Caulleriella angusticrista, 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 : 307-308

Caulleriella angusticrista new species

Figure 3

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Material examined. Caribbean Sea, Carib 1, R/V Alpha Helix , Panama, Playita Point, San Blas Peninsula, Sta. ND-24-1000, 09°32.8ʹN, 78°59.5ʹW, 30 June 1977, subtidal, dredged at a depth of 5 m, along edge of man- grove, holotype ( USNM 1557499 ) .

Description. Holotype complete, 3.5 mm long for 65 setigers, 0.25 mm wide across thorax. Anterior or thoracic region with 15 narrow, crowded setigers, with elevated notopodial tori. Thoracic segments rectangular in cross section with thickened notopodial ridge at superior corners and low neuropodial ridge at inferior corners. Middle body segments not as wide as those of thorax, notopodia not elevated dorsally and segments longer, depressed, oval in cross section; parapodial lobes forming low ridges. Color in alcohol pale tan.

Pre-setiger region short, slightly wider than long ( Fig. 3 A–B). Prostomium conical, narrowing to rounded apex; small, weakly pigmented nuchal organs located dorsolaterally, but dorsally visible beneath first peristomial annulation; eyespots absent; peristomium wider than long, with three annulations; ( Fig 3 A–B); mid-dorsal posterior margin of peristomium extending as narrow ridge to anterior border of setiger 2 ( Fig. 3A ). Dorsum of thorax flattened, with narrow mid-dorsal crest extending from posterior peristomial ridge ( Fig. 3A ). Dorsal tentacles on setiger 1, lateral to peristomial ridge and medial to first pair of branchiae; branchiae dorsal to notosetae on edge of swollen notopodial lobe ( Fig. 3 A–B); subsequent branchiae similarly positioned relative to notosetae.

Notosetae include 4–8 capillaries for first 15 setigers, single bidentate hook accompanied by three capillaries from setiger 16; subsequent notopodia with 1–3 hooks accompanied by 1–3 capillaries or, occasionally, capillaries absent. Neurosetae include single bidentate hook and two accompanying capillaries in setiger 1, subsequent thoracic setigers with 1–3 hooks and 1–3 accompanying capillaries, last thoracic neuropodia with only three hooks; abdominal neuropodia with 2–5 (usually 5) bidentate hooks, capillaries absent. Hooks with curved shaft; narrow apical tooth above larger main fang, hood absent ( Fig. 3C ). Last four body segments asetigerous, pygidium rounded with no cirri, anus dorsal.

Methyl Green stain. Body stains a uniform dark blue with the thorax somewhat more intensely stained; pygidium and prostomium do not stain.

Remarks. Caulleriella angusticrista n. sp. is similar to C. magnaoculata Hartmann-Schröder, 1962 from shallow water off Peru in having pigmented nuchal organs that can be mistaken for eyespots, dorsal tentacles that arise between the parapodia of setiger 1, and the first branchiae present lateral to the dorsal tentacles and dorsal to the notosetae on setiger 1. The holotype of C. magnaoculata was redescribed by Blake (2018), who pointed out that the large eyespots reported by Hartmann-Schröder (1962) were actually pigmented nuchal organs. The two species differ in that, unlike C. angusticrista n. sp., there is a prominent peristomial dorsal crest on C. magnaoculata that extends from the middle of the peristomium posteriorly and carries the dorsal tentacles to a position at the level of setiger 1; however, C. magnaoculata does not have a dorsal ridge on the anterior segments as in C. angusticrista n. sp. In addition, the bidentate hooks of C. magnaoculata begin on setiger 10 in the neuropodia and setiger 37 in the notopodia; in contrast, the hooks of C. angusticrista n. sp. begin on setiger 1 in the neuropodia and setiger 16 in the notopodia. The far posterior segments of the holotype of C. magnaoculata are regenerating and notosetae are entirely absent, thus making a comparison of the posterior segments with C. angusticrista n. sp. and other species not feasible.

Caulleriella angusticrista n. sp. is also similar to C. cristata Blake, 1996 from central California in having neuropodial bidentate hooks from setiger 1, a triannulate peristomium, dorsal tentacles shifted posterior to setiger 1, and the first branchiae lateral to the dorsal tentacles. In C. cristata , the neuropodia have 7–8 hooks but no capillaries and there is a prominent dorsal crest over the entire three annuli of the peristomium. In contrast, C. angusticrista n. sp. has 1–5 hooks and a few capillaries at least in the anterior segments and there is no dorsal crest on the peristomium.

Etymology. The name is derived from the Latin angustus, for narrow and crista for crest and emphasizes the narrow longitudinal ridge on the dorsum of the anterior thorax.

Distribution. Known only from Panama, from shallow subtidal sediments of mangroves in Playita Point, San Blas Peninsula.

Figures

FIGURE 3. Caulleriella angusticrista n. sp. Holotype (USNM 1557499): A, anterior end, dorsal view; B, anterior view, lateral view; C, neuropodial acicular spine from posterior setiger.