Streptodonta, San Martin & Hutchings, 2006

San Martin, G & Hutchings, PA, 2006, Eusyllinae (Polychaeta: Syllidae) from Australia with the Description of a New Genus and Fifteen New Species, Records of the Australian Museum 58, pp. 257-370 : 353

Genus Streptodonta n.gen.

Type species. Opisthodonta pterochaeta Southern, 1914 , herein designated.

Diagnosis. Body long, slender, tapered anteriorly and posteriorly, with numerous segments. Prostomium pentagonal to triangular, with 4 eyes and 2 anterior eyespots. Three antennae. Palps short, fused basally, triangular in shape. Nuchal organs as 2 ciliated grooves between peristomium and prostomium. Two pairs of tentacular cirri. Antennae, tentacular and dorsal cirri elongated, smooth, distally tapered. Ventral cirri triangular. Compound chaetae with translucent hood on margin, ornamented with several rows of minute spines. Dorsal simple chaetae with translucent hood. Ventral simple chaetae probably absent. Aciculae of several anterior parapodia distinctly enlarged. Pharynx and proventricle long, pharyngeal tooth located laterally and distinctly posteriorly, close to proventricle. Reproduction by epigamy.

Remarks. The species Opisthodonta pterochaeta differs in several characters from the emended diagnosis of Opisthodonta , such as having palps fused basally, pharyngeal tooth located laterally, extremely long pharynx and proventricle, and, also having enlarged aciculae on several anterior segments and with different types of chaetae. As suggested by Kudenov & Harris (1995), a new genus was needed for this species.

Streptodonta n.gen., is similar to Streptosyllis in having enlarged aciculae on some anterior parapodia, but differs in having a pharyngeal tooth, much longer pharynx and proventricle, and in the shape of the compound chaetae.

It is probably more closely related to Psammosyllis Westheide, 1990 , than to Opisthodonta , sharing with the former some unusual characters, such as the position of the pharyngeal tooth (see Westheide, 1990).

Etymology. The name of the new genus is a combination of the prefix streptos, from the Greek, meaning twisted, (in reference to Streptosyllis ), and the suffix donta, (in reference to Opisthodonta ), because it shares characters of both genera, thick, enlarged aciculae, like those present in Streptosyllis and a posterior pharyngeal tooth, like those present in Opisthodonta .