Estudo taxonômico das espécies de Myleinae (Characiformes: Serrasalmidae) dos trechos alto e médio do Rio Tocantins, com a descrição de uma nova espécie

Abstract

The subfamily Myleinae was initially proposed by Eigenmann, 1903 with the name Mylesinaeto house herbivorous serrasalmids. The subfamily Myleinae is comprised of nine genera [Acnodon Eigenmann 1903, Mylesinus Valenciennes 1850, Myleus Müller & Troschel 1844, Myloplus Gill 1896, Ossubtus Jégu 1992, Paramyloplus Norman 1929, Prosomyleus Géry 1972, Tometes Valenciennes 1850 and Utiaritichthys Miranda Ribeiro 1937] and 39 valid species. The present study morphologically analyzed the species of the subfamily Myleinae sensu Kolmann et al., 2020 from the upper and middle reaches of the Tocantins River basin, and diagnosed nine species for the studied stretch [Acnodon normani Gosline, 1951; Mylesinuspaucisquamatus Jégu & Santos, 1988; Myleus setiger Müller & Troschel, 1844; Myloplus arnoldi Ahl, 1936; Myloplus asterias Müller & Troschel, 1844; Myloplus rubripinnis Müller &Troschel, 1844; Tometes ancylorhynchus Andrade et al., 2016 and Tometes siderocarajensis Andrade et al., 2017] one not yet described (Myloplus sp. n “anal macula”). Of the nominal species diagnosed, four were originally described for the Tocantins-Araguaia basin [Acnodon normani, Mylesinus paucisquamatus, Tometes ancylorhynchus and Tometes siderocarajensis],and M. paucisquamatus and T. siderocarajensis are endemic to the Tocantins-Araguaia basin. T. ancylorhynchus and T. siderocarajensis were described for the lower portion of the basin, this being the first record of the two species in the upper and middle portions of the basin. An identification key for all diagnosed species is provided.