Big thanks to Ted Daeschler for advising me as an undergrad on this project, and to my coauthors A.R Cicarrielo, and @nshubin.bsky.social for their work on this project.

My first lead-author paper! Meet Onychodus mikijuk from the Late Devonian Nordstrand of the Canadian Arctic. A small new addition to a very strange group of lobe-finned fishes.

I think those may be vestigial lower tusk alveoli. Perhaps there were deciduous lower tusks there early in life? There is a juvenile specimen from the type locality of the Nebraska Megabelodon (M.lulli) but I am unsure if the presence/absence of tusks is conclusive there.

Maybe. Li et al 2024’s tree recovered Megabelodon and Eubelodon as early diverging Amebelodonts.

Some have suggested Megabelodon could be a Choerolophodont. The Nebraska Megabelodon specimens have downturned upper tusks with enamel bands, unlike even the most primitive Asian Choerolophodonts, which makes me doubt that.

Finite element analysis. Like what Li et al., (2024) used here for Gomphotherium, Platybelodon, and Choerolophodon. elifesciences.org/articles/90908

FEA could be a powerful tool for testing what’s up with the long tuskless mandibles of Megabelodon and Eubelodon.

Megabelodon’s funky spoonbill mandible seems like it must have been good for something. NM and NE Megabelodon both have large anterior mental foramina with a long tube like fossa leading to that spoonbill, but what the soft tissue pad/lower lip looked like remains uncertain.