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| Astyanax varii Zanata, Burger, Vita & Camelier, 2019 |
ABSTRACT
A new species of Astyanax from tributaries of the rio de Contas, Bahia, Brazil, is described. The new species differs from congeners by having three horizontal series of scales from lateral line to pelvic-fin origin and the distal margin of third infraorbital distinctly separated from vertical and horizontal limbs of preopercle, leaving a broad area not covered by superficial bones. The new species further differs from most congeners by the presence of bony hooks on all fins of mature males. Particularly from congeners occurring in rivers of the Northeastern Mata Atlântica freshwater ecoregion, it further differs by having the highest body depth just anterior to the dorsal-fin origin, 34-37 pored lateral line scales, a vertically elongated conspicuous dark humeral blotch reaching below the lateral line and a conspicuous dark wide midlateral stripe extending from the clear area on the rear of the humeral blotch to the end of middle caudal-fin rays and forming an inconspicuous blotch on caudal peduncle.
Keywords: Endemism; Northeastern Mata Atlântica freshwater ecoregion; Sexual dimorphism; Taxonomy
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| Astyanax varii, Brazil, Bahia State: (a) MZUSP 121062, holotype, 41.4 mm SL,Ubaitaba, lower rio de Contas basin, rio Coricó; (b) live paratype, not catalogued. |
Astyanax varii, new species
Astyanax sp. 6.-Camelier, Zanata (2014):686, tab. 1 [listed; species from the Northeastern Mata Atlântica freshwater ecoregion].
Astyanax sp.-Barreto et al. (2018): 1158 [citation; co-occurence with Nematocharax varii].
Diagnosis. Astyanax varii can be distinguished from most congeners, except A. brachypterygium Bertaco & Malabarba, A. brucutu, A. cremnobates Bertaco & Malabarba, A. epiagos, A. eremus Ingenito & Duboc, A. gymnogenys Eigenmann, A. rupestris Zanata, Burger & Camelier, A. taeniatus (Jenyns), A. totae Haluch & Abilhoa, and A. varzeae Abilhoa & Duboc, by having the distal margin of third infraorbital distinctly separated from vertical and horizontal limbs of preopercle (Fig. 2), leaving a broad area without superficial bones (vs. margins of the third infraorbital close to the limbs of preopercle, with narrow or no space between the two bones). The new species differs from the aforementioned species by having three horizontal series of scales from the lateral line to the pelvic-fin origin (vs. four or more series of scales) and by having small bony hooks on all fins of mature males (vs. bony hooks absent or not present on all fins of mature males). Astyanax varii also differs from the species listed above by having highest body depth approximately at vertical through dorsal-fin origin (vs. body deepest on a vertical through middle or posterior portion of pectoral fin in A. brachypterygium, A. cremnobates, A. epiagos, A. eremus, A. gymnogenys, A. rupestris, A. totae, and A. varzeae), five horizontal series of scales from the dorsal-fin origin to the lateral line (vs. six or more in A. brachypterygium, A. brucutu, A. cremnobates, A. eremus, A. rupestris, A. totae, A. taeniatus, and A. varzeae), 14 horizontal scale rows around caudal peduncle (vs. 15 or more in A. brachypterygium, A. eremus, A. gymnogenys, and A. totae), and 34-37 pored lateral line scales (vs. 38 or more in A. eremus, A. gymnogenys, and A. taeniatus).
Etymology. The specific name varii is in honor to the ichthyologist Richard P. Vari for his friendship, mentoring, and outstanding contribution to the systematic of South American freshwater fishes.
Angela Maria Zanata, Rafael Burger, eorge Vita and Priscila Camelier. 2019. A New Species of Astyanax (Characiformes: Characidae) from the rio de Contas basin, Bahia, Brazil. Neotropical Ichthyology. 17(3) DOI: 10.1590/1982-0224-20190061
RESUMO: Uma espécie nova de Astyanax de tributários do rio de Contas, Bahia, Brasil, é descrita. A espécie nova difere das congêneres por ter três séries horizontais de escamas entre a linha lateral e a origem da nadadeira pélvica e margem distal do terceiro infraorbital distintamente separada dos ramos vertical e horizontal do pré-opérculo, deixando uma ampla área sem ossos superficiais. A espécie nova difere, ainda, da maioria das congêneres pela presença de ganchos ósseos em todas as nadadeiras de machos maduros. Particularmente das congêneres que ocorrem nas drenagens da Ecorregião Mata Atlântica Nordeste, difere ainda por ter a maior altura do corpo imediatamente anterior à origem da nadadeira dorsal, 34-37 escamas perfuradas na linha lateral, presença de uma mancha umeral conspícua, verticalmente alongada, ultrapassando ventralmente a linha lateral e uma faixa escura mediana lateral larga, estendendo-se da área clara após a mancha umeral até o fim dos raios medianos caudais e formando uma mancha inconspícua no pedúnculo caudal.
Palavras-chave: Dimorfismo sexual; Ecorregião Mata Atlântica Nordeste; Endemismo; Taxonomia