Morphology and dynamics of male gametogenesis in Sympterygia bonapartii (Chondrichthyes, Rajidae) from Northern Patagonia

Abstract

ABSTRACT. The smallnose fanskate, Sympterygia bonapartii Müller & Henle, 1841 is one of the most disembarked items in commercial harbors in Argentina. In this work, the microscopic architecture of mature male gonads and the dynamics of cysts development are analyzed as a contribution to awareness of the reproductive biology of the species. Some biological data related to reproduction are given as well. Two seasons were sampled (fall and spring) and length classes's frequency distribution and maturity stages frequency distribution are given. Size at first sexual maturation for males was estimated at 57 cm of total length. Testes are symmetric, peer, lobed, with several germinal zones. Inside the gonads, there are many spermatocysts, containing reproductive cells at the same developmental stage. On the basis of their cytological and microanatomical features, several maturative degrees of the spermatogenic series were differentiated. Few Leydig cells were recognized at the interstitial tissue among cysts. The microscopic and semiquantitative analysis performed in this work provides morphological information about male gametogenesis and some biological data for the North Patagonian population of this economically and ecologically important species.

CARACTERIZAÇÃO HISTOMORFOLÓGICA DOS TESTÍCULOS DE Dendropsophus nanus (BOULENGER, 1889) (ANURA, HYLIDAE)

“…Decrescentemente, as espermátides apresentando área média de 186 µm e diâmetro médio de 44 µm, os espermatócitos I apresentaram valores de área média 176 µm e diâmetro médio de 44 µm, enquanto que os espermatócitos II mostraram os menores valores com área média de 151 µm e diâmetro médio 37 µm. Moya et al, (2015) (PACHECO et al, 2016), 18,6% em Lithobates catesbeianus (Anura, Ranidae) (GOMES et al, 2012). Conquanto, em mamíferos este componente encontra-se em proporção variável.…”

Growth and reproduction in captivity unveils remarkable life-history plasticity in the smallnose fanskate, Sympterygia bonapartii (Chondrichthyes: Rajiformes)

“…The smallnose fanskate, Sympterygia bonapartii Müller & Henle, 1841, occurs regularly from off Santos, Brazil (24° S, Menni, Stehmann, 2000) to Santa Cruz Province, Argentina (49° S, Cousseau et al, 2007), from the intertidal to 100 m deep (Menni, Stehmann, 2000). The reproductive biology of S. bonapartii has been extensively studied and parameters such as size at maturity and fecundity are well known (Mabragaña et al, 2002;Oddone, Velasco, 2004;Oddone, Vooren, 2008;Galíndez et al, 2010;Díaz-Andrade et al, 2013;Basallo, Oddone, 2014;Moya et al, 2015;Estalles et al, 2017). Recently, growth parameters and age at maturity of this species in the wild have been estimated (Hozbor, Massa, 2015).…”