Cirratulidae Ryckholt 1851

Family Cirratulidae Ryckholt, 1851

Diagnosis. Body elongate with numerous short segments; not divided into distinct regions, but anterior and/or posterior segments sometimes expanded and crowded. Prostomium narrow and conical or broad and wedge-shaped, without appendages; eyespots present or absent; paired nuchal organs present dorso-laterally. Peristomium achaetous, smooth or with two or more distinct annuli. Grooved dorsal tentacles arise as a single pair or as multiple groups of filaments on posterior margin of peristomium or on one or more anterior setigerous segments. Branchiae long, filamentous, usually occurring over numerous segments. Parapodia biramous with rudimentary podial lobes. Setae simple, including capillaries, acicular spines or bidentate hooks. Pygidium a simple lobe sometimes with sub-anal disk, or with one or two terminal cirri. Pharynx ventral, unarmed. Sexual and asexual reproduction may occur.

Remarks. The generic definitions of cirratulid collections from the MMS surveys from the 1980s were based on Hartman’s (1961, 1969) system where most bitentaculate species with unidentate acicular spines were referred to Chaetozone and those with only capillary setae were mostly referred to Tharyx. As a result the numerous provisional taxa that were established as part of those projects have required considerable review in order to align and re-evaluate them with the genera now in use (Blake 1991, 2016, 2018; Blake & Magalhães 2019). Furthermore, the offshore collections reported in this study are derived from over 2500 samples, mostly retained on fine mesh sieves with 300- and 500 µm openings. Because of this, thousands of specimens are available and sorting through and evaluating these materials has therefore taken considerable time and effort.

Genus Caulleriella Chamberlin, 1919

Type species: Cirratulus viridis Langerhans, 1881. Original designation by Chamberlin 1919.

Diagnosis. (after Blake & Magalhães 2019). Prostomium elongate, conical to pointed. Peristomium elongated to short, with dorsal tentacles usually beginning anterior to setiger 1. Middle body segments not beaded; parapodia often with noto- and neuropodia widely separated laterally. Modified setae including capillaries and bidentate crotchet-like hooks, not arranged into modified cinctures. In some species, unidentate hooks may occur in some regions of the body in addition to bidentate hooks. Pygidium either a simple conical lobe or with one or two anal cirri.

Remarks. After Blake (2021b) reported on species of Caulleriella from the U.S. Atlantic coast, another species was discovered among lower continental slope specimens that had been erroneously referred to Chaetozone during the ACSAR program. The new species is most similar to C. bathytata Blake, 2019 from abyssal depths of the Pacific Ocean. The new species is here described as Caulleriella cryptica n. sp.