School of Engineering and Materials Sciences, Queen Mary University of London, London, UK.
Section Palaeontology, Bonn Institute of Organismic Biology, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany.
Sci Adv. 2024 Aug 9;10(32):eado4555. doi: 10.1126/sciadv.ado4555. Epub 2024 Aug 7.
We use synchrotron x-ray tomography of annual growth increments in the dental cementum of mammaliaforms (stem and crown fossil mammals) from three faunas across the Jurassic to map the origin of patterns of mammalian growth patterns, which are intrinsically related to mammalian endothermy. Although all fossils studied exhibited slower growth rates, longer life spans, and delayed sexual maturity relative to comparably sized extant mammals, the earliest crown mammals developed significantly faster growth rates in early life that reduced at sexual maturity, compared to stem mammaliaforms. Estimation of basal metabolic rates (BMRs) suggests that some fossil crown mammals had BMRs approaching the lowest rates of extant mammals. We suggest that mammalian growth patterns first evolved during their mid-Jurassic adaptive radiation, although growth remained slower than in extant mammals.
我们使用同步加速器 X 射线断层扫描技术对来自侏罗纪三个动物群的哺乳动物牙齿牙骨质中的年度生长增量进行研究，以绘制哺乳动物生长模式的起源图谱，这些模式与哺乳动物的温血特性内在相关。虽然所有研究的化石都表现出比现代哺乳动物更慢的生长速度、更长的寿命和更晚的性成熟，但最早的冠齿哺乳动物在生命早期的生长速度明显快于茎齿哺乳动物，而在性成熟时则降低。基础代谢率 (BMR) 的估计表明，一些化石冠齿哺乳动物的 BMR 接近现存哺乳动物的最低水平。我们认为，哺乳动物的生长模式首先在中侏罗世的适应辐射中进化，但仍然比现存哺乳动物慢。
