Dispio glandulosa, Delgado-Blas & Díaz-Díaz & Viéitez, 2019

Delgado-Blas, Víctor Hugo, Díaz-Díaz, Óscar & Viéitez, José M., 2019, Two new species of spionids from the genera Dispio and Prionospio (Polychaeta Spionidae) from the Iberian Peninsula with redescription and notes on Prionospio (Minuspio) multibranchiata Berkeley, 1927, Zootaxa 4604 (3), pp. 562-574 : 563-568

Dispio glandulosa sp. nov.

Figure 1 A–W

Material examined. Mediterranean Sea: Puerto de Sagunto to Puerto de Castellón (Valencia), 39º48’ N, 00º05’ W, coll. G. San Martín, Holotype ( MNCN 16.01 /6033); paratype ( MNCN 16.01 /18455).

Description. Holotype incomplete, 25 mm long, 2.0 mm wide, for 57 chaetigers. Paratype incomplete, 55 mm long, 2.2 mm wide for 100 chaetigers.

Prostomium elliptic, pointed anteriorly ( Fig. 1A ), posteriorly tapered with a long, narrow caruncle as a long longitudinal nuchal ridge, extending to the anterior margin of chaetiger 2 ( Fig. 1A ). Two pairs of rounded, black subdermal eyes (very small and with slight pigmentation) ( Fig. 1A, B ), arranged in a transversal line (eyes absent in holotype). Palps lost in both specimens. Ciliated nuchal organs starting between the palps scars and beginning of caruncle as a pair of dorsal loops extending to the posterior margin of chaetiger 1 ( Fig. 1A ). Peristomium long ( Fig. 1A, B ) partially enveloping prostomium and extending around scar at base of palps forming low lateral wings ( Fig. 1A, B ), separated from chaetiger 1.

Anterior notopodial postchaetal lamellae completely fused to branchiae, distal ends short, pointed ( Fig. 1A , B–E); notopodial postchaetal lamellae on chaetiger 1 shifted dorsally ( Fig. 1A, B ), about 1/2 as large as those on subsequent chaetigers ( Fig. 1A, B ). Notopodial postchaetal lamellae of chaetiger 1 and subsequent chaetigers entire, short and narrow on first two chaetigers ( Fig. 1 A–C), thereafter wider and longer with a wider, rounded basal margin ( Fig. 1B , C–E); lamellae on chaetigers 24–28 (holotype 24) with elongated ventral edges ( Fig. 1 F–G), gradually reducing in size from about chaetigers 29–30 and becoming pointed along ventral edges ( Fig. 1 H–J), overlapping enlarged neuropodial postchaetal lamellae ( Fig. 1 H–J). Distal and middle regions of notopodial postchaetal lamellae with highly glandular cell margins ( Fig. 1A, B , D–J) from chaetiger 5, glandular cells gradually increasing in number in all noto- and neuropodial post- and prechaetal lamellae ( Fig. 1 G–J) on subsequent chaetigers to ends of the fragments, and in ventral regions of middle segments; posterior lamellae dorsally pointed and elongated ( Fig. 1 I–J), reduced in size posteriorly. Notopodial prechaetal lamellae on anterior chaetigers large, rounded with enlarged dorsal edges ( Fig. 1 C–J), thereafter decreasing in size.

Each segment with a pair of O-shaped dorsal organs arranged between each transverse band of cilia from chaetiger 2 ( Fig. 1A ). Lateral organs between notopodial and neuropodial postchaetal lamellae ( Fig. 1 H’) present from about chaetigers 16–18; distribution of these organs irregular.

Neuropodial postchaetal lamellae tongue-shaped and smooth ( Fig. 1B, C ) shifted to dorsal side on chaetiger 1 ( Fig. 1B ), rounded on chaetigers 2–6 ( Figs. 1D, E ), becoming rectangular, wider on chaetigers 7–14, and rounded, wider from chaetigers 15–17, developing into a pointed upper edge from around chaetigers 27–37 (holotype 27) ( Fig. 1 F–J). Anterior neuropodial prechaetal lamellae small, rounded, wide ( Fig. 1 B–H), larger on middle chaetigers, and decreasing gradually in size with triangular upper and lower edges ( Fig. 1 I–J) up to end of fragments; these lamellae not fused with neuropodial postchaetal lamellae at the base.

Branchiae present from chaetiger 1; all anterior and middle branchiae smooth, long, tapering, completely fused to notopodial lamellae ( Fig. 1 A–H), branchial tips becoming free from notopodial lamellae at chaetigers 48–52, distal tips pointed ( Fig. 1 I–J); posterior branchiae with tips with highly glandular cell margins ( Fig. 1 I–J), longer than notopodial lamellae. Each branchia with a dense band of cilia along the inner edge ( Fig. 1 C–I). Accessory branchiae lacking.

Notochaetae on chaetiger 1 arranged in a dorsal tuft and a ventral fascicle; dorsal tuft with short, smooth, alimbate, slender capillaries extending beyond margins of notopodial lamellae; ventral fascicle arranged into an anterior row of basally striated and, then reticulate, granulated, unilimbate capillaries with short tips ( Fig. 1K ), and a posterior row of smooth, unilimbate capillaries with long pointed tips, striated basally ( Fig. 1L ). Notochaetae on chaetiger 2 and subsequent chaetigers arranged similarly to those on chaetiger 1, except dorsal tufts with long, slen- der, smooth, alimbate capillaries. Notochaetae on about chaetiger 12 similar to those on anterior chaetigers, except chaetae on anterior row with wider limbation ( Fig. 1M ), those on posterior row form striated, long, unilimbate capillaries ( Fig. 1N ). Chaetae on posterior notopodia arranged in a dorsal tuft with granulated, reticulated, unilimbate capillaries ( Fig. 1O ). Notopodial hooded hooks absent.

Neurochaetae on chaetiger 1 and subsequent chaetigers arranged in two rows and a ventral tuft; anterior row composed of short reticulated, granulated, unilimbate capillaries ( Fig. 1P ); posterior row of longer, smooth, unilimbate capillaries with pointed tips ( Fig. 1Q ); ventral tuft of three short, slender, smooth, alimbate capillary chaetae located in ventral most position ( Fig. 1R ). Neurochaetae on about chaetiger 13 and subsequent chaetigers similar to those on anterior ones, but with ventral tuft chaetae reticulated and unilimbated ( Fig. 1S ). Middle and posterior chaetigers with a row of unidentate neuropodial hooded hooks ( Fig. 1T ) from chaetigers 30–31 (31 in holotype), 4–8 hooks present per neuropodium with open hoods and slightly recurved shafts subdistally ( Fig. 1T ), each one accompanied by 2–3 slender, short, smooth, alimbate capillaries ( Fig. 1U ); posterior row with granulated, reticulated, unilimbate capillaries ( Fig. 1V ); ventral tuft with granulated, reticulated, alimbate chaetae in ventral most position ( Fig. 1W ).

Pygidium unknown.

Remarks. Dispio glandulosa sp. nov. is similar to D. oculata Imajima 1990b from Japan, D. magna ( Day, 1955) from South Africa, and D. brachychaeta Blake, 1983 from Argentina in that the branchiae are completely fused to the notopodial postchaetal lamellae anteriorly but are free posteriorly. Also, D. glandulosa sp. nov. is similar to D. oculata and D. brachychaeta , in that accessory branchiae are absent; chaetiger 1 bears short notopodial chaetae; all the notopodial poschaetal lamellae have entire margins; and the branchiae on chaetiger 1 are between 1/3 and 1/2 as long as those on subsequent chaetigers. However, Dispio glandulosa sp. nov. differs from D. oculata in that in the former the prostomium is elliptical in shape (rather than elongate); the notopodial postchaetal lamel- lae of chaetiger 1 are not fused with the peristomium (peristomium dorsally fused with chaetiger 1); almost all the noto- and neuropodial postchaetal lamellae have a highly glandular cell margin (absent in D. oculata ); the branchial tips are free from the notopodial lamellae on chaetigers 48–52 (rather than chaetigers 36–38); the distal tips of the posterior branchiae do not show granules (present in D. oculata ), but some branchial tips do have (rather than lack) a highly glandular cell margin. Also, D. glandulosa sp. nov. differs from D. brachychaeta in that the former has a caruncle in the form of a longitudinally long nuchal ridge extending to the anterior margin of chaetiger 2 (rather than being indistinct); the branchiae are partially (rather than entirely) free from the notopodial lamellae in posterior chaetigers; and the hooks have open (rather than closely applied) hoods. Finally, Dispio glandulosa sp. nov. differs from D. magna in having an elliptic or spheroid (rather than a fusiform) prostomium; the first branchiae are smaller (rather than similar) in length to the succeeding ones; and the accessory branchiae are absent (rather than present).

Etymology. The epithet, glandulosa , is from the Latin glandis meaning gland and refers to the numerous glandular cells that cover the parapodial lamellae and the ventral region of the body.

Distribution. To date this species has only been found off the coast of Valencia in the western Mediterranean.

Genus Prionospio Malmgren, 1867

Prionospio (Minuspio) multibranchiata Berkeley, 1927

( Figure 2 A–G)

Prionospio multibranchiata E. Berkeley, 1927:414 , Pl. 1, fig.1.

Prionospio (Minuspio) multibranchiata: Maciolek 1985: 365 –367 (in part, Fig. 15b, not Fig. 15a, c–f).

Material examined. North Pacific Ocean, Canada, British Columbia, Vancouver, Burrad Sound Inlet, Port of Vancouver, dock opposite Canada Place, 49°17’3.5” N, 123°06’38.47” W, 0.3 m, from mud inside tire attached to dock, hand, Sta. BCX 13, coll. & id. Leslie Harris, 26 Feb. 1999, 9 specimens (LACM-AHF-POLY 11125).

Description. Complete specimen 15 mm long, 0.4 mm wide for 72 chaetigers. Incomplete specimens 2.4–2.5 mm long, 0.7 mm wide for 32–43. Color in alcohol straw yellow.

Prostomium triangular, anterior margin truncate ( Fig. 2A ), longer than wide, posteriorly tapered, with long caruncle swollen by nuchal organs that surround it, extending to the anterior edge of chaetiger 2. Two pairs of large, reniform, reddish brown eyes, arranged in a trapezoid; anterior pair more widely separated, posterior pair larger ( Fig. 2A ). Palps lost. Peristomium moderate, collar-like, surrounding the prostomium, fused dorsally, with large, rounded notopodial postchaetal lamellae (distally curled back) on chaetiger 1 ( Fig. 2A ). Neuropodial postchaetal lamellae on chaetiger 1 small, rounded ( Fig. 2B ).

Nine to ten pairs of branchiae present on chaetigers 2–11, all triangular and small ( Fig. 2A, B ); anterior most branchiae same size as notopodial lamellae ( Fig. 2B ) except last pair larger than lamellae ( Fig. 2C ).

Notopodial postchaetal lamellae triangular and long on chaetigers 2–10 ( Fig. 2 A–C), longest on chaetigers 4–9, becoming rounded and broader on chaetiger 11, then progressively diminishing in size towards end of body, but always visible. Dorsal crests absent. Ventral edges of notopodial lamellae not in contact with dorsal edges of neuropodial lamellae on any chaetigers. Notopodial pre-chaetal lamellae of anterior region rounded, large ( Fig. 2C ), posteriorly becoming low lobes.

Neuropodial postchaetal lamellae of chaetiger 2 largest, square-shaped, with a small ventral projection ( Fig. 2B ); neuropodial postchaetal lamellae on chaetiger 3 and subsequent chaetigers becoming rounded ( Fig. 2C ), progressively diminishing in size towards end of body, forming rounded lobes. All neuropodial pre-chaetal lamellae low, rounded lobes ( Fig. 2C ). Ventrolateral interparapodial pouches absent.

Notopodial capillaries on anterior chaetigers arranged in two rows: anterior row short, smooth, alimbate; posterior row longer, thick, slightly granulated. Notopodial capillaries of middle and posterior chaetigers short, smooth, alimbate. Neuropodial capillaries on anterior chaetigers arranged in two rows; all capillaries smooth. Sabre chaetae from chaetigers 11–12, up to two per fascicle; each stout, distinctly curved, basally smooth, heavily granulated, without sheaths ( Fig. 2D ). Neuropodial hooded hooks from chaetigers 14–16; notopodial hooded hooks from chaetigers 37–40, up to six per fascicle. All hooks with four pairs of accessory teeth above main tooth; secondary hood present ( Fig. 2E ).

Pygidium with long dorsal cirrus and two large lateral lobes ( Fig. 2F ).

Remarks. The morphology of the material examined agrees well with the original description ( Berkeley 1927), although a few slight differences were observed. The original description identified 8–9 pairs of branchiae, and the neuropodial hooded hooks were described as having three pairs of accessory teeth. No mention was made in the original description of dorsal crests or the first chaetiger that sabre chaetae and notopodial hooks appear on. A later description ( Berkeley & Berkeley 1952:28–29, Figs. 52–53) does mention these characters but, since parts of the descriptions of Fauvel (1927) are clearly incorporated, this cannot be relied upon. Also, Berkeley & Berkeley (1952) mention hooded hooks with four pairs of accessory teeth and a secondary hood, and referred the specimens to P. (M). cirrifera . The type material has unfortunately been lost ( Pettibone 1967). The differences between the original description given by Berkeley (1927) and these specimens are thus the number of accessory teeth (3 vs 4) and the number of branchial pairs (8–9 vs 9–10). This could be due to the different quality of the optics, and/or the size of the organisms. The discovery of these specimens near the type locality has, however, provided us with additional information.

As previously noted by Dagli & Çinar (2011), P. (M). multibranchiata likely represents a species complex. We agree with these authors that the specimens identified by Mackie (1984) from Scotland, England and Sweden as P. (M). multibranchiata likely represent a new species. Mackie’s (1984) specimens differ morphologically from the original description of P. (M). multibranchiata and the specimens we examined. Mackie (1984) described the European specimens as having small spherical eyes (rather than large, reniforme or crescent-shaped), an anteriorly rounded prostomium, 6–13 pairs of cirriform branchiae (rather than 8–10 triangular pairs), rectangular neuropodial lamellae with rounded edges on chaetiger 2 (rather than square-shaped, with a small ventral projection), and dorsal crests on a maximum of about 20 segments from chaetigers 13–15 (rather than dorsal crests absent).

Maciolek (1985) mentioned that the morphological characters of specimens from Washington (Bainbridge Island, Skif Point), Mexico ( Ascension Bay, Quintana Roo), Gulf of Mexico, and Florida (Hutchinson Island) agreed with the original description of Berkeley (1927) by having the large crescent-shaped eyes, the form of the peristomial wings, and the structure of the hooded hooks with three pairs of apical teeth. However, Berkeley (1927) described P. (M). multibranchiata with 8–9 pairs of branchiae (rather than 7–11 pairs), and did not mention the presence of dorsal crests. The mixture of specimens from several localities leads to a very broad morphological characterization (particularly in the 7–11 pairs of branchiae and the presence of dorsal crests). Maciolek’s (1985) specimens from the Puget Sound, Washington specimens correspond to P. (M.) multibranchiata ; however, it is necessary to re-examine the materials reported as this species from the Atlantic.

Dagli & Cinar (2011) described specimens from Bazan Bay ( Canada) and conclude that the morphological characters of the specimens in their study agree with the original ( Berkeley 1927) and subsequent ( Maciolek 1985) descriptions of Prionospio (M.) multibranchiata . However, despite the geographical proximity of Bazan Bay to the type locality (Vancouver), the Dagli & Cinar (2011) specimens differ morphologically from the original description of P. (M.) multibranchiata in having peaks on the anterior margin of the prostomium and dorsal crest present, rather than absent; prostomium subrectangular rather than triangular; and notopodial lamellae lacking (rather than present) on chaetiger 1. Further differences between P. (M.) multibranchiata Berkeley 1927 as originally described (and expanded on in this study) from the purported records of this species are shown in Table 1.

Distribution. British Columbia, Canada, Vancouver Island, Nanaimo District, intertidal (Type locality); mainland, near City of Vancouver, Burrad Sound Inlet, dock opposite Canada Place, British Columbia Exotics Survey shallow water (– 0.3 m).

Figures

FIGURE 1. Dispio glandulosa sp. nov: A) anterior end, dorsal view (holotype MNCN 16.01/6033), with diagrammatic view of O-shape dorsal organs; B) anterior end, lateral view (holotype MNCN 16.01/6033); C) chaetiger 1, anterior view; D–E) chaetigers 2 and 3, respectively, anterior view; F–G) chaetigers 24 and 26 respectively, anterior view; H) chaetiger 29, anterior view; I–J) chaetigers 48 and 50 respectively, anterior view; K) unilimbate capillary notochaeta from anterior row on chaetiger 1; L) smooth, unilimbate capillary notochaeta from posterior row on chaetiger 1; M) anterior row unilimbate capillary notochaeta from chaetiger 12; N) posterior row striated, long, unilimbate capillary notochaeta from chaetiger 12; O) granulated, reticulated, unilimbate capillary notochaeta from posterior notopodium; P) anterior row short, reticulated, granulated, unilimbate capillary neurochaeta from anterior chaetigers; Q) posterior row smooth, unilimbate capillary from anterior chaetigers; R) ventral tuft neurochaeta; S) ventral tuft reticulated, unilimbated neurochaeta from chaetiger 13; T) unidentate neuropodial hooded hooks; U) slender, short, smooth, alimbate capillary companion chaeta; V) posterior row: granulated, reticulated, unilimbate capillary chaeta; W) granulated, reticulated, alimbate ventral tuft chaeta. O-sDo: O-shape dorsal organ. Scale bars: A: 2 mm; B: 1 mm; C–J: 0.5 mm; K–W: 0.02 mm.

FIGURE 2. Prionospio (M.) multibranchiata (Berkeley, 1927), (LACM-AHF-POLY 11125). A) anterior end in dorsal view; B) anterior end in lateral view; C) parapodium with branchiae from chaetiger 5; D) sabre chaeta; E) hooded hook; F) pygidium. Scale bars: A, 0.5 mm, B, 0.24 mm, C, 0.2 mm, D, 0.29 mm, E, 0.23 mm, F, 0.3 mm.