Evolution of Viviparity and PlacentationViviparity (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 (family, genera, and species), which makes this group an ideal model system for studying the evolution of viviparity.
The evolution of viviparity imposes several challenges that need to be overcome, including the elimination of metabolic waste, the exchange of respiratory gases, and the 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 snake embryo
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Related publications
- Braz HB, Almeida-Santos SM, Murphy CR, Thompson MB. 2018. Uterine and eggshell modifications associated with the evolution of viviparity in South American water snakes (Helicops spp.). Journal of Experimental Zoology Part B: Molecular and Developmental Evolution (DOI: 10.1002/jez.b.22800).
- Braz HB, Scartozzoni RR, Almeida-Santos SM. 2016. Reproductive modes of the South American water snakes: A study system for the evolution of viviparity in squamate reptiles. Zoologischer Anzeiger 263: 33–44 (DOI: https://doi.org/10.1016/j.jcz.2016.04.003).
Reproductive Biology
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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/birth). Moreover, I also want to understand how these aspects are affected by biotic and abiotic factors and how the reproductive patterns are constrained by phylogeny.
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A false-coral snake (Oxyrhopus guibei) laying eggs. Photo: Fausto Barbo.
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Related publications (* = mentored student)
- Migliore SN*, Braz HB, Barreto-Lima AF, Almeida-Santos SM. 2017. Reproductive timing and fecundity in the Neotropical lizard Enyalius perditus. Acta Herpetologica 12: 187-191 (DOI: http://dx.doi.org/10.13128/Acta_Herpetol-19981).
- Braz HB, Kasperoviczus KN, Almeida-Santos SM. 2014. Reproductive ecology and diet of the fossorial snake Phalotris lativittatus in the Brazilian Cerrado. Herpetological Journal 24(1): 49-57.
- Almeida-Santos SM, Braz HB, Santos LC, Sueiro LR, Barros VA, Rojas CA, Kasperoviczus KN. 2014. Biologia reprodutiva de serpentes: recomendações para a coleta e análise de dados. Herpetologia Brasileira 3(1): 14-24.
Natural History
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In parallel, I have always been interested in
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Enyalius iheringii. Photo: Serena Migliore
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Related publications (* = mentored student)
- Braz HB, Marques OAV. 2016. Tail-first ingestion of prey by the false coral snake, Erythrolamprus aesculapii: Does it know where the tail is? Salamandra (German Journal of Herpetology) 52(2): 211–214.
- Torello-Viera NF*, Araújo DP, Braz HB. 2012. Annual and daily activity patterns of the snail-eating snake Dipsas bucephala (Serpentes, Dipsadidae) in southeastern Brazil. South American Journal of Herpetology 7(3): 252-258 (DOI: https://doi.org/10.2994/057.007.0307).
Developmental Plasticity
Snake eggs during an incubation experiment
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© 2018 by Henrique Braz
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Last updated February 2018
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