This research project was the basis of my PhD thesis at George Mason University. Here is a brief description of the problem, method, and results of this research:
Problem
Undescribed/historically described paleontological specimens carry limited (to no!) information on species that were once part of ancient ecosystems, and are missing data on the diversity, disparity, anatomy, and evolutionary relationships of past life.
Methods
visited the museum collections, took measurements, photographs, and notes on specimens, put them in an analysis of evolutionary relationships for the first time.
Results
(1) Squalodon bellunensis illustrates the key features of the Squalodontidae found by Nelson et al. (2025a), supporting those taxonomic findings, however morphology of the periotic demonstrates it is a unique species of Squalodon.
(2) Squalodon peregrinus is formally identified and described as a unique species of Squalodon with a unique cranial morphology that strongly suggests S. peregrinus occupied a very different ecological niche relative to other members of Squalodon.
(3) Our phylogenetic results are consistent with past studies and suggest that a unique speciation event occurred in the proto-Mediterranean.
(4) The trace fossil Osspecus on the mandible of S. bellunensis demonstrates that the bone-eating worm Osedax was present in shallow marine/deltaic environments in the Early Miocene; shark predation/scavenging on small odontocetes is evident.
(5) Specimens of S. bellunensis exhibit heavy tooth wear compared to other species of Squalodon. This tooth wear indicates heavy tooth-on-tooth action, suggesting that S. bellunensis utilized a more macrophagous feeding strategy.
Works Cited
Nelson, M. D., Lambert, O., & Uhen, M. D. (2025). Reassessment of the iconic Oligo-Miocene heterodont dolphin Squalodon: a redescription of the type species S. grateloupii. Papers in Palaeontology.