Boom and bust: ancient and recent diversification in bichirs (Polypteridae: Actinopterygii), a relictual lineage of ray-finned fishes.

摘要: Understanding the history that underlies patterns of species richness across Tree Life requires an investigation mechanisms not only generate young species-rich clades, but also those maintain species-poor lineages over long stretches evolutionary time. However, diversification dynamics underlie ancient are often hidden due to a lack fossil evidence. Using information from record and time calibrated molecular phylogenies, we investigate lineage in Polypteridae, which is sister all other ray-finned fishes (Actinopterygii). Despite originating at least 390 million years (Myr) ago, timetrees support Neogene origin for living polypterid species. Our analyses demonstrate polypterids exceptionally depauperate with stem duration exceeds 380 (Ma) significantly longer than durations observed fish lineages. Analyses show early Late Cretaceous (100.5-83.6 Ma) peak genus richness, followed by 60 Ma low richness. The radiation evidence high-diversity intervals geological past suggest "boom bust" pattern contrasts common perceptions relative stasis so-called "living fossils."