PROC. BIOL. SOC. WASH. 103(3), 1990, pp. 525-542 MOOJENICHTHYS MIRANDA-RIBEIRO (PISCES: OSTARIOPHYSI: CHARACIDAE), A PHYLOGENETIC REAPPRAISAL AND REDESCRIPTION Ricardo M. C. Castro and Richard P. Van Abstract.— The Neotropical characiform characid genus Moojenichthys Mi-randa-Ribeiro is hypothesized to form a monophyletic lineage with Triportheus Cope on the basis of shared derived features of the pectoral girdle and perhaps of the first infraorbital. Autapomorphies for Moojenichthys are discussed. Moo-jenichthys myersi Miranda-Ribeiro, the only member of the genus, is rede-scribed. This species is apparently endemic to the Rio do Bra^o system of the state of Bahia, Brazil. Resumo. — Uma hipotese de relafoes filogeneticas reunindo em um so grupo monofiletico os generos neotropicais Moojenichthys e Triportheus, ambos per-tencentes a familia Characidae e a ordem Characiformes, e formulada com base na posse em comum de caracteres derivados na cintura escapular e, pos-sivelmente, primeiro infra-orbital. Moojenichthys myersi Miranda-Ribeiro, o unico membro do genero, e redescrito. Esta especie e, aparentemente, endemica da bacia do Rio do Brago, no estado da Bahia, Brasil, e consiste na unica ocorrencia de um representante da linhagem evolutiva Triportheus-Moojenich-thys nos rios costeiros do leste do Brasil, excluindo o rio Sao Francisco. Miranda-Ribeiro (1956:546) proposed the was "related" to Triportheus Cope (1872) characid genus Moojenichthys for a single and Clupeacharax Pearson (1924) both of species, M. myersi, first described in that which also have elongate, laterally com-publication on the basis of two specimens pressed bodies characterized by varyingly collected in the Rio do Bra90, near Ilheus developed mid-ventral keels. Miranda-Ri-in the state of Bahia of eastern Brazil. Af CO-beiro did not explicitly state which char-jenichthys myersi has a number of external acters lead him to propose that these species anatomical features unusual within the are "related," presumably closely. It seems Characiformes. Perhaps the most striking reasonable, nonetheless, to assume that the of these are its elongate, laterally flattened overall similarities in body shapes, partic-body, and the pronounced, laterally com-ularly the presence of mid-ventral keels, pressed mid-ventral keel. Although the tho-contributed significantly to this hypothesis, racic keel is not obvious in specimens of Despite the distinctive external mor-Moojenichthys under 15 mm SL, mid-to phology of Moojenichthys myersi, subse-large-sized individuals of the genus have a quent references to the genus and species distinct mid-ventral ridge extending from are extremely limited. Gery (1972:55), in the isthmus posteriorly to the origin of the his key to New World characiforms, com-pelvic fin. mented that Triportheus and Moojenichthys In his original description of Moojenich-are probably derived from Brycon Miiller thys Miranda-Ribeiro stated that the genus and Troschel, and on the next page pro-
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