Abstract
Recently discovered male specimens of Phallotorynus pankalos are described and diagnosed from males of congener species on the basis of gonopodial morphology, color pattern and number of dorsal and anal-fin rays. The phylogenetic hypothesis of relationships among Phallotorynus species is reappraised with the inclusion of P. pankalos. Phallotorynus pankalos is hypothesized as sister to P. jucundus, a clade sister to P. victoriae or to a clade composed of P. dispilos and P. psittakos. Biogeography of Phallotorynus species is discussed, and it is suggested: (1) an early basal split between the rio Paraíba do Sul drainage and the Paraná-Paraguay system, separating P. fasciolatus from the ancestor of the remaining Phallotorynus species followed by a dispersal to rio Paraíba do Sul; (2) that the formation of the Sete Quedas falls may have isolated the ancestors of P. psittakos and P. dispilos. However, the sequence of events associated with the evolutionary history of Phallotorynus remains unclear and unsatisfactory.
Highlights
Phallotorynus Eigenmann, a genus of the cyprinodontiform Poeciliidae, is endemic to southern South American drainages of rio Paraíba do Sul, rio Paraná, and rio Paraguay
Male specimens of Phallotorynus pankalos can be distinguished from males of its congeners, except P. jucundus Ihering: (1) by the color pattern; (2) by the size of the lateral processes on the trowel-like appendix; (3) and by left and right halves of the trowel-like appendix united along its whole extension
Judging from its distribution, Lucinda et al (2005) speculated that P. pankalos was more closely related to the clade composed of P. victoriae, P. jucundus, P. dispilos, and P. psittakos, and originated in upper Paraná
Summary
Phallotorynus Eigenmann, a genus of the cyprinodontiform Poeciliidae, is endemic to southern South American drainages of rio Paraíba do Sul, rio Paraná, and rio Paraguay. Lucinda et al (2005) proposed Phallotorynus as monophyletic based on seven uniquely derived and unreversed synapomorphies of the cephalic sensory pore system, gonactinostal and gonopodium complexes. These authors recognized six valid Phallotorynus species describing three new species. The description of one of these species, Phallotorynus pankalos Lucinda, Rosa & Reis was based only on females because males were unavailable for study. For this reason, Lucinda & Reis (2005) did not include the species in their phylogenetic analysis of the subfamily Poeciliinae, which was based principally on male morphology. The aims of this paper are to formally describe male specimens of P. pankalos and to reappraise the phylogenetic hypothesis of relationships among Phallotorynus species with the inclusion of P. pankalos in the phylogenetic framework of Lucinda & Reis (2005)
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