Aphelochaeta bimaculata Blake 2018, new species

• Main Author: Blake, James A.
• Format: Other/Unknown Material
• Language: unknown
• Published: 2018
• Subjects: Biodiversity; Taxonomy; Animalia; Annelida; Polychaeta; Terebellida; Cirratulidae; Aphelochaeta; Aphelochaeta bimaculata; Antarctic; Antarctic Peninsula; Weddell Sea; Weddell; Antarc*
• Online Access: https://zenodo.org/record/3798628; https://doi.org/10.5281/zenodo.3798628

Aphelochaeta bimaculata new species Figures 4–5 Chaetozone sp.: Hartman 1978: 166 (in part). Material examined. Weddell Sea, E of Antarctic Peninsula. Glacier Sta. 69-11, 05 Mar 1969, 77.15°S, 38.97°W, 851 m holotype (USNM 1490704) and 12 paratypes (USNM 1490705). Description. An elongate, threadlike species, with narrow pre-setiger region (Figs. 4 A–B, 5C–D), expanded anterior segmental region, becoming narrow again in posterior segments (Fig. 5A, D). All specimens incomplete; holotype narrow pre-setiger region becoming wider by setiger 3, then narrowing again by setiger 12 (Figs. 4B, 5 C–D), 6.25 mm long, 0.45 mm wide across peristomium, 0.87 mm wide across expanded anterior segments, with 31 setigers. Body with distinctive pigmentation; all specimens with black spots on posterior lateral margin of peristomium (Fig. 4 A–B), one paratype with black pigment on lower lip of mouth; all specimens with black pigment spots on middle and anterior margins of parapodia (Figs. 4 A–B; 5A–B), variable between specimens, best developed on holotype on all segments, other specimens with these spots reduced or limited to middle body segments. All specimens with distinctive paired black spots within ventral groove on each segment (Fig. 5 A–B); sometimes with additional spots in groove (Fig. 5B). Overall color in alcohol, light tan, with black pigment spots conspicuous or faint. Anterior expanded segments narrow, about 10 times wider than long (Fig. 4 A–B); posterior segments becoming longer (Fig. 5A, D). One posterior fragment with last setigers about as long as wide. Dorsum without groove, weakly rounded on posterior portion of each segment; venter with narrow shallow groove extending along entire body. Pre-setiger region very long, narrow, about 2.2 times as long as wide (Figs. 4 A–B; 5C–D), relatively smooth. Prostomium conical to triangular, narrowing to rounded tip; eyespots absent; nuchal organs not observed. Peristomium elongate, weakly divided into three annular rings, with grooves observed only laterally, not crossing ...