{"id":197232,"date":"2015-07-15T13:20:22","date_gmt":"2015-07-15T16:20:22","guid":{"rendered":"http:\/\/revistapesquisa.fapesp.br\/?p=197232"},"modified":"2015-09-14T14:39:08","modified_gmt":"2015-09-14T17:39:08","slug":"a-caribbean-cousin","status":"publish","type":"post","link":"https:\/\/revistapesquisa.fapesp.br\/en\/a-caribbean-cousin\/","title":{"rendered":"A Caribbean cousin"},"content":{"rendered":"

\"058-059_tartarugas_233\"<\/a>One species from Madagascar and seven from northern South America, all of them freshwater species such as the giant Amazon River turtle (Podocnemis expansa<\/em>), are the only remaining living forms of the Podocnemididae family of turtles. Most of the known species of this group have disappeared from the Earth. Although there are no present-day members of this family that are adapted to marine environments, a number of fossils suggest that there were lineages of saltwater Podocnemididae in the distant past. A team of Brazilian and Venezuelan paleontologists has described a new extinct turtle species, discovered in northern Venezuela, that provides further evidence in support of that theory. The researchers believe the newly named species Bairdemys thalassica<\/em>, which lived 12 million years ago, belonged to the \u201clast marine lineage\u201d of Podocnemididae turtles. The new name was chosen to emphasize the turtle\u2019s habitat: in Greek, thalassa<\/em> means \u201csea.\u201d The species is described in a paper published in the June 2015 issue of the online scientific journal PeerJ<\/em>.<\/p>\n

The B. thalassica<\/em> fossils consist of a nearly complete skull from the El Miedo Cave located in Cerro Misi\u00f3n, less then 40 kilometers from the Caribbean Sea. Although the fossil has been in the collection of the Paleontology Laboratory of the Venezuelan Institute for Scientific Research in Caracas for several years, it was not studied until mid-2013. \u201cThey didn\u2019t have a turtle specialist to work on the material,\u201d says Professor Max Langer, a paleontologist at the University of S\u00e3o Paulo (USP), Ribeir\u00e3o Preto campus, and co-author of the paper that introduced the species. But Langer had his then-master\u2019s student Gabriel de Souza Ferreira, a biologist and turtle specialist, who is presently working on his PhD. Langer is doing collaborative research with the Venezuelans as part of his work as principal investigator of a thematic project on dinosaur origin and radiation, which led him to undertake joint excavations in that country. The invitation to study the turtle fossil looked like an attractive opportunity, and Ferreira accepted the challenge.<\/p>\n

Two types of evidence indicate that B. thalassica<\/em> lived in a saltwater environment: the characteristics of the fossil site where it was found, and details of the turtle\u2019s anatomy. The cave where it was found is rich in carbonates, which are typically formed in marine environments. In addition to the turtle remains, the walls of the El Miedo Cave contained fossils of cetaceans, fish and seabirds. These clues lend additional support to the idea that the waters of the Caribbean once extended into that area. \u201cThe cave was in an area without continental influence,\u201d Ferreira says. \u201cIn the Middle Miocene between 16 million and 11.6 million years ago, the entire area was beneath the sea.\u201d The environment where the fossils of the other six species of the extinct genus Bairdemys<\/em> were found indicates that these turtles exhibited some measure of tolerance to saltwater, and may have lived in estuarine areas of transition between river and ocean environments. \u201cIn none of these cases is it possible to say unequivocally\u2014as we are doing with reference to B. thalassica\u2014<\/em>that these turtles were from an open sea environment,\u201d Langer notes.<\/p>\n

The morphology of the Venezuelan fossil\u2014a skull measuring 10 cm, slightly larger than that of the extant species of Podocnemididae\u2014also provides clues to its marine habits. The species featured an expansion of the grinding surfaces of the upper and lower jaws, which means there was a larger area used to process solid food. \u201cWe analyzed the geometric measurements of the skull, and we believe this expansion was an adaptation to durophagy,\u201d Ferreira says. \u201cThis turtle most likely ate hard-shelled prey, such as mollusks and crustaceans.\u201d Among the living species of saltwater turtles, the loggerhead sea turtle (Caretta caretta<\/em>), found in oceans throughout the world, also displays an anatomy adapted to durophagy.<\/p>\n

The turtle species that now live in the oceans are completely unrelated to living or extinct members of the Podocnemididae family. They descended from separate lineages of turtles that became dominant in the oceans during the Middle Miocene, precisely the period when B. thalassica <\/em>lived. According to the USP researchers, it is possible that the disappearance of the Podocnemididae turtles from ocean environments is related to the emergence and diversification of other turtles adapted to marine life.<\/p>\n

Project<\/strong>
\nThe origin and rise of dinosaurs in Gondwana (late Triassic \u2013 early Jurassic) (n\u00ba 2014\/03825-3<\/a>); Principal Investigator<\/strong> Max Langer (USP Ribeir\u00e3o Preto); Grant Mechanism<\/strong> Thematic Project; Investment<\/strong> R$1,587,258.45 (FAPESP).<\/p>\n

Scientific article
\n<\/em>FERREIRA, G. S. et al<\/em>. The last marine pelomedusoids (Testudines: Pleurodira): a new species of Bairdemys<\/em> and the paleoecology of Stereogenyina<\/em>.<\/a> PeerJ<\/strong>. June 30, 2015.<\/p>\n","protected":false},"excerpt":{"rendered":"Fossil of 12 million-year-old is a distant relative of South American turtles","protected":false},"author":13,"featured_media":0,"comment_status":"open","ping_status":"open","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":[255],"coauthors":[101],"class_list":["post-197232","post","type-post","status-publish","format-standard","hentry","category-science","tag-paleontology"],"acf":[],"_links":{"self":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts\/197232","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\/13"}],"replies":[{"embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/comments?post=197232"}],"version-history":[{"count":0,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts\/197232\/revisions"}],"wp:attachment":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/media?parent=197232"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/categories?post=197232"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/tags?post=197232"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/coauthors?post=197232"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}