PROC. BIOL. SOC. WASH. 101(3), 1988, pp. 503-508 SEMAPROCHILODUS VARII, A NEW SPECIES OF PROCHILODONTID FISH (OSTARIOPHYSI: CHARACIFORMES) FROM THE MAROWIJNE RIVER, SURINAM Ricardo M. C. Castro Abstract.— Semaprochilodus varii is described from localities in the lower and upper portions of the Marowijne River, Surinam. The species is distin-guished from all other Semaprochilodus species by its lower number of pored scales in the lateral-line (40 or 41). In addition the combination of the low lateral-line count and other meristic characters outlined in the text further distinguish 5. varii within the genus. Resumo.— Semaprochilodus varii, uma nova especie da familia Prochilo-dontidae, e descrita de duas diferentes localidades na bacia do rio Marowijne, Suriname. S. varii pode ser separada das outras especies do genero por possuir um baixo numero de escamas perfuradas na linha-lateral (40 ou 41). Alem disso, o baixo numero de escamas na linha-lateral em combina9ao com outros caracteres meristicos descritos no texto tambem distingue S. varii dentro do genero. During ongoing phylogenetic and revi-sionary studies of the family Prochilodon-tidae, specimens of a new species belonging to the genus Semaprochilodus Fowler were found in the collections of the American Museum of Natural History and the Insti-tuut voor Taxonomische Zoologie (Zoolo-gish Museum). The specimens originated in two different localities in the Marowijne River system in Surinam; one in the upper reaches and another near the mouth of the river, with the species presumably widely distributed throughout the basin. Semapro-chilodus specimens from the Marowijne River system were previously wrongly iden-tified as S. insignis (Schomburgk), due to the present confused state of prochilodontid taxonomy. Methods and materials. —The methods of counting and measuring specimens in this paper are those outlined in Fink & Weitz-man (1974:1-2). Standard length (SL) and other body measurements were taken in mm and are expressed as percentages of the stan-dard length or, in the case of subunits of the head, as percentages of the bony head length. Ranges of counts include all specimens, with the values in square brackets being those of the holotype. Counts of total vertebrate are from radiographs and include the four ver-tebrae of the Weberian apparatus, with the fused PU, +Ui of the caudal skeleton count-ed as a single element. All perforate lateral-line scales were counted. In counts of fin rays, lower case Roman numerals indicate unbranched fin rays, and Arabic numbers indicate branched fin rays. In the dorsal-fin ray counts the predorsal spine is treated as an unbranched ray. Tooth counts were tak-en from the left side of the jaws. Specimens examined for this study are deposited in the following institutions: American Museum of Natural History, New York (AMNH); Museu de Zoologia da Universidade de Sao Paulo, Sao Paulo (MZUSP); National Museum of Natural
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