Paleontology: early mammals were fast-paced and short-lived | Nature | nature wallet

One of the oldest large mammals that appeared after the age of dinosaursPantulamda Bathmodongrow twice as fast and live shorter than modern mammals of similar body size, reports this week’s newspaper.temper nature They will be published in the study revealing the unique life history of this species in prehistoric times and help explain how mammals came to dominate after the extinction of the dinosaurs.

Mammals diversified and grew in size in response to the extinction of the dinosaurs. Rodent mammals are known to be the oldest taxa among the large herbivores that appeared during this period. Formidable mammals evolved into a variety of forms, but became extinct in the Eocene, and their relationship to later mammals is unknown. In this study, Gregory Funston, Steve Brusatte and colleagues used a variety of methods (including dental trace element mapping) to identify a mammal of . Age 62 million years.Pantulamda BathmodonThe clearest life history has an estimated gestational period of about 7 months, consistent with the gestation period of modern mammals of similar body size, butP. bathmodonThey have been found to grow faster and have a shorter life span. Juveniles are born advanced, are weaned within one to two months, and die before they reach the age of ten.

No modern mammal displays such a life history.P. bathmodonReproductively similar to placental mammals, they lived at an unusually fast pace for their large body size. Our findings suggest that long gestation periods were already in existence 62 million years ago, and that the large body size of the offspring may have contributed to the rapid growth observed in early placental mammals, suggesting sexual activity.

doi: 10.1038/s41586-022-05150-w

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