Orbiniella rugosa, Blake, 2020

Blake, James A., 2020, New species and records of deep-water Orbiniidae (Annelida, Polychaeta) from the Eastern Pacific continental slope, abyssal Pacific Ocean, and the South China Sea, Zootaxa 4730 (1), pp. 1-61 : 45-47

Orbiniella rugosa new species

Figure 23

urn:lsid:zoobank.org:act:B4156792-6AC0-4B23-A766-AF2DA124F512

Material examined. South China Sea, off Brunei, Island of Borneo, Site CA2 , R / V Emma , coll. P.A. Neubert, box corer, Sta. SA6 , 29 Jun 2011, 5°36.318′N, 113°37.76′E, 2178 m, holotype ( MCZ 153582 ); Sta. SA1 , 29 Jun 2011,

5°34.093′N, 113°39.735′E, 2075 m, paratype ( MCZ 153583 ); Sta. SA5 , 29 Jun 2011, 5°36.943′N, 113°41.123′E, 2162 m, 1 specimen ( UBD) ; Sta. SE 3, 29 Jun 2011, 5°32.454′N, 113°43.246′E, 2008 m, 1 specimen ( MCZ 153584 ) ; Sta. TA5 , 2 Jul 2011 5°27.844′N, 113°26.572′E 2008 m, 1 paratype ( MCZ 153585 ).— Site CA1 , R / V Emma , coll.

J.A. Blake, box corer, Sta. 47, 2 Jun 2011, 5°47.364′N, 114°17.179′E, 1242 m, 1 specimen ( MCZ 153587); Sta. 49, 2 Jun 2011, 5°44.405′N, 114°13.993′E, 1199 m, 1 paratype ( MCZ 153586).

Description. A small species, holotype complete, with 32 setigers, 5.0 mm long and 0.22 mm wide across anterior setigers. Other specimens incomplete. Body more or less cylindrical in cross section; segments generally short, about three times wider than long ( Fig. 23A ); dorsal and ventral grooves absent. All parapodia lateral, posterior parapodia not shifted dorsally. Anterior segments with narrow intersegmental groove ( Fig. 23 A–B); most segments with 2–3 transverse rows of reticulated wrinkles producing rough appearance across dorsum with a similar pattern on the venter ( Fig. 23 A–B). Color in alcohol: white to tan.

Pre-setiger region about as long as first three setigers; about half as wide as anterior setigers ( Fig. 23A ). Prostomium broadly rounded anteriorly, wider than long; eyespots absent, nuchal organs on lateral margins as low ciliated mounds. Peristomium with two annular rings, distinctly separated from one another, first generally narrower than second ( Fig. 23 A–B); both rings with 2–3 rows of reticulated raised mounds visible dorsally; ventrally, first ring incorporating posterior lip of mouth ( Fig. 23B ).

Branchiae entirely absent. Noto- and neuropodia with elongate podial lobes rounded apically, setae emerge from distal tip ( Fig. 23D ). Noto- and neurosetae consisting of 5–8 long, camerated capillaries and 1–3 notoacicular and 1–2 neuroacicular spines; spines from setiger 1 to end of body ( Fig. 23D ). Capillaries with a row of barbs or camerations along margin, similar throughout. Acicular spines thick, pointed, tapering apically to narrow tip ( Fig. 23 D–F). Furcate and flail setae absent.

Pygidium narrow, with four anal cirri of moderate length ( Fig. 23C ).

Methyl Green stain. No pattern, body stains uniformly.

Remarks. Orbiniella rugosa n. sp. belongs to a group of Orbiniella species having a notopodial lobe together with acicular spines in the noto- and neuropodia. In contrast to other species, the entire surface of the body of O. rugosa n. sp. has a lumpy appearance consisting of numerous folds and wrinkles. Superficially the lumpy integument is reminiscent of the annular rows of pads found on species of the Scalibregmatidae .

Etymology. The epithet is from the Latin, ruga for folds or wrinkles, referring to the rugose or rough reticulated appearance of the epithelium caused by numerous folds.

Distribution. South China Sea, off Brunei, Island of Borneo, 1199–2178 m.

Figures

FIGURE 23. Orbiniella rugosa n. sp. A, anterior end, dorsal view; B, anterior end, ventral view; C, posterior end, dorsal view; D, middle body parapodium, anterior view; E, notopodial acicular spine; F, neuropodia acicular spine. A, paratype (MCZ 153583); B, C, E–F, holotype (MCZ 153582); D, paratype (MCZ 153586).