Pseudanos winterbottomi: A New Anostomine Species (Teleostei: Characiformes: Anostomidae) from Venezuela and Brazil, and Comments on Its Phylogenetic Relationships
Pseudanos winterbottomi n. sp. from the Orinoco drainage of Venezuela and the Tapajós drainage of Brazil resembles Pseudanos gracilis (Kner) in meristic and morphometric characters but differs from it in possession of a single midlateral stripe instead of a series of lateral spots, four branchiostegal rays instead of three, two pores on the sensory canal of the nasal instead of one, four pores on the sensory canal of the first infraorbital arranged in a square instead of three pores arranged in a line or shallow V, a dorsal process on the mesopterygoid that wraps around the posterior of the palatine (vs absence of such a process), the absence of a thin, posteriorly directed process on the ectopterygoid running ventral to the palatine (vs presence of such a process), a thick, blocklike palatine instead of a thinner, platelike palatine, and an almost completely closed metapterygoid/quadrate fenestra (vs an open fenestra). An updated key to the anostomine characiforms of the genera Anostomus, Gnathodolus, Pseudanos, Sartor, and Synaptolaemus is presented.
Pseudanos winterbottomi n. sp. de la cuenca del Orinoco en Venezuela y la cuenca del Tapajós en Brazil se parece a Pseudanos gracilis (Kner) en caracteres merísticos y morfométricos, pero se diferencia de esta especie por la posesión de una sola banda medio lateral en vez de una serie de motas laterales, cuatro radios branquiostegales en vez de tres, dos poros en el canal sensorial del nasal en vez de uno, cuatro poros en el canal sensorial del primer infraorbital ordenados en un cuadrado en vez de tres poros ordenados en una línea o una V poco profunda, un proceso dorsal del mesopterigoideo que se envuelve alrededor del extremo posterior del palatino (en contraste con la ausencia de tal proceso), la ausencia de un proceso delgado, dirigido posteriormente sobre el pterigoideo corriendo ventral al palatino (en contraste con la presencia de tal proceso), un grueso palatino, como un bloque en vez de un palatino mas delgado, como una placa, y una fenestra metapterigoideo/cuadrado casi completamente cerrada (en contraste con una fenestra abierta). Se presenta una clave actualizada para los caraciformes de los géneros Anostomus, Gnathodolus, Pseudanos, Sartor, y Synaptolaemus.Abstract
Pseudanos winterbottomi, holotype MBUCV 32210 (ex FMNH 104020), SL = 129.4 mm SL. Dotted lines mark presumed extent of undamaged fins
Lateral views, left infraorbital series of (A) Pseudanos gracilis, FMNH 103454, 81.6 mm SL, and right infraorbital series of (B) Pseudanos winterbottomi (paratype), FMNH 104020, 76.7 mm SL. Drawing in (B) reversed for ease of comparison with (A). The fusion of the left fourth and fifth infraorbital bones in the illustrated specimen of P. gracilis (A) is atypical and not diagnostic of the species. Dashed line in (A) indicates the typical division between the fourth and fifth infraorbital; dotted lines delineate areas of damage to the sixth infraorbital. The other available infraorbital series for this species also have atypical features (a supplementary canal, an extra pore, or an additional ossification) or are extensively damaged. Abbreviations: 1–6 = infraorbitals one to six (6 = dermosphenotic), ANT = antorbital, NAS = nasal, SUP = supraorbital
Venezuelan collection localities for Pseudanos winterbottomi and Pseudanos gracilis. For P. winterbottomi, holotype locality (Rio Ventuari) a black star, paratype localities black circles. Open circles represent material likely to belong to P. winterbottomi but not seen by the authors. Open circles are based upon an illustration and citation by Taphorn (1992, Rio Aguaro) or upon material at MBUCV identified by F. Provenzano and listed herein. Open squares indicate the Venezuelan collection localities of specimens of P. gracilis seen by the authors. Symbols sometimes represent multiple collection localities. Inset map by Marilyn Weitzman
The only known collection locality for Pseudanos winterbottomi in the Tapajós drainage of Brazil (marked by the arrow), on the Rio Jamanxim just before its confluence with the Tapajós. Inset map by Marilyn Weitzman
Lateral views of anterior suspensoria of (A) Pseudanos gracilis, FMNH 103454, 81.6 mm SL, and (B) Pseudanos winterbottomi (paratype), FMNH 104020, 76.7 mm SL. Drawings were prepared from dissections of the right side of the head and reversed for ease of comparison with published illustrations. Abbreviations: ECT = ectopterygoid, MES = mesopterygoid, MET = metapterygoid, PAL = palatine, PRE? = tubular ossifications around sensory canal anterior to preopercular canal, possibly homologous with part of preopercle in other species, QUAD = quadrate, SYM = symplectic. Dotted line in (A) delineates area of damage to the metapterygoid
Three possible phylogenetic placements of Pseudanos winterbottomi. After Winterbottom (1980)
Contributor Notes
(BLS) University of Chicago, Committee on Evolutionary Biology, 1025 East 57th Street, Culver Hall 402, Chicago, Illinois 60637 and Division of Fishes, Field Museum, 1400 South Lake Shore Drive, Chicago, Illinois 60605; and (GMS) Instituto Nacional de Pesquisas da Amazônia, av. andré Araújo, 2936, CX.P 478, BAirro Petrópolis, Manaus– am, 69060-001, Brazil. E-mail: (BLS) bls@uchicago.edu; and (GMS) gsantos@inpa.gov.br Send reprint requests to BLS.