Asclerocheilus Ashworth, 1901

Blake, James A., 2023, New Species of Scalibregmatidae (Annelida) from Slope and Abyssal Depths off Eastern Australia, Records of the Australian Museum (Rec. Aust. Mus.) 75 (3), pp. 271-298 : 273

Genus Asclerocheilus Ashworth, 1901

Type species. Lipobranchius intermedius Saint Joseph, 1894 . Designated by Ashworth (1901).

Synonym. Kebuita Chamberlin, 1919:390 . Type species: Eumenia glabra Ehlers, 1887 . Fide Blake, 2000.

Diagnosis. Body elongate, arenicoliform. Prostomium T-shaped with frontal horns. Parapodia of posterior segments reduced; dorsal and ventral cirri absent; interramal papillae or cilia present or absent; postsetal lamellae absent. Branchiae absent. Setae include capillaries, furcate setae, and large, conspicuous curved spines on setigers 1 to 4, sometimes accompanied by short spinous setae. Pygidium with long anal cirri.

Remarks. The genus Asclerocheilus is the second largest in the family with 15 species, including the one described here. One species, A. tasmanius Kirkegaard, 1996 is herein transferred to the genus Oligobregma because the holotype has well-developed podial lobes and parapodial cirri. By definition such parapodia are not found in the genus Asclerocheilus .

The genus Asclerocheilus was reviewed by Hartmann-Schröder (1994) and Blake (2000). Both authors reviewed existing species and described new species. HartmannSchroder (1994) described a new species, A. shanei from shelf depths of 122 m in Tasmania, Australia. She also reviewed and tabulated the distribution of acicular spines, capillaries, and furcate setae for the nine then-known species.

Blake (2000) redescribed A. beringianus, Ushakov, 1955 , A. californicus Hartman, 1963 and established a new species, A. kudenovi Blake, 2000 , based on old and newly collected offshore material from California. Blake (2000) also synonymized the genus Kebuita Chamberlin, 1919 with Asclerocheilus . In so doing, he also noted that Oncoscolex (Eumenia) heterochaetus Augener, 1906 had earlier been synonymized with Kebuita glabra ( Ehlers, 1887) by Hartman (1938) and that because the latter was being referred to Asclerocheilus , the specimens identified A. heterochaetus Kudenov & Blake, 1978 from southeasternAustralia became a junior homonym of O. heterochaetus Augener, 1906 . For this reason, the homonym was renamed by Blake (2000) as A. victoriensis . Blake (2000) prepared a tabular summary of the 12 known species, expanding on the earlier summary by Hartmann-Schröder (1994). Subsequent to Blake (2000), Eibye-Jacobsen (2002) described two new species of Asclerocheilus from the Thai sector of the Andaman Sea in shelf depths of 40– 80 m.

One new species, Asclerocheilus abyssalis sp. nov. has been discovered from off New South Wales. Each of the 15 known species of Asclerocheilus is compared in Table 1 , thus updating the data reviewed by Hartmann-Schröder (1994) and Blake (2000). With the transfer of A. tasmanius to Oligobregma , A. abyssalis sp. nov. is the only member of the genus known from abyssal depths of 3000 m or greater. Although both A. beringianus and A. intermedius (Saint Joseph, 1894) are reported from deep-sea habitats, these depths are from the lower continental slope of ~ 2000 m, not abyssal depths. The remaining 12 species are from shallower continental shelf or upper slope depths ( Table 1 ).