Benirivulus
Owiyeye
Melanorivulus
Relationships and taxonomy of the killifish genus Rivulus (Cyprinodontiformes: Aplocheiloidei: Rivulidae) from the Brazilian Amazonas river basin, with notes on historical ecology.Abstract
Relationships among species of Rivulus endemic to the Brazilian Amazonas river basin are evaluated through an analysis of morphological characters, including terminal taxa representative of all Rivulus lineages. Based on the present morphological phylogeny and previous molecular analyses, seven sugenera are recognized: Rivulus, Cynodonichthys, Anablepsoides, Benirivulus n. subgen., Laimosemion, Owiyeye n. subgen., and Melanorivulus n. subgen. Benirivulus is diagnosed by a unique colour pattern and includes a single species, R. beniensis, from the Rio Madeira drainage; Owiyeye is diagnosed by the absence of dermosphenotic, a derived pattern of frontal squamation, and a colour pattern of the mandibular region, and includes species from the Amazonas and Orinoco river basins; Melanorivulus is diagnosed by the apomorphic morphology of preopercle, and derived colour patterns of male postorbital region and female unpaired fins, and includes species from southern Amazonian tributaries, Paraná-Paraguay river system, and Parnaiba and São Francisco river basins. Eighteen species from the Amazonas river basin of Brazil are recognized as valid: R. urophthalmus, R. taeniatus, R. micropus, R. ornatus, R. beniensis, R. strigatus and R. dibaphus, which are herein redescribed, and R. atratus, R. romeri, R. kirovskyi, R. uatuman, R. uakti, R. amanapira, R. tecminae, R. modestus, R. zygonectes, R. violaceus, and R. litteratus, described or redescribed recently. Field data indicate that species of different lineages included in the clade comprising Benirivulus, Laimosemion, Owiyeye, and Melanorivulus are found in different kinds of aquatic environments, suggesting a divergent evolution for habitat preference.
WJEM Costa
Aqua Journal of Ichthyology and Aquatic Biology 11: 133–175, 2006.