All articles tagged with #viviparity
Analysis of a 236-million-year-old cynodont fossil from Argentina reveals a neonatal bone line indicating live birth, with a newborn mass around 1.68 kg (about 10–20% of an adult), suggesting viviparity originated in the mammalian lineage far earlier than thought (roughly 90–95 million years ago) and proposing two plausible evolutionary scenarios for this trait's emergence.
Brazilian and Uruguayan fossils from the Early Permian reveal 280-million-year-old mesosaur embryos preserved inside adults and an isolated egg, suggesting mesosaurs may have retained embryos in the uterus or laid eggs at late development; this finding pushes the oldest known amniote embryos and earliest viviparity back by about 60 million years, offering rare insights into reproduction and potential parental care in Paleozoic reptiles.
Researchers report 280-million-year-old mesosaur embryos from Brazil and Uruguay, providing the oldest direct evidence that these ancient aquatic reptiles could give birth to live young, pushing the origin of viviparity back about 60 million years; findings also indicate potential parental care, with some fossils suggesting a mixed strategy where at least one egg was found at an advanced stage of development.
Researchers in Taiwan discovered the first fossils of five freshwater mollusk species from the Early Pleistocene, including rare evidence of a juvenile snail shell inside its mother's shell, indicating ancient live birth behavior. This finding sheds light on the early biogeography and reproductive strategies of freshwater snails in East Asia, highlighting Taiwan's role as a migratory corridor during glacial periods and providing crucial insights into the evolution of freshwater biodiversity.