Eoneophron
From Greek eos, 'dawn/early', + Neophron (genus of Egyptian vulture); means 'dawn Neophron', drawing a comparison to the vulture genus and emphasizing its early appearance
Late Cretaceous stages
Eoneophron is an extinct genus of caenagnathid theropod dinosaur from the Late Cretaceous Hell Creek Formation of South Dakota, US. The genus contains a single species, E. infernalis, known from a partial hindlimb.
Diagnosis
- Astragalocalcaneum fused to tibia at maturity (tibiotarsus coossification), unique within Caenagnathoidea
- Shaft of metatarsal IV with a well-developed oblique longitudinal ridge on anterior surface extending along the distal three-quarters of the shaft
- Femoral head directed dorsomedially rather than perpendicular to shaft, meeting long axis at obtuse angle (~100°)
- Distal tarsal IV coossified with proximal end of metatarsal IV at maturity
- Proximal ends of metatarsals III and IV project posteriorly to form a proximal protuberance
Species
Eoneophron infernalis Atkins-Weltman et al., 2024
Type species
From Latin 'infernalis' meaning 'of hell', referencing the Hell Creek Formation in which the fossil material was discovered.
- Holotype
- CM 96523 , Carnegie Museum of Natural History
- Material
- Partial right hindlimb: femur, tibia with fused astragalocalcaneum, metatarsals III and IV
- Horizon
- Hell Creek Formation, Maastrichtian, Late Cretaceous , 72.2–66.0 million years ago
- Locality
- South Dakota, United States
References
- Atkins-Weltman, K. L.; Simon, D. J.; Woodward, H. N.; Funston, G. F.; Snively, E. (2024). A new oviraptorosaur (Dinosauria: Theropoda) from the end-Maastrichtian Hell Creek Formation of North America. PLOS ONE 19(1): e0294901. Public Library of Science (PLoS). doi:10.1371/journal.pone.0294901 atkins-weltman2024a
-
Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Theropods. Princeton University Press.
Source of the body length estimate.
jones2026c