PROC. BIOL. SOC. WASH. 97(4), 1984, pp. 792-800 GENERIC REVISION OF MASTOBRANCHUS AND PERESIELLA (POLYCHAETA: CAPITELLIDAE) WITH DESCRIPTIONS OF TWO NEW SPECIES FROM THE GULF OF MEXICO AND ATLANTIC OCEAN R. Michael Ewing Abstract.— Tv^o new species of capitellid polychaetes from the Gulf of Mexico and Atlantic Ocean are described: Mastobranchus variabilis and Peresiella spath-ulata. Emended diagnoses for these genera are proposed. Two species currently assigned to Mastobranchus, M. dollfusi Fauvel, 1936, and M. indicus Southern, 1921, are considered incertae sedis. Keys to the species of Mastobranchus Eisig, 1887, and Peresiella Harmelin, 1968, are presented. From 1975 to 1981 the Bureau of Land Management (BLM; now Mineral Management Services) funded several large scale benthic studies of the Gulf of Mexico outer continental shelf The polychaete fauna from these benthic collec-tions was examined in great detail in a taxonomic standardization program con-ducted by Barry A. Vittor and Associates, Mobile, Alabama; an atlas of Gulf of Mexico polychaetes was pubhshed by this firm in mid-1984. The BLM-OCS samples yielded numerous undescribed taxa in several polychaete families. Two of the new species of Capitellidae encountered during the polychaete standard-ization program are described in this paper; these capitellids were collected from the MAFLA (Mississippi, Alabama and Florida) and SOFLA (Southwest Florida) study areas. In the course of examining the BLM material, additional specimens of these new taxa were found in benthic samples collected by Interstate Electronics Corporation (lEC) at dredged material disposal sites off Florida, North Carohna, and Puerto Rico. Several specimens of one of these species, collected near Hutch-inson Island, Florida by the Florida Department of Natural Resources, were also examined. Description of these species necessitated generic revisions of Mastobranchus Eisig, 1887, and Peresiella Harmehn, 1968. The generic diagnoses and dichoto-mous keys provided in this paper reflect only adult characters. Type-specimens are deposited in the National Museum of Natural History (USNM), Smithsonian Institution, Washington, D.C., and the Allan Hancock Foundation (AHF), University of Southern Cahfomia, Los Angeles, California. Family Capitellidae Grube, 1862 Genus Mastobranchus Eisig, 1887, emended Type-species.— Mastobranchus trinchesii Eisig, 1887. Diagnosis.— i:\ior2iy. with achaetous peristomium and 11 setigerous segments. First setiger with or without neurosetae. Setigers 1-9 with capillary setae only; last 2 thoracic segments with capillary setae only or hooded hooks only. Two or
Generic Revision Of Mastobranchus And Peresiella (Polychaeta, Capitellidae) With Descriptions Of 2 New Species From The Gulf Of Mexico And Atlantic Ocean
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