Cytogenetics and sperm ultrastructure of Atelopus spumarius (Anura, Bufonidae) from the Brazilian Amazon

Abstract

The current taxonomy of most Atelopus species is based on morphological and color data only. Recent studies suggest that A. spumarius may represent a species complex assigned under the same name. Karyotypic data and description of sperm ultrastructure for 13 specimens of A. spumarius are presented here for the first time. A chromosomal analysis revealed 2n = 22 chromosomes, with centromeric heterochromatin in all pairs and a nucleolar organizer region (NOR) on the telomere of pair 7. The sperm was of the bufonoid type, presenting a filiform nucleus covered by an acrosomal complex and a mitochondrial collar in the neck region. The tail was composed of an axoneme, an undulating membrane and an axial rod. A karyotype analysis of A. spumarius showed the same chromosome number and similar chromosomal morphology as described for congeneric species, with slight differences probably resulting from pericentric inversions. The NOR location (on pair 7) was the same as that observed for species belonging to the genus Rhinella. The spermatological findings indicate a close relationship between Atelopus and the bufonoid lineage. The present data are useful for reference in future studies to determine whether more than one species are assigned to A. spumarius.

Ultrastructure variation in the spermatozoa ofPseudopaludicolafrogs (Amphibia, Anura, Leptodactylidae), with brief comments on its phylogenetic relevance

“…A fine undulating membrane observed in the spermatozoa of P. falcipes (Amaral et al, ) has also been described in Rhinella marina, Litoria fallax (Lee and Jamieson, ), Litoria cryptotis (Meyer et al, ), and Atelopus spumarius (Siqueira et al, ), whereas a thick undulating membrane, similar to that observed in this study, has been observed in spermatozoa of Litoria brevipes (Meyer et al, ). However, the extrapolation of these data to a wider taxonomic perspective is limited due to the prevalence of homoplasies (Scheltinga and Jamieson, ).…”

Histology and structure of the testicles in three species of Atelopus frogs (Anura: Bufonidae) endemic to the Sierra Nevada de Santa Marta, Colombia

“…Several authors have studied important aspects of reproductive biology associated mainly with the breeding season, reproductive effort, and the interspecific amplexus (Pérez-González et al, 2017;Rocha-Usuga et al, 2017). However, other issues such as gonadal morphology (McDiarmid, 1971;Siqueira et al, 2013), sexual maturity (La Marca et al, 1989), and mating patterns (Barrantes-Cartín, 1986;Crump, 1988;Lötters, 1996;Karraker et al, 2006) are still unknown to most representatives of the genus. This group of harlequin frogs is one of the most endangered in the world (La Marca et al, 2005), whose populations have decreased in high mountain habitats, including areas with little intervention (Pounds & Crump, 1994;Pounds et al, 2006).…”