The ancestors of primates and marsupials are one of the only arboreal mammals that survived the k-pg extinction
Arboreal species are particularly at risk of extinction due to global deforestation caused by wildfires caused by asteroid impacts. In this study, computer models, fossil records and information from living mammals show that most surviving mammals do not rely on trees, although a few surviving arboreal mammals – including human ancestors – may have enough flexibility to adapt to the disappearance of trees
the study points out that this extinction event is the so-called Cretaceous Paleogene extinction event (k-pg event for short) has an impact on shaping the early evolution and diversity of mammals.
Jonathan Hughes, the co-first author of the paper and a doctoral student in Jeremy Searle laboratory, Professor of ecology and evolutionary biology, School of agriculture and Life Sciences, said: “Although primates are arboreal, one possible explanation for how they survive across the k-pg boundary is the flexibility of some behaviors, which may be a key factor for their survival.” co first author Jacob berv is currently a life science researcher at the University of Michigan.
the study was published on October 11, 2021 In the journal ecology and evolution.
the earliest mammals appeared about 300 million years ago and may have diversified synchronously with the expansion of flowering plants about 20 million years before the k-pg event. Hughes said that many strains of these mammals became extinct when the asteroid hit.
Hughes said: “At the same time, the surviving mammals have diversified in all the new ecological environments opened up after the extinction of dinosaurs and other species.”
in this study, researchers used published mammalian phylogeny maps (tree branch diagram showing the evolutionary relationship between biological groups) Then, based on these phylogenies, they divided each living mammal into three categories – arboreal, semi arboreal and non arboreal – based on their favorite habitats. They also designed computer models to reconstruct the evolutionary history of mammals.
mammalian fossils near k-pg are very rare and difficult to explain animal habitat preferences. Researchers Compare the information of known living mammals with existing fossils to help provide additional background for their results.
in general, these models show that the surviving species in the k-pg event are mainly non arboreal, with two possible exceptions: primate ancestors and marsupials. In each model, primate ancestors and their close relatives It was found to be arboreal before the k-pg event. The ancestors of marsupials were found to be arboreal in half of the model reconstruction.
the researchers also examined how mammals as a group changed over time. Hughes said: “We can see that before the k-pg event, about that time period, there was a great peak in the transition from arboreal and semi arboreal to non arboreal, so we see not only most non arboreal (species), but things are rapidly transitioning from arboreal to non arboreal.”