Odontosyllis Claparède, 1863

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 : 281-282

Genus Odontosyllis Claparède, 1863

Odontosyllis Claparède, 1863: 47 .

? Eurymedusa Kinberg, 1865: 61 .

Parautolytus Ehlers, 1900: 213 .

? Alluaudella Gravier, 1905: 372 .

? Atelesyllis Pruvot, 1930: 39 .

Pharyngeovalvata Day, 1951: 26 .

Odontoautolytus Hartmann-Schröder, 1979: 112 .? Synpalposyllis Hartmann-Schröder, 1983: 132.

Umbellisyllis Sars, 1869: 254 .

Type species. Syllis fulgurans Audouin & Milne Edwards, 1833 , designated by Hartman, 1959.

Diagnosis. Body of variable size, from <5 mm to> 10 mm in length, with numerous segments, cylindrical, dorsally highly convex, flattened ventrally. Prostomium with 4 eyes and, sometimes, pair of anterior eyespots. Three antennae. Palps broad, free for almost all their length, fused basally. Peristomium usually reduced dorsally; 2 pairs of tentacular cirri. Occipital flap present, usually well developed, covering peristomium dorsally and prostomium partially. Nuchal organs as 2 ciliated grooves between prostomium and peristomium, extending sometimes to lateral areas of prostomium. Dorsal cirri elongated, smooth, distally tapered, but sometimes short or indistinctly articulated. Parapodia usually with pre- and postchaetal lobes. Ventral cirri digitiform to pillow-shaped. Compound chaetae heterogomph, usually with shafts distally spinose. Dorsal and ventral simple chaetae present on some parapodia. Pharynx short, distinctly shorter than proventricle, provided with several teeth, usually few, pointing backwards, pharyngeal mid-dorsal tooth absent; pharynx when not everted situated posteriorly to chaetiger 1, inside tube that leads to mouth opening on peristomium. Proventricle usually long and wide, massive. Pygidium with 2 anal cirri. Reproduction by epigamy; epigamic specimens sometimes strongly modified and phosphorescent ( Fischer & Fischer, 1995; Gaston & Hall, 2000).

Remarks. The structure of the anterior part of the gut in this genus is distinct and unusual, with the pharynx being short and the opening located posteriorly to the mouth; a tube is present that surrounds the pharynx and that leads to the mouth. This must be removed to see the trepan and the two lateral plates of the pharynx. Occasionally specimens lack any teeth on the trepan, and we suggest that individuals can regenerate these teeth. The genera that we have synonymized with Odontosyllis have been inadequately examined previously with regard to the structure of the anterior part of the gut. For example, GSM examined one paratype of Pharyngeovalvata natalensis (BMNH 1961.16.16-17, Natal Shore, South Africa Stn. 47.8, coll: J.H. Day) and it is identical to specimens of Odontosyllis ctenostoma Claparède, 1868 . Both species possess a pharynx with a trepan; even though the description of the pharynx of Pharyngeovalvata by Day (1951) states that the pharynx lacks a trepan, the paratype possesses one. We therefore have synonymized these two species that are the type species of their respective genera and Pharyngeovalvata is synonymized with Odontosyllis . We suspect that Atelesyllis Pruvot, 1930 , is also identical to Odontosyllis with the pharynx contracted, but the types appear to be lost. We have also examined the holotype of Synpalposyllis australiensis Hartmann-Schröder, 1983 (HZM P-17400), a species known only from the holotype, which is less than 5 mm in length, with the prostomium and the anterior part of the pharynx damaged so it is not possible to verify the presence or absence of the palps, but the chaetae and aciculae are similar to those of O. australiensis . In our opinion, this specimen may be a juvenile of O. australiensis . Types of Alluaudella madagascariensis Gravier, 1905 were not available for examination but this species appears to be related to some species of Odontosyllis with short dorsal cirri and indistinct ventral cirri, distally located, and partially fused, appearing as absent, although this should be checked on material from the type locality. We have examined type material of the other species of the genus, Alluaudella longicirrata Mohammad, 1973 , and it is clearly a species of Odontosyllis . We suggest that it is likely that the genus Alluaudella should be synonymized with Odontosyllis , and it certainly does not belong in the subfamily Autolytinae where it has previously been placed ( Gravier, 1905).

The key below includes nine species, an additional two species have been reported from Australia, but they are not included in the key. Odontosyllis hyalina Grube, 1878 , was reported by Hartmann-Schröder (1990); and we have examined the specimen (HZM P-20185) and it is a small, probably a juvenile specimen, belonging to O. australiensis ; the original description ( Grube, 1878) is based on a single, epigamic specimen (MPUW, 325), in poor condition, but the compound chaetae are similar to those of O. australiensis but the shafts are proportionally larger, the blades are shorter, some of them almost unidentate. Haswell (1920) reported two specimens of Odontosyllis suteri Benham, 1915 , from Port Jackson, Sydney, as the type description from New Zealand specimens is incomplete and no details of the chaetae are given it is therefore difficult to verify Haswell’s identification, and we suggest that they may represent individuals of Odontosyllis polycera . So neither of these records of O. hyalina and O. suteri from Australia are likely to be valid.