Goniocotes Burmeister, 1838

Gustafsson, Daniel R., Tian, Chunpo, Ren, Mengjiao, Li, Zhu, Sun, Xiuling & Zou, Fasheng, 2024, Separation of Goniocotes Burmeister, 1838, and Dictyocotes Kéler, 1940 (Phthiraptera: Ischnocera), with descriptions of four new species, European Journal of Taxonomy 968, pp. 1-36 : 5-10

Genus Goniocotes Burmeister, 1838

Ricinus De Geer, 1778: 69 [in partim].

Goniodes Nitzsch, 1818: 293 [in partim].

Goniocotes Burmeister, 1838: 431 .

Type species

Ricinus gallinae De Geer, 1778: 79 , by subsequent designation ( Johnston & Harrison 1911: 326).

Diagnosis

Goniocotes is morphologically variable (see below), but all species here retained in Goniocotes can be separated from the species of Dictyocotes by the following combination of morphological characters: 1) male genitalia without mesosome in Goniocotes (e.g., Fig. 4 ), but with mesosome in Dictyocotes ( Fig. 19 ); 2) female vulval margin gently rounded in Goniocotes (e.g., Fig. 5 ; expect Goniocotes chapini Clay, 1936 ), but margin notched or concave medianly in Dictyocotes ( Fig. 20 ; except in D. rolandi Gustafsson et al., 2021 ); 3) male parameres continuous with lateral margins of basal apodeme in Goniocotes (e.g., Fig. 4 ), but with parameres separated from, and possibly articulating with, basal apodeme in Dictyocotes ( Fig. 19 ).

Many additional characters are variable within Goniocotes as circumscribed here, which may indicate that this genus is paraphyletic or consisting of several monophyletic groups that may deserve recognition as subgenera or genera in a future revision. The following characters can separate the type species of Goniocotes and many morphologically similar species from Dictyocotes : male tergopleurites II–V with 1–2 tergocentral setae (ss + tps) on each side in Goniocotes s. str. (e.g., Fig. 1 ), but at least some of these segments (typically at least II–III) with>5 tergocentral setae on each side in males of Dictyocotes ( Fig. 16 ); apart from abdominal segment VI, each abdominal segment has a single sts on each side in Goniocotes s. str. (e.g., Fig. 1 ), but at least some segments (typically III–V) have 2–4 sts on each side in Dictyocotes ( Fig. 16 ); male lateral tergopleurite IX+X slender and small in Goniocotes s. str. (e.g., Fig. 1 ), but larger, triangular or irregular in shape in Dictyocotes ( Fig. 16 ). In almost all Goniocotes there are a maximum of 15 short, slender vms on each side of the female vulval margin (e.g., Fig. 5 ), whereas in Dictyocotes there are always>20 on each side ( Fig. 20 ); however, Goniocotes cacumentalis sp. nov. has>20 vms on each side ( Fig. 10 ) but is otherwise morphologically similar to Goniocotes s. lat. and is here included in that genus.

Description

Very small lice of the body louse ecomorph (sensu Johnson et al. 2012). Head shape variable among species: preantennal head gently rounded to somewhat flattened at frons, temples may be parallel or slightly divergent posteriorly, typically rounded at site of mts1, and with a more or less pronounced posterior occipital bulge at site of mts5. Marginal and ventral carinae uninterrupted; marginal carina may be very narrow or very broad, with clear attendant canals connecting to apertures of many setae (e.g., dsms, as1–3, avs1). Dorsal preantennal suture absent, but inner dorsal curved line may be present, delimiting a less densely sclerotized central part dorsal to the mandibles and ventral carina; typically, this line becomes obscure posteriorly and does not completely surround the less sclerotized area. Preantennal nodi variable, may be roughly square-shaped, elongated, or rather small. Antennae sexually monomorphic. Eyes often proportionately large. Marginal temporal carina typically broad, with undulating median margin and a distinct occipital nodus originating marginally median to mts5 on each side. Head chaetotaxy: all usual head setae present; as1–3 and avs1 marginal or submarginal, vsms1–2 much separated; pns micro- to mesoseta, s1–6 typically all present as sensilla, but may be difficult to see or absent (particularly s5), and additional sensilla may be present ( Fig. 3 ); pts typically mesoseta; os may be macroseta in male, but always microseta in female (except in G. cacumentalis sp. nov.); pos positioned far posterior to eye; mts1 and mts3 macrosetae, mts5 may be thorn-like, mts2 and mts4 microsetae.

Prothorax wider than long, with ppss macroseta on postero-lateral corner. Pterothorax variable, but typically pentagonal, with 2 lpts macrosetae on postero-lateral corners, separated by clear gap from 2 ipts macrosetae; single smns micro- or mesoseta present submarginally, but may be difficult to see if small, or alternatively may be absent; mpts absent. Proepimera extensive, may be fused medianly. Meso- and metasterna absent, but mss and mets present. Legs short and stout, most notably with three stout ventral setae on tibiae II–III (likely tbII-v3–5 and tbIII-v3–5, but homology uncertain). Other leg chaetotaxy variable, and many setae very short. In G. gallinae and similar species: tbI-a1–2, fI-v2, cII-a1, tbII-a1–2, tbII-p1–2, tbIII-p4–5, tbII-dm3, cIII-a1, tbIII-a1–2, tbIII-p1–2, tbIII-4–5, tbIII-dm3 all very short microsetae or absent; fII-p1, fII-dm4, fIII–p1, fIII-dm4 absent.

Abdomen broadly rounded, more elongated in female. Tergopleurites II–IX+X divided medianly, typically with posterior tergopleurites more reduced compared to anterior tergopleurites (especially in male). Male abdominal segment IX+X with lateral sclerite on each side and central sclerite anterior to dorsal ano-genital opening. Female tergopleurites IX+X fused medianly. Paratergal plates may be indistinct, absent, or clearly visible and broad. Sternal plates generally absent, but reticulated, lightly sclerotized areas may be visible on ventral side of female abdominal segments II–VI ( Fig. 12 ), or on segments II–VI in both sexes (not shown). Male subgenital plate variable, may be divided medianly; female subgenital plate absent. Subvulval plates may be present, but indistinct in many species. Abdominal chaetotaxy variable among species; anterior seta of tergopleurite II present. In G. gallinae and similar species, chaetotaxy is much reduced: ss present on tergopleurites II–VII (male; typically mesosetae in anterior segments and microsetae in posterior segments) or II–VIII (female; typically of uniform length); tps absent (female and males of some species) or present only on tergopleurites II, II–III, or II–IV (males of some species); psps typically present on tergopleurites II–VII (male) or V–VII (female; but sensilla may be visible on II–IV), but variable and may be absent more anteriorly in males, or be associated with a single shorter more median seta (tps?) in some segments. In other groups the dorsal abdominal chaetotaxy is much more extensive. Ventral side with 1 sts on each side of segments II–V, and 2 sts on each side on segments VI. Macrosetae present on ventral side of abdominal segments VII–VIII in both sexes.

Male genitalia solenoid, consisting of slender, elongated (anterior end may reach abdominal segment II) basal apodeme fused distally with simple parameres. Distal to male genitalia are often diaphanous, irregular structures of uncertain homologies, which in rare cases may have visible sensilla. In some species, parameral sensilla are visible, but these are easily overlooked if the male genitalia are pale or the specimen is poorly clearer; often, the sites of these sensilla are visible only because the parameres are swollen. Distal margin of basal apodeme may be indistinct median to parameres, or may be clearly delimited. In a few species, a vague, slightly reticulated structure which may be a genital sac is visible. Female vulval margin typically gently rounded to somewhat flattened medianly, with a small number (<15) vms microsetae and 2–4 (in most species 3) vss thornlike setae on each side; vos microsetae variable in number and location, and may form distally convergent rows, but rarely numerous.

Host and geographical distribution

Goniocotes is only known from hosts in the order Galliformes Temminck, 1820 , but distribution is somewhat scattered. Species of Goniocotes are known from at least some of the hosts in each of the three divisions of Phasianidae Horsfield, 1821 by Kimball et al. (2021), as well as on Numididae de Sélys Longchamps, 1842 and Megapodiidae Lesson, 1831 . However, the genus is largely absent on more boreal hosts, almost all New World hosts (except Meleagris gallopavo Linnaeus, 1758 , which has acquired G. gallinae probably as stragglers in domestic settings), and many alpine hosts ( Price et al. 2003). The presence of this genus on megapodiid hosts also appears to be limited ( Mey 1997), and the Goniocotes species from numidid hosts, as well as many other species, are morphologically aberrant and may warrant separation into different genus. No species are known from cracid or odontophorid hosts.

Included species

In anticipation of a broader revision of the genus, all species placed in Goniocotes by Price et al. (2003: 181–182) are here retained in this genus, with the exception of the species listed under Dictyocotes below and those separated into the genus Pavoniocotes by Gustafsson et al. (2023).

Goniocotes afer Tendeiro, 1989: 70 .

Goniocotes afropavo ( Clay, 1938: 9) [in Goniodes ]

Goniocotes albidus Giebel, 1874: 189 .

Goniocotes homocerus Kéler, 1940: 151 .

Goniocotes phasiani Kéler, 1940: 151 .

Goniocotes cacumentalis sp. nov.

Goniocotes caoi sp. nov.

Goniocotes castaneicollis Tendeiro, 1965: 79 .

Goniocotes chapini ( Clay, 1938: 7) [in Goniodes ].

Goniocotes chrysocephalus Giebel, 1874: 189 .

Goniocotes clayae Tendeiro, 1954a: 316 .

Goniocotes congolensis Tendeiro, 1989: 82 .

Goniocotes coxatus Piaget, 1885: 43 .

Goniocotes crassicauda Tendeiro, 1989: 82 .

Goniocotes creber Kellogg, 1896b: 519 .

Goniocotes diasi Tendeiro, 1954b:81 .

Goniocotes diplogonus Nitzsch in Giebel, 1866: 389.

Goniocotes eurygaster Piaget, 1885: 43 .

Goniocotes gallinae ( De Geer, 1778: 79) [in Ricinus ].

Goniocotes hologaster ( Nitzsch, 1818: 294) .

Goniocotes gregarius (Nitzsch in Giebel, 1866: 388) [in Goniodes ]. Goniocotes ictiorhynchi Tendeiro, 1989: 76 .

Goniocotes ignitus Eichler, 1947: 12 .

Goniocotes ignitus rufus Eichler, 1947: 13 .

Goniocotes irregularis Rudow, 1869: 23 [unidentifiable]. Goniocotes jifrufti Ansari, 1947: 298 .

Goniocotes keleri Tendeiro, 1989: 73 .

Goniocotes keniensis Tendeiro, 1989: 75 .

Goniocotes kivuensis Tendeiro, 1960: 119 .

Goniocotes kristinae Gustafsson, Tian & Zou, 2021: 301 .

Goniocotes laticeps Piaget, 1885: 41 [unidentifiable].

Goniocotes maculatus Taschenberg, 1882: 76 .

Goniocotes nigromaculatus Mjöberg, 1910: 106 .

Goniocotes numidae Kéler, 1940: 147 .

Goniocotes valdezi Tendeiro, 1954a: 327 .

Goniocotes megalocephalus Uchida, 1916: 86 .

Goniocotes macrocephalus Uchida, 1916: 86 .

Goniocotes microcephalus Uchida, 1917: 177 .

Goniocotes microthorax ( Stephens, 1829: 333) [in Goniodes ].

Goniocotes alatus Piaget, 1885: 45 .

Goniocotes simillimus Kéler, 1937: 128 .

Goniocotes nahanii Tendeiro, 1989: 67 .

Goniocotes obscurus Giebel, 1874: 188 .

Goniocotes pallidiflavus Piaget, 1890: 235 .

Goniocotes pallidomaculatus Piaget, 1880: 227 .

Goniocotes plumiferae Tendeiro, 1989: 81 .

Goniocotes pternistis Tendeiro, 1965: 74 .

Goniocotes pucherani Tendeiro, 1989: 79 .

Goniocotes punctatus Neumann, 1891: 91 .

Goniocotes pusillus (Nitzsch in Giebel, 1866: 387) [in Goniodes ].

Goniocotes rectangulatus Nitzsch in Giebel, 1866: 389.

Goniocotes rectangulus Giebel, 1874: 185 .

Goniocotes reticulatus Kéler, 1940: 142 .

Goniocotes rotundiceps Piaget, 1880: 223 .

Goniocotes sarissa sp. nov.

Goniocotes schraderi Tendeiro, 1989: 74 .

Goniocotes shelleyii Tendeiro, 1989: 66 .

Goniocotes vulturini Tendeiro, 1989: 78 .

Remarks

Goniocotes as circumscribed here is undoubtedly morphologically variable, and several groups may deserve recognition as at least subgenera. However, adequate illustrations and descriptions of most species in the genus have never been published, and a general revision is sorely needed. From published descriptions and the specimens we have examined from various East Asian hosts, it is clear that the following character sets may be especially useful for separating species groups or future genera in the Goniocotes -group:

Ocular seta – in G. gallinae and many other species this seta is sexually monomorphic, but the os are macrosetae in males of, e.g., G. albidus , G. pusillus , and G. cacumentalis sp. nov. ( Fig. 6 ).

Pterothoracic setae – in almost all species, there is only a single smns on each side submedianly (e.g., Fig. 6 ), but in G. kristinae and G. sarissa sp. nov. there is a patch of several setae in this area ( Fig. 11 ). In some other species the smns may be absent, but as these setae may be sensillous they may have been overlooked in the specimens we have examined.

Male abdominal chaetotaxy – in G. gallinae and many other species this is reduced, with at most 1 tps on each side on some or all of tergopleurites II–IV. However, in many other species the number of tps is substantially higher (e.g., Fig. 11 ), with setal rows that may reach psps in species like G. albidus and G. pusillus . Moreover, the distribution of psps on male tergopleurites varies among species, and these setae may be absent in more anterior segments (e.g., in G. pusillus ). In G. maculatus , there are single tps macrosetae roughly equidistant between the psps and ss.

Abdominal plates – sternal plates are absent in almost all species of Goniocotes , but present in the form of reticulated but poorly sclerotized plates in females of G. kristinae and G. sarissa sp. nov. ( Fig. 12 ), and as small reticulated plates in G. albidus . In G. maculatus , there are small nodi lateral to spiracle openings on abdominal segments II–V. Moreover, whereas reticulation patterns are indistinct or absent in most Goniocotes , they are clear and extensive in G. kristinae , G. sarissa ( Figs 11–12 ), G. albidus , and some other species.

Some of the morphological variation within Goniocotes , and the corresponding characters in Dictyocotes , are summarized in Table 2.

Figures

Figs 3–5. Goniocotes caoi sp. nov. 3–4. Holotype, ♂ (BMNH, slide 57, box E0026203). 3. Head, dorsal and ventral views. 4. Genitalia, dorsal view. 5. Female genitalia, ventral view. Abbreviations: as1–3 = anterior setae 1–3; avs1 = anterior ventral seta 1; dsms = dorsal submarginal seta; mts1–5 = marginal temporal setae 1–5; os = ocular seta; pns = postnodal seta; pos = preocular seta; pst = parameral seta; s1–6 = sensilla of dorsal head 1–6; vms = vulval marginal seta; vos = vulval oblique seta; vsms 1–2 = ventral submarginal setae 1–2; vss = vulval submarginal seta.

Figs 18–20. Dictyocotes furcatus sp. nov. 18–19. Holotype, ♂ (BMNH, slide 29, box E0026136). 18. Head, dorsal and ventral views. 19. Genitalia, dorsal view. 20. Female genitalia, ventral view.

Fig. 1. Goniocotes caoi sp. nov., holotype, ♂ (BMNH, slide 57, box E0026203). Habitus, dorsal and ventral views. Abbreviations: ipts = intermediate pteronotal seta; lpts = lateral pteronotal seta; mets = metathoracic seta; mss = mesothoracic seta; ppss = pronotal post-spiracular seta; ps = paratergal seta; psps = principal post-spiracular seta; ss = sutural seta; sts = sternal seta.

Fig. 16. Dictyocotes furcatus sp. nov., holotype, ♂ (BMNH, slide 29, box E0026136). Habitus, dorsal and ventral views.

Figs 8–10. Goniocotes cacumentalis sp. nov. 8–9. Holotype, ♂ (NHML, slide NHMUK010676049). 8. Head, dorsal and ventral views. 9. Genitalia, dorsal view. 10. Paratype, ♂ (NHML, slide NHMUK010676049). Genitalia, ventral view.

Fig. 12. Goniocotes sarissa sp. nov. Female habitus, dorsal and ventral views.

Fig. 6. Goniocotes cacumentalis sp. nov. Male habitus, dorsal and ventral views. Abbreviations: smns = submarginal mesometanotal seta; tps = tergal posterior seta.

Fig. 11. Goniocotes sarissa sp. nov., holotype, ♂ (BMNH, slide 95, box E0026011). Habitus, dorsal and ventral views.