Caulleriella pintada Blake 2021, new species

Caulleriella pintada new species

Figures 4–5

urn:lsid:zoobank.org:act: FE3FC01F-8A0A-4D02-87C0-D31C1DF978F5

Caulleriella sp. 3: Blake et al. 1987: C-2 (in part); Blake & Grassle, 1994: 854–855; Hilbig 1994: 940 (in part).

Material examined. (83 specimens). Southeastern USA, off Charleston, South Carolina, U.S. South ACSAR Program, J.A. Blake, collector: Sta. 14A: Cruise SA-5, R/ V Gyre, Rep. 1, 20 Sep 1985, 32°32.25ʹN, 77°15.24ʹW, 600 m holotype (USNM 1642599), 40 paratypes (USNM 1642600); Rep. 2, 20 Sep 1985, 32°32.26ʹN, 77°15.29ʹW, 605 m, 21 paratypes (USNM 1642601); Rep. 3, 20 Sep 1985, 32°32.22ʹN, 77°15.31ʹW, 605 m, 20 paratypes (USNM 1642602).

Description.A moderately large, elongate, threadlike species with body generally narrow throughout (Figs. 4A– B; 5A, C); some groups of anterior setigers variably inflated, but overall consistently narrow throughout, narrowest in far posterior setigers. Holotype complete, 11.2 mm long, 0.4 mm wide across anteriormost segments, about 0.2 mm wide in mid-body and posterior segments, with 67 setigerous segments. Anterior and middle setigers relatively short, about twice as wide as long (Fig. 4B); posterior setigers about as wide as long, weakly moniliform (Fig. 5F); some specimens with eggs in middle segments (Fig. 5G). Venter with shallow groove in anterior and middle segments, sometimes outlined with dark pigment (Fig. 4A); dorsal surface rounded throughout. Color in alcohol opaque white to light tan; larger specimens with dark brown to black pigment in variable patterns, sometimes outlining parapodia or ventral groove; pigment intense on some specimens including holotype (Figs. 4A, D, 5A), lighter on others; smallest specimens generally not exhibiting pigment.

Pre-setiger region elongate, cylindrical, up to as long as first five setigers in holotype and largest paratypes (Figs. 4A–B, 5A, C); some specimens with peristomium medially inflated (Fig. 5C–D). Prostomium conical, tapering to bluntly rounded apex (Figs. 4A–B, 5A, C–D); eyespots absent; nuchal organs low mounds at posterior-lateral margins prostomium. Peristomium indistinctly separated from prostomium, with no visible annular rings, entire surface smooth, or wrinkled in larger specimens (Figs. 4A–B, 5A, C–D); paired dorsal tentacles arising from near posterior margin (Fig. 4A–B). First branchiae arising dorsal to notosetae on setiger 1; subsequent branchiae in similar position. Most branchiae missing or limited to scars, when retained branchiae long and thin.

Parapodia reduced, weakly developed podia present only in anterior-most setigers, thereafter no podial lobes or lamellae observed, with setae arising directly from body wall. Notosetae of anteriormost setigers with 4–5 capillaries; notoacicular bidentate hooks first present from setiger 8 in holotype; with one hook at first, increasing to two hooks through mid-body segments, usually accompanied by 1–2 thin capillaries; posterior setigers with 2–3 hooks and 1–2 thin capillaries. Neuropodia with 4–5 long capillaries on setigers 1–4, replaced by bidentate hooks from setiger 5; one hook at first increasing to 2–3 hooks through mid-body segments; with 3–5 hooks in posterior setigers; neuropodial hooks accompanied 1–2 thin capillaries. Hooks in noto- and neuropodial fascicles directed toward one another, vis-à-vis. Individual hooks with relatively thick shaft, weakly curved, tapering to blunt-tipped main fang directed at about 45° with shaft (Figs. 4D–E, 5H–I); apical tooth smaller, point conforming to curve of shaft, directed forward and appearing to be an extension of an ‘alate’ flange or hood on the convex side of shaft (Fig. 4D–E). Neuropodial hooks heavier and shorter (Figs. 4E, 5H) than notopodial hooks (Figs. 4D, 5I).

Pygidium a simple lobe bearing two ventral anal cirri (Figs. 4C, 5B, E).

Methyl Green staining. No pattern.

Remarks. Specimens identified as Caulleriella sp. 3 during the ACSAR program actually include two different species: (1) C. pintada n. sp., which appears to be restricted to sandy sediments at 600 m off South Carolina, and (2) C. filiformia n. sp., which occurred in fine-grained sediments along the 2000 m isobath off North and South Carolina and off New England.

Caulleriella pintada n. sp. is unusual among species of Caulleriella in the nature of the elongate narrow peristomium that consists of a single ring that is distinctly wrinkled and pigmented in larger specimens. The body has brown to black pigment in variable patterns along the body; this pigment is intense on the holotype and most paratypes. This species, like C. filiformia n. sp., has bidentate setae with an apical tooth that is an extension of an ‘alate’ hood or flange on the convex side of the shaft, but differs in having the elongate pre-setiger region, branchiae from the posterior margin of the peristomium instead of setiger 1, and distinct pigmentation.

Biology and Habitat. Cruise SA-5, was the only ACSAR survey on which samples were collected at Sta. 14A. The results presented by Blake et al. (1987) and Blake & Grassle (1994) indicate that Caulleriella pintada n. sp. (as Caulleriella sp. 3) was the most abundant invertebrate species encountered at the site with 14% of the total number of individuals. The sediment consisted of 94–95% sand with low water content. The coarse grain size of the sediments at Sta. 14A appears to be important for this species because it was not encountered at other 600 m stations off Cape Lookout and Cape Hatteras where the sediments have a high silt + clay content. Several paratypes were mature females with eggs about 100–110 µm in diameter (Fig. 5G).

Etymology. The epithet pintada, is from the Spanish pintado, for painted or mottled, referring to the irregular pigmentation patterns found on the larger specimens of this species.

Distribution. Off Charleston, South Carolina, 600– 605 m.