Evolution of Viviparity and Placentation

Viviparity (live-birth) has evolved independently at least 150 times in vertebrates. Most of these origins (115+) has occurred in squamates (snakes and lizards) and in different taxonomic levels, which makes this group an ideal model system for studying the evolution of viviparity. The origin of viviparity imposes several challenges that need to be overcome, including the elimination of metabolic waste, exchange of respiratory gases, and transport of water and nutrients. In addition, the evolution of viviparity has important ecological and behavioral implications. 
I have studied the evolution of viviparity by focusing on morphological, ecological, and phylogenetic aspects. My aim is to understand how and why different species have achieved this evolutionary transition.
A developing snake embryo.
Related publications

Reproductive Biology

Brazil has more than 730 species of squamates (lizards, snakes, and amphisbaenians), but the reproductive cycles of most of these species remain poorly known. One of my research interests is thus to describe the processes and timing of various aspects of the reproductive cycles of squamates (gametogenesis, mating, sperm storage, ovulation, and egg-laying/parturition). Moreover, I also want to understand how these aspects are influenced by biotic and abiotic factors and how the reproductive patterns are constrained by phylogeny.
A false-coral snake (Oxyrhopus guibei) laying eggs. Photo: Fausto Barbo.
Related publications ​(* = mentored student)

Natural History

As with reproductive biology, many aspects of the natural history of Brazilian snakes and lizards are still poorly understood. ​Thus in parallel, I have always been interested in various aspects of the natural history of snakes and lizards, including feeding ecology, feeding behavior, activity patterns, and geographic distribution. 
Enyalius iheringii. Photo: Serena Migliore
Related publications (* = mentored student)
© 2018 by Henrique Braz
Last updated May 2019