News Release

Diversity decline in mackerel sharks

Peer-Reviewed Publication

Proceedings of the National Academy of Sciences

Researchers examine factors influencing shark diversity. A multitude of factors, including variations in speciation and extinction rates, determines species richness, but the causes of lineage decline and disappearance are unclear. To better understand the diversity decline in mackerel sharks, Fabien L. Condamine and colleagues analyzed diversification and extinction models and compared the fossil records of extant and extinct species of mackerel sharks with the fossil records of extant and extinct species of ground sharks. In the early Late Cretaceous, mackerel shark diversity peaked at up to 3 times the current diversity. Over the last 20 million years, mackerel shark diversity declined. Younger mackerel shark species have a higher extinction rate than older species, and this extinction rate increased due to cooler temperatures during Cenozoic climate cooling as well as clade competition for resources. Cenozoic climate cooling may also have caused mackerel shark extinction to exceed speciation. Clade competition with ground sharks also influenced the diversification of medium and large mackerel sharks, though the largest mackerel sharks exhibited some of the lowest extinction and speciation rates. The results suggest that both abiotic and biotic factors influence the diversity of marine apex predators, according to the authors.

Article #19-02693: "Climate cooling and clade competition likely drove the decline of lamniform sharks," by Fabien L. Condamine, Jules Romieu, and Guillaume Guinot.

MEDIA CONTACT: Fabien L. Condamine, French National Centre for Scientific Research, Montpellier, FRANCE; tel: +33-674932296; email: fabien.condamine@gmail.com

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