SPAWN TILL YOU DIE: THE RISE, FALL AND TRANSCENDENCE OF EDESTOID SHARKS

Chondrichthyans belonging to the Edestoidae have unique dentitions concentrated in spiral whorls in the symphysis of the jaw. The curious arrangement of teeth coupled with the usual lack of anatomical context has made the edestoids fodder for a wide range of artistic reconstructions. How did these bizarre tooth whorls evolve in the first place? New methods in visualizing historic edestoid fossils of Edestus, Parahelicoprion, Sinohelicoprion, Helicoprion, and Toxoprion are testing many preconceptions of the group, and through the iterative process of artistic renderings, we are making headway to elucidate the form, function and phylogeny of the group. Edestoid fossils span Pennsylvanian–Triassic time and are found primarily along the margins and inland seas of ancient Pangaea, from the Russian platform to the arctic and western interior of Laurentia. The range of morphological specialization in the detention is remarkable. Current taxonomy emphasizes the orientation of the base of teeth, but differences in tooth fusion, tooth count, spiral curvature and growth may further support phylogenetic trajectories observed in the crown members of the clade.