Rivulus duckensis (Teleostei; Cyprinodontiformes): New Species from the Tarumã Basin of Manaus, Amazonas, Brazil, and Its Relationship to Other Neotropical Rivulidae

A new killifish species, Rivulus duckensis, is described from the Reserva Adolpho Ducke, Manaus, Amazonas, Brazil. It is distinguished from other central Amazonian Rivulus species by maximum body size, adult color pattern, habitat preference and mitochondrial DNA sequences. Based on the phylogenetic analysis of molecular sequence data, our best hypothesis suggests that R. duckensis is sister taxon to a clade of Rivulus species occurring in the upper Río Orinoco basin, Amazonas state, Venezuela and Rivulus rectocaudatus, Amazonas department, Peru.

Resumen

Uma nova espécies de Rivulídeo, Rivulus duckensis, é descrita da Reserva Adolpho Ducke, Manaus, Amazonas, Brasil. A espécies se distingue de outras espécies de Rivulus amazônicos pelo tamanho máximo do corpo, pelo padrão de coloração nos adultos, pela preferência do habitat e pelas seqüências de DNA mitocondrial. Baseado em análises filogenéticas de dados de seqüências moleculares, nossa melhor hipótese sugere que R. duckensis é o táxon irmão do clado das espécies de Rivulus que ocorrem na bacia do Alto Rio Orinoco, no estado do Amazonas, Venezuela, e Rivulus rectocaudatus, na Amazonia peruana.

Fig. 1.

Distribution of representative members of the Guyana Shield clade of Rivulus used and discussed in phylogenetic analysis, and their geographic relationship to Rivulus duckensis n. sp

Fig. 2.

Rivulus duckensis, wild caught male from the type locality, about 19 mm SL. For a color photo, see www.cyprinodontiformes.org

Fig. 3.

Maximum likelihood estimate of phylogenetic relationships of the Rivulidae, and of Rivulus duckensis to other rivulid species. −ln L = 58615.49484, α = 0.701072, pinvar = 0.137588. Numbers above nodes represent Bayesian likelihood values; unlabeled nodes have values of at least 95%. Generic names of species from Hrbek and Larson (1999) are updated according to Costa (2003) with the exception of Rivulus obscurus keeping with the first reviser's (Huber, 1992) precedent. Rivulus duckensis as well as the two central Amazonian species (R. obscurus and Rivulus compressus), and Rivulus geayi (Rivulus strigatus) and R. geayi (Rivulus dibaphus) are highlighted in bold

Contributor Notes

(TH) Washington University School of Medicine, Department of Anatomy and Neurobiology, Campus Box 8108, 660 South Euclid Avenue, St. Louis, Missouri 63110; (CPD) Instituto Nacional de Pesquisas da AmazÔnia (INPA), CoordenaÇÃo de Pesquisas em Biologia AquÁtica (CPBA), CP 478, 69011–970 Manaus, AM, Brazil; (IPF) Universidade Federal do Amazonas, Departamento de Biologia, ICB, 69077-000 Manaus, AM, Brazil. (TH) hrbek@pcg.wustl.edu; (CPD) claudias@inpa.gov.br; and (IPF) izeni@argo.com.br Send reprint requests to TH.

Accepted: 28 Apr 2004