of egg fossils in the paleozoic amniote fossil record. One Mesosaurus specimen called MCN-PV 2214 comprises a medium-size adult with a small individual in its rib cage which is interpreted as a fetus ‘in utero’, even suggesting that Mesosaurus like many other marine reptiles, gave live birth. If this interpretation is correct, this specimen would represent the earliest known example of viviparity in the fossil record. The isolated fetus FC-DPV 2504, however, rather points to an ovoviviparous reproduction strategy in Mesosaurus. A study on vertebral column proportions suggested that, while young Mesosaurus might have been fully aquatic, adult animals spent some time on land. This is supported by the rarity of adult animals in aquatic settings, and a coprolite possessing drying fractures. However, how terrestrial these animals were is difficult to say, as their pachyostosis and other adaptations for an aquatic lifestyle would have made foraging on land difficult. Distribution Mesosaurus was significant in providing evidence for the theory of continental drift, because its remains were found in southern Africa, Whitehill Formation, and eastern South America (Melo Formation, Uruguay and Irati Formation, Brazil), two widely separated regions. As Mesosaurus was a coastal animal, and therefore less likely to have crossed the Atlantic Ocean, this distribution indicated that the two continents used to be joined together. Gallery References Further reading Parker, Steve. Dinosaurus: the complete guide to dinosaurs. Firefly Books Inc, 2003. Pg. 90 Prehistoric marine reptiles Prehistoric reptile genera Permian reptiles of Africa Fossils of Namibia Fossils of South Africa Permian reptiles of South America Permian Brazil Fossils of Brazil Permian Uruguay Fossils of Uruguay Paraná Basin Fossil taxa described in 1865 Taxa named by Paul Gervais