New Astyanax from the upper rio Tapajós drainage, Central Brazil (Characiformes: Characidae)

Abstract

Astyanax utiariti, new species, is described from the upper rio Tapajós drainage, Mato Grosso, Brazil. Astyanax utiariti has a horizontally oval black humeral spot, a lozenge-shaped caudal-peduncle spot, continuing to the tip of the middle caudal-fin rays, and two brown bars in the humeral region that allows its inclusion in the A. bimaculatus species group. It also possesses a black stripe extending along midlateral body. The new species is distinguished from its congeners by a reticulate scale pattern, a black longitudinal stripe, toothless maxilla, larger dentary teeth and teeth of the inner row of the premaxilla with five to seven cusps, body depth 33.3-39.9% of standard length (SL), head length (HL) 23.9-26.4% of SL, caudal-peduncle depth 12.0-13.4% of SL, orbital diameter 28.5-34.3% of HL, interorbital width 32.7-38.4% of HL, 36-38 perforated scales along the lateral line, and 22-26 branched anal-fin rays.Astyanax utiariti, nova espécie, é descrita da drenagem do alto rio Tapajós, Mato Grosso, Brasil. Astyanax utiariti tem uma mancha umeral preta horizontalmente ovalada, uma mancha losangular preta no pedúnculo caudal continuada até a extremidades dos raios caudais medianos e duas barras marrons na região humeral, que permite sua inclusão no grupo de espécies A. bimaculatus. Também possui uma faixa preta estendida ao longo do meio do corpo. A nova espécie distingue-se de suas congêneres pelo padrão reticulado nas escamas, uma faixa preta longitudinal, maxilar sem dentes, dentes maiores do dentário e dentes da série interna do pré-maxilar com cinco a sete cúspides, altura do corpo de 33,3-39,9% do comprimento padrão (CP), comprimento da cabeça (CC) de 23,9-26,4% do CP, altura do pedúnculo caudal 12,0-13,4% do CP, diâmetro orbital de 28,5-34,3% do CC, largura interorbital de 32,7-38,4% do CC, 36-38 escamas perfuradas ao longo da linha lateral e 22-26 raios ramificados na nadadeira anal.

Comparative morphology of gill glands in externally fertilizing and inseminating species of cheirodontine fishes, with implications on the phylogeny of the family Characidae (Actinopterygii: Characiformes)

“…Among taxa of Clade A, gill glands were found to be present on histological preparations by JRB (unpublished) in mature inseminating males of Creagrutus melasma and Monotocheirodon species, and in mature males of externally fertilizing species of the genera Bryconamericus, Caiapobrycon, Creagrutus, Cyanocharax, Hemibrycon, Hypobrycon, Knodus, Piabina, Rhinobrycon, and Rhinopetitia. The absence of a gill gland has been registered for some taxa belonging to Clade C of Javonillo et al (2010) and Oliveira et al (2011), further supporting this hypothesis: Astyanax utiariti by Bertaco & Garutti (2007) courensis by , Astyanax obscurus and A. laticeps by Bertaco & Lucena (2010), Ectrepopterus uruguayensis by Malabarba et al (2012) [see Thomaz et al, 2010 for the relationships of Ectrepopterus uruguayensis, formerly as Hyphessobrycon uruguayensis, with clade C taxa], Hasemania kalunga by , Hemigrammus tocantinsi by Carvalho et al (2010), Hemigrammus ora by , Hyphessobrycon melanostichos and Hyphessobrycon notidanos by Carvalho & Bertaco (2006), Hyphessobrycon vinaceus by , and Oligosarcus itau by Mirande et al (2011).…”

Redescription of Astyanax goyacensis Eigenmann, 1908 (Ostariophysi: Characiformes: Characidae)

“…Furthermore, A. goyacensis possesses a black stripe extending along midlateral body portion, deeper along caudal-peduncle and extending through medium caudal-fin-rays, more conspicuous in alcohol preserved specimens. These characteristics allow its inclusion in the putative "black lateral stripe" sub-group of the A. bimaculatus species complex, as recognized by Garutti (1999), which currently includes ten species (Bertaco & Garutti, 2007): A. argyrimarginatus Garutti, 1999, A. clavitaeniatus Garutti, 2003, A. goyacensis, A. incaicus Tortonese, 1942, A. novae Eigenmann, 1911, A. rupununi Fowler, 1914, A. saltor Travassos, 1960, A. siapae Garutti, 2003, A. unitaeniatus Garutti, 1998, and A. utiariti Bertaco & Garutti, 2007 In recent collections in the rio Vermelho 20 topotypes of A. goyacensis were captured which, along with the holotype and the five other topotypes previously collected, compose a good series to support the redescription presented herein.…”

Gill‐derived glands in species of Astyanax (Teleostei: Characidae)

“…When present, the gill-derived glands of all the species exam-ined by Oliveira et al (2012) had the same structure; therefore, these authors proposed that the glands were homologous, appeared in the phylogeny of the Characidae only once and had multiple reversions to absence. Oliveira et al (2012) interpreted their observations on the phylogenetic hypotheses by Javonillo et al (2010) and Oligosarcus itau (Carvalho and Bertaco 2006;Bertaco and Garutti 2007;Vera Alcaraz et al 2009;Bertaco and Lucena 2010;Carvalho et al 2010;Mirande et al 2011;Malabarba et al 2012). Based on that information, they considered the gill-derived glands as absent in the 'clade C' of the phylogenetic hypotheses of Javonillo et al (2010) and Oliveira et al (2011).…”

“…Oliveira et al . () cited published observations (most of them macroscopic) about the absence of a gill‐derived gland in Astyanax courensis, A. goyanensis, A. jordanensis, A. laticeps, A. obscurus and A. utiariti; Ectrepopterus uruguayensis; Hasemania kalunga; Hemigrammus ora, H. tocantinsi, Hyphessobrycon melanostichos, H. notidanos and H. vinaceus; and Oligosarcus itau (Carvalho and Bertaco ; Bertaco and Garutti ; Bertaco et al . , ; Vera Alcaraz et al .…”