{"id":519087,"date":"2024-08-20T14:45:14","date_gmt":"2024-08-20T17:45:14","guid":{"rendered":"https:\/\/revistapesquisa.fapesp.br\/?p=519087"},"modified":"2024-08-20T14:45:14","modified_gmt":"2024-08-20T17:45:14","slug":"the-explosive-evolution-of-snakes","status":"publish","type":"post","link":"https:\/\/revistapesquisa.fapesp.br\/en\/the-explosive-evolution-of-snakes\/","title":{"rendered":"The explosive evolution of snakes"},"content":{"rendered":"

At meal times, a snake can\u2014or not\u2014attack and snatch up its prey. It can kill it quickly by injecting a venomous substance that causes various effects on the victim’s body, such as necrosis and extensive neurological damage. It can also strangle and slowly swallow a meal much larger than itself. It can eat while hanging from the branches of a tree, under water, or on the ground, and can even dig in search of underground prey. The variety of feeding methods among species is huge, as is the size of the menu. It is surprising, even more so for a limbless animal. \u201cImagine going to a steakhouse and ordering a 30 kilogram [kg] steak of beef and swallowing it only using your mouth, without chewing or handling it,\u201d compares biologist Guarino Colli, of the University of Bras\u00edlia (UnB). He is the coauthor of an article published in February in the journal Science<\/em>, which shows that this prodigious diet is a large part of the secret of success behind these animals: no other group is able to consume such varied diets, using such a large range of strategies.<\/p>\n

\u201cThere were many authors on account of the geographical and taxonomic diversity included in the study about snakes,\u201d explains the researcher. It is a major work because it includes the DNA sequencing of almost 7,000 species from around the world, which is a massive undertaking in itself, and it gave rise to the most reliable phylogeny ever obtained for Squamata, the order of reptiles that includes snakes and lizards and is the most diverse among terrestrial animals: it currently contains almost 11,000 species. Together with this evolutionary tree, the researchers also took information about the ecology (relationship with the environment) and morphology (appearance and anatomy) of the animals into consideration. \u201cAn individual is enough to get DNA and include a species on the tree, but it is not enough to trace the ecology and behavior that characterize it,\u201d adds Colli. The leader of the group is evolutionist Daniel Rabosky, of the University of Michigan, in the USA, known for his work in the field of evolutionary statistics. \u201cWe formed a research network that has lasted for around three decades,\u201d says Colli, listing students who have completed their training by moving between the research groups involved in the work.<\/p>\n

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Guarino Colli\u2009\/\u2009UnB<\/span>The snake Liotyphlops beui<\/em>Guarino Colli\u2009\/\u2009UnB<\/span><\/p><\/div>\n

The big question is: why did the group of snakes become so different, with much faster evolution than seen in lizards? The answer, for the time being, is because of the prodigious diet added to an out of the ordinary sensory ability. By repeatedly sticking out its forked tongue and bringing it back into its mouth, a snake is able to produce a chemical map of its surroundings; some also sense variations in temperature as well. Not forgetting about the locomotion without feet. \u201cBecause of their unusual use of the environment, they inhabit an extremely specialized ecological niche that is theirs alone,\u201d defines Colli.<\/p>\n

Therefore, it is possible that the same ecosystem is home to a large diversity of snakes, without the competition for resources causing conflict between them. \u201cIn the region of Bras\u00edlia, we have around 70 species,\u201d says Colli. \u201cThe city of S\u00e3o Paulo also used to have a similar number when it had sufficient Atlantic Forest.\u201d Like snakes, some species of lizards are also limbless, others have heightened sensory abilities, and there are even some that are able to eat large prey. But, from an evolutionary perspective, they are dead ends: they did not form diverse groups. Snakes, apparently, stood out because they adopted all of these strategies simultaneously, with great efficiency. The crucial thing here is the mobility of the skull, made up of bones that articulate and separate, opening the path for the meal that can be digested over the course of days.<\/p>\n

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Guarino Colli\u2009\/\u2009UnB<\/span>The red worm lizard Amphisbaena alba<\/em>Guarino Colli\u2009\/\u2009UnB<\/span><\/p><\/div>\n

By estimating dates for the branches of the evolutionary tree based on genetic data, the researchers noticed that the diversification of snakes happened very rapidly from around 65 million years ago, when an asteroid collided with the earth and caused the extinction of the majority of the dinosaurs. The fact that there was a rapid explosion in the number of species is not a complete surprise. \u201cBut the comparison with the other lineages of lizards had not yet been made,\u201d ponders Colli. The results showed that the species that were emerging, quickly became very different from their ancestors\u2014on an evolutionary time scale.<\/p>\n

\u201cThe genomic revolution has a huge impact in this area,\u201d assesses paleontologist Hussam Zaher, from the Museum of Zoology of the University of S\u00e3o Paulo (MZ-USP), who did not participate in the work. For him, the size of the databases used\u2014spanning an immense set of DNA segments, skull shape, type of diet, body size, and ecology, with the ability to infer dates\u2014allowed for a much greater breakdown of this evolutionary process than was previously available. \u201cIt is a brilliant study, very elegant, with a precise vision,\u201d he assesses.<\/p>\n

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Hussam Zaher \/ USP<\/span>Haasiophis terrasanctus<\/em>, the ancestor of snakes, had tiny hind legs (above<\/em>)Hussam Zaher \/ USP<\/span><\/p><\/div>\n

Without detracting from the merit of laboratory and computational analyses, Colli highlights the importance of fieldwork. \u201cThe global-scale research relied on databases that would not exist if there were not so many researchers out collecting in the field.\u201d Several authors of the article have accumulated three or four decades of experience in the wild, searching for and capturing animals. \u201cIn sum, it equates to a few centuries of effort.\u201d<\/p>\n

Enigmas still remain, however. \u201cThe origin of snakes has not been resolved,\u201d states Zaher, who edited a book in 2022 precisely about the origin and evolution of the group with herpetologist David Gower, of the Natural History Museum of London. For the researcher from USP, knowledge of paleontology will be essential in this leap in knowledge. This is because phylogenetic trees are constructed from samples of the species that exist today. \u201cWe are unable to extract DNA from fossils,\u201d he reminds us. Because the explosive emergence of species was accompanied by many extinctions throughout the evolutionary process, there are gaps in the evolutionary reconstruction.<\/p>\n

He says fossils have been found that could be central to clarifying the unanswered questions, such as animals with many of the characteristics of current day snakes, but still with small legs. Additionally, although it is not possible to predict when new pieces of the puzzle will be found amongst the rocks, the drawers in paleontology museums may hold precious pieces. \u201cThere are fossils that were not well understood at the time they were collected and may be rediscovered,\u201d he recognizes, adding that some recent results were obtained from “lost” specimens in museums.<\/p>\n

Scientific article<\/strong>
\nTITLE, P. O. et al<\/em>. The macroevolutionary singularity of snakes<\/a>. Science<\/strong>. Vol. 383, no. 6685, pp. 918\u201323. Feb. 22, 2024.<\/p>\n

Book<\/strong>
\nGOWER, D. J. & ZAHER, H. The origin and early evolutionary history of snakes<\/strong>. Cambridge: Cambridge University Press, 2022.<\/p>\n","protected":false},"excerpt":{"rendered":"A combination of genetic, ecological, and morphological data reveals the secrets of success behind these legless reptiles","protected":false},"author":3,"featured_media":519097,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_exactmetrics_skip_tracking":false,"_exactmetrics_sitenote_active":false,"_exactmetrics_sitenote_note":"","_exactmetrics_sitenote_category":0,"footnotes":""},"categories":[159],"tags":[206,224,231,237,255,266],"coauthors":[1601],"class_list":["post-519087","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-science","tag-biodiversity","tag-ecology","tag-evolution","tag-genetics","tag-paleontology","tag-zoology"],"acf":[],"_links":{"self":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts\/519087","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/comments?post=519087"}],"version-history":[{"count":1,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts\/519087\/revisions"}],"predecessor-version":[{"id":519113,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts\/519087\/revisions\/519113"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/media\/519097"}],"wp:attachment":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/media?parent=519087"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/categories?post=519087"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/tags?post=519087"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/coauthors?post=519087"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}