Caulleriella suroestense Blake 2018, new species

Caulleriella suroestense new species

Figure 27

Material examined. Off Chile, Juan Fernandez Islands, Robinson Crusoe Island, the embayment behind Punta Suroeste, SEPBOP, R / V Anton Bruun, Cr. 12, Sta. DRAB 134, 13 Dec 1965, 33.623°S, 78.906°W, diving, holotype (USNM 1490725) and 3 paratypes (USNM 1490726).

Description. Small species with thick, tumid body and numerous crowded segments. All four type-specimens complete with curved or coiled bodies. Holotype 6.1 mm long, 0.45 mm wide across anterior segments, 0.65 mm wide across middle and posterior segments, with about 85 setigerous segments; paratypes similar, but smaller. Body with dorsum rounded, elevated over lateral parapodia throughout (Fig. 27 A–B), venter with broad groove along most of body (Fig. 27C). Color in alcohol tan, heavily pigmented with numerous black subdermal cells; pigment scattered in patches over most of body, concentrated in parapodia of middle and posterior segments.

Prostomium triangular, tapering to narrow tip (Fig. 27 A–B); eyespots absent; nuchal organs small oval openings on posterior of prostomium, lateral and dorsal to mouth opening (Fig. 27A). Peristomium thick, with one short anterior ring and one large posterior ring incised with indistinct folds and grooves (Fig. 27 A–B); broad dorsal crest present. Dorsal tentacles close to one another on posterior margin of peristomium (Fig. 27B). First branchiae on setiger 1 dorsal to notosetae (Fig. 27 A–B); following segments with branchiae in similar position; branchiae long, narrow anteriorly; short, thick posteriorly, continuing to near end of body.

Parapodia with noto- and neuropodia widely separated from one another throughout, forming prominent shoulders both dorsally and ventrally (Fig. 27A, C). Notosetae include about 12 long capillaries on first 15 setigers, then reduced to 8–10 capillaries with first hooks appearing by setigers 27–28; hooks 1–2 at first with 3–4 thin capillaries, increasing to 4–5 hooks and 2–3 thin capillaries, continuing to near posterior end. Neurosetae with hooks from setiger 1, numbering four per neuropodium at first, increasing to five hooks along most of body; no capillaries in neuropodia throughout. Hooks short, thick, weakly sigmoid in shape with thick main fang surmounted by short, closely applied secondary tooth (Fig. 27D); hooks without hood or sheath.

Posterior end terminating in pygidial segment with anal opening surrounded by about eight short papillae and ventral lobe (Fig. 27C).

Methyl Green stain. Stain not retained.

Etymology. This species is named for the collection site near Punta Suroestense, Juan Fernandez Islands.

Remarks. The short curved body with thick, crowded segments and the distinctive overall pigmentation caused by numerous black pigmented cells readily distinguishes Caulleriella suroestense n. sp. from other congeners. The five species of Caulleriella described by Dean & Blake (2007) from intertidal and shallow sediments off Costa Rica, C. ecuadoriana n. sp. described in the present study from shallow water off Ecuador, and C. suroestense n. sp. are the only species having two peristomial rings instead of three and up to eight papillae on the pygidium dorsal to the anus plus a ventral lobe. However, C. suroestense n. sp., C. dulcei Dean & Blake, 2007, and C. murilloi Dean & Blake, 2007 each have neuropodial hooks from setiger 1 and lack capillaries in posterior neuropodia; C. murilloi has a hood covering the teeth of the bidentate hooks that is lacking in both C. suroestense n. sp. and C. dulcei. Although morphological differences are present between these shallow water species from Central and South America, great care must be taken to ensure that all relevant morphology is observed when identifying Caulleriella species from these locations.

Distribution. Off Chile, Juan Fernandez Islands, shallow subtidal depths.