Spirobranchus kraussii Baird 1865
Creators: name: Sun, Yanan
name: Ten, Harry A.
name: Qiu, Jian-Wen
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Annelida
Polychaeta
Sabellida
Serpulidae
Spirobranchus
Spirobranchus kraussii

description: Spirobranchus kraussii (Baird, 1865)
(Figure 13 A–F)
Placostegus cariniferus var. Kraussii Baird, 1865: 14.
Pomatoleios kraussii — Day 1967: 800 –801; Morton and Morton 1983: 88 –89; Wang and Huang 1993: 1 –12; Tan and Morton 1998: 392 –401; Fiege and Sun 1999: 130 –131; Sun and Yang 2001b: 213 –214; Ben-Eliahu and ten Hove 2011: 43 –45. Pomatoceros triqueter not (Linnaeus, 1758), Morton and Morton 1983: 77 (error for Pomatoleios kraussii).
Material examined. AM W41410, 10 specimens (22°21’N, 114°15’E, Hebe Haven, rocky intertidal, 0–1 m, May 25, 2009).
Description. TUBE: Tube white to blue, triangular in cross-section, with medial keel projecting into flap over the entrance. External tube diameter: from 1.9 mm to 2.4 mm (n=3, µ=2.2±0.3), lumen diameter from 1.5 mm to 2.0 mm (n=3, µ =1.8±0.3).
BRANCHIAE: radioles on each lobe arranged in circles, connected by interradiolar membrane for about one third of their length; numbers ranging from 21 to 26 (n=5, µ=23.4±1.9). Terminal filaments short. Branchial eyes not observed.
PEDUNCLE: subtriangular in cross-section, inserted just below left branchial lobe in all specimens. Pair of lateral wings proximal to opercular ampulla present, constriction not observed. Pseudo-operculum absent.
OPERCULUM: operculum slightly concave, talon absent. Opercular length from 3.8 mm to 4.6 mm (n=5, µ=4.3±0.3), width from 0.9 mm to 1.2 mm (n=5, µ=1.1±0.1).
COLLAR AND THORACIC MEMBRANES: collar high, with entire edge. Thoracic membranes forming apron across anterior abdominal chaetigers.
THORAX: with 6 chaetigers. Collar chaetae absent. Thoracic chaetae of two sizes, largest (limbate) finely serrated (Figure 13 A). Uncini along entire thorax saw-shaped, with 9 curved teeth and gouged fang (Figure 13 B). Tori of similar size along thorax, approaching each other posteriorly, leaving ventral depression.
ABDOMEN: total number of abdominal chaetigers varies from 68 to 86 (n=5, µ=78.8±0.2). Uncini sawshaped throughout, with 8 to 9 teeth and gouged peg (Figure 13 C, E–F). Chaetae true trumpet-shaped, abruptly bent, distally with two rows of denticles separated by a groove forming long pointed tip (Figure 13 D). Posterior abdominal capillaries absent.
SIZE: total worm length: 7.0 mm to 11.0 mm (n=5, µ=9.1±1.5), thoracic width: 1.5 mm to 1.8 mm (n=5, µ=1.7±0.1). Branchiae and operculum accounting for one fourth of entire length.
COLOUR: in ethanol operculum bluish, peduncle and wings light blue with dark blue pigmentation, branchial radioles banded blue and white, thorax and anterior abdomen blue, posterior abdomen colourless.
Habitat. Depth: 1 to 3 m, on rocks in higher intertidal zone.
Remarks. Spirobranchus kraussii has been reported as one of the dominant species in fouling communities in Hong Kong, forming intertidal aggregations (Wang and Huang 1993, as Pomatoleios kraussii).
Distribution. Widely distributed in the Indo-Pacific; South Africa; Lessepsian migrant to the Mediterranean Levant.
description: Published as part of Sun, Yanan, Ten, Harry A. & Qiu, Jian-Wen, 2012, Serpulidae (Annelida: Polychaeta) from Hong Kong, pp. 1-42 in Zootaxa 3424 on pages 28-30, DOI: 10.5281/zenodo.213363