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in Lu, Deng, Rummy, Zheng et Zhang, 2023. Illustration by Chung-Tat Cheung facebook.com/ChungTatCheung |
Highlights:
• Fossil rhinoceros from 18 mya is monotocous
• Reproductive traits in living rhinoceroses have been evolving at least since 18 mya
• Litter size of perissodactyls has an origin of singleton pregnancy
Summary
Reproductive strategy is among the most important characteristics of organism. Here, we report reproductive strategy of singleton pregnancy of a fossil rhinoceros, Plesiaceratherium gracile, from 18 mya of the Shanwang Basin, China. Dental and body development data revealed that after birth, the calf of P. gracile is breastfed for 2–3 years; at approximately 5 years of age, when the M2 tooth is slightly worn, the female has already reached sexual maturity and attained a size close to that of an adult and could give birth to the first calf. Furthermore, given litter size is phylogenetically conservative and closely correlates with body size, we conclude that the litter size of perissodactyls is determined by the singleton pregnancy since the Eocene. By contrast, other reproductive traits are highly variable and have a different pace of evolution, and traits observed in living rhinoceroses have been evolving at least since 18 mya.
Xiao-Kang Lu, Tao Deng, Paul Rummy, Xiao-Ting Zheng and Yuan-Tao Zhang. 2023. Reproduction of A Fossil Rhinoceros from 18 mya and Origin of Litter Size in Perissodactyls. iScience. 26(10); 107800. DOI: 10.1016/j.isci.2023.107800
