{"id":225496,"date":"2016-10-04T13:22:57","date_gmt":"2016-10-04T16:22:57","guid":{"rendered":"http:\/\/revistapesquisa.fapesp.br\/en\/?p=225496"},"modified":"2016-10-04T13:22:57","modified_gmt":"2016-10-04T16:22:57","slug":"heart-of-stone","status":"publish","type":"post","link":"https:\/\/revistapesquisa.fapesp.br\/en\/heart-of-stone\/","title":{"rendered":"Heart of stone"},"content":{"rendered":"
\"A

Murilo de Carvalho \/ lnbio CT <\/span>A fish fossil of Rhacolepis buccalis<\/em> collected at the Araripe Basin, with internal organs in an excellent state of preservationMurilo de Carvalho \/ lnbio CT <\/span><\/p><\/div>\n

Paleontology now has a heart. Brazilian researchers have found an organ preserved in the fossil of a fish that lived 115 million years ago in what is today the Northeast region of Brazil. For the first time in the paleontological record, a fossilized heart is being described\u00a0\u00a0and, because of its excellent state of preservation, the petrified organ belonging to the fish Rhacolepis buccalis<\/em> \u00a0has revealed to us a hitherto unknown stage in the evolution of the heart.<\/p>\n

Three-dimensional images of the entire animal (measuring 13 cm in length) and its internal organs were produced from high-resolution CT scans.\u00a0 To the researchers\u2019 surprise,\u00a0they found that the heart had five valves (one controlling the flow of blood throughout the rest of the body), as distinct from the single-valve fish of today.\u00a0 \u201cThis shows that organisms don\u2019t always become more complex as they evolve,\u201d explains physician Jos\u00e9 Xavier Neto, a researcher at the National Biosciences Laboratory (LNBio) and coordinator for the group that discovered the fossilized heart. \u201cIn some cases, they become less so.\u201d<\/p>\n

The R. buccalis<\/em> belongs to the Actinopterygii class of bony fishes, meaning those that are ray-finned.\u00a0 Its heart appears to be at the evolutionary mid-point among the current species in this group, like the zebrafish (in Brazil, the paulistinha<\/em><\/span>), which has a single cardiac valve, and other species (like the dozens of fish of the genus Polypterus<\/em>) which have undergone little evolutionary change over the past 390 million years. \u201cWe don\u2019t know the context in which this simplification occurred,\u201d says Neto, who published the findings in the April 2016 edition of the journal eLife, <\/em>\u201cbut it usually happens after what we know as a surge of complexity.\u201d Also unknown is whether valve-loss was just a random change or amounted to a true evolutionary advantage for the species.<\/p>\n

The 3D Fossil<\/strong>
\nFinding and describing a fossilized heart only became possible thanks to synchrotron-light technology, which has been making important contributions in the field of paleontology over the past few years. \u201cSoft tissue, like the heart, is very hard to maintain itself in a state of preservation,\u201d says paleontologist M\u00edrian Pacheco of the Federal University of S\u00e3o Carlos (UFSCar) in Sorocaba, S\u00e3o Paulo. Pacheco also uses synchrotron light to study animal fossils (hard to find intact and mostly of invertebrates that lived approximately 540 million years ago) of the Ediacaran geological period.\u00a0 Fossilized brains, ovaries, muscles, intestinal contents, umbilical cords and swim bladders have all been found, but, according to the researchers, never a heart.<\/p>\n

\"Anthropocene\"<\/a>Neto joined the select group of researchers who described the fossilized invertebrates when he became convinced that he should focus his search on the R. buccalis<\/em> a few years ago. While vacationing with his family in the south of their home state of Cear\u00e1, Neto spoke with geologists Francisco Idal\u00e9cio Freitas, executive coordinator of Geopark Araripe, and Jos\u00e9 Artur de Andrade of the National Mineral Production Department, who advised him to focus his research on the R. buccalis<\/em>. The species was very common to the Araripe Basin in the interior region of the states of Cear\u00e1, Pernambuco and Piau\u00ed, an area known for its well-preserved fossils of the Cretaceous period. When found, fossils of R. buccalis<\/em> normally have the advantage of a three-dimensional form, thus increasing the likelihood that internal organs are preserved. In Campinas, biologists Laura Maldanis and Murilo de Carvalho prepared the samples and analyzed the material. Because the second-generation synchrotron at the National Synchrotron-Light Laboratory (adjacent to LNBio at the National Center for Energy and Materials Research, or CNPEM) did not have the capacity to produce images of samples (like those of the 15 x 5 cm fossilized fishes), the material was analyzed at the European Synchrotron Radiation Facility in Grenoble, France, using fourth-generation equipment capable of higher-energy beam generation.\u00a0 \u201cWe weren\u2019t able to see the heart cavities in the first CT scans,\u201d Neto recalls, \u201cbut the resolution was so good that that we could see\u2014in the fishes\u2019 intestinal tracts\u2014the shrimp that they had consumed.\u201d Finally, two samples showed not only the heart, but also details of its inner region.<\/p>\n

Such high degree of precision was possible because the synchrotron\u2019s CT scan has a resolution almost 100 times greater than that of ordinary medical CT scanning devices. While conventional devices can distinguish points that are 500 micrometers apart, synchrotron light reduces this distance to six micrometers (each micrometer measures one one-thousandth of a millimeter). The device produces a series of \u201clayers\u201d of x-rays of the sample, creating a precise image of its internal \u201crelief.\u201d Software is then used to join the layers into a 3D image.\u00a0 \u201cThe resulting image is almost as precise as seeing a dissected heart,\u201d says Neto.\u00a0 Yet another advantage of the synchrotron is that its light poses no danger of damaging the samples.<\/p>\n

According to Pacheco, who is not a member of the research group, \u201cthis material can be analyzed again in terms of other characteristics.\u00a0 The team\u2019s achievements have placed Brazil at an international level of competition in the field of paleontology.\u201d There is hope, if the present timetable is maintained, that Sirius\u2014a new source of synchrotron light similar to the one in France\u2014will be operational in Campinas so fossils and other materials can finally be analyzed in Brazil.<\/p>\n

Project<\/strong>
\nMolecular evolution of regulatory regions of HOX genes associated with the morphology of fish fins, with special emphasis on Chondrichthyes (n\u00ba 2012\/05152-0<\/a>); Grant Mechanism: <\/strong>Post-doctoral research grant; Principal Investigator: <\/strong>Marcelo Rodrigues de Carvalho – USP; Grantee<\/strong>: Murilo de Carvalho; Investment:<\/strong> R$255,270.00.<\/p>\n

Scientific Article<\/em>
\nMALDANIS, L. et al<\/em>. Heart fossilization is possible and informs the evolution of cardiac outflow tract in vertebrates<\/a>. eLife<\/strong>.\u00a0 V. 5, No. e14698. April 19, 2016<\/p>\n","protected":false},"excerpt":{"rendered":"New fossil record reveals an unforeseen pathway in the evolution of the heart","protected":false},"author":576,"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":[231,241,255],"coauthors":[1539],"class_list":["post-225496","post","type-post","status-publish","format-standard","hentry","category-science","tag-evolution","tag-history","tag-paleontology"],"acf":[],"_links":{"self":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts\/225496","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\/576"}],"replies":[{"embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/comments?post=225496"}],"version-history":[{"count":0,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts\/225496\/revisions"}],"wp:attachment":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/media?parent=225496"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/categories?post=225496"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/tags?post=225496"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/coauthors?post=225496"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}