A Middle Eocene Haplorhine Frontal Bone From the Tornillo Basin of Texas, and Its Implications for the Phylogenetic Relationships of Rooneyia and Other Paleogene Primates.
Document Type
Article
Publication Date
4-1-2025
Abstract
OBJECTIVES: Here we describe a well-preserved primate frontal bone (TMM 46513-1) recovered from Middle Eocene exposures of the Devil's Graveyard Formation in the Tornillo Basin of Texas. We also discuss the significance of frontal bone morphology for understanding early haplorhine phylogeny.
MATERIALS AND METHODS: TMM 46513-1 was mechanically prepared, μCT scanned, and compared with a broad array of extant and fossil crown primates. Revised dates for the specimen were provided using 40Ar/39Ar geochronology. Dice-CT scans of Saguinus were used to investigate the contents of bony canals found within the frontal bones of many euarchontans.
RESULTS: TMM 46513-1 resembles Rooneyia viejaensis in several key features, including: (1) the presence of a ventral flange on the lateral process of the frontal that intervenes between the posterosuperior orbit and temporal fossa, (2) the presence of a bony canal system ("orbitofrontal canal") within the frontal that connects a foramen on the posterior aspect of the lateral process ("lateral process foramen") with the superomedial orbit and the anterior cranial fossa, (3) a metopic suture that is unfused at its rostral end but obliterated at its caudal end, and (4) an anterior cranial fossa that overlaps the posteromedial portions of the orbits.
CONCLUSIONS: The lateral segment of the orbitofrontal canal and substantial ventral expansion of the lateral process are features restricted to the Haplorhini among crown primates. The morphological features shared by TMM 46513-1 and Rooneyia suggest that they may be stem haplorhines, but are less consistent with the hypothesis that Rooneyia is a stem anthropoid.
Publication Title
American Journal of Biological Anthropology
Volume
186
Issue
4
First Page
70045
Last Page
70045
PubMed ID
40214110
Recommended Citation
Kirk, E Christopher; Campisano, Christopher J; Deino, Alan L; Egberts, Sebastian; Kemp, Addison D; Lundeen, Ingrid K; and Rodwell, Benjamin, "A Middle Eocene Haplorhine Frontal Bone From the Tornillo Basin of Texas, and Its Implications for the Phylogenetic Relationships of Rooneyia and Other Paleogene Primates." (2025). PCOM Scholarly Works. 2311.
https://digitalcommons.pcom.edu/scholarly_papers/2311
DOI: https://doi.org/10.1002/ajpa.70045
Comments
This article was published in American Journal of Biological Anthropology, Volume 186, Issue 4.
The published version is available at https://doi.org/10.1002/ajpa.70045.
Copyright © 2025 Wiley Periodicals LLC.