx and seems to disappear afterwards. Pharyngeal glands have not been observed. Chaetae are always single (not in pairs), with ventrals much larger than dorsals (cf. Forbes 1890: figs 1 – 2, Smith 1918: figs 5 – 6, Hrabě 1931: fig. 8, Yamaguchi 1936: figs A – C). Other characters considered diagnostic in the literature, such as ‘ Timm’s glands’ (Timm 1883: fig 12, Forbes 1890: figs 5 – 7, Hrabě 1931: fig. 9 c) and nephridia (Forbes 1890: fig. 10, Benham 1905: fig. 8) are difficult to see in some preparations, and none of the present specimens is mature enough to observe the reproductive characters, other than rudimentary gonads. Several described species would be attributed to Haplotaxidae s. s. as defined here, but the majority have been traditionally synonymized with Haplotaxis gordioides due to the unavailability of fully-mature specimens in most species descriptions, combined with a supposedly high intra-population variability in somatic characters, particularly the distribution of dorsal chaetae (Michaelsen 1899, Brinkhurst 1966, Brinkhurst and Jamieson 1971). Consequently, although the present analysis indicates multiple species having regional affinities, it is premature to assign these either to new or to previously-described species. It should be noted that a morphologically diverse group of Afrotropical species (to be described elsewhere) is well separated from the Holarctic species in the present analysis, and the Holarctic examples (representing up to 10 species) appear separated more by geography than by obvious morphological characters. For example, the two Japanese species in the DNA analysis are easily differentiated from each other by somatic characters, including extent of the muscular pharynx and morphology of the midventral (Timm’s) glands (Fig. 2 B, C) — yet (aside from a somewhat shorter pharynx) these do not appear to be consistent synapomorphies separating them from Nearctic species. It is important to note that some morphologically distinctive species recognized as haplotaxids by previous revisions (Brinkhurst and Jamieson 1971, Brinkhurst 1988) and conforming to Haplotaxidae as defined above, were unavailable for our molecular analysis. Among the more conspicuous examples, the Neotropical Haplotaxis aedeochaeta Brinkhurst & Marchese, 1987 has gonadal segments reduced to XI (testes) and XII (ovaries); there are narrow genital chaetae; dorsal chaetae are lacking; and the muscular pharynx is in V – VI (instead of the more common IV – V). Haplotaxis gastrochaetus Yamaguchi, 1953 (Japan) has some segments with remarkably enlarged ventral chaetae, without a nodulus (Yamaguchi 1953: fig. 14); in addition, dorsal chaetae are lacking, there is a single ovarian segment (progynous), and the ‘ gizzard’ is described as ‘ vestigial’. Haplotaxis forbesi Smith, 1918 (eastern North America) appears to have only one testicular segment; ovaries are unknown, but conspicuous organs associated with nephridia in XV – XVII resemble gonadal tissue (Brinkhurst, 1966). Haplotaxis heterogyne Benham, 1903 (New Zealand) has a single ovarian segment, and the muscular pharynx is reduced to IV only. In addition to these examples, rare observations of mature haplotaxid specimens have shown that they differ in reproductive characteristics, including genital chaetae (e. g. Haplotaxis dubius) and number of spermathecae (e. g. Haplotaxis ascaridoides). An examination of over 200 whole mounted (mostly immature, but many with developing gonads) Nearctic haplotaxid specimens by one of the authors (S. F.) suggests that populations have consistent differences in characters that include distribution of dorsal chaetae, thickness and presence of glandular cells in the epidermis, circular musculature of body wall, thickness of cuticle, extent and muscular development of the pharynx, chaetal morphology (Fig. 3 I – J), and number of ovarian segments; rare mature specimens indicate that at least two populations have distinctive genital chaetae. This indicates that the species included in the present analysis are just a limited sample of the world fauna, and that taxonomy of the group will evolve as material becomes available.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFB9FF92155BA2C7FDE7AAD6.taxon	distribution	The geographical distribution of Haplotaxis material in our analysis is Afrotropical and Holarctic. Based on published morphological descriptions, species conforming to our diagnosis of Haplotaxidae also occur in the Australasian (Haplotaxis heterogyne), Indomalayan (Haplotaxis vermivorus), and Neotropical (Haplotaxis aedeochaeta) regions.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFB2FF931699A276FB6CA9EB.taxon	description	ZooBank LSID: urn: lsid: zoobank. org: act: 67210344 - 489 D- 458 F- 9 CC 7 - D 9 EE 83952089	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFB2FF931699A276FB6CA9EB.taxon	type_taxon	Type genus: By original designation, Pelodrilus Beddard, 1891.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFB2FF931699A276FB6CA9EB.taxon	diagnosis	Diagnosis Body form not unusually narrow and elongate, cuticular layer thin, peristomium not elongate, brain in peristomium. Chaetae 4 pairs per segment, usually simple-pointed, but may have distal ornamentation or keel; dorsal chaetae not much smaller than ventrals, present in most or all segments. Pharynx with an eversible dorsal pad; conspicuous pharyngeal glands present. Nephridia present in some, but not all segments; ducts elongate-tubular, of various forms, but not forming a dense mass filling much of the segment. Dorsal and ventral blood vessels connected by simple commissural vessels. Clitellum one cell thick. Spermathecae anterior to gonadal segments. Two pairs of testes; one or two pairs of ovaries with the second pair being lost where reduction has occurred; eggs mesolecithal. Gonoducts simple, without attached prostate glands, but there may be glands around the pores; male ducts tubular, usually plesioporous.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFB2FF931699A276FB6CA9EB.taxon	discussion	Remarks This proposed family is most closely associated with megadriles (Metagynophora, Opisthopora, Crassiclitellata Jamieson, 1988) by the molecular evidence. Although members of Pelodrilidae may be large and thick-bodied, they differ morphologically in several respects from typical megadriles: (i) the clitellum is relatively thin, composed of a single cell layer, (ii) the brain is in the peristomium, (iii) the lateral blood vessels are simple commissures, (iv) eggs are large and yolky (mesolethical), (v) male ducts are usually plesioporous (not opisthoporous sensu Michaelsen), and not embedded in the body wall, and (v) ovaries are in GIII (progynous, rather than metagynous). Genera: Pelodrilus Beddard, 1891 (type species, Pelodrilus violaceus Beddard, 1891); Hologynus Brinkhurst, 1988 (type species, Pelodrilus hologynus Michaelsen, 1907); Delaya Brinkhurst, 1988 (type species, Pelodrilus bureschi Michaelsen, 1925). [Incertae sedis: Alphadrilus Brinkhurst, 1988 (type species, Phreoryctes smithii Beddard, 1888); Adenodrilus Čekanovskaja, 1959 (type species, Adenodrilus denticulatus Čekanovskaja, 1959); Heterochaetella Yamaguchi, 1953 (type species, Heterochaetella glandularis Yamaguchi, 1953); and Omodeodrilus Kammerer, 2006 (type species, Villiersia guanivora Omodeo, 1987)].	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFB2FF931699A276FB6CA9EB.taxon	materials_examined	Morphologically examined material: Hologynus cf. hologynus (Michaelsen, 1907): WAM V 12029 and V 12030: Western Australia, Manjimup, south of Pemberton, Spring Gully at Gloucester Rd.; two slide-mounted anterior ends (CE 17254 – 17255). Pelodrilus cf. darlingensis Michaelsen, 1907, WAM V 9004: South Western Australia, Augusta-Margaret River Region, Upper Margaret River, south of Busselton, Rapids Conservation Park, Canebrake Pool: one slide-mounted, anterior end (CE 17262). All this material collected 16 Sep 2012 by C. Erséus, A. Pinder, and Y. - D. Cui. For more details, see also Table 1 and Supporting information, Table S 1. Delaya species in the molecular analyses were not examined for morphology. They have a very similar general appearance and internal anatomy, making them difficult to identify. Their identification is essentially based on subtle chaetal characteristics (ornamentation and position) and the presence of species complexes cannot be excluded, especially for a species such as Delaya bureschi (Michaelsen, 1925), which has a wide geographical distribution (Greece, Slovenia, Bulgaria, Romania, Macedonia; Hrabě 1963, Botea and Botoşaneanu 1966, Delay 1970, Juget and Dumnicka 1986, Giani et al. 2001). Hence, the identification of the specimens of Delaya leruthi (Hrabě, 1958) (CE 13922) and D. bureschi (CE 33796) is made on a provisional basis and relies more on their presence in caves where their population has been known and followed for many years (D. leruthi: L’Estelas cave, France, Delay 1970, D. bureschi: Mrzla cave, Slovenia, Hrabě 1963) than on morphological examination. The unidentified species Delaya spIT (CE 7161) and Delaya spGR (CE 33797) were attributed to this genus by their genetic similarity to the other two taxa.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFB2FF931699A276FB6CA9EB.taxon	description	Descriptive notes The specimens identified as Hologynus cf. hologynus in the present analysis have a dorsal pharyngeal pad in II- 1 / 2 III, and large pharyngeal glands in V – VI (smaller in VII – VIII) (Supporting information, Fig. S 3 A). As noted by Brinkhurst (1966), there is no secondary annulation. The single pair of spermathecae has pores on the lateral lines at 6 / 7; the ampullae are quite elongate, extending back into VIII, as described for both Hologynus hologynus [Brinkhurst 1966 and Benham 1909 (as Pelodrilus aucklandicus)] and Hologynus bipapillatus (Michaelsen, 1925). The worms are hologynous, with ovaries in XII and XIII, and female pores intersegmental on 12 / 13 and 13 / 14 (Supporting information, Fig. S 3 B). The anterior male ducts are clearly plesioporous, with pores just posterior to ventral chaetae of XI (Supporting information, Fig. S 3 C); the posterior male ducts are just behind intersegment 11 / 12 (indistinctly plesioporous); both pores are adjacent to secretory surfaces of ventral gland clusters. The probable Pelodrilus specimen analysed here is partially mature, with one pair of rudimentary spermathecal pores on the lateral line, at 7 / 8. The dorsal pharyngeal pad and extensive pharyngeal glands (Fig. 2 F) are similar to those of Hologynus hologynus. There are partially developed gonads in X – XII (most likely testes in X and XI and ovaries in XII), and rudimentary female funnels appear to be developing on 12 / 13. The location of the spermathecal pores at 7 / 8, as well as the apparent ovaries in XII only (progynous condition) is consistent with Pelodrilus darlingensis Michaelsen, 1907, and these characters distinguish it from Hologynus species.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFB2FF931699A276FB6CA9EB.taxon	discussion	Remarks Our Pelodrilus specimen was collected about 100 km south-west of the type locality of P. darlingensis, in a town called Collie, and the Hologynus collection site was about 200 km south of the type locality for Hologynus hologynus, near Yarloop, Western Australia. We are unable to find a clear apomorphy for the widespread (but well-supported) Clade 2, represented by both Palaearctic (Delaya) and Australasian (Pelodrilus and Hologynus) species in the present analysis. These worms all have a dorsal pharyngeal pad in II- 1 / 2 III, and large pharyngeal glands from about V to VIII, and there is no ‘ gizzard’ (Fig. 2 F; see also Michaelsen 1907, Benham 1909, Hrabě 1958). Anterior gut morphology thus differs markedly from Haplotaxidae s. s. as defined here (Fig. 2 A – C) but appears to be typical for microdrile oligochaetes. Although the male ducts are quite simple, and usually plesioporous, members of the family show some variation in reproductive characters. For example, the posterior pair of male pores in Hologynus is shifted anteriad within the segment (Michaelsen 1907, 1924, Benham 1909), and may even enter the preceding segment (i. e. the prosoporous condition, resembling what is seen in Lumbriculidae, Branchiobdellida, and Kurenkovia Sokolskaja, 1969). In contrast, Pelodrilus violaceus Beddard, 1891 may show a rearward shift of the anterior male pores to a position ahead of the posterior pores on XII, approaching an opisthoporous condition, typical for megadrile families (Beddard 1891: figs 22, 27). The second ovarian segment is absent (the progynous condition, as in typical microdriles) in Pelodrilus species, unlike other (hologynous) members of the group (Brinkhurst 1988). Species of both Pelodrilus and Hologynus tend to have a reduced number of spermathecal segments (one or two) compared with other ‘ Haplotaxidae s. l. ’, whereas Delaya may have three or four (Brinkhurst 1966). Brinkhurst (1988) was unable to find a clear autapomorphy for Delaya, although all species have keeled or ornamented chaetae and plesioporous female ducts; the various species are separated by number of spermathecae and cutaneous / sexual glands, position of chaetal bundles, and details of chaetal morphology (Delay 1972, 1973). It should be noted that the molecular analysis does not support inclusion of the morphologically similar Ohtakiana kakidaensis (described below) from Japan (= Clade 4) in this clade, but rather associates it with the Lumbriculidae and Hirudinea-like taxa. The simple male ducts and general (unremarkable) body form of Ohtakiana resemble those of Pelodrilidae as defined above, but also resemble those of several additional taxa listed above as ‘ incertae sedis ’ — all of which are rare and monotypic, and unavailable in this study. These taxa also generally resemble Pelodrilidae in other typical microdrile characters, e. g. paired chaetae, eversible pharynx with pharyngeal glands. As a whole, i. e. including all the genera we have listed as putative members, the family Pelodrilidae has a wide distribution in the world. Taxa included in the present analysis were Australasian representatives of Pelodrilus and Hologynus, plus the Palaearctic Delaya. Additional Pelodrilus species have been described from the Afrotropical (Pelodrilus africanus Michaelsen, 1905) and Palaearctic (Pelodrilus ignatovi) regions; however, it should be noted that the latter was regarded as atypical by Brinkhurst (1988). Of the remaining genera not analysed here Omodeodrilus is Afrotropical, Heterochaetella and Adenodrilus are Palaearctic, and Alphadrilus is Australasian.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFB3FF931509A36DFB8FACB9.taxon	description	ZooBank LSID: urn: lsid: zoobank. org: act: C 439 AB 3 E- 4 C 5 B- 46 AD- 83 BD- 11603 F 48 A 3 D 3	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFB3FF931509A36DFB8FACB9.taxon	type_taxon	Type genus: Haplotaxoides Fend gen. nov.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFB3FF931509A36DFB8FACB9.taxon	diagnosis	Diagnosis As for type genus.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFB3FF931509A36DFB8FACB9.taxon	discussion	Remarks The new family closely resembles members of Haplotaxidae in general habitus. Although the narrow-elongate body form, thick integumental cuticle, and the unpaired chaetae (with enlarged ventrals) all closely resemble those of Haplotaxis, differences in pharyngeal musculature, ventral glands, coelomocytes, and position of the (metagynous) ovaries suggest a separate family on morphological grounds. The establishment of the new family is also justified with molecular data, as all species of the genus Haplotaxoides are grouped together in a clade with maximal support, distinctly separate from Haplotaxidae s. s. within the phylogeny of Clitellata (Fig. 1).	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFB3FF9015B9A58FFD31AC1F.taxon	description	ZooBank LSID: urn: lsid: zoobank. org: act: A 4 B 96 C 04 - 5 B 05 - 4 B 0 C-B 92 D- 16 CB 89 A 95516	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFB3FF9015B9A58FFD31AC1F.taxon	type_taxon	Type species: Haplotaxoides decipiens Fend sp. nov.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFB3FF9015B9A58FFD31AC1F.taxon	etymology	Etymology Morphologically similar to (Latin, - oides) Haplotaxis.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFB3FF9015B9A58FFD31AC1F.taxon	diagnosis	Diagnosis Body form narrow and elongate, body wall with thick cuticular layer, peristomium elongate, extending well anterior to the mouth. Secondary annulation present from V. Brain anterior to mouth in peristomium. Ventral chaetae large, single, with a straight shaft and strongly hooked distally, simple-pointed, but may have a dorsal keel; dorsal chaetae small, single, present in all segments from II. Buccal-pharyngeal region thickened dorsally, with radial muscle bands extending to the body wall, interspersed with longitudinal and circular muscle bands surrounding gut. Oral cavity reduced to II, not extensive; a sleeve of circular muscles surrounds pharynx in II – III; conspicuous pharyngeal glands absent; gut wall in pharyngeal area not highly muscular. Nephridia present in all middle and posterior segments; ducts with large, irregular cells, forming a compact mass filling much of the segment. Dorsal and ventral blood vessels connected by simple commissural vessels. Conspicuous, ovate coelomocytes usually present in all segments. In III and onward, all segments with 3 (2) elongate, transparent to granular glands inserting between ventral chaetae with external secretory patches; smaller glands may be present in I and II. Spermathecae possibly present but structure and number at maturity unknown. Paired testes in XII and XIII, one pair of ovaries in XV. Gonoducts simple. Modified genital chaetae in at least one species.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFB3FF9015B9A58FFD31AC1F.taxon	discussion	Remarks This new genus is referred to its own, monotypic, family, Haplotaxoididae fam. nov., and for the time being, the diagnosis of Haplotaxoides is identical to that of the family. For comparisons with other genera, see ‘ General remarks on Haplotaxoides material’ below. All of the analysed Haplotaxoides material, as well as most collections of morphologically similar specimens (see below), are from the western Nearctic region. Two groundwater records indicate that the genus also occurs in central North America (see below: ‘ Other Haplotaxoides material (not analysed for DNA) ’). In the material used for molecular analysis, we seem to have five distinct species of Haplotaxoides, all from the western USA (seeFig. 1). However, we conclude that only for two of them, the available material is sufficient for formal description of (named) new species; see below. For the three others (spp. A – C), we present preliminary morphological observations only.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFB0FF8E1680A569FBF1ACFB.taxon	description	(Figs 2 D, 4, 5) ZooBank LSID: urn: lsid: zoobank. org: act: C 869 EC 41 - 8 CBB- 4463 - AF 37 - 3515 C 8 C 9 F 982	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFB0FF8E1680A569FBF1ACFB.taxon	materials_examined	Holotype: USNM 1716307: a partially mature worm (with developing gonads), anterior end whole mounted, posterior end analysed for DNA (CE 30888); COI DNA-barcode in GenBank (acc. no. PP 988425); for other molecular data, see Table 1. Type locality: USA, California, Santa Clara Co., Guadalupe Creek above reservoir, 37.18237 ° N, 121.87236 ° W, in cobblegravel bed, 15 May 2016, collected by S. Fend. Paratypes: USNM 1716308 – 1716311, 1716313, from the type locality: 15 May 2016, an immature worm, whole mounted anterior end, posterior end analysed for DNA (CE 30889), COI DNA-barcode in GenBank (acc. no. PP 988426), for other molecular data, see Table 1. 8 April 2007, a partially mature whole mount. 25 March 2007, two partially mature whole mounts. 23 June 2011, an immature whole mount. USNM 1716312: USA, California, Santa Clara Co., Los Gatos Creek above Aldercroft Heights, 37.1478 ° N, 121.9562 ° W, 26 May 1998; a partially mature whole mount. Other material: SMNH 108431: USA, California, Santa Clara Co., Los Gatos Creek above reservoir, 26 May 1998; a partially mature worm, anterior end whole mounted, posterior end analysed for DNA (CE 438); for molecular data, see Table 1. S. Fend collection: California, Santa Clara Co., the type locality 25 Mar 2007; three whole mounts. 8 Apr 2007; three whole mounts. 11 May 2008; three whole mounts. 24 Mar 2011, two whole mounts. 20 Jun 2011; three whole mounts, two sagittally sectioned. 26 May 2012; two whole mounts. 21 Jun 2014; four whole mounts. Los Gatos Creek above reservoir, 9 – 26 May 1998; 23 whole mounts, one dissected. Rincon Creek near confluence with Guadalupe Creek, 5 Sep 2000; one whole mount. All collected by S. Fend.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFB0FF8E1680A569FBF1ACFB.taxon	etymology	Etymology Named decipiens (Latin for ‘ deceiving’), as it was originally assumed to be a Haplotaxis species, based on general morphology. In this study, we included the specimen (CE 438) identified as Haplotaxis cf. gordioides by Erséus and Källersjö (2004), but now found to be Haplotaxoides decipiens.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFB0FF8E1680A569FBF1ACFB.taxon	description	Description The primary description is based on specimens from the type locality and nearby tributaries (Los Gatos and Rincon Creeks) to the Guadalupe River, Santa Clara Valley, California. No fully mature specimens were available for study; measurements in the description are based on partially mature specimens with well-developed testes and sperm morulae, and with small ovaries. Length 26 – 58 mm, diameter in X 0.25 – 0.41 mm, maximum diameter 0.28 – 0.47 mm, 142 – 220 segments (Fig. 5 A). Secondary annulation beginning in V, an anterior ring about 1 / 4 – 1 / 3 segment length, may be strong or indistinct in middleposterior segments of fixed specimens. Chaetae single in dorsal and ventral bundles from II; all with a distinct nodulus 0.35 – 0.5 the chaetal length from the tip. Dorsal chaetae (Fig. 4 A) slightly sigmoid, simple-pointed, length 65 – 90 μm, diameter 3 – 5 μm. Ventral chaetae (Figs 4 A, 5 F) larger, increasing in length from 60 – 70 μm in anterior segments, to 130 – 180 μm in middle and posterior segments, diameter 9 – 11 μm, with a straight basal shaft and strongly arcuate distal part, tip may have small dorsal keel, or may be simple-pointed (perhaps from wear). Cuticle thick, about 5 – 6 μm throughout (Fig. 5 E). Prostomium demarcated posteriorly by transverse groove, longer (205 – 250 μm) than wide (135 – 205 μm), with epidermis 18 – 25 μm thick, transverse muscle layer 8 – 12 μm thick, inside thinner longitudinal muscle layer (Figs 4 I, 5 B). Peristomium with thin, irregular epidermal layer (6 – 12 μm); transverse muscle fibers of body wall thinner than in prostomium. Segments from II and posterior with thin, irregular, and often indistinct epidermis, cells interspersed with fibres of thin circular muscle layer, the combined layer about 10 – 12 μm in anterior segments, thinner posteriorly; longitudinal muscle layer 10 – 20 μm thick in anterior and middle segments. Brain at anterior margin of peristomium, at transverse groove (Figs 4 I, 5 B); ventral nerve cord flanked by two thick, glandular pads in each segment beginning in II (Fig. 4 G). Septa thin in first few segments, but thick beginning at 4 / 5. Anterior foregut a buccal-pharyngeal cavity with thickened dorsal wall in I – II, the thin epithelium surrounded by a muscular mass formed by small bundles of transverse fibres interspersed with strong bands anchoring it to the dorsal body wall, and an indistinct layer of thinner, longitudinal muscles (Figs 2 D, 5 C, D); ventral area thinner, but with similar musculature. A weak continuation of radiating muscle bands extending from mid-II to mid-III; circular muscles forming a weak sleeve surrounding gut in III (Figs 2 D, 4 I, 5 C – E); no pharyngeal glands. Gut wall thin and uniform beginning in mid-III (Fig. 5 M), epithelial cells gradually becoming somewhat granular and taller in mid-body; gut epithelium thicker, irregularly folded, and distinctly granular (similar to chloragogen) posterior to about LXX (Fig. 5 N – O). Cuticle thick in the first 1 / 3 of the muscular buccal region, then gradually thins until it is barely perceptible within the region of the circum-pharyngeal muscle ring. Chloragogen layer thin or not apparent on gut in post-gonadal segments. Anus terminal. Coelomocytes numerous throughout body, oval, 10 – 15 μm long (Fig. 5 I). All segments beginning in III with a cluster of mostly transparent, elongate-sacciform glands inserting midventrally on the body wall between ventral chaetae (Figs 4 F, G, 5 H, I); glands usually 3 (2) per cluster, 120 – 250 μm long, 40 – 70 μm wide in mid-body. Similar, but much smaller glands visible in I and / or II in some specimens. Cell structure of glands is obscure in most specimens, but in others, each gland appears to be composed of several elongate cells with ental nuclei and narrowing ectally; glands sometimes with an irregular lumen. Glands join at the epidermis in adjacent secretory disks, each with 6 – 10 apparent cell termini at the surface (Fig. 5 J, K). Cells somewhat resemble nephridial tissue, but vary histologically; typically, 2 glands in each cluster appear somewhat granular, and the third is more transparent. Nephridia paired; small in VII – XV (XVI), then larger from about XVI through remaining segments. In middle to posterior segments a small (25 – 30 μm long) anteseptal funnel leads to a thick (30 – 35 μm) nephridial duct that extends up to above gut, folding back on itself to form an irregular mass filling much of the segment (Figs 4 H, 5 G), and ending in a thinner duct terminating in an inconspicuous nephridiopore just anterior to the ventral chaeta. Nephridial tissue with large, irregular cells, mostly indistinct and transparent, but usually containing some darkly granular tissue in ental part. Dorsal blood vessel forks at brain, the two branches then enter prostomium, turn back around the mouth, and join in III to form ventral vessel. Lateral, commissural blood vessels long and convoluted, prominent in anterior segments, thinner and adjacent to posterior septa in middle and posterior segments. Spermathecal pores not obvious in partially mature worms; cell clusters that may be partially developed spermathecae visible anterior to dorsal chaetae in V – VIII in 14 specimens having dense sperm morulae both in testicular segments and in small sperm sacs extending as far back as XIV (Fig. 4 F). Testes in XII – XIII, sperm morulae fill both segments in several partially mature specimens, extending posteriad within small sperm sac (Fig. 5 L); partially developed male funnels on posterior septa of testicular segments, but sperm ducts not developed. Ovaries of most partially mature worms in XV only, female funnels not developed.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFB0FF8E1680A569FBF1ACFB.taxon	discussion	Remarks The thicker integumental cuticular layer (4 – 7 μm) may be the most consistent character separating Haplotaxoides decipiens from Haplotaxoides tehama sp. nov. (see below, 2 – 3.5 μm), although body dimensions and size of ventral chaetae were also generally greater. As mature Haplotaxoides decipiens specimens were not available, there is little basis for separating this species from Haplotaxoides tehama using the usual morphological characters related to reproductive organs. The dorsal cell clusters seen in segments V – VIII of partially mature Haplotaxoides decipiens are in a position similar to that of spermathecae in other haplotaxid-like oligochaetes, and thus may be either developing spermathecae or some unknown type of gland. No such organs were observed in the two mature Haplotaxoides tehama specimens (see below), or in any of the immature ones. Site descriptions Collection sites on Guadalupe and Los Gatos are small, low order streams in a densely forested landscape; with cool water, supporting native salmonids; benthic fauna at both sites is dominated by pollution intolerant insects (Carter and Fend 2000). The Los Gatos Creek site has permanent streamflow, due to upstream reservoir releases. Streamflow at the unregulated Guadalupe Creek site is intermittent in some years, with little or no surface flow in summer; but subsurface flow contributes to low temperatures in scattered permanent pools. Haplotaxoides decipiens was generally found in gravel patches within cobble-boulder riffles. The Los Gatos Creek site is the type locality for the lumbriculid Eremidrilus felini Fend & Rodriguez, 2003, and the Guadalupe Creek site is the type locality for the rhyacodriline naidids Rhyacodrilus alcyoneus Rodriguez & Fend, 2013 and Rhyacodrilus longichaeta Rodriguez & Fend, 2013.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFAEFF8C15C2A44DFBA7ABFC.taxon	description	(Fig. 4 C – D, J – L) ZooBank LSID: urn: lsid: zoobank. org: act: 37 FA 866 E- 433 C- 45 C 3 - A 409 - DDFECAD 66 EAB	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFAEFF8C15C2A44DFBA7ABFC.taxon	materials_examined	Holotype: USNM 1716314: an immature worm, anterior end whole mounted, posterior end analysed for DNA (CE 36030). COI DNA-barcode in GenBank (acc. no. PP 988403); for other molecular data, see Table 1. Type locality: USA, California, Tehama Co., Sacramento River at Tehama Bridge, in side channel on left bank. 40.0273 º N, 122.1180 º W, 9 Dec 2016; collected by S. Fend. Paratypes: USNM 1716315 – 1716316: from the type locality, 22 Oct 1996; one whole mounted, nearly mature worm (without DNA data); 9 Dec 2016; one whole mounted, mature worm (without DNA data). USNM 1716 317 – 1716318: from the type locality, 9 Dec 2016; two immature worms, anterior ends on slides, posterior ends analysed for DNA (CE 36028, CE 36029); COI DNA-barcodes in GenBank (acc. nos PP 988401, PP 988457); for other molecular data of CE 36028, see Table 1; individual CE 36029 was not used in our phylogenetic analyses. Other material: S. Fend collection: USA, California, from the type locality, 22 Oct 1996; 10 whole mounts. 9 Nov 2016; two whole mounts. Shasta Co., Sacramento River at Redding, 21 Oct 1996; four whole mounts. All immature, all collected by S. Fend.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFAEFF8C15C2A44DFBA7ABFC.taxon	etymology	Etymology Named tehama for the type locality, near Tehama, California. The word is of uncertain origin, but most likely a Nomlaki word for the location on the Sacramento River.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFAEFF8C15C2A44DFBA7ABFC.taxon	description	Description, nearly mature specimens Length 41 – 42 mm, diameter in X 0.28 – 0.30 mm, maximum diameter 0.28 – 0.37 mm, 159 – 169 segments. Dorsal chaetae (Fig. 4 C) slightly sigmoid, simple-pointed, length 48 – 65 μm, diameter 3 μm with nodulus 0.43 – 0.49 the chaetal length from the tip. Ventral chaetae with a straight basal shaft and strongly arcuate distal part, tip with a small dorsal keel; length to 102 – 119 μm in middle and posterior segments, diameter 5 – 7 μm, nodulus 0.37 – 0.43 the length from the tip. Head and musculature of mouth and anterior gut as described above, for Haplotaxoides decipiens (cf. Fig. 4 I). Cuticular layer of body wall about 3 μm thick throughout. Prostomium anterior to transverse groove longer (190 – 200 μm) than wide (90 – 130 μm). Coelomocytes numerous throughout body, oval, 10 – 20 μm long, 7 – 10 μm wide. Midventral glands as described above for Haplotaxoides decipiens, usually 3 per cluster, to 150 μm long, 30 – 50 μm wide in mid-body. Nephridia as described above. Blood vessels obscure in available material. Reproductive organs: testes in XII – XIII, sperm sac extending anteriad to IX or X, posteriorly through XIX; ovaries in XV. Large, transverse pores anterior to ventral chaetae in XIII; pores surrounded by a thick, glandular mass of columnar cells, about 120 μm wide (Fig. 4 K – L). Male funnels on 12 / 13 and 13 / 14, large and thick, each extending into anterior segment, but without sperm. Vasa deferentia simple, thin and inconspicuous; sinuous, apparently terminating in front of modified chaetae in XIII and XIV. Simple female funnels on 15 / 16 apparently extending into XVI. Spermathecae were not seen in either specimen.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFAEFF8C15C2A44DFBA7ABFC.taxon	materials_examined	In the mature 2016 specimen (paratype USNM 1716316), ventral chaetae in XIII – XIV strongly curved at base, remainder straight, with faint nodulus near basal 1 / 3; length about 175 μm, diameter about 6 μm, slightly widened at spear-shaped tip (Fig. 4 D, J). Midventral glands in XIII – XIV enlarged and highly granular (Fig. 4 J, K). Ovaries in XV only, simple female funnels to 70 μm high, on 15 / 16. One or two of the ventral glands in XVI greatly enlarged (to 350 × 220 μm) and highly granular (Fig. 4 J); corresponding chaetae enlarged and modified, to 185 μm long and 8 – 19 μm thick, straight and simple-pointed (Fig. 4 D). The 1996 specimen (paratype USNM 1716315) (Fig. 4 L) had partially developed genital chaetae in XIII – XIV and in XVI, adjacent to normal somatic chaetae. Midventral glands in XIII and XIV were somewhat enlarged, and two glands in XVI were larger, extending up the sides of the segment.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFAEFF8C15C2A44DFBA7ABFC.taxon	discussion	Remarks Although not sequenced, the specimens used to describe the sexual structures are considered paratypes, as all types are reasonably similar and were found in the same microhabitat. As noted above, Haplotaxoides tehama specimens are generally smaller than Haplotaxoides decipiens, and the cuticular layer of the integument is thinner. Spermathecae or dorsal glands (cf. Fig. 4 F) were not seen in anterior segments. Other characters, such as morphology of chaetae, development of the pharynx, and distribution of coelomocytes were not noticeably different between the two taxa. Further morphological differentiation among species within this family may await collections of reproductively mature specimens. Site description The Sacramento River site is a large river with flow controlled by the upstream Shasta Reservoir. Although the region is subject to intensive agricultural land use, water temperature is generally between 10 and 20 ° C, and many native fish populations are maintained (Domagalski et al. 2000, May and Brown 2000). The sampled site is a riffle area in a side channel, with gravel to cobble-size substrate.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFACFF8C1268A548FBC2AEAD.taxon	description	(Fig. 4 B)	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFACFF8C1268A548FBC2AEAD.taxon	materials_examined	Material examined: USNM 1716319 – 1716320: USA, California, Del Norte Co., Smith River below forks, approximately 41.8715 º N, 124.1248 º W (see Table 1), 21 Jun 2017; two immature worms, anterior and posterior segments slide mounted, middle segments analysed for DNA (CE 32193, CE 32194); for molecular data, see Table 1. All collected by S. Fend.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFACFF8C1268A548FBC2AEAD.taxon	description	Description Length unknown, maximum diameter 260 μm; cuticular layer of body wall 3 – 4 μm. Dorsal chaetae slightly sigmoid, length 58 – 73 μm, diameter 3 – 4 μm, nodulus 0.43 – 0.51 the chaetal length from the tip (Fig. 4 B). Ventral chaetae strongly hooked, some with dorsal keel at tip; length 95 – 135 μm, diameter 6 – 8 μm, nodulus at 0.3 – 0.42 the chaetal length from the tip. Cuticular layer of body wall 3 – 3.5 μm. Mouth, pharynx and other gut characters as described above. Coelomocytes numerous, 8 – 20 μm long; ventral glands to 180 μm, usually 3 / bundle. Small, partially developed gonads in XII – XIII.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFACFF8D1268A79BFEE0A9C3.taxon	materials_examined	Material examined: USNM 1716321: USA, Oregon, Lane Co., McKenzie River below Leaburg Fish Hatchery, approximately 44.116 ° N, 122.634 ° W, 2 Feb 2017; anterior end of immature worm on slide, posterior end analysed for DNA (CE 32195); for molecular data, see Table 1. S. Fend collection: 2 Feb 2017; three whole mounts. All collected by S. Fend.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFACFF8D1268A79BFEE0A9C3.taxon	description	Description Length 20 – 36 mm, maximum diameter 168 – 190 μm; 97 – 157 segments. Dorsal chaetae slightly sigmoid, length 32 – 54 μm, diameter 2 – 3 μm, nodulus 0.42 – 0.46 x the chaetal length from the tip. Ventral chaetae strongly hooked, some with dorsal keel at tip; length 76 – 95 μm, diameter 4 – 6 μm, nodulus at 0.35 – 0.42 the length from the tip. Cuticular layer of body wall 1.5 – 2.5 μm. Mouth, pharynx, and other gut characters as described above. Coelomocytes numerous, 8 – 18 μm long; ventral glands to 130 μm, usually 3 / bundle.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFADFF8D1721A0B5FA38AA0B.taxon	description	(Fig. 4 E)	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFADFF8D1721A0B5FA38AA0B.taxon	materials_examined	Material examined: USNM 1716322: USA, Oregon, Jefferson Co., Metolius River above Camp Sherman, near Metolius Spring, 44.4387 ° N, 121.6392 ° W, 4 Dec 2019; anterior end of immature worm on slide, posterior end analysed for DNA (CE 36019); for molecular data, see Table 1. S. Fend collection: 4 Jun 2018; four whole mounts; 4 Dec 2019; eight whole mounts. All collected by S. Fend.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFADFF8D1721A0B5FA38AA0B.taxon	description	Description Length 21 – 37 mm, maximum diameter 164 – 250 μm; 95 – 180 segments. Dorsal chaetae slightly sigmoid, length 40 – 56 μm, diameter 2 – 3 μm, nodulus 0.40 – 0.53 the chaetal length from the tip (Fig. 4 E). Ventral chaetae strongly hooked, some with dorsal keel at tip; length 88 – 110 μm, diameter 5 – 6 μm, nodulus at 0.30 – 0.38 the chaetal length from the tip. Cuticular layer of body wall 2 – 3 μm. Mouth, pharynx, and other gut characters as described above. Coelomocytes very sparse, only seen in anterior segments, 8 – 10 μm long; ventral glands to 150 μm, usually 3 / bundle.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFADFF8D1721A0B5FA38AA0B.taxon	materials_examined	Other Haplotaxoides material (not analysed for DNA) Material examined: All material in S. Fend collection, collected by S. Fend unless otherwise noted; all specimens immature or with developing gonads: USA, California, Santa Clara Co., Coyote Creek above reservoirs, below Gilroy Hot Springs, 24 Apr 2011; two whole mounts. Monterey Co., Nacimiento River below upstream camp, 17 Mar 2008; one whole mount. Humboldt Co., Van Duzen River, 27 May 2002; one whole mount. Eel River at Elk Creek, 24 Jun 2001; one whole mount. Butte Co., North Fork Feather River, 1 Oct 1999, collected by W. Fields; three whole mounts. Colusa Co., Stony Creek at Stonyford, 4 Nov 2002; five whole mounts. Colorado, South Platte River drainage, hyporheic samples, 2018, collected by S. J. Taylor; four whole mounts. Idaho, Lemhi Co., Hayden Creek, 30 Apr 2000, collected by D. L. Gustafson; four whole mounts. Nevada, Washoe Co., Lake Tahoe, 59 m depth, collected by A. Caires; two whole mounts. Illinois, St. Clair Co., Stemler Cave, 2 miles north-east of Columbia, Jun 1999, collected by S. J. Taylor; one whole mount. Missouri, Carter Co., Phillips Spring, Ozark National Scenic Riverways, 29 Jul 2019, collected by D. E. Bowles; three whole mounts. Shannon Co., Pulltite Spring, Ozark National Scenic Riverways, 24 Jul 2018, collected by D. E. Bowles; three whole mounts.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFADFF8D1721A0B5FA38AA0B.taxon	discussion	Remarks All specimens from these sites resembled the type material of Haplotaxoides decipiens in body form, single chaetae, thick cuticle, and gut morphology. All had small, sigmoid dorsal chaetae and larger, distally hooked ventral chaetae present in all segments from II. All had the characteristic coelomocytes, midventral glands, and nephridia. Where partially formed gonads were visible, they were invariably located in XII – XIII (testes) and XV only (ovaries). Anterior segments in three specimens from the North Fork Feather River (California) and a single specimen from Fall Creek, Oregon have 2 – 4 prominent bands of cells that are distinctly enlarged, appearing vacuolized; these are present, but less frequent in posterior segments. The epidermis of most Haplotaxoides specimens is thin (3 – 12 μm) and uniform in anterior segments.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFADFF8B15FDA376FEBBAB30.taxon	description	Somatic characters The apparently convergent morphology (chaetae single, hooked, and strongly developed ventrally; peristomium extending well anterior of the mouth; narrow-elongate body form with thick cuticular layer; midventral glands in most segments; massive nephridia; pharyngeal glands not developed) of Haplotaxoides (Clade 3) and Haplotaxis (Clade 1) is indeed remarkable and may be partly related to predaceous habits. However, the narrow body form and characters related to chaetae and ventral glands may be more general adaptations for medium-size worms living in groundwater. As in typical Haplotaxis species, Haplotaxoides chaetae are single, with dorsals much smaller than ventrals, and ventral chaetae are distally hooked. Despite these general similarities, other somatic characters easily distinguish known populations of Haplotaxoididae from typical haplotaxids. The strongly developed musculature surrounding the buccal area in Haplotaxoides resembles that of Haplotaxis, but in contrast to a well-developed muscular pharynx (Figs 2 A – C, 3 A – C), Haplotaxoides specimens have a thin, short, circular muscle layer surrounding a section of the simple pharynx at about 2 / 3 (Figs 2 D, 4 I, 5 D). The musculature surrounding the pharynx may have a similar function to that of the haplotaxid pharynx, in which more extensive musculature is incorporated within the gut wall. Haplotaxoides also lacks the capacious oral cavity of Haplotaxi s. Pharyngeal glands, which are well developed in many taxa in the present analysis, including those assigned here to Pelodrilidae (Fig. 2 F), have not been seen in either Haplotaxis or Haplotaxoides. Unlike in most other microdrile taxa, the brain of both Haplotaxoides and Haplotaxis appears to be located well anterior to the mouth, within the fore part of the elongated peristomium — probably a consequence of the highly developed buccal musculature. Other characters related to gut histology, including the chloragogen layer, should be further studied and compared among haplotaxid-like taxa. A well-developed surface layer of chloragogen tissue was never observed on the Haplotaxoides gut wall (Fig. 5 N, O). In comparison, available Haplotaxis preparations show a distinct chloragogen layer on the gut, beginning in middle segments (Fig. 3 E, F). The monotypic, Japanese Heterochaetella glandularis also lacks chloragogen on the gut, but has a dense such layer on the dorsal blood vessel (Yamaguchi 1953). Abundant coelomocytes have not been described for any Haplotaxis species, nor have we seen them in Haplotaxis specimens used in the present study, but they are common in most observed Haplotaxoides populations (the only exception being ‘ species C’), and they are at least superficially similar to the flat, oval discs described in many Enchytraeidae (reviewed by Schmelz and Collado 2010). The body wall of Haplotaxoides has a distinct cuticular layer, about 5 μm thick in Haplotaxoides decipiens and the Stony Creek population, although it is somewhat thinner (2 – 3 μm) in other populations. This differs from the very thin layer seen in most microdriles, but resembles the Haplotaxis specimens in the present analysis, as well as published descriptions of Haplotaxis s. s. The diagnosis of Haplotaxidae (s. l.) by (Brinkhurst 1966) stated ‘ Body-wall with cuticle thick in at least some species’. The description of Haplotaxis gastrochaetus states that body wall cuticle is 10 μm thick (Yamaguchi 1953), and de Eguileor et al. (1990) note 4.5 μm in Haplotaxis gordioides from Europe. A review of about 200 slide-mounted, North American haplotaxid specimens (S. Fend, unpublished data) indicates a wide range in cuticle thickness among populations, from less than 1 to 7 μm, although the median was only 1.5 μm. The large ventral glands are usually 3 per segment in all Haplotaxoides populations, and although they are midventral, with external secretory areas, the elongate-tubular form differs from the small, compact midventral ‘ Timm’s glands’ (Figs 2 A – C, 3 H) seen and described in Haplotaxis species (Timm 1883: fig. 12, Forbes 1890: figs 5 – 7, Hrabě 1931: fig. 9 a, Yamaguchi 1937, Brinkhurst 1966). Other body-wall glands are diverse and species-specific in taxa previously assigned to Haplotaxidae (e. g. Heterochaetella glandularis; Adenodrilus denticulatus), but we are not aware of any that closely resemble those of Haplotaxoides. For instance, A. denticulatus has long, tubular glands — but these are restricted to reproductive segments (X – XIII), and located on the chaetal lines (Čekanovskaja 1959). Although the gland tissue appears similar to that of nephridia (transparent, granular) in Haplotaxoides, we did not observe any connections to nephridial ducts, and the glands also occur in pre-nephridial segments. Nephridia (Fig. 4 H, 5 G) are difficult to see in most available Haplotaxoides preparations, but appear similar to those of Haplotaxis (Fig. 3 G): the indistinct ducts are difficult to follow through a large mass of slightly granular tissue, which fills much of the dorsolateral coelom. However, they are generally more transparent than those of Haplotaxis, and nephridial glands (as described by Brinkhurst 1966 in Haplotaxis forbesi, Smith, 1918) were not seen in our material. The Haplotaxoides nephridia bear no resemblance to the more simple, tubular ones in the Pelodrilus, Hologynus, Limpluvia setoensis sp. nov., or Ohtakiana kakidaensis sp. nov. specimens used in the present analysis, nor to those of lumbriculids and enchytraeids. Delaya also has tubular nephridia, as described by Delay (1970: fig. 9). Reproductive characters Testes are located in XII – XIII in partially mature specimens of all Haplotaxoides populations investigated, distinguishing these worms from known Haplotaxis species, where they are typically in X – XI (less commonly beginning in IX). Partially developed ovaries were seen in XV in some specimens from most sampled populations, but always appeared absent in XIV, suggesting that mature individuals are metagynous — and this is confirmed by the two nearly-mature specimens from the Sacramento River. Again, this differs from most other taxa that have been associated with Haplotaxidae. The family diagnosis by Brinkhurst (1988) specifies that haplotaxids are hologynous or progynous, whereas metagynous taxa with haplotaxid-like male ducts were attributed to Metataxis Righi, 1985 (Metagynophora sensu Jamieson, 1988). Metataxis (sensu Omodeo, 1987) includes a diverse set of species, differing from both Haplotaxis and Haplotaxoides in having paired chaetae and a typical (eversible) pharynx with pharyngeal glands. Unfortunately, no Metataxis species were available in the present study, which leaves their family classification, as well as their relationship to Haplotaxoides unknown. However, other Metagynophora, including a specimen tentatively identified as ‘ Alluroididae sp’. and several earthworms (Crassiclitellata) did not appear closely related to Haplotaxoides in the present DNA analysis. No fully mature worms of Haplotaxoides decipiens were observed, so morphology of genital ducts in this species is unknown. Small organs that may represent developing spermathecae were seen in segments V – VIII in several partially mature specimens from the Haplotaxoides decipiens type locality, and their dorsolateral location, anterior to the dorsal chaetal bundles of preclitellar segments, is reasonably consistent with positions of spermathecae described in some Haplotaxis (Benham 1903, Michaelsen 1905, Hrabě 1931, Brinkhurst & Marchese 1987), and in other ‘ Haplotaxidae s. l. ’. (Beddard 1891, Hrabě 1958), and Metataxis (Cook 1975, Omodeo 1987). The simple, prosoporous male ducts observed in the two nearly mature (but unmated) Haplotaxoides tehama resemble those described for Haplotaxis, as well as those of Pelodrilidae and other taxa previously associated with the Haplotaxidae. However, spermathecae were not visible in those specimens, and there was no evidence of the dorsolateral cell masses seen in anterior segments of Haplotaxoides decipiens. This may relate to poor preservation, and small spermathecae may simply have been obscured by contents of the sperm sacs. The paired gland masses in XIII of Haplotaxoides tehama resemble ‘ copulatory glands’ described for some Haplotaxis species (e. g. Haplotaxis heterogyne, Haplotaxis vermivorus), as well as Pelodrilus, and Hologynus species (e. g. Brinkhurst 1966). Both the basally hooked, elongate chaetae at the male pores, and greatly thickened chaetae associated with female pores of mature Haplotaxoides tehama differ from genital chaetae of other taxa associated with the former concept of Haplotaxidae s. l. Genital chaetae are infrequently reported in descriptions of Haplotaxidae s. s., although they have been described for Haplotaxis aedeochaeta and Haplotaxis dubius. Those in Haplotaxis aedeochaeta are long and hair like, and associated with male pores in XII (Brinkhurst and Marchese 1987); genital chaetae in Haplotaxis dubius are associated with large chaetal glands in XII – XIV and have thin, hair-like tips (Hrabě 1931: figs 8 – 9). Genital chaetae have also been reported in other taxa formerly associated with Haplotaxidae s. l. Those of Omodeodrilus guanivorus bear some resemblance to the elongate, basally hooked chaetae at male pores of the mature Sacramento River specimens. However, although O. guanivorus has been associated with Haplotaxidae s. l., it differs from both Haplotaxidae and Haplotaxoididae (as defined here) in terms of body form, chaetae, nephridia and arrangement of gonads (Omodeo 1987: fig. 3). Genital chaetae are mentioned, but not well described for Omodeodrilus kraepelini (Michaelsen, 1914) and the metagynophoran Metataxis eliae Righi, 1985. Gut contents Some Haplotaxoides specimens had guts partially filled with very fine organic matter that appeared detrital; although gut contents sometimes included diatom frustules, large amounts of mineral particles and obvious plant detritus (filamentous algae, macrophyte fragments) were never seen. At the type locality and nearby sites, 15 specimens of Haplotaxoides decipiens contained small amounts of amorphous, often transparent organic matter; seven had small amounts of detritus, and five contained chaetae from other oligochaete taxa, including Haplotaxis sp., Rhyacodrilus sp., and Eremidrilus sp. One specimen contained a chironomid larva (cf. Parametriocnemus sp.), and 24 had empty guts. Across all other sites, guts of 10 Haplotaxoides spp. individuals contained small amounts of fine detritus, 24 had amorphous organic matter, 10 had oligochaete chaetae, two had dipteran (Chironomidae) fragments, and 29 had empty guts. The unidentified organic matter sometimes consisted of small globules (probably lipid), and in other cases appeared striated (possibly animal tissue).	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFABFF8B16EEA4E6FA03A96E.taxon	type_taxon	Type species: By monotypy, Ohtakiana kakidaensis Fend & Torii sp. nov.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFABFF8B16EEA4E6FA03A96E.taxon	etymology	Etymology Named for Prof. Akifumi Ohtaka, in appreciation for his many contributions to the study of Japanese oligochaetes and branchiobdellidans.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFABFF8B16EEA4E6FA03A96E.taxon	diagnosis	Diagnosis Chaetae four pairs per segment, simple-pointed, sigmoid, nodulate, with dorsal pairs slightly smaller than ventral. Pharynx eversible, with large pharyngeal glands; gut with chloragogen layer. Nephridial ducts simple, tubular. Dorsal and ventral blood vessels connected by long commissural vessels. Large midventral glands in post-clitellar segments. Clitellum one cell thick. Spermathecae 3 pairs, pores anterolateral in VI – VIII. Two pairs of testes in X – XI, two pairs of ovaries in XII – XIII, eggs mesolecithal. Gonoducts simple, plesioporous; male ducts tubular, with pores slightly anterior to ventral chaetae; female ducts are conical funnels, with pores anterior to ventral chaetae.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFABFF8B16A0A2C5FE9DAD96.taxon	description	ZooBank LSID: urn: lsid: zoobank. org: act: 1 C 4 EB 4 C 4 - F 385 - 45 A 9 - AE 8 B- 72 EEC 11 E 3 C 13	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFABFF8B16A0A2C5FE9DAD96.taxon	type_taxon	Type genus: Ohtakiana Fend & Torii gen. nov.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFABFF8B16A0A2C5FE9DAD96.taxon	diagnosis	Diagnosis As for type genus.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFABFF8B16A0A2C5FE9DAD96.taxon	discussion	Remarks This family is currently monotypic, and morphologically distinguished only by the characters listed below in the genus diagnosis and species description. Morphologically, it resembles members of the Pelodrilidae, particularly Hologynus, and more detailed anatomical study is needed for comparison. At this point, the best distinguishing character appears to be the large midventral glands.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFABFF861509A0DEFB79AE01.taxon	description	(Figs 2 E, 6 – 7) ZooBank LSID: urn: lsid: zoobank. org: act: 98055747 - 7 DFF- 4 DFD- 9961 - B 7 EA 8 AEDE 978	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFABFF861509A0DEFB79AE01.taxon	materials_examined	Holotype: NSMT An- 1892: a mature worm, anterior end dissected, stained with borax carmine and slide-mounted, part of tail analysed for DNA (CE 30883); COI DNA-barcode in GenBank (acc. no. PP 988423); for other molecular data, see Table 1. Type locality: Japan, Shizuoka Prefecture, Kakida River, Doniwa, Shimizu-cho, Sunto-gun, 8 Jan 2010. Collected by T. Torii. Paratypes: NSMT An- 1893 - 1896, from the type locality, 19 Aug 2008; one mature whole mount. 8 Jan 2010; one mature worm, anterior end and part of tail stained with hematoxylin, dissected, and slide mounted, part of tail analysed for DNA (CE 30882) and for molecular data, see Table 1; one mature worm, dissected on slide; one immature worm with small gonads, whole mounted. All collected by T. Torii.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFABFF861509A0DEFB79AE01.taxon	etymology	Etymology From the Kakida River.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFABFF861509A0DEFB79AE01.taxon	description	Description Length of mature, preserved worms up to 40 mm; diameter 1.2 – 1.5 mm in anterior segments, 1.1 mm in posterior segments; 94 – 105 segments (Fig. 6 A). Prolobous, but prostomial groove may be faint; prostomium rounded-conical, length shorter than or about equal to width (Fig. 7 A, B). Peristomium not elongate. Secondary annulation a very narrow anterior ring from IV or V (Fig. 6 A), gradually increasing to more than 1 / 3 of segment length by mid-body, and up to 1 / 2 in posterior segments; furrows distinct anteriorly, less conspicuous from about XV. Epidermis to 40 μm thick and columnar in prostomium, vacuolated and 10 – 20 (median 12) μm thick in next few segments; cuticle about 1 μm. In middle and posterior segments, epidermis of posterior (setigerous) ring darkly staining (hematoxylin), 10 – 12 μm thick with large vacuoles; thinner in anterior ring (5 – 10 μm) and not darkly staining (Fig. 7 D, E, H). Clitellum indistinct in external view, from about IX to XVI, but glandular epidermis may extend to XX; clitellar epidermis to 25 – 45 μm thick in two specimens. Secretory area of ventral glands on the ventral midline, one gland within the posterior annulus of each mid-body and posterior segment; secretory area may appear as a flat disk (to about 0.2 mm diameter) or may be produced as a low tubercle (Figs 6 A, 7 D, E). All chaetae paired, simple-pointed, without obvious keel or other ornamentation; chaetae sigmoid with a faint nodulus, thickness 6 – 10 μm anteriorly, to about 15 μm in posterior segments (Figs 6 C – F, 7 F, G). In anterior segments, ventral chaetae 180 – 260 μm long; in posterior half of body, ventrals 215 – 315 (mostly> 260) μm; dorsals slightly shorter and thinner. Chaetal formula (aa: bc: dd) in anterior and middle segments about 1: 1: 1.5 or 1: 1: 2; dorsal chaetae closer to lateral line than are ventral chaetae in anterior segments; on the lateral line in posterior segments. Chaetae in genital segments not modified. Brain in peristomium (Fig. 7 B). Septa indistinct anteriorly, thicker from 4 / 5. Pharynx II-III or IV, thickened and concave dorsally, forming a slight pouch, but otherwise not modified; pharyngeal glands (IV) V – VII (VIII) (Figs 2 E, 7 C). Chloragogen layer thin, beginning on gut by about VII; may be indistinct in posterior segments, and not apparent on blood vessels. Blood-vascular system simple, without hearts, parietal vessels or subneural vessel. Long, convoluted commissural blood vessels in anterior segments. Dorsal blood vessel prominent, appressed to gut posterior to about VI; ventral blood vessel thin, between gut and ventral nerve cord. Other blood vessels difficult to see, but most posterior segments with one pair of lateral vessels, thin and convoluted dorsally, and straighter and thicker in ventral half. Nephridia difficult to see in available material; may be present in VIII and in many post-clitellar segments. Nephridial funnel small; postseptal part composed of long and convoluted tubules; for most of their length tubules paired or joined in ribbon-like clusters of four or more, forming loops extending to near dorsum (Fig. 7 K, L), and terminating in a simple pore just anterior to ventral chaetae. Midventral glands in XI – XII of mature worms, weak or absent for the next several segments, then well-developed in all segments posterior to about XXV; glands composed of a circular cluster of multicellular lobes, with individual cell extensions joining the external secretory surface; lobes of glands go to either side of the ventral nerve cord (Figs 6 C – F, 7 I, J). Each gland with 10 or more lobes 100 – 200 μm high, forming a mass to 250 μm wide in XI – XII and at mid-body, but smaller in other segments. No obvious glands in dorsal part of segment; no large glands associated with the chaetae. A single immature worm with small glands in XXII, larger glands, to about 200 μm wide, from about XXX. Spermathecal pores inconspicuous, oval openings on lateral line, at 5 / 6, 6 / 7, and 7 / 8 (Fig. 6 B). Spermathecae extend into VI, VII, and VIII, via short ducts (40 – 60 μm long by 30 – 40 μm diameter); ampullae of mated worms ovate, increasing in size from VI – VIII; the largest to 600 × 250 μm (Fig. 6 B). Spermathecal ampullae with thick (20 – 50 μm), somewhat vacuolated epithelium; sperm in ampulla loosely clumped, but not associated with the epithelium, and not forming distinct arrangements. Octogonadal, with two pairs of testes and two pairs of ovaries in consecutive segments. Testes small and narrow, extending to mid-segment in X and XI. Mature worms with sperm filling segment X, but no anterior sperm sacs; posterior sperm sacs extend as far back as XV or XVI. Male funnels on 10 / 11 and 11 / 12, slightly extending into anterior segment; male ducts plesiopore, about 500 μm long by 30 μm in diameter; winding, leading to simple and inconspicuous pores just anterior to ventral chaetae, in region of midventral glands (Fig. 6 B). Ovaries small, in XII and XIII; egg sacs with large, yolky eggs may extend 1 or 2 segments behind sperm sacs. Female funnels on 12 / 13 and 13 / 14; ducts plesiopore, simple and straight, about 150 μm long, leading to inconspicuous pores at the annular groove of the posterior segment, between ventral chaetae and anterior septum in XIII and XIV (Fig. 6 B). Guts were densely packed with dark organic matter, consisting of fine particles in one specimen; of coarser fragments / pieces (30 – 150 μm diameter) in the other worms, and mixed with some small mineral particles and a few diatoms. Site descriptions The Kakida River is located on the southern slope of Mt Fuji in Shizuoka Prefecture. Although only 1.2 km long, it is regarded as one of the clearest major streams of Japan. The spring water is derived from the rainfall and snow on Mt. Fuji and flows at 7000 to 1 million tons of water per day.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFABFF861509A0DEFB79AE01.taxon	discussion	Remarks Morphology associates Ohtakiana kakidaensis with genera formerly assigned to the Haplotaxidae (s. l.) on the basis of their rather simple male ducts, but lacking the muscular pharynx, unpaired chaetae, and elongate body of Haplotaxis. Despite this general similarity to the genera newly assigned here to the Pelodrilidae, DNA results (Fig. 1) suggest a separate family-level classification. Given the limited material available for morphological comparison, the only consistent diagnostic character separating Ohtakiana from Pelodrilidae specimens examined by us (as defined above) appears to be the prominent midventral glands in middle to posterior segments. By itself, this character is hardly convincing as a diagnostic character, given the general similarity of these glands to those in other clitellate taxa, e. g. the unknown Lumbriculidae sp. described below. The species currently attributed to Pelodrilus (Australia, New Zealand, South Africa, and central Asia) differ from Ohtakiana kakidaensis in having a single ovarian segment, intersegmental female pores, and usually a single spermathecal segment. Some Pelodrilus species have the anterior male pores shifted back behind the chaetae within XI, or even into XII in the type species, Pelodrilus violaceus. The five species of Delaya usually have three spermathecal segments, two ovarian segments, and two pairs of male pores located near the ventral chaetae in XI and XII, respectively. Large copulatory glands, paired and ventrolateral, are associated with ventral chaetae in or near the genital segments (VII, VIII, or IX to XII or XIII); these glands are compact (Hrabě 1958: fig. 10) rather than multi-lobed. Species assigned to Hologynus, from Australia, New Zealand, and associated islands, differ from the new species in having male pores exiting close together in XI and XII, within large, ventral glands (Benham 1909: fig. 15, Michaelsen 1925: fig. 2). Most Hologynus species have only one spermathecal segment. Other pelodrilid-like genera have been associated with the Haplotaxidae s. l. (Omodeo 1987, Brinkhurst 1988), but specimens of these were unavailable for the present analysis; these include Alphadrilus smithii from New Zealand; Adenodrilus denticulatus from central Asia; and Omodeodrilus guanivorus from Guinea. Alphadrilus was described as having morphologically similar male and female ducts (Brinkhurst 1966), in contrast to Ohtakiana (and the pelodrilid genera), where the male ducts are more elongate than the female ones. Adenodrilus denticulatus seems easily separated by a combination of bifid chaetae, long and slim tubular copulatory glands, a forward shift in gonad sequence to IX – XII (instead of X – XIII), and a single spermathecal segment with dorsal pores (Čekanovskaja 1959) The gonad sequence is also shifted anteriad in O. guanivorus; however, that species has only one testicular segment (in X) (Omodeo 1987). With regard to the known Japanese fauna, the reproductive organs of O. kakidaensis appear most similar to those of Heterochaetella glandularis, known from the Mino-o River, Osaka Prefecture (also in southern Japan). The two species also appear similar in general habitus, the simple pharynx, and the secondary annulation. Heterochaetella glandularis was assigned to a monotypic genus based on three unique characters: multicellular glands associated with dorsal chaetal bundles, clubshaped unicellular glands projecting into the coelom from the body wall, and each chaetal pair consisting of a large bifid and a smaller simple-pointed chaeta (Yamaguchi 1953: figs 17 – 18). Thus, although it was described from the same region, both the genus and species names are derived from unusual somatic characters not shared with O. kakidaensis. Heterochaetella glandularis also differs from the new species in having four spermathecal segments (VI – IX), and it lacks the large ventral glands in reproductive and posterior segments. The distribution of chloragogen tissue is also unusual in Heterochaetella glandularis; the cell layer is conspicuously thick, but limited to the surface of the dorsal blood vessel (Yamaguchi 1953: fig. 11).	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFA6FF8715EFA734FF7AA9EB.taxon	description	ZooBank LSID: urn: lsid: zoobank. org: act: E 499 FF 2 B-FFE 1 - 4 D 5 B- 9 F 38 - 946 EBB 0 B 0821	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFA6FF8715EFA734FF7AA9EB.taxon	type_taxon	Type genus: Limpluvia Fend & Torii gen. nov.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFA6FF8715EFA734FF7AA9EB.taxon	diagnosis	Diagnosis As for type genus.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFA6FF8715EFA734FF7AA9EB.taxon	discussion	Remarks The semiprosoporous male ducts (one pair prosoporous, one plesioporous) somewhat resemble the basic arrangement of the Lumbriculidae — typical members of which have a similar body form, including four pairs of chaetae per segment. However, morphology of the reproductive system appears closer to another monotypic family, Kurenkovidae Sokolskaja, 1983 — although the single species, Kurenkovia magna Sokolskaja, 1969 has subsequently been placed within in the Lumbriculidae, based on the (morphological) cladistic analysis of Brinkhurst (1989). The family Limpluvidae is currently monotypic, and morphologically distinguished by the characters listed below in the genus diagnosis and species description for Limpluvia setoensis.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFA7FF8716D3A35DFD2CAD05.taxon	type_taxon	Type species: By monotypy, Limpluvia setoensis Fend & Torii sp. nov.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFA7FF8716D3A35DFD2CAD05.taxon	etymology	Etymology Limpluvia (fem., portmanteau word derived from the Latin ‘ limpidus ’, clear, transparent, and ‘ pluvia ’, rain) by allusion to the semi-transparent and iridescent aspect of the worm when alive.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFA7FF8716D3A35DFD2CAD05.taxon	diagnosis	Diagnosis Chaetae paired, simple-pointed, sigmoid, nodulate. Pharynx eversible, with diffuse pharyngeal glands closely associated with the dorsal pharyngeal pad, but not extending posteriad as a series of ‘ septal’ glands; pharynx also associated with two short tubular structures that may also function as glands. Nephridial ducts simple, tubular. Clitellum one cell thick. Spermathecae one pair, pores anterolateral in IX. Two pairs of testes in X – XI, one pair of ovaries in XII, eggs mesolecithal. Gonoducts simple, anterior pair of male ducts plesioporous, posterior pair prosoporous, both extending to separate male pores in XI. Female ducts are conical funnels, with pores at 12 / 13. Limpluvia is currently monotypic, and morphologically distinguished by the characters listed below in the species description for Limpluvia setoensis.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFA7FF821606A472FC6EAFCB.taxon	description	ZooBank LSID: urn: lsid: zoobank. org: act: 34 CDDCF 2 - 7 E 25 - 4 EB 1 - A 088 - E 70 B 6 BC 75 B 77	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFA7FF821606A472FC6EAFCB.taxon	materials_examined	Holotype: NSMT An- 1897: a mature worm, anterior end dissected and slide mounted, part of tail analysed for DNA (CE 30790); COI DNA-barcode in GenBank (acc. no. PP 988456); this individual was not used in our phylogenetic analyses. Type locality: Japan: Shizuoka Prefecture: Seto River, Terashima, Fujieda-shi, 34.8830 ° N, 138.2156 ° E, elevation 54 m, 8 Jan 2010; collected by T. Torii. Paratypes: NSMT An- 1898, from the type locality (8 Jan 2010): anterior end on slide, tail analysed for DNA (CE 30789) COI DNA-barcode in GenBank (acc. no. PP 988419); for other molecular data, see Table 1. NSMT An- 1899 – 1900: two whole mounts. NSMT An- 1901, from Asahina River, 34.9431 ° N, 138.2583 ° E, 9 Dec 2007: one dissected, slide mounted specimen. NSMT An- 1902 – 1903, from Asahina River, Hazama, Okabe-cho, 34.9432 ° N, 138.2584 ° E, 6 Jan 2008: two whole mounts. All collected by T. Torii. Other material: NSMT An- 1904 – 1914. From the type locality, 8 Jan 2010; two whole mounts and two dissected. Asahina River, Fujieda-shi, Gyokuro-no-Sato, 34.9509 ° N, 138.2509 ° E, 2 May 2008; three partially mature whole mounts. Asahina River, 34.9431 ° N, 138.2583 ° E, 9 Dec 2007; four dissected.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFA7FF821606A472FC6EAFCB.taxon	etymology	Etymology From the Seto River.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFA7FF821606A472FC6EAFCB.taxon	description	Description Length of preserved specimens 17 – 25 mm, 60 – 70 segments. Diameter 0.4 – 0.6 mm in X, maximum diameter to 0.7 mm. Prostomium rounded, length less than width, separated from peristomium by dorsal groove; peristomium not elongate (Figs 8 B, 9 A). Epidermis in anterior segments 12 – 16 μm thick, in clitellum 20 – 35 μm, and 4 – 10 μm posteriorly. Circular muscle of body wall 10 – 12 μm, longitudinal muscle layer 30 – 40 μm thick in anterior segments. Clitellum with unordered glandular cells XI – XIII or XIV. Secondary annulation a narrow anterior ring from III, usually distinct in pre-clitellar segments; may be obscure or lacking in posterior segments. Chaetae simple-pointed, moderately sigmoid, dorsal and ventral pairs similar or dorsals slightly shorter; length 140 – 228 μm in anterior region (shorter in II – III), 146 – 214 μm posteriorly; thickness 5 – 7 μm; nodulus 0.41 – 0.52 the chaetal length from the tip (Figs 8 C, D, 9 F). Dorsal chaetae absent in II. Brain in peristomium (Figs 8 B, 9 A). Septa not thickened. Pharynx wall moderately thickened in II – III (IV), thicker dorsally (to 50 μm), covered with a dorsal pad of apparently glandular cell bodies (Figs 8 B, 9 B). Pharynx with paired, apparently tubular organs (pharyngeal diverticula) to about 200 μm long by 30 – 40 μm wide, joining the pharynx dorsolaterally at about intersegment 2 / 3, extending to about 3 / 4 (Figs 8 A – B, 9 C); tubules transparent and difficult to observe. Chloragogen layer thin and indistinct on gut. First nephridia usually paired in VIII; nephridia in a few posterior segments, starting in XIV, typically about XIV – XVII and XX – XXV. Nephridial ducts are simple tubules, without postseptal expansion; tubules folded, with multiple loops conjoined in part (Figs 8 E, 9 D); anteseptal funnels small; ducts terminate in simple tubes leading to inconspicuous nephridiopores just anterior to chaetae. Blood vessels are simple commissures in preclitellar segments, long and sinuous in II – III, shorter in IV – VIII; not observed in posterior segments. Ventral blood vessel originates at about 2 / 3. Multilobed, weakly-staining, glands usually occurring singly in one or more segments from VI to XIII in mature worms (Figs 2 G, 8 F – G, 9 G – H), each gland formed of 8 – 14 multicellular lobes (height 100 – 250 μm), entire gland mass to 150 – 300 μm wide; glands converge to an indistinct, ectal secretory surface about 100 μm wide. Gland position variable; may be midventral or ventrolateral, in anterior or posterior part of segment. Mature worms also have more darkly staining glands paired in XI, behind ventral chaetae, surrounding male pores, and extending to the posterior septum; appearing as two longitudinal rows of 5 – 10 multicellular lobes in ventral view (Fig. 8 H); gland mass 150 μm x 350 μm; secretory area indistinct, 120 – 190 μm diameter (Figs 8 F – I, 9 I – J). Spermathecal pores inconspicuous, on lateral lines at septum 8 / 9, or near 8 / 9 in IX; male pores inconspicuous, within secretory area of ventral glands behind chaetae in XI, the anterior just behind ventral chaetae, the posterior just anterior to septum 11 / 12; female pores on chaetal line at intersegment 12 / 13. Testes extend to about mid-segment in X and XI; ovaries in XII, may be elongate, extending to the posterior septum, rarely into XIII; sperm sacs X – XIII or XIV. Egg sacs extending back to XV or XVI; eggs large and yolky; female funnels simple, to 150 μm high. Tubular spermathecal duct short, total length 40 – 60 μm (Figs 8 F – G, 9 E). Spermathecal ampulla of mated worms elongate-sacciform, length 400 – 800 μm, width 70 – 120 μm, extending through IX (Fig. 8 F – G). Ampulla with thin, non-glandular epithelium (12 – 24 μm); sperm loosely arranged or lined up along epithelium. Male funnels 80 – 160 μm high and convoluted, on 10 / 11 and 11 / 12; usually anterior and posterior pairs similar (Figs 8 F, 9 I), but posterior funnels smaller and without sperm in two unmated specimens. Male ducts (vasa deferentia) thin (12 – 25 μm) and convoluted, length 260 – 360 μm; posterior pair penetrates the posterior septum, forming a small loop in XII before entering XI (Fig. 8 F, I); both pairs appear free in the coelom, without entering body wall musculature; ducts travel through the ventral gland mass and end separately in anterior and posterior pores within the secretory area of each gland, on line of ventral chaetae (Figs 8 G, H, 9 J). Male ducts are simple tubes throughout their length, not expanded as atria or otherwise modified. Live specimens swim actively, resembling lumbriculids in the field. Guts were densely packed with dark-coloured, fine particulate organic matter, with small amounts of very fine mineral particles and diatoms, suggesting that these worms are ordinary detritivores. Site descriptions	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFA7FF821606A472FC6EAFCB.taxon	discussion	The Seto River and its tributary, the Asahina River are located in central Shizuoka Prefecture. A large quantity of subsurface water emerges as springs around the type locality. Although the amount of flow from springs is unknown, many subterranean crustaceans [e. g. Mackinia japonica Matsumoto, 1956, Nipponasellus hubrichti (Matsumoto, 1956), Eoniphargus kojimai (Uéno, 1955), Lucioblivio kozaensis Tomikawa, 2007] are found there (Torii, unpubl. data). Remarks Morphologically, L. setoensis could be attributed to the Lumbriculidae based on the semiprosoporous male ducts with a post-septal loop of the posterior pair, considered byBrinkhurst (1989) to be ancestral for the family. However, among species associated with the Lumbriculidae, simple male ducts, lacking an atrium, are a character shared only with the monotypic Kurenkoviamagna Sokolskaya, 1969, fromKamchatka. Moreover, our phylogenetic analysis supports that L. setoensis is outside (a monophyletic) Lumbriculidae s. s. and instead, it is the sister to the clade comprising the latter plus all Hirudinea. Kurenkovia magna is sufficiently different from typical lumbriculids that it was later assigned to a monotypic family, the Kurenkovidae Sokolskaya, 1983, although it is still assumed to be a lumbriculid by some authors (Brinkhurst 1989, Timm 1999), based on the (morphological) cladistic analysis of Brinkhurst (1989). Unlike typical lumbriculids, anterior and posterior ducts of L. setoensis and K. magna species open in separate male pores beneath a glandular mass (compare Fig. 8 G with Sokolskaja 1983: fig. 23). In addition to a similar arrangement of male ducts, both species have unpaired ‘ copulatory glands’ in some non-genital segments, and paired glands surrounding the male pores. Both species have spermathecae laterally placed, two segments anterior to the male pores (i. e. in IX or VII). Inclusion of the new species within Kurenkovia would be problematic, as this would require a broadened definition of the genus to also accommodate a shift of reproductive organs by two segments, i. e. male and spermathecal pores in XI and IX, respectively, vs. IX and VII in K. magna. Kurenkovia magna also differs from the new species in that the vasa deferentia are partially embedded in the body wall (a character associated with Crassiclitellata or ‘ megadriles’); moreover, it has unique structures (termed ‘ rudimentary atria’) in VIII (Sokolskaya 1983: fig. 23 - 2). As the latter are not connected to the male ducts, they may resemble glandular structures in some species of Rhynchelmis Hoffmeister, 1843 (Lumbriculidae), or perhaps the prostate glands of some megadrile families. Other characters of L. setoensis are atypical for the Lumbriculidae, but occur in some genera. Male and female pores are one segment posterior to the usual lumbriculid position in X – XI, with gonads beginning in X instead of IX (Brinkhurst 1989). The spermathecal pores are anterior to the usual positions in the Lumbriculidae, and their lateral position is also uncommon, but not unknown in lumbriculids (e. g. Martinidrilus carolinensis Fend & Lenat, 2007). The lack of obvious pharyngeal glands, other than the two tubular organs described above, is certainly unusual, and the nephridia are composed of multiple conjoined tubules, apparently without the glandular, post-septal expansion typical of lumbriculids (cf. Fend and Brinkhurst 2010: fig. 4 A). Unfortunately, it is difficult to assess details of these and other organs (e. g. the blood vessels) in the available material. Despite erecting a new family for K. magna, Sokolskaja (1983) suggested the species could instead be attributed to the Haplotaxidae s. l. (as traditionally defined) on the basis of morphology. The simple male ducts are somewhat similar to those of Hologynus species (now in the Pelodrilidae) where the posterior male duct has shifted forward; for example, Benham (1909) considered the posterior male pore of Hologynus aucklandicus (Benham, 1909) to be in XI, although it appears to be at the anterior margin of XII in figure 15 of that paper. The anterolateral placement of the spermathecal pores is also consistent with typical haplotaxids and pelodrilids. As already mentioned, in the present phylogenetic analysis, L. setoensis is sister to the clade containing lumbriculids and hirudinean taxa, but as K. magna was not available for study, the relationship to that genus is unknown. Rather than compromise the status of Kurenkovia (or Kurenkovidae), based only on limited morphological data, it seems best at this point to propose a new family, which is well supported by the molecular analysis.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFA3FF8016B5A1CDFE9DA8ED.taxon	description	(Figs 2 H, 10)	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFA3FF8016B5A1CDFE9DA8ED.taxon	materials_examined	Material examined: USNM 1716322: an immature worm, anterior end whole mounted, part of tail analysed for DNA (CE 32192), COI DNA-barcode in GenBank (acc. no. PP 988429); for other molecular data, see Table 1. Locality: USA: Oregon, Curry Co., Euchre Creek, near Ophir, 10 Jul 2017.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFA3FF8016B5A1CDFE9DA8ED.taxon	description	Description Habitus thin, elongate, appearing similar to Haplotaxis specimens in the same sample; 100 segments remain, estimated to be 1 / 2 of the original worm. Diameter 0.32 mm on slide. Prostomium longer (260 μm) than wide (190 μm); peristomium not elongate (Fig. 2 H). Chaetae paired, simple pointed, sigmoid; ventrals 111 – 126 μm long, 5 – 7 μm thick, nodulus 0.33 – 0.37 the chaetal length from tip; dorsals 84 – 94 μm long, about 3 μm thick, nodulus 0.33 – 0.42 the chaetal length from the tip (Fig. 10 A). Pharynx not strongly developed, about equally thickened dorsally and ventrally, without conspicuous musculature; no obvious pharyngeal glands. Chloragogen on gut beginning in about XV, becoming progressively more developed posteriorly, very dense from about XXXV. Midventral glands beginning in V, strongly developed from X posteriad (Figs 2 H, 10 B); each segment with a cluster of densely packed, petiolate multicellular glands about 50 – 60 μm high, interspersed with circular muscle strands of body wall; glands extend up to ventral nerve cord, but do not surround it (as in Timm’s glands). Gland clusters about 130 – 150 μm wide. Additional large cells are loosely associated with septa in ventral part of coelom; cells are about 10 – 25 μm wide, irregular and highly granular.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
80735A2DFFA3FF8016B5A1CDFE9DA8ED.taxon	discussion	Remarks This unidentified lumbriculid was originally considered a possible haplotaxid, based on its unusually elongate body form, enlarged ventral chaetae, midventral glands, and the pharynx lacking a dorsal pad or conspicuous pharyngeal glands. The single sequenced specimen was preserved in ethanol, and middle segments were used for DNA analysis — thus limiting descriptive detail. Although the specimen is immature, it clearly represents an undescribed species. Specimens similar in general appearance, with similar pharynx, chaetae, and midventral glands have been collected at several other sites in Pacific coastal streams from California and Oregon. The granular, irregular cells associated with the septa in the sequenced worm may be glandular tissue, but as they were not observed in specimens from other collections, an alternative possibility is that they represent some kind of parasite. The gut of the sequenced specimen appeared empty, but of 37 morphologically similar specimens from streams in western North America, 13 contained oligochaete chaetae (lumbriculids, Nais, Mesenchytraeus), and two contained a chironomid head. Guts of most of the remainder were empty or contained small amounts of stream sediment (in less than 10 % of segments). As in the case of haplotaxids, only immature specimens have been found at most sites. Two mature individuals from central California could not be sequenced, but arrangement of their reproductive organs resembles that of the genus Stylodrilus Claparède, 1862.	en	Martin, Patrick, Fend, Steven, Martinsson, Svante, Klinth, Mårten, Torii, Takaaki, Erséus, Christer (2024): Towards an integrative revision of Haplotaxidae (Annelida: Clitellata). Zoological Journal of the Linnean Society (zlae 141) 202 (4): 1-38, DOI: 10.1093/zoolinnean/zlae141, URL: https://doi.org/10.1093/zoolinnean/zlae141
