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| Infernogallus jamesi Funston, Dudgeon, Simon, Dufault, Boyd, Fowler, Currie & Evans, 2026 |
Abstract
The diversification of herbivorous dinosaurs and the rise of angiosperms in the Late Cretaceous are each well established, but the link between them is debated. Broad-scale diversity patterns in the two groups appear not to closely align, and there is no direct evidence of dinosaur adaptation to angiosperm-based diets. Here we describe Infernogallus jamesi gen. et. sp. nov., a diminutive caenagnathid oviraptorosaur, and show that these theropods were specialised herbivores that originated alongside the rise of fleshy angiosperm fruits. The nearly complete, articulated skull of Infernogallus jamesi—the first for the clade—reveals drastic changes to the adductor musculature organisation, unique in non-avian theropods but converged upon by extant frugivorous parrots. These modifications enabled extensive oral processing of soft food using anteroposterior movement of the mandible and occlusion of ridges and grooves on opposed elements. Altogether, this attests to a highly specialised herbivorous diet in caenagnathids, which likely consisted in large part of fleshy angiosperm fruits, which increased in size and diversity in concert with the radiation of oviraptorosaurs. Caenagnathids thus provide one of the strongest candidates for angiosperm-based diet adaptations in dinosaurs, but their role in the Late Cretaceous proliferation of fruit—which shaped early Cenozoic flora—remains unclear.
Systematic palaeontology
Theropoda
Oviraptorosauria
Caenagnathidae
Eucaenagnathinae Clade nov.
Definition. The most inclusive monophyletic group including Anzu wyliei and Elmisaurus rarus, but not Anomalipes zhaoi.
Diagnosis. Eucaenagnathines (meaning ‘true caenagnathids’) are distinguished from other caenagnathids by the morphology of the fused dentaries, with an upturned tomial edge marked with lateral and anterior occlusal ridges, and a midline sulcus bordered by longitudinal lingual ridges separated from the tomial edge by a lingual groove.
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| Infernogallus jamesi (ROM VP 65050). Photograph (a) and line drawing (b) of ROM VP 65050. c Skeletal reconstruction of Infernogallus jamesi based on ROM VP 65050 and other eucaenagnathines (shaded areas are preserved in ROM 65050). d Palaeohistological thin section of the femur of ROM VP 65050, showing lines of arrested growth (arrows) and an external fundamental system indicative of advanced age and skeletal maturity. cv cervical vertebrae, dv dorsal vertebrae, efs external fundamental system, fe femur, ga gastralia, hu humerus, il ilium, ma manus, pb pubis, pp plane-polarised light, sc scapulacoracoid, sk skull, tb tibia, xp cross-polarised light. Scale bars as indicated. |
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| Cranial anatomy of Infernogallus jamesi gen. et sp. nov. Photograph (a) and line drawing (b) of the skull of ROM VP 65050 in left lateral view. ... |
Infernogallus jamesi gen et. sp. nov. (Figs. 1–4)
Etymology. The name comes from the Latin “Inferno” (Hell) and “gallus” (chicken), referring to the Hell Creek Formation and the small, bird-like appearance of the species; “jamesi”, a patronym for James William Boyd, the paternal grandfather of author CAB, who sparked his interest in the field of palaeontology.
Holotype. ROM VP 65050, articulated partial skeleton including the skull, cervical and dorsal vertebrae, right pectoral girdle and forelimb, partial pelvic girdle, and partial right hindlimb. Paratypes. ROM VP 64193, dentaries; ROM VP 64194, articularsurangular-coronoid complex; ROM VP 88690, left and right pterygoids; NDGS 4351, dentaries.
Locality and horizon. Hell Creek Formation (late Maastrichtian), Garfield County, Montana; Meade County, South Dakota; and Bowman County, North Dakota, USA.
Diagnosis. Small (femur length 185 mm; est. 12 ± 3 kg body mass) caenagnathid oviraptorosaur diagnosed by the following autapomorphies: broad jugal with large anterior ascending process and which contacts the squamosal posteriorly; infratemporal fenestra extremely reduced, about 25% the diameter of the orbit; quadratojugal with greatly enlarged, circular posterior process; squamosal with dorsoventrally broad body lacking a depression and ridge for adductor musculature; pterygoids concave dorsally, unfused along the midline, and with a lateral buttress; ectopterygoid–pterygoid bar greatly expanded and extending far ventrally; long axis of vomer oriented ...
Gregory F. Funston, Thomas W. Dudgeon, D. Jade Simon, Danielle M. Dufault, Clint Boyd, Denver Fowler, Philip J. Currie and David C. Evans. 2026. Fruit-eating Adaptations in a Late Cretaceous oviraptorosaur (Theropoda). Nature Communications. DOI: doi.org/10.1038/s41467-026-78343-w [10 October 2026]
