Paraopisthosyllis Hartmann-Schröder, 1991

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 : 316-317

Genus Paraopisthosyllis Hartmann-Schröder, 1991

Paraopisthosyllis Hartmann-Schröder, 1991: 27 .

Type species. Opisthosyllis brevicirra Hartmann-Schröder, 1979 , designated by Hartmann-Schröder, 1991.

Diagnosis. Body robust, cylindrical, broad anteriorly, tapered posteriorly, with many segments. Dorsal and ventral surfaces covered with numerous, small papillae. Prostomium with 4 lensed eyes and 3 antennae. Palps broad, fused at base, ventrally folded. Peristomium shorter than subsequent segments, sometimes covered dorsally by chaetiger 1; 2 pairs of tentacular cirri. Nuchal organs as 2 ciliated grooves between prostomium and peristomium. Dorsal and ventral cirri on all chaetigerous segments. Antennae, tentacular, anal and dorsal cirri smooth, enlarged, club-shaped to foliaceous. Dorsal cirri usually provided with distinct cirrophores; on some species, dorsal cirri of anterior segments alternating in size between large and small ones, larger cirri arising more dorsally. Parapodia with compound, heterogomph chaetae, and dorsal and ventral simple chaetae on posterior parapodia. Pharynx wide, with pharyngeal tooth inserted far from anterior rim. Proventricle wide, voluminous. Pygidium small, with 2 anal cirri.

Remarks. According to Hartmann-Schröder (1991), this genus belongs to the Eusyllinae . It has some unusual morphological characters, however, such as the shape and arrangement of dorsal cirri, epidermal papillae, shape of pharynx and proventricle; its method of reproduction is unknown. It appears to be closely related to Rhopalosyllis , and therefore should be considered as a member of the subfamily Syllinae . Until its method of reproduction is determined, we are retaining it within the Eusyllinae according to its original designation. The genus is known only from Australia.

Key to Australian species of Paraopisthosyllis

1 Dorsal cirri inflated, club-shaped ( Fig. 50A) ................................................................................ 2

—— Dorsal cirri otherwise ..................................................................................................................... 3

2 Blades of some dorsal compound chaetae bidentate. Dorsal cirri alternating in size, larger ones located more dorsally than others ................. P. alternocirra n.sp.

—— All blades unidentate. Dorsal cirri all similar in size except those of chaetiger 1, inserted close to parapodial lobes ( Fig. 53A) ..................................... P. brevicirra

3 Some dorsal cirri foliaceous ( Fig. 55A). Pharyngeal tooth located on anterior half of pharynx ........................................................................................ P. phyllocirra

—— Anterior dorsal cirri provided with distal, digitiform button ( Fig. 54A). Pharyngeal tooth located on posterior half of pharynx .......................... P. ornaticirra n.sp.