These ancient fish swam our Cretaceous seas 122-109 million years ago. Interestingly, we've been able to recover complete fossilized hearts from this species using X-ray synchrotron microtomography.
Lara Maldanis and her team published a paper on this back in 2016. They were looking at the evolution of cardiac outflow tracts in vertebrates and had a breakthrough moment when an x-ray revealed enough detail to show that Rhacolepis hearts contain a conus arteriosus containing at least five-valve rows making them a transitional morphology between the primitive, multivalve, conal condition and the derived, monovalvar, bulbar state of the outflow tract in modern actinopterygians.
Le premier et unique géoparc mondial UNESCO est situé dans le Cariri du Ceará (géoparc Araripe), dans l'intérieur semi-aride de la région Nordeste, Brésil. Reference: Maldanis et al. (2016) Heart fossilization is possible and informs the evolution of cardiac outflow tract in vertebrates.
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