MUSEO ARGENTINO DE CIENCIAS NATURALES "BERNARDINO RIVADAVIA"
Unidad Ejecutora - UE
Sexual dimorphism and morphometric relationships in pelvic bones of Commerson's dolphins (Cephalorhynchus c. commersonii) from Tierra del Fuego, Argentina
CASERES-SAEZ, IRIS; DELLABIANCA, NATALIA ANDREA; PIMPER, LIDA ELENA; PEREYRA-BONNET, FEDERICO; CASSINI, GUILLERMO HERNÁN; GOODALL, RAE NATALIE PROSSER
MARINE MAMMAL SCIENCE
WILEY-BLACKWELL PUBLISHING, INC
Lugar: Londres; Año: 2015 vol. 31 p. 734 - 734
The Commerson's dolphin, Cephalorhynchus commersonii (Lacépède 1804), is found in shallow waters of the continental shelf off the eastern coast of South America between 40ºS and 56ºS (Goodall et al. 1988). It is probably the most abundant dolphin near shore, affected by incidental catch in Tierra del Fuego (Goodall 1978; Goodall et al. 1988, 1994, 2008) and vulnerable to other anthropogenic threats, such as pollution, habitat disturbances and commercial shipping traffic through its range (Pimper et al. 2010; Cáceres-Saez et al. 2013a, b). Based on geographic, morphological, and genetic data, a separate new subspecies (C. c. kerguelensis) was determined at the Kerguelen Islands in the Indian Ocean (Robineau et al. 2007). Externally, the gender of both subspecies of Commerson's dolphin can be determined from differences in the genital patch (Robineau 1984; Goodall et al. 1988). In decomposed carcasses, external pigmentation, internal reproductive organs and other soft tissue may be damaged or destroyed, hindering the ability to identify sex in those specimens. If the pelvic bones are present, they may contribute to determination of sex. Although other studies have shown the existence of sexual dimorphism in this species (Collet and Robineau 1988; Goodall et al. 1988), they have failed to quantify morphometric relationships between the pelvic bones and age or total body length of individuals. The aim of this study was to determine sexual dimorphism across ontogeny in the Commerson's dolphins from southern South America. On the basis of our observations we conclude that the sex of Commerson's dolphins can be determined through morphometric and morphological assessment of their pelvic bones. As regards to LPB and WPB, we suggest that they might be employed to differentiate between sexes; particularly for specimens beginning at Class I and Class II (WPB and LPB; respectively).