Sexual Size Dimorphism and Age in Odontophrynus cf. barrioi (Anura: Odontophrynidae) from the Monte Desert, Argentina
Current knowledge on sexual dimorphism and population structure in the genus Odontophrynus is limited. We studied age structure, age at maturity, and longevity in Odontophrynus cf. barrioi, with skeletochronology. We also determined whether sexual dimorphism in body size exists in this species, and evaluated its relation to demographic life history traits. We found that females were larger in four variables corresponding to the morphology of the head. In addition, females of O. cf. barrioi have a longer tibia-fibula and femur than males. Nevertheless, Odontophrynus cf. barrioi shows no sexual dimorphism in snout–vent length. We suggest the possibility that sexes have different growth trajectories after the onset of reproduction, as they are exposed to different selection pressures, or even predation rate, because of size differences.Abstract
Amplexus of Odontophrynus cf. barrioi from Quebrada de las Flores, San Juan, Argentina.
Cross sections of phalanges stained with Ehrlich's hematoxylin of Odontophrynus cf. barrioi. Upper left: juvenile of 32.8-mm SVL, without LAGs formed. Upper right: male of 47.4-mm SVL and 1 yr. Lower left: male of 48.3-mm SVL and 2 yr. Lower right: male of 52.3-mm SVL and 3 yr. LAGs are indicated by black arrows. White arrow: line of endosteal resorption. eb: endosteal bone; mc: medullar cavity; pbm: periosteal bone margin. Scale bars: 100 μm. All figures are at the same magnification.
Age distribution of Odontophrynus cf. barrioi from Quebrada de las Flores, San Juan, Argentina.
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