Dimorfismo sexual de las aletas pélvicas en Potamotrygon motoro (Batoidea: Potamotrigonidae)

DANTE, PEREZ; GABRIELA, OLEA; TANIA, BLANCO COHENE; FLORENCIA EVELIN, RODRIGUEZ; CAROLINA, FLORES QUINTANA

Revista de Investigaciones Veterinarias del Perú

Universidad Nacional Mayor de San Marcos. Facultad de Medicina Veterinaria

Año: 2023 vol. 34 p. 1 - 10

Claspers in chondrichthyans are specialized elongations on the posterior side of thepelvic fins of males that are used for sperm transfer during copulation. The aim of thisstudy was the description and characterization of the external morphology and skeletalcomponents of the pelvic fin clasper of Potamotrygon motoro (Batoidea:Potamotrygonidae). The study included three juvenile specimens (2 males and 1 female)and two adult specimens (1 male and 1 female) from the Paraná River, Corrientes Capital.The samples were fixed in 10% formalin and processed using the diaphanization technique.The material was preserved in glycerol for observation. Macroscopically, sexualdimorphism is evident in males, through a structure in the posterior region called aclasper, with a slightly tapered conical shape, visible dorsally and ventrally. In diaphanoussamples, the posterior cartilaginous elements can be distinguished, differentiating apropterygium and a basipterygium, which together with it are located the basal segmentsand the radial cartilages of the pelvic fins; however, only males develop a clasper ormixopterygian. In females, the only skeletal structures posterior to the basipterygium aresmall nodular elements (terminal cartilages). It was evidenced that these specimens intheir first days of life already present the sexual dimorphism associated with the presenceof clasper in males and its absence in females; however, juvenile males do not present thefull development of the mixopterygian that forms the clasper.