標題: The first fossilised heart ever found in a prehistoric animal [打印本頁] 作者:
fossilshk 時間: 2016-4-21 01:23 AM 標題: The first fossilised heart ever found in a prehistoric animal
A new discovery, announced today in the journal eLife, shows the perfectly preserved 3D fossilised heart in a 113-119 million-year-old fish from Brazil called Rhacolepis .This is the first definite fossilised heart found in any prehistoric animal.
Using X-ray synchrotron microtomography, we show that Rhacolepis fossils display hearts with a conus arteriosus containing at least five valve rows. This represents a transitional morphology between the primitive, multivalvar, conal condition and the derived, monovalvar, bulbar state of the outflow tract in modern actinopterygians.
Journal eLife: https://elifesciences.org/content/5/e14698v1
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This 119 million year old fish, Rhacolepis , is the first fossil to show a 3D preserved heart which gives us a rare window into the early evolution of one of our body’s most important organs.
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Phase contrast synchrotron micro tomography of teleost fossil hearts.
(a,b) 3D reconstructions of specimen CNPEM 27P obtained from PPC-SR-μCT. (a), Left lateral view. (b), Ventral view. (c,d), (e,f) Sagittal sections of specimens CNPEM 01P and CNPEM 17P, respectively. Blue masks in (d) and (f) highlight fossil cardiac chambers and pericardium in the specimens CNPEM 01P and CNPEM 17P, respectively. Note that thin trabeculae are associated to the atrium (arrows) and that thick trabeculae are typical of the ventricle (arrowheads) Abbreviations: A, atrium; C.A., conus arteriosus; P, pericardium; S.V., sinus venosus; V, ventricle.
Heart fossilization is possible and informs the evolution of cardiac outflow tract in vertebrates
Lara Maldanis,
Murilo Carvalho,
Mariana Ramos Almeida,
Francisco Idalécio Freitas,
José Artur Ferreira Gomes de Andrade,
Rafael Silva Nunes,
Carlos Eduardo Rochitte,
Ronei Jesus Poppi,
Raul Oliveira Freitas,
Fábio Rodrigues,
Sandra Siljeström,
Frederico Alves Lima,
Douglas Galante,
Ismar S Carvalho,
Carlos Alberto Perez,
Marcelo Rodrigues de Carvalho,
Jefferson Bettini,
Vincent Fernandez ,
José Xavier-Neto
ORCID
ORCID
ORCID
ORCID
University of Campinas, Brazil; Brazilian Biosciences National Laboratory, Brazil; University of São Paulo, Brazil; Geopark Araripe, Brazil; Ministry of Mines and Energy, Brazil; Brazilian Synchrotron Light Laboratory, Brazil; SP Technical Research Institute of Sweden, Sweden; Universidade Federal do Rio de Janeiro, Brazil; Brazilian Nanotechnology National Laboratory, Brazil; European Synchrotron Radiation Facility, France
Elucidating cardiac evolution has been frustrated by lack of fossils. One celebrated enigma in cardiac evolution involves the transition from a cardiac outflow tract dominated by a multi-valved conus arteriosus in basal actinopterygians, to an outflow tract commanded by the non-valved, elastic, bulbus arteriosus in higher actinopterygians. We demonstrate that cardiac preservation is possible in the extinct fish Rhacolepis buccalis from the Brazilian Cretaceous. Using X-ray synchrotron microtomography, we show that Rhacolepis fossils display hearts with a conus arteriosus containing at least five valve rows. This represents a transitional morphology between the primitive, multivalvar, conal condition and the derived, monovalvar, bulbar state of the outflow tract in modern actinopterygians. Our data rescue a long-lost cardiac phenotype (119-113 Ma) and suggest that outflow tract simplification in actinopterygians is compatible with a gradual, rather than a drastic saltation event. Overall, our results demonstrate the feasibility of studying cardiac evolution in fossils.
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