220-6 Triceratops Specimens from the Glenrock Exposure of the Lance Formation

Session: Life and Environments Through Time and Space: Multi-Record Approaches to Stratigraphic Paleobiology (Posters)

Poster Booth No.: 132

Presenting Author:

Monika Angner

Authors:

Angner, Monika Devin¹, Price, Madison², Steelman, William³, Persons, Walter Scott⁴

(1) Geology, College of Charleston, Charleston, SC, USA, (2) Geology, College of Charleston, Charleston, SC, USA, (3) Geology, College of Charleston, Charleston, SC, USA, (4) Geology, College of Charleston, Charleston, SC, USA,

Abstract:

The Glenrock Exposure is a roughly 0.26 km outcrop of the Lance Formation (Upper Cretaceous).  Since 1995, the Glenrock Paleon Museum has excavated and prepared fossil material from this exposure. This work has uncovered multiple large skeletal deposits, trackways, and micro-vertebrate assemblages. Throughout, large ceratopsians (predominantly Triceratops) material is more common than that of any other dinosaur. ​This project reports on 10 partial ceratopsian skeletons from the Glenrock Exposure that are ascribable to the Triceratopsini –a tribe of derived ceratopsians including Triceratops and Torosaurus. This material includes a juvenile orbital horn core (17.5 cm long), elements with tooth marks diagnostic of tyrannosaurs, and two narial horns identifiable as Triceratops prorsus (T. prorsus) and Triceratops horridus (T. horridus). The Lance Formation is stratigraphically equivalent to the Hell Creek Formation. Past research in the Hell Creek Formation has proposed the stratigraphic separation of Triceratops morphospecies, with T. prorsus restricted to the upper member and T. horridus restricted to the lower member. The two diagnostic Glenrock specimens are consistent with this stratigraphic pattern. Obtaining a larger number of diagnostic specimens from the Lance Formation would allow independent testing of the stratigraphic relationship between T. prorsus and T. horridus to further support research on Triceratops evolution.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-8743

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