Heart fossilization is possible and informs the evolution of cardiac outflow tract in vertebrates

Author(s):Show less -

Maldanis, Lara ^{[1, 2]} ; Carvalho, Murilo ^{[2, 3]} ; Almeida, Mariana Ramos ^[4] ; Freitas, Francisco Idalecio ^[5] ; Ferreira Gomes de Andrade, Jose Artur ^[6] ; Nunes, Rafael Silva ^[7] ; Rochitte, Carlos Eduardo ^[8] ; Poppi, Ronei Jesus ^[4] ; Freitae, Raul Oliveira ^[7] ; Rodrigues, Fabio ^[9] ; Siljestrom, Sandra ^[10] ; Lima, Frederico Alves ^[7] ; Galante, Douglas ^[7] ; Carvalho, Ismar S. ^[11] ; Perez, Carlos Alberto ^[7] ; de Carvalho, Marcelo Rodrigues ^[3] ; Bettini, Jefferson ^[12] ; Fernandez, Vincent ^[13] ; Xavier-Neto, Jose ^[2]

Affiliation:Show less -

^[1] Univ Estadual Campinas, Dept Pharmacol, Campinas, SP - Brazil

^[2] Brazilian Biosci Natl Lab, Campinas, SP - Brazil

^[3] Univ Sao Paulo, Dept Zool, Biosci Inst, Sao Paulo - Brazil

^[4] Univ Estadual Campinas, Inst Chem, Campinas, SP - Brazil

^[5] Geopk Araripe, Crato - Brazil

^[6] Minist Mines & Energy, Natl Dept Mineral Prod, Crato - Brazil

^[7] Brazilian Synchrotron Light Lab, Campinas, SP - Brazil

^[8] Univ Sao Paulo, InCor, Inst Heart, Sao Paulo - Brazil

^[9] Univ Sao Paulo, Inst Chem, Sao Paulo - Brazil

^[10] SP Tech Res Inst Sweden, Dept Chem Mat & Surfaces, Boras - Sweden

^[11] Univ Fed Rio de Janeiro, Dept Geol, Rio De Janeiro - Brazil

^[12] Brazilian Nanotechnol Natl Lab, Campinas, SP - Brazil

^[13] European Synchrotron Radiat Facil, BP 220, F-38043 Grenoble - France

• Document type: Journal article
• Source: eLIFE; v. 5, APR 19 2016.
• Web of Science Citations: 10

Abstract

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. (AU)

• FAPESP's process: 12/05152-0 - Molecular evolution of regulatory regions of HOX genes associated with the morphology of fish fins, with special emphasis on Chondrichthyes
• Grantee: Murilo de Carvalho
• Support Opportunities: Scholarships in Brazil - Post-Doctoral