NEWS - Palaeontologists have been able to measure the lifespan and growth rates of ancient animals and even when they reached sexual maturity. The Jurassic period appears to have been a crucial time for this change. The typical mammalian life history pattern, characterized by a high metabolic rate and a long nurturing phase, has evolved over millions of years.
Researchers from Queen Mary University of London and the University of Bonn studied growth rings in fossilized tooth roots to determine the growth stages of Jurassic animals. This is the first time that researchers have been able to reconstruct the growth patterns of ancient mammals in such detail.
Elis Newham from Queen Mary University and his team analysed the tooth roots of mammal species from the Early to Late Jurassic (200-150 million years ago) found at three separate sites. The fossils from Wales represent mammals from the Early Jurassic, while the fossils from Oxfordshire represent a variety of early mammals that lived side by side and the fossils from Portugal are from the Late Jurassic.
The team used a technique called synchrotron X-ray tomography, which does not require cutting up the fossils and allows them to be analysed as a whole. Furthermore, the images obtained are of higher quality than those obtained from conventional X-ray microtomography.
Researchers have been able to detail tiny growth rings in the cement of fossil roots that attach teeth to jaws. The rings are similar to those in trees, but on a microscopic scale. By counting the rings, analyzing their thickness and texture, they can reconstruct the growth patterns and lifespans of these extinct animals.
Early mammals grew much more slowly but lived much longer than today’s small mammals. Lifespans ranged from 8 to 14 years, rather than the 1 or 2 years of modern mice. However, early mammals took years to reach sexual maturity, unlike their modern descendants, who reach sexual maturity in just a few months.
Original research
Elis Newham et al. The origins of mammal growth patterns during the Jurassic mammalian radiation. Science Advances. 10, eado4555 (2024). DOI:10.1126/sciadv.ado4555
Researchers from Queen Mary University of London and the University of Bonn studied growth rings in fossilized tooth roots to determine the growth stages of Jurassic animals. This is the first time that researchers have been able to reconstruct the growth patterns of ancient mammals in such detail.
Elis Newham from Queen Mary University and his team analysed the tooth roots of mammal species from the Early to Late Jurassic (200-150 million years ago) found at three separate sites. The fossils from Wales represent mammals from the Early Jurassic, while the fossils from Oxfordshire represent a variety of early mammals that lived side by side and the fossils from Portugal are from the Late Jurassic.
The team used a technique called synchrotron X-ray tomography, which does not require cutting up the fossils and allows them to be analysed as a whole. Furthermore, the images obtained are of higher quality than those obtained from conventional X-ray microtomography.
Researchers have been able to detail tiny growth rings in the cement of fossil roots that attach teeth to jaws. The rings are similar to those in trees, but on a microscopic scale. By counting the rings, analyzing their thickness and texture, they can reconstruct the growth patterns and lifespans of these extinct animals.
Early mammals grew much more slowly but lived much longer than today’s small mammals. Lifespans ranged from 8 to 14 years, rather than the 1 or 2 years of modern mice. However, early mammals took years to reach sexual maturity, unlike their modern descendants, who reach sexual maturity in just a few months.
Original research
Elis Newham et al. The origins of mammal growth patterns during the Jurassic mammalian radiation. Science Advances. 10, eado4555 (2024). DOI:10.1126/sciadv.ado4555