Dorvilleidae (Annelida:Polychaeta) from the U.S. Atlantic slope and rise. Description of two new genera and 14 new species, with a generic revision of Ophryotrocha

Abstract

The present paper contains descriptions of 14 new species of dorvilleid polychaetes that are part of a highly diverse benthic infauna sampled on the U.S. Atlantic slope and rise between the Canadian border and South Carolina. Quantitative samples were taken with a Hessler‐Sandia box core during 18 cruises between 1983 and 1987. Samples were sieved through screens having a mesh opening of 300 μ. The newly described species belong to the genera Ophryorrocha. Exallopus. Parophryotrocha and two new genera, Pseudophryotrocha gen.n. and Anchidorvillea gen.n. An emended generic diagnosis of Ophryotrocha is provided to accommodate some of the new species, but also to include a group of atypical species described earlier by several authors who had modified the generic concept of Ophryotrocha without providing a formal emendation. The genus Ophryotrocha is revised to contain 31 species helonging to two species groups. A comparison of a suite of morphologic characters, however. indicates that these species addressed in this paper are discussed in the context of the entire family Dorvilleidae.

Polychaete systematics: Past and present

“…In the Capitellidae, new genera have been based on a combination of numbers of chaetigers with limbate chaetae and the total number of thoracic chaetigers (Fauchald 1972(Fauchald , 1977Amaral 1980) without any strictly synapomorphic characters named. In the Dorvilleidae, increased description of small-bodied species has yielded many new genera (Westheide 1982;Westheide & Riser 1983;Westheide & Nordheim 1985;Nordheim 1987;Hilbig& Blake 1991). In addition, the synonymization of two families (Dinophilidae and Iphitimidae) with the Dorvilleidae (Eibye-Jacobsen & Kristensen 1994) have had consequences that have yet to be analyzed, perhaps mostly because many of the species-rich genera (e.g.…”

Redescription of <em>Parophryotrocha isochaeta</em> (Eliason, 1962) and a new species of <em>Parophryotrocha</em> (Polychaeta: Dorvilleidae) from the Skagerrak and North Sea

“…Ophryotrocha, however, represents a large genus with high interspecific variability. At the present state of knowledge, it has not been possible to split the genus into more homogeneous subgroups (Hilbig and Blake, 1991;Eibye-Jacobsen and Kristensen, 1994). The generic separation among Ophryotrocha-like species in the wide sense is therefore unclear.…”

“…Hartmann-Schröder (1971) considered the lack of antennae, palps, parapodia and composite chaetae as diagnostic features of Parophryotrocha. Hilbig and Blake (1991) emended the diagnosis to encompass P. gesae which has antennae and distinct parapodia. The present redescription of P. isochaeta shows that palps and parapodial cirri are also present.…”

“…The chaetae are slimmer and more distinctly curved distally. Parophryotrocha gesae is distinguished by having simple chaetae of three types and mandibles with a serrated anterior margin (Hilbig and Blake, 1991).…”

“…1962) from the Norwegian part of the Skagerrak, and P. gesae Hilbig and Blake, 1991 from the US Atlantic slope. Recently, a third species of Parophryotrocha was collected during environmental monitoring in the northern North Sea.…”