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| Ueloca colemanorum Gentry, Burns, Ebersole, Gregson, Martinez & Parham, 2025 |
Abstract
The modern leatherback sea turtle Dermochelys coriacea possesses a unique, flexible mosaic carapace adapted for deep diving. The evolutionary origins of this structure remain poorly understood because of the fragmentary nature of the fossil record. Here we describe Ueloca colemanorum n. gen. n. sp., a novel ridgeless leatherback turtle from the lower Oligocene Glendon Limestone of Alabama, USA. This specimen (MSC 49490) represents one of the most complete fossil leatherback carapaces known and provides new insight into dermochelyid diversity and shell evolution. The carapace is composed of parallel rows of enlarged ossicles interspersed with smaller ossicles arranged in distinctive floriform patterns. Histological analysis reveals a cancellous core with an external cortex but no basal cortex, a condition also observed in Dermochelys coriacea. Phylogenetic analysis places Ueloca within a clade of ridgeless leatherbacks (Uelocini), which diverged from ridge-bearing Dermochelyini in the Eocene. Our revised phylogeny suggests that Uelocini and Dermochelyini represent the two main lineages of dermochelyines, both characterized by mosaic carapaces that undergo parallel morphological trends. These findings clarify the deep history of leatherback shell evolution and emphasize the need for additional well-preserved fossils to further refine dermochelyid systematics.
KEYWORDS: Dermochelys, Glendon Limestone Member, Gulf Coastal Plain, North America
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| Ueloca colemanorum n. gen. n. sp. from the lower Oligocene of Alabama, USA. A, B – MSC 49490, holotype, carapace in dorsal view. Scale bar = 10 cm. |
Dermochelyinae Weems, 1988
Uelocini new clade
Ueloca new genus
Etymology: The generic name, Ueloca (pronounced Wee-low-juh), is a Mvskoke (Creek) name derived from the Mvskoke words “Uewv” for water and “Loca” for turtle. This name honors the indigenous people of southern Alabama and serves as recognition of the contributions of Poarch Creek Indian tribal members to this project.
Ueloca colemanorum n. gen. n. sp.
Ueloca colemanorum new species
Etymology: The species name, colemanorum, honors the Coleman family (Adrienne, Adam, Talah, and Corey) of Mobile, Alabama, who discovered MSC 49490 and then dedicated an extraordinary amount of time, energy, and resources to its recovery.
Holotype: MSC 49490.
Occurrence: Site AMo-10, Monroe County, AL, USA. Lower Oligocene (Rupelian) Glendon Limestone Member of the Byram Formation (NP 22, 33–32 Ma).
Diagnosis: Ueloca colemanorum can be differentiated from most dermochelyids by an absence of carapacial ridges and by having a carapace with parallel, anteroposteriorly oriented rows of enlarged ossicles and clusters of ossicles arranged in floriform or ‘sunflower’ patterns. U. colemanorum. can be distinguished from other ridgeless dermochelyids with floriform ossicle patterns (Ca. rupeliensis and N. peruvianus) by having unsculptured ossicles that regularly exceed 4 cm in length, that are not associated with either floriform patterns or rows of enlarged ossicles, lacking deeply interdigitating ossicle sutures, and having central ossicles of floriform patterns which are only moderately scalloped.
Andrew D. Gentry, Michael E. Burns, Jun A. Ebersole, Kimberly A. Gregson, Emma C. Martinez and James F. Parham. 2025. A New Leatherback Marine Turtle from the lower Oligocene of North America and A Phylogenetic Nomenclature for Dermochelyidae. Palaeodiversity. 18(1):127-149. DOI: doi.org/10.18476/pale.v18.a6 [12 September 2025]
