Two new species of Knodus (Characidae: Stevardiinae) from the upper rio Tocantins basin, with evidence of ontogenetic meristic changes

Autor(es)

Gabriel de Carvalho Deprá ^[1] ; Renata Rúbia Ota ^[2] ; Oscar Barroso Vitorino Júnior ^[3] ; Katiane Mara Ferreira ^[4]

Afiliação do(s) autor(es)

^[1] Universidade Estadual de Maringá. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais - Brasil

^[2] Universidade Estadual de Maringá. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais - Brasil

^[3] Universidade Estadual de Maringá. Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais - Brasil

^[4] Universidade Federal de Mato Grosso. Instituto de Biociências. Departamento de Biologia e Zoologia - Brasil

• Tipo de documento: Artigo Científico
• Fonte: Neotropical Ichthyology; v. 19, n. 1 2021-03-08.

Resumo

ABSTRACT Two new species from the upper rio Tocantins basin are described in Knodus based on the traditional definition of the genus. The new species are distinguished from other congeners by meristic and morphometric characters, such as the number of cusps in the premaxillary and dentary teeth, the number of scale series between dorsal-fin origin and lateral line, the orbital diameter and the body depth. With the two new species, the number of endemic species in the upper rio Tocantins basin upstream of the mouth of the rio Paranã, rises to 53 (89 to the confluence with rio Araguaia). The existence of a meristic character that changes through ontogeny (allomery), viz. the number of scale series between dorsal-fin origin and lateral line, was detected in some species of Knodus through a regression analysis. Additionally, this paper describes an unambiguous, more informative and precise new method for counting vertebrae, which will enhance the efficacy of this trait in species comparisons. (AU)

• Processo FAPESP: 02/05464-0 - Análise filogenética e revisão taxonômica do gênero Knodus Eigenmann, 1910 (Characiformes: Characidae)
• Beneficiário: Katiane Mara Ferreira
• Modalidade de apoio: Bolsas no Brasil - Doutorado