10-3 An unusual vertebrate microfossil bonebed from the Oldman Formation of Alberta preserving an early occurrence of Habrosaurus and abundant trematode-infected molluscs

Session: Undergraduate and Graduate Geoscience Student Showcase (Posters)

Poster Booth No.: 60

Presenting Author:

Kyleigh Podjuban

Authors:

Podjuban, Kyleigh Marina¹, Cullen, Thomas², Brinkman, Donald³, Ryan, Michael⁴, Evans, David⁵, Bhat, Shafi⁶, Fanti, Federico⁷

(1) Department of Geosciences, Auburn University, Auburn, AL, USA, (2) Department of Geosciences, Auburn University, Auburn, AL, USA, (3) Department of Research and Collections, Royal Tyrell Museum of Palaeontology, Drumheller, Canada, (4) Department of Earth Sciences, Carleton University, Ottawa, Canada, (5) Department of Natural History, Royal Ontario Museum, Toronto, Canada, (6) Department of Geosciences, Auburn University, Auburn, AL, USA, (7) Department of Biological, Geological, and Environmental Sciences, University of Bologna, Bologna, Italy,

Abstract:

Across the fossil record of western North America, vertebrate microfossil bonebeds have been incredibly important for reconstructing paleocommunity dynamics and recording the presence of poorly preserved small-bodied animals. The discovery of a new vertebrate microfossil bonebed in the upper Oldman Formation of the Belly River Group in southeastern Alberta, Canada could provide a new link between the more well-drained, inland sites in the underlying Oldman Formation and the more coastally-influenced sites in the overlying Dinosaur Park Formation. In this area of southern Alberta, the time-transgressive nature of these formations means that the uppermost Oldman Formation around the Milk River is roughly time-equivalent to the lower Dinosaur Park Formation in the better-studied localities further north in Dinosaur Provincial Park. This new site hosts an unusual fossil assemblage characterized by a low presence or almost complete lack of taxa like Myledaphus, turtles, and small theropods, while being in high abundance of teleost fishes, amphibians, lizards, and a few notable taxa like the recently described teleost, Acronichthys, and the sirenid amphibian, Habrosaurus. Along with the unusual assemblage of vertebrate microfossils, the site also hosts a large diversity of gastropods as well as trematode-infected bivalve shells. These infected shells, coupled with the described lithology of the site, gives us more information about what the paleoenvironment of the site may have looked like. We interpret the site as recording the first pulses of a regional transgressive cycle as we shift from the uppermost sections of the Oldman Formation to the lower and middle Dinosaur Park Formation.

Geological Society of America Abstracts with Programs. Vol. 58, No. 1, 2026

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