Taxonomic assessment of Leptodoras (Siluriformes: Doradidae) with descriptions of three new species

Abstract

The genus Leptodoras Boulenger is a monophyletic assemblage of at least ten species distributed in large, predominantly lowland rivers throughout the northern half of cis-Andean South America. Leptodoras is diagnosed in Doradidae (thorny catfishes) by unique morphologies of the oral hood (upper labial extensions distinct with comparatively smooth ventral surface, lateral margins of extensions entire, weakly scalloped or fimbriate and without marginal papillae, and interlabial membranes of narrow or moderate width), first gill arch (enlarged accessory lamellae extend well onto medial face of gill filaments), and gas bladder (reduced size and modified cordiform shape, two distinct horn-like diverticula project from posterior walls of posterior chambers, and a pair of bulbous diverticula project from lateral walls of anterior chamber). Examination of specimens of Leptodoras from throughout its range verified the distinctiveness of the seven nominal species (L. acipenserinus, L. copei, L. hasemani, L. juruensis, L. linnelli, L. myersi and L. praelongus) and revealed three new species described herein (Leptodoras nelsoni, L. rogersae, and L. cataniai). A lectotype for L. hasemani is designated.<br>O gênero Leptodoras Boulenger é um agrupamento monofilético com pelo menos dez espécies, distribuídas em rios grandes e predominantemente de terras baixas na metade norte da região cis-Andina da América do Sul. Leptodoras é diagnosticado em Doradidae pelas morfologias únicas da região bucal (extensões labiais superiores distintas com superfície ventral comparativamente lisa, margens laterais destas extensões inteiras, fracamente franjadas ou fimbriadas e sem papilas marginais, e membranas interlabiais estreitas a moderadamente largas), do primeiro arco branquial (lamellas acessórias aumentadas, extendendo-se pela face medial dos filamentos branquiais), e da bexiga natatória (tamanho reduzido e formato cordiforme modificado, dois divertículos em forma de guampas projetando-se das paredes posteriores das câmaras posteriores, e um par de divertículos bulbosos projetando-se das paredes laterais da câmara anterior). O exame de exeplares de Leptodoras em sua área de distribuição permitiu a distinção de sete espécies nominais (L. acipenserinus, L. copei, L. hasemani, L. juruensis, L. linnelli, L. myersi e L. praelongus) e revelou três espécies novas, descritas aqui (Leptodoras nelsoni, L. rogersae, e L. cataniai). É designado um lectótipo para L. hasemani

Phylogenetic relationships of the South American Doradoidea (Ostariophysi: Siluriformes)

“…As previously discussed by several authors (Higuchi, 1992: #A07, #A08;Sabaj, 2002: #8, #9, #10, #11;Sabaj, 2005;Birindelli et al, 2008;Birindelli & Sousa, 2010), the labial membrane in the doradids Anduzedoras and Leptodoras is expanded posteriorly and incorporates the bases of mental barbels forming the so-called oral hood (Fig. 6c;Sabaj, 2005: fig.…”

“…Taxonomic nomenclature follows the most recent classification of the Siluriformes as summarized by Ferraris (2007), Eschmeyer (2014) and Lundberg et al (2014), and includes Doradoidea (=Doradidae plus Auchenipteridae),to Oxydoras niger; †Doras dionae, a fossil species recently diagnosed by Sabaj-Pérez et al (2007) on the basis of a partial pectoral girdle; Doras micropoeus and D. zuanoni, two of the five valid extant species of Doras, recently revised by ; Hassar shewellkeimi and H. wilderi, two of the five valid species of Hassar, also recently revised Sabaj-Pérez & Birindelli, 2013); eight of the 12 species of Leptodoras, also recently revised (Sabaj, 2005;Birindelli et al, 2008;Birindelli & Sousa, 2010); Acanthodoras depressus and A. spinosissimus, two of three species of the genus, in need of a taxonomic revision; Agamyxis pectinifrons, one of two species of Agamyxis, recently revised (Sousa, 2010); and all Astrodoradinae, except Astrodoras asterifrons, Scorpiodoras heckelii, and Anadoras grypus, a subfamily under study by Leandro Sousa (UFPA) (see Sousa, 2010 for unpublished results). On the other hand, an intriguing undescribed species of Platydoras was included because it possesses characters of both Platydoras (color pattern) and Centrochir (gas bladder morphology, see Birindelli et al, 2009).…”

“…5). The oral hood is more developed in distal species of Leptodoras (Sabaj, 2005;Birindelli et al, 2008), but it is also present in Anduzedoras and basal most species of Leptodoras. In all other examined catfish, the aforementioned modification is absent.…”

“…Arce et al (2013) performed a comprehensive phylogenetic analysis based on molecular data for 86 species of Doradidae, using both nuclear and mitochondrial gene sequences. Sabaj (2002) and Sabaj & Ferraris (2003) compiled monographic data for all nominal doradids and resolved a number of taxonomic issues; their classification recognized 72 valid species in 30 genera. Since then, the taxonomic knowledge of the family has greatly increased.…”

“…Sousa & Rapp Py-Daniel (2005) revised Physopyxis, describing two new species. Sabaj (2005) revised Leptodoras, describing three species as new. Two years later, Birindelli et al (2007) described Rhynchodoras castilloi from Venezuela; Higuchi et al (2007) described a new genus and species, Merodoras nheco; and Sabaj Pérez et al (2007) described †Doras dionae, the only named fossil species.…”