Prionospio (Minuspio) sanmartini, 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 : 568-573

Prionospio (Minuspio) sanmartini sp. nov.

Figure 3 A–Q

Material examined. Cantabrian coast: Sta. CC 1.X-85 1M. Ría de Foz (Galicia) 43°33’ N, 7°15’ W, Coll. J. Junoy, holotype, ( MNCN 16.01 /18446); Sta. CC 1.X-85 1M. Ría de Foz (Galicia) 43º33’ N 7º15’ W Coll. J. Junoy, 7 paratypes, ( MNCN 16.01 /18447); Sta. CC 1. XII.85, 43º33’ N, 7º15’ W, Ría de Foz (Galicia) Coll. J. Junoy, 40 paratypes ( MNCN 16.01 /18448); Atlantic coast : May 1988, Sta. D 25. Río Piedras (Andalucía) 37º12’ N, 7º7’ W, Coll. L. López-Serrano, 4 paratypes, ( MNCN 16.01 /18449) ; Nov 1988, Sta. CS7 Río Piedras (Andalucía) 37°12’ N, 7°5’ W, Coll. L. López-Serrano, 13 paratypes (3 complete), ( MNCN ; May 1988 St. PI7 Río Piedras (Andalucía) 37º12’ N, 7º3’ W Coll. L. López-Serrano, 6 paratypes 16.01, ( MNCN /18450) ; May 1987, Sta. Ts 6 Río Piedras (Andalucía) 37º13’ N, 7º10’ W Coll. L. López-Serrano, 5 paratypes 16.01, ( MNCN /18451)

Description. Holotype incomplete, 7 mm long with 29 chaetigers, 0.4 mm wide. Incomplete 16.01/ paratypes 18452). 0.7–8.0 mm long, 0.9–1.1 mm wide for 5–41 chaetigers. Complete paratypes 13–16 mm long, 0.7–0.8 mm wide with 50–85 chaetigers. Color in alcohol pale white. Prostomium triangular, anteriorly truncate ( Fig. 3A ), posteriorly tapered, with long, narrow caruncle extending to anterior edge of chaetiger 2. Two pairs of black-brown subdermal eyes in a trapezoidal arrangement; anterior pair small, crescent–shaped, elongated transversally; posterior pair very large, crescent-shape and elongated longitudinally ( Fig. 3A ). Palps lost. Peristomium moderate, collar-like, surrounding prostomium fused dorsally, with large, rounded notopodial postchaetal lamellae on chaetiger 1 ( Fig. 3 A–C). Neuropodial postchaetal lamellae on chaetiger 1 small, bluntly rounded ( Fig. 3 A–C).

Eight to ten (nine in holotype) pairs of long branchiae present on chaetigers 2–10 ( Fig. 3A, B , D–F), first pair longest (lost in holotype). All branchiae cirriform ( Fig. 3 D–F), almost subequal in size, 1.5 times longer than notopodial lamellae at chaetiger 9.

TABLE 1. Taxonomic characteristics of Prionospio multibranchiata Berkeley, 1927 , P. maciolekae Dagli & Cinar, 2011 , and P. sanmartini n. sp. “?” denotes absence of information; Neuropodial hooded hooks: Nehh; Notopodial hooded hooks: Nohh.

Notopodial postchaetal lamellae short and triangular on chaetiger 2 ( Fig. 3A, B ); elongated, subtriangular, with short, blunt tips on chaetigers 3–10 ( Fig. 3A, B, D, E ); progressively decreasing in size, becoming shorter, broader and oval (holotype 11) on chaetigers 11–12 ( Fig. 3G ); rounded and progressively decreasing in size from chaetiger 13; eventually becoming small, rounded lobes ( Fig. 3H ). Notopodial postchaetal lamellae joined across dorsum on chaetigers 10–17 (10–16 in holotype) forming low crests ( Fig. 3G ). Ventral edges of notopodial lamellae and dorsal edges of neuropodial lamellae not touching on any chaetigers. Notopodial prechaetal lamellae small, rounded in anterior region, not fused basally with notopodial postchaetal lamellae ( Fig. 3 D–G).

Neuropodial postchaetal lamellae oval-shaped on chaetiger 2, with ventral edge broader than dorsal edge ( Fig. 3B ); lamellae largest on chaetigers 3–5, approximately rectangular in shape (higher than broad), with rounded edges ( Fig. 3B, D, E ), and on chaetiger 6 becoming more rounded on posterior chaetigers ( Fig. 3F ). Anterior and middle neuropodial prechaetal lamellae small, rounded ( Fig. 3A, B , C–F). Ventrolateral interparapodial pouches absent.

Notopodial capillaries on anterior chaetigers arranged in two rows: anterior row short, smooth, alimbate ( Fig. 3I ); posterior row longer, thinner, slightly granulated, alimbate ( Fig. 3J ). Notopodial capillaries on middle chaetigers arranged in two rows: anterior row short, smooth, alimbate ( Fig. 3K ); posterior row slightly granulated, alimbate, with long pointed tips ( Fig. 3L ). Posterior chaetigers with long, slender, smooth, alimbate chaetae ( Fig. 3M ). Neuropodial capillaries arranged in a tuft on chaetiger 1; from chaetiger 2 arranged in two rows; all capillaries with same structure as notopodial chaetae. Sabre chaetae on neuropodia from chaetigers 12–16 (14 in holotype), up to two per fascicle, each chaeta stout, distinctly curved, basally smooth, heavily granulated medially and distally, without sheaths ( Fig. 3N ). Neuropodial hooded hooks ( Fig. 3O ) from chaetigers 13–17 (holotype 15), up to eight per fascicle, accompanied by thin, alimbate capillaries ( Fig. 3P ). Neuropodial hooks with five pairs of small teeth above large main fang, and small secondary hoods ( Fig. 3Q ). Notopodial hooded hooks from chaetigers 32–35, up to two per fascicle, with four pairs of small teeth above large main tooth, and small secondary hoods.

One specimen with oocytes in coelom from the chaetiger 31 until the end of fragment (paratype MNCN 16.01/18449).

Pygidium of posterior fragment largest with long middorsal cirrus, and two shorter ventro-lateral lobes.

Remarks. Prionospio (M.) sanmartini sp. nov. resembles P. (M.) multibranchiata, Berkeley, 1927 , in that both species have the same prostomial shape, the notopodial lamellae on chaetiger 1 are rounded, they have almost the same number of branchiae (8–10 and 9–10), and the structure of the notopodial and neuropodial chaetae is the same. However, the specimens of P. (M.) sanmartini sp. nov. examined in this study differ from P. (M.) multibranchiata in that in the former the nuchal organs surrounding the caruncle are absent (rather than present and swollen), the branchiae are cirriform (rather than triangular), the dorsal crests are present (rather than absent), the neuropodial lamellae on chaetigers 3–5 are rectangular (rather than rounded), sabre chaetae are present from chaetigers 12–16 (rather than from chaetiger 11).

Prionospio (M.) sanmartini sp. nov. is most similar to specimens examined by Mackie (1984) from Scotland that he called to P. (M.) multibranchiata as both share the same branchial structure, the neuropodial postchaetal lamellae are small and bluntly rounded on chaetiger 1, and the first appearance of the sabre chaetae and neuropodial hooks occurs on the same range of chaetigers. However, P. (M.) sanmartini sp. nov. differs from the Mackie (1984) specimens, in that the former has an anteriorly truncate (rather than rounded) prostomium; the number of branchiae ranges between 8–10 pairs (rather than 6–13), the neuropodial lamellae are oval (rather than rectangular) on chaetiger 2, dorsal crests are present on a maximum of about 8 segments from chaetigers 10–17 (rather than about 20 segments from chaetigers 13–15), and notopodial hooks first appear on chaetigers 32–35 (rather than on chaetigers 20–52). In addition, Mackie’s (1984) specimens have small inconspicuous eyes, not the larger more characteristic eyes of Berkeley’s (1927) material and that of P. (M.) sanmartini sp. nov.

Finally P. (M.) sanmartini sp. nov. is similar to P. (M.) maciolekae Dagli & Cinar, 2011 in the number of branchiae (8–10 pairs on chaetigers), the shape of anterior notopodial postchaetal lamellae, and the start of notopodial hooded hooks. However, P. (M.) sanmartini sp. nov. differs from the Dagli & Cinar, 2011 specimens, in that the former has the prostomium shape triangular with anterior margin truncate (rather than subrectangular with broadly rounded anteriorly), a long, narrow caruncle extending to anterior edge of chaetiger 2 (rather than a blunt caruncle reaching to base of chaetiger 1), nuchal organs absent (rather than present), notopodial postchaeta lamellae large, rounded on chaetiger 1 (rather than absent), neuropodial postchaetal lamellae on 1 buntly rounded (rather than finger like), neuropodial postchaetal lamellae on chaetiger 2, oval-shaped (rather than rectangular), and occurrence of dorsal crests on chaetigers 10–16/17 (rather than 10/11–25/28), all noto– and neuropodial capillaries from anterior row smooth (rather than moderately granulated), sabre chaetae on neuropodia from chaetigers 12–16 (rather than 13–14), neuropodial hooded hooks from chaetigers 13–17 (rather than 14–15), hooks with five pairs of teeth (rather than three pairs). Further differences between this new species and the other species examined are provided in Table 1.

Distribution. Cantabrian Sea (Galician coast) and East Atlantic (Andalusian coast). From the intertidal zone to 10 m depth.

Figures

FIGURE 3. Prionospio (Minuspio) sanmartini sp. nov.: A) anterior end, dorsal view (holotype MNCN 16.01/18446); B) anterior end, lateral view (holotype MNCN 16.01/18446); C) prostomium, peristomium and chaetiger 1, lateral view; D) chaetiger 3, anterior view; E) chaetiger 4, anterior view; F) chaetiger 9, anterior view; G) chaetiger 12, anterior view; H) chaetiger 16, anterior view; I) anterior row notochaeta on anterior chaetiger; J) posterior row notochaeta on anterior chaetiger; K) anterior row notochaeta on mid-chaetiger; L) posterior row notochaeta on mid-chaetiger; M) notochaeta from posterior chaetigers; N) sabre chaeta; O) neuropodial hooded hook; P) alimbate capillary companion chaeta; Q) notopodial hooded hook. Scale bars: A, B: 0.4 mm; C–H: 0.3 mm; I–N, O–Q: 0.01 mm.