Search results for "Galeaspida"

Functional assessment of morphological homoplasy in stem-gnathostomes

2021

Osteostraci and Galeaspida are stem-gnathostomes, occupying a key phylogenetic position for resolving the nature of the jawless ancestor from which jawed vertebrates evolved more than 400 million years ago. Both groups are characterized by the presence of rigid headshields that share a number of common morphological traits, in some cases hindering the resolution of their interrelationships and the exact nature of their affinities with jawed vertebrates. Here, we explore the morphological and functional diversity of osteostracan and galeaspid headshields using an innovative approach that combines geometric morphometrics and computational fluid dynamics, thereby constraining the underlying fa…