Spirobranchus Blainville, 1818

Sun, Yanan, Ten, Harry A. & Qiu, Jian-Wen, 2012, Serpulidae (Annelida: Polychaeta) from Hong Kong, Zootaxa 3424, pp. 1-42 : 28

Genus Spirobranchus Blainville, 1818

[including Pomatoceros Philippi, 1844 and Pomatoleios Pixell, 1913 fide Pillai (2009)].

Type-species: Serpula gigantea Pallas, 1766

Number of species: 35

Diagnosis. Tube white, blue, pink, sometimes salmon inside. Typically (sub)triangular in cross-section. Longitudinal keels may be present, hyaline granular layer absent. Operculum with inverse conical ampulla, covered by calcareous endplate, with or without processes. Peduncle broad with lateral wings, triangular in cross-section, inserted at base of branchial crown just left of median line. Pseudo-operculum absent. Radioles arranged in circles or in a spiral of up to 8 whorls, interradiolar membrane present, branchial eyes maybe present. Stylodes absent. 7 thoracic segments. Collar trilobed, tonguelets present. Thoracic membranes forming ventral apron across anterior abdominal segments. Collar chaetae usually bayonet type and narrowly limbate capillaries; sometimes limbate only or absent. Subsequent chaetae of two sizes, limbate and capillary. Apomatus chaetae absent. Uncini saw-shaped, anterior fang gouged, apparently rounded. Thoracic triangular depression present. Abdominal chaetae true trumpetshaped, abruptly bent, distally with two rows of denticles separated by a groove; uncini similar to thoracic ones but smaller. Achaetous anterior abdominal zone absent. Posterior capillary chaetae absent. Posterior glandular pad absent.