A case of intersex occurrence in Steindachneridion parahybae (Siluriformes: Pimelodidae) under captivity condition: a cytogenetic and morphological study

PANDOLFI M; HONJI RENATO; LO NOSTRO F; CANNEPELE D; GUIMARAES MOREIRA R

NEOTROPICAL ICHTHYOLOGY

SOC BRASILEIRA ICTIOLOGIA

Lugar: Porto Alegre; Año: 2016

1679-6225

Little is known about reproductive biology of endangered Steindachneridion parahybae, a gonochoristic teleost speciesinhabiting the Paraíba do Sul River Basin, and herein is the first description of intersex in S. parahybae juvenile. The normalappearance of ovaries and testes in juvenile from the same lot of breeding were also described for comparison, even ascytogenetic analysis was performed in these juveniles. One specimen was a priori classified as female due to the macroscopiccharacteristic of ovaries, with small yellow oocytes, without fringes (a main characteristic of catfish male), and larger thantestes; however the microscopic analysis revealed the presence of ovotestes, including the complete spermatogenesis. S.parahybae had diploid number, 2n = 56 chromosomes with no evidence of differentiated sex chromosomes or supernumerarychromosomes among them. These findings may be due to the result of exposure to endocrine disrupting compounds or mayalso be influenced by environmental conditions. The possibility of intersexes might also happen spontaneously and it cannotbe ruled out. Therefore, the functional significance and reproductive consequences of this anomaly remain to be determined,suggesting that this species may be susceptible to endocrine disruption. These results contribute to gain expertise aboutreproductive biology of an endangered species in captivity