What does the rapid rise of ichthyosauromorphs tell us about marine ecosystem recovery in the Triassic?
Ichthyosaurs were a group of Mesozoic marine reptiles that became perfectly adapted to life in the open ocean and evolved streamlined bodies strikingly similar to those of modern dolphins. Ichthyosaurs and their close relatives – hupehsuchians and nasorostrans (grouped together within Ichthyosauromorpha) – first appeared around 250 million years ago, shortly after the Permian-Triassic Mass Extinction (PTME). Whereas huephsuchians and nasorostrans are known only from the Early Triassic, ichthyosaurs remained important predators in Mesozoic seas until their extinction in the early Late Cretaceous. Because predators are sensitive to environmental stress, understanding the evolutionary dynamics of ichthyosauromorphs can help us illuminate the tempo and mode of marine ecosystem recovery after the PTME. It is currently thought that marine ecosystems did not fully regenerate from the PTME until the Middle Triassic, but fossils of a diverse array of ichthyosauromorphs discovered in South China in the last decade suggest a more rapid ecosystem recovery, indicating complex food webs were already established in the Early Triassic. However, this view is based mostly on studies of ichthyosauromorphs and other marine reptiles from shallow marine environments, but relatively little is known about ecosystem recovery in the open ocean.
Nature Portfolio Ecology & Evolution Community
Ichthyosaurs were a group of Mesozoic marine reptiles that became perfectly adapted to life in the open ocean and evolved streamlined bodies strikingly similar to those of modern dolphins. Ichthyosaurs and their close relatives – hupehsuchians and nasorostrans (grouped together within Ichthyosauromorpha) – first appeared around 250 million years ago, shortly after the Permian-Triassic Mass Extinction (PTME). Whereas huephsuchians and nasorostrans are known only from the Early Triassic, ichthyosaurs remained important predators in Mesozoic seas until their extinction in the early Late Cretaceous. Because predators are sensitive to environmental stress, understanding the evolutionary dynamics of ichthyosauromorphs can help us illuminate the tempo and mode of marine ecosystem recovery after the PTME. It is currently thought that marine ecosystems did not fully regenerate from the PTME until the Middle Triassic, but fossils of a diverse array of ichthyosauromorphs discovered in South China in the last decade suggest a more rapid ecosystem recovery, indicating complex food webs were already established in the Early Triassic. However, this view is based mostly on studies of ichthyosauromorphs and other marine reptiles from shallow marine environments, but relatively little is known about ecosystem recovery in the open ocean.
Nature Portfolio Ecology & Evolution Community