New species and records of Uncispionidae and Pygospiopsis (Polychaeta, Spionida) from deep water off the east and west coasts of North America, the Gulf of Mexico, the Antarctic Peninsula, and Southeast Asia.

Five new species and one new genus of the obscure spioniform family Uncispionidae are described together with three new species of the rare and unusual spionid genus Pygospiopsis Blake, 1983. All species are from offshore habitats with most from deep-sea continental slope depths. Among the Uncispionidae are the second and third species of the genus Uncopherusa Fauchald Hancock, 1981, collected from off Brunei in the South China Sea and off Louisiana in the Gulf of Mexico; two new species of Uncispio Green, 1982, the third and fourth to be described, from deep water off the U.S. Atlantic coast and the Gulf of Mexico; and a new species of a new genus, Rhamphispio n. gen., from off the U.S. Atlantic coast. All species of Uncispionidae are compared and a key to the known species is presented. The genus Pygospiopsis Blake, 1983, is currently known for only two species: P. dubia (Monro, 1930) from Antarctic and sub-Antarctic waters and P. occipitalis Blake, 1996, from shelf depths off southern California. In the present study, new collections of the type-species P. dubia from the Antarctic Peninsula include post-larvae and juveniles as well as adults, thus permitting documentation of the development of some key adult morphology. Three new species of Pygospiopsis are described from deep water off the U.S. Atlantic and Pacific coasts and from the Antarctic Peninsula. A review of all species of Pygospiopsis suggests that, based on branchial distribution patterns, the closely related Pseudatherospio fauchaldi Lovell, 1994, should be referred to Pygospiopsis, bringing the total known species to six. All of these are compared and contrasted and the generic definition of Pygospiopsis updated. The status of Pygospiopsis within the Spionidae relative to the closely related genus Atherospio Mackie Duff, 1986, is discussed.

Bitentaculate Cirratulidae (Annelida, Polychaeta) collected chiefly during cruises of the R/V Anton Bruun, USNS Eltanin, USCG Glacier, R/V Hero, RVIB Nathaniel B. Palmer, and R/V Polarstern from the Southern Ocean, Antarctica, and off Western South America.

Forty-one species in five genera of bitentaculate cirratulids are reported from new collections from South America, the Southern Ocean, and seas around Antarctica. Twenty-seven species are new to science; one new genus is described to deal with some species formerly identified as Chaetozone. New records, synonymies, and new combinations are reported. Previous records are reviewed with type specimens of most species reexamined and redescribed. The sub-Antarctic species Aphelochaeta cincinnata (Ehlers, 1908) does not occur in Antarctica: the numerous published records of this species instead belong to several new species. The types of Tharyx epitocus Monro, 1930, and Tharyx fusiformis Monro, 1939, have spines in posterior setigers and are referred to other genera. Among the 41 species treated in this study, 11 belong to Aphelochaeta, eight are new; eight species belong to Caulleriella, six are new; six species belong to Chaetocirratulus n. gen., three are new; 12 species belong to Chaetozone, seven are new; and four species belong to Tharyx, three are new. Numerous samples come from slope and abyssal depths, expanding our knowledge of the distribution of Southern hemisphere deep-sea cirratulids.

Polychaeta Orbiniidae from Antarctica, the Southern Ocean, the Abyssal Pacific Ocean, and off South America.

The orbiniid polychaetes chiefly from Antarctic and subantarctic seas and off South America are described based on collections of the National Museum of Natural History and new material from surveys conducted by the United States Antarctic Program and other federal and privately funded sources as well as participation in international programs. A total of 44 species of Orbiniidae distributed in 10 genera are reported from the Pacific Ocean and waters off South America and Antarctica. Twenty-one species are new to science; one species is renamed. Berkeleyia heroae n. sp., B. abyssala n. sp., B. weddellia n. sp.; B. hadala n. sp., Leitoscoloplos simplex n. sp., L. plataensis n. sp., L. nasus n. sp., L. eltaninae n. sp., L. phyllobranchus n. sp., L. rankini n. sp., Scoloplos bathytatus n. sp., S. suroestense n. sp., Leodamas hyphalos n. sp., L. maciolekae n. sp., L. perissobranchiatus n. sp., Califia bilamellata n. sp., Orbinia orensanzi n. sp., Naineris antarctica n. sp., N. argentiniensis n. sp., Orbiniella spinosa n. sp., and O. landrumae n. sp. are new to science. A new name, Naineris furcillata, replaces N. chilensis Carrasco, 1977, a junior homonym of N. dendtritica chilensis Hartmann­Schröder, 1965, which is raised to full species status. Leodamas cochleatus (Ehlers, 1900) is removed from synonymy and redescribed. A neotype is established for Leodamas verax Kinberg, 1966, the type species. A general overview of Leodamas species is provided. The Leitoscoloplos kerguelensis (McIntosh, 1885) complex is reviewed and partially revised. Definitions of the genera of the Orbiniidae are updated to conform to recently described taxa. Several new synonymies are proposed following a reexamination of previously described type specimens. The morphological characters used to identify and classify orbiniids are reviewed. The biogeographic and bathymetric distributions of the South American and Southern Ocean orbiniid fauna are reviewed.

Aphelochaeta (Polychaeta: Cirratulidae) from the Pacific coast of Costa Rica, with a description of five new species.

Five new species of bitentaculate Cirratulidae belonging to the genus Aphelochaeta are herein described from the Pacific coast of Costa Rica, all from shallow subtidal depths. Aphelochaeta antelonga sp. nov. is characterized by a long biannulate peristomium and fibrillated capillary setae and is from 11-18 m in the Gulf of Nicoya. Aphelochaeta guimondi sp. nov., with a wide dorsal trough in the thorax and hirsute capillaries (visible using SEM), is described from 11-26 m in the Gulf of Nicoya. Aphelochaeta praeacuta sp. nov., with its first peristomial annulation extending as a dorsal crest over the second annulation and first setiger, was collected from 11-28 m in Bahia Culebra. Aphelochaeta striata sp. nov., collected from 11-28 m in the Gulf of Nicoya, is recognized by its narrow body and the transverse blue stripes across the venter of setigers 5-8 produced with methyl green stain. Aphelochaeta zebra sp. nov., collected from a coral reef in Golfo Dulce, is characterized by its expanded posterior end and the darkly staining intersegmental regions using methyl green stain. Additionally, A. glandaria Blake, 1996, a species reportedly with a widespread geographic distribution (Blake, 1996), was also encountered subtidally from the Gulf of Nicoya and Golfo Dulce.

The Orbiniidae (Annelida: Polychaeta) of Pacific Costa Rica.

Seven species of Orbiniidae are described from the Pacific coast of Costa Rica including two new species. Leodamas hamatus n. sp., a commonly occurring species on the coast of Pacific Costa Rica, is described from 11‒18 m in the Gulf of Nicoya and Bahia Culebra. This species is unusual in that the neuropodial uncini differ morphologically from anterior to posterior in the thorax. Scoloplos cryptospinigerus n. sp. is described from 18-22 m in the Gulf of Nicoya and has only a few short, toothed spines amidst numerous capillary setae in most of the thoracic neuropodia. This arrangement of thoracic neurosetae is unusual and has been seen only in one other described species of Scoloplos from Australia.