Evolution of Viviparity and PlacentationViviparity (live-birth) has evolved independently an extraordinary number of times (>150) among vertebrates. The origin of viviparity imposes several physiological challenges that need to be overcome (elimination of metabolic waste, exchange of respiratory gases, and transport of water and nutrients). Moreover, viviparity dramatically changes the way an organism interacts with its environment.
I have studied the evolution of viviparity in squamates (snakes and lizards), the group that, by far, exhibits most (~75%) origins of viviparity. Specifically, I focus on morphological, ecological, and phylogenetic aspects of the transition to viviparity. I aim to understand how and why multiple species have achieved this evolutionary transition. |
A developing snake embryo.
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Related publications
- Braz HB, Grazziotin FG, Almeida-Santos SM. Does the cold climate hypothesis explain the evolution of viviparity in tropical snakes? In preparation.
- 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 330(3): 165-180.
- 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.
Reproductive BiologyBrazil 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 to describe various aspects of squamate reproductive output (clutch size, reproductive frequency) and reproductive cycles (gametogenesis, mating, sperm storage, ovulation, and egg-laying/parturition). Moreover, I also want to understand how reproductive traits are influenced by biotic and abiotic factors and how they 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)
- Braz HB, Kasperoviczus KN, Guedes TB. 2019. Reproductive biology of the fossorial snake Apostolepis gaboi: a threatened and poorly species from the Caatinga region. South American Journal of Herpetology 14(1): 37-47.
- 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.
- 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
As with reproductive biology, many other aspects of the natural history of Brazilian snakes and lizards are still poorly understood. Thus, I have always been interested in investigating various aspects of the natural history of squamates, including feeding ecology, feeding behavior, activity patterns, and geographic distribution.
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Enyalius iheringii. Photo: Serena Migliore
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Related publications (* = mentored student)
- Nogueira CC, Argôlo AJS, Arzamendia V, Azevedo JA, Barbo FE, Bérnils RS, Bolochio BE, Borges-Martins M, Brasil-Godinho M, Braz HB, Buononato MA, Cisneros-Heredia DF, Colli GR, Costa HC, Franco FL, Giraudo A, Gonzalez RC, Guedes TB, Hoogmoed MS, Marques OAV, Montingelli GG, Passos P, Prudente ALC, Rivas G, Sanchez PM, Serrano FC, Silva-Jr NJ, Strüssmann C, Vieira-Alencar JPS, Zaher H, Sawaya RJ, Martins M. Atlas of Brazilian snakes: Verified point-locality maps to mitigate the Wallacean shortfall in a megadiverse snake fauna. South American Journal of Herpetology 14(sp1): 1-274.
- von May R, Albuquerque NR, Braz HB, Santa-Cruz R, Biggi E, Tomasinelli F, Rabosky DL. 2019. Distribution of the Neotropical water snakes Hydrops caesurus, H. martii, and H. triangularis in South America, with new records from Peru and Brazil. Amphibian & Reptile Conservation 13(1): 122–142.
- Guedes TB, Sawaya RJ, Zizka A, Laffan S, Faurby S, Pyron RA, Bérnils RS, Jansen M, Passos P, Prudente ALC, Cisneros-Heredia DF, Braz HB, Nogueira CC, Antonelli A. 2018. Patterns, biases and prospects in the distribution and diversity of Neotropical snakes. Global Ecology and Biogeography 27: 14-21.
- 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 in southeastern Brazil. South American Journal of Herpetology 7(3): 252-258
© 2018 by Henrique Braz
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Last updated May 2020
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