Chaetocirratulus Blake, 2018

Blake, James A., 2023, New Species of Cirratulidae (Annelida) from Continental Slope and Abyssal Depths off Eastern Australia, Records of the Australian Museum (Rec. Aust. Mus.) 75 (3), pp. 249-270 : 255

Genus Chaetocirratulus Blake, 2018

Type species: Heterocirrus andersenensis Augener, 1932 . Original designation by Blake (2018).

Diagnosis. (after Blake, 2018) Prostomium broadly rounded anteriorly or wedge-shaped; eyespots absent; with a pair of small nuchal slits or depressions at posterior edge. Peristomium with a single pair of grooved dorsal tentacles arising from posterior margin or interface with setiger 1. First pair of branchiae arising from posterior margin of peristomium, an achaetous segment, or setiger 1. Body typically thick and fusiform over many segments, rarely with middle or posterior body segments beaded or moniliform; individual segments short, numerous. Setae include capillaries on most setigers and thick, pointed acicular spines in neuropodia and a few in notopodia or spines in neuropodia only; spines few, often small and inconspicuous, not forming cinctures. Individual spines straight to weakly sigmoid. Pygidium with a simple ventral lobe.

Remarks. Species of Chaetocirratulus include a small group of bitentaculate cirratulids that share characteristics of both the multitentaculate genus Cirratulus Lamarck, 1818 and the bitentaculate genus Chaetozone . The genus was established by Blake (2018) to accommodate a group of large bodied Chaetozone species that had a short wedge-shaped prostomium and only a few acicular spines, not arranged in spreading fascicles or in the more typical cinctures. Blake (2018) reported on six species of this genus, three new to science, all from the southern hemisphere: four from Antarctica; two from off western South America. Blake (2022) reported on four additional species from the western North Atlantic Ocean, three of which were new to science. In the present study, two new species agreeing with the diagnosis of Chaetocirratulus have been encountered, bringing the total number of known Chaetocirratulus species to twelve.