The nearshore cradle of early vertebrate diversification
Authors: Lauren Sallan, Matt Friedman, Robert Sansom, Charlotte Bird, Ivan Sansom
Publication Date: 26 October, 2018
School of: Earth and Environmental Sciences
Where did our early ancestors originate and diversify?
Most of what we know about the relationship between evolutionary diversifications and environments is based on ancient marine invertebrates. The influence of the environment on the evolution our own fishy vertebrate ancestors previously remained a mystery. Together researchers at the Universities of Manchester, Pennsylvania, Birmingham, and Michigan assembled a new large dataset for fossil vertebrates and their occurrences. Applying knowledge of evolutionary relationships to the distributions of species in different times and environments, the researchers demonstrated that diversifications took place in shallow near shore environments, for example lagoons. From there, many lineages subsequently, and repeatedly, colonised deeper marine and freshwater habitats. These dispersals were also related to body shape – robust forms remained near-shore whilst gracile forms moved into deeper water. These evolutionary dynamics and dispersals have been be linked to the mobility of the vertebrates, and may have influenced the structure of their early fossil record and diversification.
- Our early evoltuionary origins as vertebrates are well documented in the fossil record of jawless and jawed fishes
- Reconstructing the relationships and environments of these early representatives has revealed the dynamics of evoluiton
- Our ancestors diversified in shallow marine environments and repeatedly dispersed from there into deep sea and freshwater environments
- These dispersals were also related to the robust and armoured body forms of these early fish