Molecular phylogenetic relationships and the coevolution of placentotrophy and superfetation in Poecilia (Poeciliidae: Cyprinodontiformes).

Members of Poeciliidae are used as model organisms for experimental studies on natural and sexual selection, and comparative studies of life-history evolution. The latter have demonstrated multiple origins of both superfetation and placentotrophy within Poeciliidae. Most recently, placentotrophy has been described in five species of Poecilia (Pamphorichthys), but only one of these (P.

Molecular phylogenetic relationships and the evolution of the placenta in Poecilia (Micropoecilia) (Poeciliidae: Cyprinodontiformes).

Poeciliids are one of the most intensively studied groups within Cyprinodontiformes owing to their use as model organisms for experimental studies on natural and sexual selection, and comparative studies of life-history evolution. Life-history studies have demonstrated multiple origins of placentotrophy and superfetation in poeciliids, including the recent description of placentotrophy in three species of Poecilia (Micropoecilia): P. bifurca, P.

Interpopulation variation in life-history traits of Poeciliopsis prolifica: implications for the study of placental evolution.

Placental reproduction is widespread across vertebrate taxa, but little is known about its life-history correlates and putative adaptive value. We studied variation in life-history traits in two populations of the placental poeciliid fish Poeciliopsis prolifica to determine whether differences in post-fertilization maternal provisioning to embryos have a genetic basis and how food availability affects reproduction. Life histories were characterized for wild-caught females and for second-generation lab-born females raised under two levels of food availability.