The study looks at early cartilaginous fish evolution using Bayesian tip dating methods. It finds that total-group chondrichthyans evolved in the Middle Ordovician and that major acanthodian clades diverged from the stem in quick succession, making this early radiation difficult to resolve
New Research Article published in OPal 🔬
Respiratory structures in cornute stylophorans (Echinodermata)
By Christophe Dupichaud, Bertrand Lefebvre, Ninon Allaire, Enzo Birolini, Malo Meyruey, and Martina Nohejlová
www.openpalaeo.org/article/view...
Stylophorans are an extinct class of Paleozoic echinoderms with complex morphology. In general, they lack the radial symmetry typical of other echinoderms. Given their occurrence in the Cambrian, this group is often studied to understand the basic nature and origination of the metazoan body plan.