Reproductive Biology and Hatchling Morphology of the Amazon Toad-headed Turtle (Mesoclemmys raniceps) (Testudines: Chelidae), with Notes on Species Morphology and Taxonomy of the Mesoclemmys Group

Abstract

Mesoclemmys raniceps is a medium-sized aquatic turtle widely distributed throughout the northern Amazon Basin in South America. Little information has been published about its reproductive biology. Because there is a significant problem identifying juveniles of this species found in the wild, and a controversy concerning the taxonomic status of the Mesoclemmys nasuta group, we incubated eggs from known females from known localities at controlled and ambient temperatures. We describe the hatchlings produced. The eggs hatched after an incubation period of 249 d at 28°C. Incubation experiments found both M. raniceps and Mesoclemmys heliostemma phenotypes hatching from the same clutch of eggs, suggesting that these taxa are conspecific. Mesoclemmys wermuthi had been incorrectly synonymized with M. nasuta and later absorbed by M. raniceps when M. raniceps was elevated to species status, resulting in the confusion of M. raniceps being different from M. heliostemma. Mesolemmys wermuthi is a distinct species separate from M. raniceps; however, M. wermuthi is preceded by Hydraspis maculata, which was synonymized with M. raniceps and is available for this species as Mesoclemmys maculata. © 2019 Chelonian Research Foundation.