Scolelepis alisonae, Williams, Jason D., 2007

Williams, Jason D., 2007, New records and description of four new species of spionids (Annelida: Polychaeta: Spionidae) from the Philippines: the genera Dispio, Malacoceros, Polydora, and Scolelepis, with notes on palp ciliation patterns of the genus Scolelepis, Zootaxa 1459, pp. 1-35 : 13-17

Scolelepis alisonae sp. n.

( Figs. 8–10)

Material examined. Holotype Philippines, Morong, Bataan, sandy beach, 28 Feb 1999 ( USNM 1096804).— Paratypes, same data as holotype (16 anterior ends, two posterior ends, one middle piece in alcohol, USNM 1096805; one complete specimen on SEM stub, four anterior ends on SEM stubs, one set of palps on SEM stub, USNM 1096806); same location as holotype, 1 Mar 1999 (one anterior end, USNM 1096807); same location as holotype, 25 April 1999 (one complete specimen, eight anterior ends, ZRC 2006.0222).

Etymology. The species is named in honor of my wife, Dr. Alison S. Carson, for her help in collection of these specimens (sometimes under quite adverse conditions). Her cultural psychology studies in the Philippines (supported by the National Science Foundation and a Fulbright Scholarship) allowed for travel to make these collections.

Diagnosis. A species of Scolelepis with notosetae on setiger 1, notopodial hooded hooks and lacking an occipital tentacle. Palps short, palp sheaths absent, palps with two weakly separated transverse rows of cilia. Prostomium conical, with two pairs of eyes. Caruncle extending to middle of setiger 1, nuchal cilia in Ushaped pattern on sides of caruncle. Postsetal notopodial lamellae fused with branchiae from setiger 2, lamellae composed of up to nine conical lobes by setiger 5, number of lobes gradually decreasing posteriorly. Bidentate notopodial hooded hooks from setiger 68–99, with up to three per fascicle. Postsetal neuropodial lamellae with up to three lobes in anterior setigers. Bidentate neuropodial hooded hooks from setiger 25–33, with up to 11 hooks in middle and posterior fascicles. Pygidium broadly rounded, with short conical papillae surrounding anus.

A B C Pa C-G D E F G H I J K L M J-M Description. Largest specimen of 136 setigers, 47.6-mm long and 0.9-mm wide by setiger 8; holotype of 125 setigers, 37.5-mm long, 0.52-mm wide by setiger 8. Body widest anteriorly, gradually tapering to posterior end; body nearly rectangular in cross section. Color in alcohol opaque white, no pigmentation present.

Prostomium conical, extending anteriorly to long, tapering point, posteriorly extending to short caruncle with rounded posterior margin, ending in middle of setiger 1, caruncle not free on posterior margin ( Figs. 8 A– B, 9A–C). Two pairs of eyes, one pair of kidney-shaped eyes laterally, one pair of round eyes medially, all eyes in nearly straight row between base of palps ( Fig. 8 B); occipital tentacle absent. Palps short, extending to setigers 6–10 ( Figs. 8 B, 9C), with two weakly separated transverse rows of cilia along the ventral surface, long rows of cilia approximately 45 µm long, short rows approximately 24 µm long (short rows on medial side), long and short rows in approximately 1:1 ratio, rows of mucus secreting cells represented by tubular necks present proximal to transverse ciliary rows; ciliary rows extending to distal ends of palps, median ciliated groove lacking ( Figs. 10 A–B, 18C). Palpal sheaths absent. Nuchal cilia in U-shaped pattern on both sides of caruncle, posterior to base of palps ( Fig. 9 B).

Setiger 1 well developed with bluntly pointed, triangular notopodial and neuropodial postsetal lamellae, notosetae and neurosetae present ( Figs. 8 C, 9D). Postsetal notopodial lamellae fused with branchiae from setiger 2 ( Figs. 8 D, 9F), lamella composed of 2–6 conical lobes, number of lobes increasing to 5–9 on lamellae by setiger 5 ( Figs. 8 E, 9A, C), then gradually decreasing to two conical lobes distally and rounded basal portion by setigers 20–30 ( Figs. 8 F, 9G), posteriormost setigers with one conical lobe distally, with rounded basal portion free from branchiae ( Figs. 8 G, 9H, 10C). Neuropodial postsetal lamellae of setiger 1 rounded or conical ( Figs. 8 C, 9D), lamellae of setiger 2 with rounded base extending into short, bluntly pointed lobe ( Figs. 8 D, 9F), lamellae of setigers 3–5 sometimes with 2–3 bluntly pointed lobes ( Fig. 9 C), lamellae from setigers 6-20 with broadly rounded lobe ( Fig. 8 F, 9G), developing notch dividing lamellae by setiger 30, on posterior setigers ventral lobe small, triangular, dorsal lobe elongate with dorsal end free and pointed, ventral end rounded ( Figs. 8 I, 9H), by setiger 65 ventral lobe reduced, dorsal lobe digitate ( Fig. 10 C). Lateral organs between notopodial and neuropodial postsetal lamellae present from setiger 1 to posterior setigers ( Fig. 9 G).

Notosetae of setiger 1 and subsequent setigers arranged in two vertical rows of bilimbate capillaries, the dorsal notosetae of these rows longer than ventral ones, often loosely coiled along their distal ends ( Figs. 8 L, 9A, C, F), one notopodial hooded hook beginning on setiger 68–99 ( Figs. 8 J, K, 10C), with up to three notopodial hooded hooks in posterior most setigers; notopodial hooded hooks with acute main fang and single accessory tooth. Neurosetae of setiger 1 and subsequent setigers arranged in two vertical rows of bilimbate capillaries ( Fig. 9 F–G), 1–3 neuropodial hooded hooks from setiger 25–33, up to 5–11 neuropodial hooded hooks in middle to posterior setigers ( Fig. 8 G); neuropodial hooded hooks with acute main fang and single accessory tooth ( Fig. 8 M). Notosetae and neurosetae with minute spinelets ( Fig. 9 E).

Branchiae present from setiger 2 to end of body, fused with postsetal notopodial lamellae but with tips free in anterior setigers ( Fig. 9 F), separated from notopodial lamellae in posterior setigers, with band of cilia along inner edge and joined to corresponding branchiae on opposite side by a single band of cilia across dorsum ( Fig. 9 B).

Pygidium broadly rounded, with short conical papillae surrounding dorsal anal opening ( Figs. 8 H–I, 10D).

Remarks. The genus Scolelepis was reviewed by Maciolek (1987) and more recently by Hutchings et al. (1998), both studies provided summary tables for the known members of the genus. Since then, nine species of Scolelepis , including those treated in this paper, have been described, and there are now 58–59 species within this genus ( Table 1). Confusion exists in the total number of species because MacCord & Amaral (2005) resurrected Scolelepis goodbodyi ( Jones, 1962) , a species that was previously considered a synonym of S. squamata ( Müller, 1806) ( Pettibone 1963; Foster 1971a; Light 1978; Maciolek 1987). However, MacCord & Amaral (2005) provided no taxonomic evidence to support the conclusion that these species are distinct (their identification was based on the authority of Radashevsky; pg. 829).

Scolelepis alisonae sp. n. belongs to a group of six species including S. blakei Hartmann-Schröder, 1980 ; S. carunculata Blake & Kudenov, 1978 ; S. chilensis ( Hartmann-Schröder, 1962) ; S. hutchingsae Dauer, 1985 ; and S. kudenovi Hartmann-Schröder, 1981 , that possess notosetae on setiger 1, notopodial hooded hooks, bidentate neuropodial hooded hooks and that lack an occipital tentacle. Scolelepis alisonae sp. n. is distinguished from all these species in the possession of notopodial postsetal lamellae with up to nine lobes in anterior setigers and neuropodial postsetal lamellae with up to 3 lobes in anterior setigers. Scolelepis alisonae sp. n. and S. laciniata Eibye-Jacobsen, 1997 are similar in the possession of notopodial postsetal lamellae with conical lobes; however, Scolelepis alisonae sp. n. is easily distinguished by the presence of notosetae on setiger 1 and notopodial hooded hooks (both absent in S. laciniata ).

The palp morphology of S. alisonae sp. n., is uniquely different from previously described species in exhibiting weakly separated long and short transverse rows of cilia in a 1:1 ratio. See Discussion for a comparative analysis of the palp morphology in members of the genus Scolelepis .

Distribution. Sandy beach in Morong of the Bataan province in the Philippines; shallow subtidal (<5 m).

Figures

FIGURE 9. Scolelepis alisonae sp. n. A – H, paratypes (USNM 1096806) SEM micrographs. A, anterior end, oblique lateral view (palps missing); B, anterior end, dorsal view; C, anterior end, lateral view; D, setiger 1 and base of palp, lateral view; E, tips of neurosetae from setiger 3; F, setiger 2, lateral view; G, setiger 19 & 20 (left to right), lateral view (arrowheads indicate lateral organs); H, setigers 49 – 51 (top to bottom), lateral view. Scale bars: A – C = 250 µm; D = 100 µm; E – H = 200 µm.

FIGURE 10. Scolelepis alisonae sp. n. A – D, paratypes (USNM 1096806) SEM micrographs. A, proximal region of palp, frontal view (arrowhead indicates faint division in transverse rows of cilia; short rows top, long rows bottom; note that at point of arrowhead there are two long rows below and only one short row above); B, distal tip of palp, frontal view; C, setiger 68, oblique dorsolateral view; D, posterior setigers and pygidium, dorsal view. Scale bars: A – B = 25 µm; C = 100 µm; D = 250 µm.