Polydora and related genera (Polychaeta: Spionidae) from the Grand Caribbean region Author Vı Author Delgado-Blas, ctor H. text Journal of Natural History 2008 2008-01-31 42 1 - 2 1 19 http://dx.doi.org/10.1080/00222930701831240 journal article 10.1080/00222930701831240 1464-5262 4651778 Dipolydora anatentaculata sp. nov. ( Figure 2 ) Type material Gulf of Mexico : Rookery Bay , Florida (26 ° 209N, 81 ° 789W), holotype (USNM- 1073344) . Description Holotype Incomplete specimen with 59 anterior segments, 8.5 mm long, 0.5 mm wide at chaetiger 6. Prostomium bifid, deeply notched along anterior margin, with two rounded antero-lateral processes. Four black eyes present in trapezoid arrangement.Caruncle extending posteriorly to segment 4. Occipital antenna present ( Figure 2A ) at posterior end of prostomium, thick basally, tapering to pointed apex ( Figure 2A ). Palps extending posteriorly for 23 segments. Colour in alcohol pale yellow. Body and palp pigmentation absent. Figure 2. Dipolydora anatentaculata sp. nov. (USNM-1073344). (A) Anterior region, dorsal view; (B) posterior notochaeta; (C) granulated capillary neurochaeta of anterior segment; (D) hooded hooks of anterior and posterior segment; (E) chaetiger 5 notochaetae; (F) companion chaetae of chaetiger 5; (G) spines and companion chaetae of chaetiger 5. Scale bars: 25 mm (A); 200 mm (B–G). Chaetiger 1 with well-developed neuro- and notopodial lamellae ( Figure 2A ), two to three capillaries in notopodia, and numerous longer capillaries in neuropodia. Winged capillary notochaetae of segments 2–4, 6 arranged in two rows; posterior notochaetae consisting of two types : anterior row of bristled chaetae, and posterior row of long slender capillaries ( Figure 2B ). Neurochaetae of chaetigers 2–4, and 6 with two rows of unilimbate capillaries having fine granulations on shaft ( Figure 2C ). Five bidentate hooded hooks ( Figure 2D ) in neuropodia from chaetiger 7, with up to six hooks in a series at chaetiger 13, accompanied by two capillary chaetae on chaetigers 7–10, and up to five capillaries at chaetiger 11; hooks curved with wide angle between main fang and shaft, narrow angle between main fang and apical tooth, no constriction on shaft ( Figure 2D ). Chaetiger 5 greatly modified, larger than adjacent segments, lacking postchaetal lamellae, with five dorsal superior alimbate capillaries and one small capillary ( Figure 2E ), and three to four ventral geniculate capillaries; slightly curved row of five major spines alternating with pennoned companion chaetae bearing bristles ( Figure 2F, G ). Major spines simple falcate, without subterminal protuberance ( Figure 2G ). Branchiae starting from chaetiger 8, continued to posterior end of fragment. All branchiae basally free of notopodial lamellae. Gizzard-like structure present in intestinal tract on segments 17–21. Pygidium unknown. Ecology Dipolydora anatentaculata is found burrowing in gastropod shells, Cerithium eburneum (Bruguière) . Remarks Dipolydora anatentaculata sp. nov. belongs to the Dipolydora concharum / coeca / flava / socialis Group as defined by Blake (1996) . It differs from all of them in possessing an occipital antenna. This species most closely resembles D. tentaculata Blake and Kudenov, 1978 in bearing an occipital antenna and in the simple nature of the major spines on chaetiger 5. It differs from D. tentaculata in having four eyes instead of none to two, simple falcate spines instead of spines with a subterminal swelling ( Blake and Kudenov 1978 , Figure 39f), angle between teeth of hooded hooks consistent within a fascicle instead of angle between teeth decreasing from dorsal to ventral side of neurosetal fascicle, and in lacking pigment bars instead of having pigment bars on some anterior chaetigers. Etymology Gr. ana -, meaning similar to D. tentaculata . Distribution Gulf of Mexico : Rookery Bay , Florida .