Neomicrorbis Rovereto, 1904

Ten Hove, Harry A. & Kupriyanova, Elena K., 2009, Taxonomy of Serpulidae (Annelida, Polychaeta): The state of affairs, Zootaxa 2036, pp. 1-126 : 64-66

23. Neomicrorbis Rovereto, 1904

( Fig. 29)

Type-species: Serpula crenatostriata Münster in Goldfuss, 1831 ( fide Regenhardt 1961: 89 ); a fossil taxon

Number of Recent species: 1

Tube transparent (vitreous), circular in cross-section, with numerous longitudinal ridges consisting of small denticles ( Fig. 29C). Tube spiral, either dextral or sinistral. Granular overlay absent. Operculum with distal calcareous plate and large talon projecting into proximal ampulla, merging into peduncle without constriction ( Fig. 29B). Peduncle second radiole right, two small distal wings. Pseudoperculum absent. Arrangement of radioles semi-circular, 10 radioles left, 7 right. Inter-radiolar membrane, branchial eyes, and stylodes absent. Mouth palps absent. Number of thoracic chaetigers asymmetric, 5 to the left and 6 to the right ( Fig. 29A). Collar non-lobed, tonguelets and length of thoracic membranes not known. Collar chaetae fin-and-blade and limbate. Apomatus chaetae present in posterior thoracic segments ( Fig. 29E). Thoracic uncini saw-shaped with 12–15 teeth and rounded peg. Thoracic depression is not known. Abdominal chaetae retro-geniculate ( Fig. 29F). Abdominal uncini rasp-shaped with 14–17 teeth in profile, 3–5 in a row ( Fig. 29D). Long anterior achaetous abdominal zone. Posterior capillary chaetae present. Posterior glandular pad absent.

Remarks. The diagnosis above is partly based on a personal communication by R. Bastida-Zavala. This is a poorly known monotypic genus with unclear affinities. According to Rzhavsky (pers. comm.), Neomicrorbis belongs to the Spirorbidae (Paralaeospirinae) because of its incomplete chaetal inversion typical for spirorbins. Reproduction is unknown, which makes placement within spirorbins difficult. Zibrowius (1972a) regards it as something intermediate between a “serpulid” and a spirorbin.

Neomicrorbis azoricus Zibrowius, 1972a , Azores, St. Paul Island, West Indian Ocean .