Microlepidogaster dimorpha, a new species of Hypoptopomatinae (Siluriformes: Loricariidae) from the upper rio Paraná system

Abstract

Microlepidogaster dimorpha, new species, is described from tributaries of rio Grande, upper rio Paraná system. Microlepidogaster dimorpha differs from M. perforatus and M. longicolla by having first dorsal-fin proximal radial attached to the neural spine of seventh vertebra, with posterior portion contacting also the eighth centrum (vs. first dorsal-fin proximal radial attached to the neural spine of eighth or ninth vertebra in M. perforatus, and to the neural spine of tenth or eleventh vertebra in M. longicolla); 29-30 vertebrae (vs. 31 in M. perforatus and 31-33 in M. longicolla); 18-21 mid-dorsal plates (vs. 9-13 in M. perforatus, and 13-17 in M. longicolla); deeper caudal peduncle (10.0-11.4% in SL vs. 7.7-8.5% in M. perforatus, and 5.4-7.3% in M. longicolla); greater distance between dorsal-fin origin and anal-fin insertion (19.4-23.8% in SL vs. 16.4-18.8% in M. perforatus, and 14.7-16.2% in M. longicolla); and nostril width markedly wider in males than in females (vs. approximately equivalent in size for both sexes, slightly wider in males than in females in M. perforatus, and equivalent in size for both sexes in M. longicolla). Microlepidogaster dimorpha also differs from M. perforatus by presence of the iris operculum (vs. absence); median plate series complete to caudal peduncle end (vs. median plate series truncated, with last two plates of dorsal and ventral series contacting in midline); greater head depth (43.4-53.1% vs. 40.7-42.3% in HL); greater orbital diameter (13.6-18.5% vs. 11.1-13.5% in HL); pelvic-fin first unbranched ray longer in males than in females (vs. equivalent in size in both sexes); and supraneural without paired anterior processes (vs. processes present). Additionally, M. dimorpha can be distinguished from M. longicolla by having anterior margin of snout with a paired rostral plate (vs. snout with small plates, naked in the anterior margin); by pectoral-fin axillary slit present, even in adult specimens (vs. pectoral-fin axillary slit present only in juvenile specimens); longer pectoral-fin unbranched ray (20.0-23.8% vs. 13.4-16.2% in SL in M. longicolla).<br>Microlepidogaster dimorpha, espécie nova, é descrita de tributários do rio Grande, drenagem do alto rio Paraná. Microlepidogaster dimorpha difere de M. perforatus e M. longicolla por apresentar o primeiro radial proximal da nadadeira dorsal contactando o espinho neural da sétima vértebra, com sua porção posterior contactando também o oitavo centro vertebral (vs. primeiro radial proximal contactando o espinho neural da oitava ou nona vértebra em M. perforatus e o espinho neural da décima ou décima primeira vértebra em M. longicolla); 29-30 vértebras (vs. 31 em M. perforatus; e 31-33 em M. longicolla); 18-21 placas médio-dorsais (vs. 9-13 em M. perforatus, e 13-17 em M. longicolla); pedúnculo caudal alto (10,011,4% no comprimento-padrão vs. 7,7-8,5% em M. perforatus e 5,4-7,3% em M. longicolla); distância entre a origem da nadadeira dorsal e a inserção da nadadeira anal 19,4-23,8% no comprimento-padrão (vs. 16,4-18,8% em M. perf...

A new species of Hisonotus (Siluriformes, Loricariidae) from rio São Francisco basin, Brazil

“…Members of Loricariidae are known to have intense sexual dimorphisms (Py-Daniel and Fernandes 2005) as we can observe in species of the genera Ancistrus Kner, 1854 (Sabaj et al 1999), Neoplecostomus Eigenmann & Eigenmann, 1888 (Zawadzki et al 2008; Roxo et al 2012; Andrade and Langeani 2014), Pareiorhaphis Miranda Ribeiro, 1918a (Pereira et al 2007), Hisonotus (Martins and Langeani 2012), Hypostomus Lacepède, 1803 and Chaetostoma Tschudi, 1846 (Nomura and Mueller 1980; Lopez and Roman-Valencia 1996), Farlowella Eigenmann & Eigenmann, 1889 (Retzer and Page 1996) and many other. In Hisonotus vespuccii , we observed five sexual dimorphic characters: the presence of a papilla at the urogenital opening, a pelvic-fin that extends beyond the anal-fin origin, the unbranched pelvic-fin ray supporting a dermal flap on their proximal dorsal surface, the nares opening wider and a body size that seems to be smaller in males than in females.…”

“…In Hisonotus vespuccii , we observed five sexual dimorphic characters: the presence of a papilla at the urogenital opening, a pelvic-fin that extends beyond the anal-fin origin, the unbranched pelvic-fin ray supporting a dermal flap on their proximal dorsal surface, the nares opening wider and a body size that seems to be smaller in males than in females. The first three characters are very common among species of Hisonotus , however differences in size of nares were only previously reported in the original description of Hisonotus piracanjuba (Martins and Langeani 2012) and differences in body size in Hisonotus ringueleti (Aquino et al 2001). Carvalho and Reis (2009) reported that the presence of the dermal flap on proximal dorsal surface of pelvic-fin on males is a plesiomorphic character shared among most members of Otothyrinae and that the derived condition evolved several times within this subfamily at the genera Schizolecis Britski & Garavello, 1984, Epactionotus Reis & Schaefer, 1998, and within Hypoptopomatinae in Acestridium Haseman, 1911, Oxyropsis Eigenmann & Eigenmann, 1889 and Hypoptopoma Günther, 1868.…”

A new species of the armored catfish genus Pareiorhaphis Miranda Ribeiro (Siluriformes: Loricariidae) from the rio Paraguaçu, Bahia State, northeastern Brazil

“…2) at the midline of lower lip, immediately behind the dentaries (vs. papillae not elevated in a bump). This feature also occurs in the hypoptopomatine Hisonotus insperatus, which possesses a distinct median series of papillae at the midline of lower lip behind to the dentaries, arranged in a bump (Britski & Garavello, 2003;Martins & Langeani, 2012). Despite of these similar morphology, H. insperatus and P. lophia are relatively distant phylogenetically and these features are likely convergent.…”

Redescription of Hisonotus notatus Eigenmann & Eigenmann, 1889 (Loricariidae: Hypoptopomatinae), the type species of the genus, and description of a new species from coastal drainages of southeastern Brazil

“…Measurements were made with digital calipers, pointto-point, on the left side of the specimens to the nearest 0.1 mm, following Martins & Langeani (2011), with the addition of the following measurements: cleithral width, body width at widest point of pectoral girdle; body depth at dorsal-fin origin; and nasal chamber length, between the anterior and posterior edges of the nostril. Morphometric data were expressed as percents of standard length (SL), except for measurements related to the head, which were given as percents of head length (HL).…”