Dasynema Saint-Joseph, 1894

Ten Hove, Harry A. & Kupriyanova, Elena K., 2009, Taxonomy of Serpulidae (Annelida, Polychaeta): The state of affairs, Zootaxa 2036, pp. 1-126 : 36-39

7. Dasynema Saint-Joseph, 1894

( Fig. 14)

Type-species: Serpula chrysogyrus Grube, 1876

Number of species: 1

Tube white, opaque, with some orange, semi-circular in cross-section, with peristomes and (5) irregular longitudinal keels. Hyaline granular overlay of the tube absent. Operculum with fleshy globular ampulla proximally, calcium carbonate infested chitinous cone distally. Peduncle smooth, without pinnules, broadly flattened, with unpaired basal wing for 2/3 rds of its length and paired small distal wings, separated from ampulla by constriction; inserted at the base of branchial crown below and between 1 st and 2 nd radioles. Pseudoperculum absent. Radioles arranged in two semi-circles and connected by short inter-radiolar membrane. Radioles with ocellar clusters and unpaired outwardly directed stylodes, up to 15 radioles per lobe ( Fig. 14A). Mouth palps not observed. 7 thoracic chaetigerous segments. Collar trilobed, tonguelets absent. Thoracic membranes ending at 5 th chaetiger, no apron. Collar chaetae limbate ( Fig. 14B). Apomatus chaetae present ( Fig. 14C). Thoracic uncini saw-shaped ( Fig. 14D), with numerous (approximately 17) teeth, anterior peg blunt (not gouged or pointed). Triangular depression present. Abdominal chaetae ( Fig. 14E) flat narrow geniculate with blunt teeth along blade ( Vermiliopsis type). Abdominal uncini saw-shaped anteriorly, with 11–12 teeth, posteriorly rasp-shaped with 2–4 rows of teeth, 14–15 teeth in profile ( Fig. 14G). Achaetous anterior abdominal zone absent. Posterior capillary chaetae present, very long ( Fig. 14F). Posterior glandular pad present.

Remarks. This relatively poorly known monotypic genus is recorded from the Indo-West Pacific (see Imajima & ten Hove 1984, Nishi 1993). Its characteristic feature, outwardly directed stylodes on the radioles, is unique for serpulids. Paired stylodes are found elsewhere only in the sabellid genera Branchiomma and Pseudobranchiomma . See also discussion by Imajima & ten Hove (1984).

Dasynema chrysogyrus ( Grube, 1876) , Japan, Philippine Islands, Ponape, Indonesia.