TY - JOUR TI - Evolution of viviparous reproduction in Paleozoic and Mesozoic reptiles AU - Blackburn, DanielG. AU - Sidor, ChristianA. T2 - The International Journal of Developmental Biology AB - Although viviparity (live-bearing reproduction) is widely distributed among lizards and snakes, it is entirely absent from other extant Reptilia and many extinct forms. However, paleontological evidence reveals that viviparity was present in at least nine nominal groups of pre-Cenozoic reptiles, representing a minimum of six separate evolutionary origins of this reproductive mode. Two viviparous clades (sauropterygians and ichthyopterygians) lasted more than 155 million years, a figure that rivals the duration of mammalian viviparity. Circumstantial evidence indicates that extinct viviparous reptiles had internal fertilization, amniotic fetal membranes, and placentas that sustained developing embryos via provision of respiratory gases, water, calcium, and possibly organic nutrients. Production of offspring via viviparity facilitated the invasion of marine habitats in at least five reptilian lineages. Thus, this pattern of embryonic development and reproduction was central to the ecology and evolution of these ancient animals, much as it is to numerous extant species of vertebrates. PY - 2014 DO - 10.1387/ijdb.150087db VL - 58 IS - 10-11-12 SP - 935 EP - 948 J2 - Int. J. Dev. Biol. LA - en SN - 0214-6282 SN - 1696-3547 UR - https://ijdb.ehu.eus/article/150087db Y2 - 2024/11/21/19:07:04 ER -