Caulleriella parapicula, Blake & Dean, 2019

Blake, James A. & Dean, Harlan K., 2019, New Species of Cirratulidae (Annelida, Polychaeta) from the Caribbean Sea, Zootaxa 4671 (3), pp. 301-338 : 311-312

Caulleriella parapicula new species

Figure 6

urn:lsid:zoobank.org:act:6E1489DF-475A-4EC0-9D4D-D00D9B2BFB84

Material examined. Caribbean Sea, Carib 1, R/V Alpha Helix , Panama, Golfo De San Blas , Playita Point, Sta. ND-26, 09°32.8ʹN, 78°59.5ʹW, 30 June 1977, dredged across seagrass in sand and coral rubble, 30–50 cm, holotype ( USNM 1557507 ) .

Description. A small species, holotype incomplete, 2.7 mm long, 0.3 mm wide across anterior segments, with 46 setigers. All segments crowded, noto- and neuropodia widely separated along entire body. Body weakly divided into an anterior or thoracic region of about 15 narrow segments six times wider than long; posterior segments about three times wider than long. Anterior segments with prominent mid-dorsal ridge, more or less following peristomial crest ( Fig. 6A ), middle and posterior segments rounded dorsally, but not as a crest. Prominent ventral groove present, best developed in middle body where neurosetae on either edge project into groove; ventral groove more shallow posteriorly. Color in alcohol light tan.

Pre-setiger region large, about as long as thoracic region, slightly longer than wide. Prostomium narrow, elongate, tapering to rounded apex; with large oval-shaped nuchal organs, pigmented internally, resembling eyespots ( Fig. 6A ). Peristomium with four annular rings of equal width, observed laterally, not crossing elevated and broadly rounded fleshy dorsal crest ( Fig. 6A ). Dorsal tentacles arise from posterior margin of dorsal crest at level of setiger 1. First branchiae on setiger 1 dorsal to notosetae and lateral to dorsal tentacles; subsequent branchiae in same position; branchiae long, thin, either intact or present as stubs or scars along most of body.

Parapodia of 15–17 anterior or thoracic segments with fleshy and swollen noto- and neuropodia from which se- tae emerge producing small shoulders on either side of dorsum ( Fig. 6A ); subsequent segments with less prominent podia. Notopodia initially with 5–7 capillaries; bidentate hooks first present from setigers 17–19, with 1–2 hooks at first, increasing to 3–4 hooks along rest of body, accompanied by 1–2 thin capillaries. Neurosetae from setiger 1 with bidentate hooks in a vertical row numbering 9–10 at first, reduced to about seven posteriorly; not accompanied by capillaries. Individual hooks recurved, weakly geniculate, tapering to pointed fang surmounted by shorter, closely adhering apical tooth ( Fig. 6B ); dorsal crest or hood not evident on shaft.

Pygidium unknown.

Methyl Green stain. No pattern, de-stains rapidly along entire body.

Remarks. Caulleriella parapicula n. sp. is most similar to C. apicula Blake, 1996 from Southern California in shallow shelf depths. Both species have an elongated prostomium with large oval-shaped nuchal organs, a distinctive high dorsal peristomial crest, dorsal tentacles that are shifted posteriorly to the level of setiger 1, a ventral groove along the body into which the neuropodial hooks protrude, and similar bidentate hooks, each with a closely adhering apical tooth. The two species differ in that C. parapicula n. sp. has a prostomium that tapers to a rounded tip and has a pair of pigmented nuchal organs, whereas in C. apicula the prostomium narrows to a pointed tip and has a pair of distinct eyespots in addition to non-pigmented nuchal organs. Additionally, C. parapicula n. sp. has a mid-dorsal crest on anterior setigers that more or less is a continuation of the peristomial crest, four lateral peristomial annular rings, and notopodial hooks that begin on setigers 17–19; in contrast, C. apicula has no dorsal ridge on anterior segments, no peristomial annular rings, and the notopodial hooks begin on setigers 80–86.

Caulleriella parapicula n. sp. exhibits some similarity to C. convexacapa n. sp. described above in having a relatively large, broad dorsal crest that carries the dorsal tentacles on to setiger 1 and an elongated prostomium with a rounded apex. However, the peristomium of C. convexacapa n. sp. has only two annular rings that cross the dorsal crest and instead of four annular rings that do not cross the dorsal crest but are limited laterally; additionally, the anterior segments of C. convexacapa n. sp. have a smooth, elevated dorsum with individual segments demarked by distinct segmental grooves instead of a high raised mid-dorsal ridge as in C. parapicula n. sp. Furthermore, the nuchal organs, while weakly pigmented, are small and inconspicuous in C. convexacapa n. sp. instead of large and conspicuous and the dorsal bidentate hooks begin on setigers 9–13 instead of 17–19.

Etymology. The epithet is from the Latin, par, for equal to or near and apiculus for pointed, and refers to the similarity of the new Caribbean species with Caulleriella apicula from California.

Distribution. Panama, shallow subtidal, in seagrass and sand.

Figures

FIGURE 6. Caulleriella parapicula n. sp. Holotype (USNM 1557507):A, anterior end, right lateral view; B, neuropodial hook from an anterior setiger.