Open Paleo

Latenivenatrix

van der Reest & Currie, 2017 Disputed

From Latin 'latens' ('hiding') and 'venatrix' ('huntress'); the name alludes both to a predator hiding in cover and to the taxon having lain unrecognized in museum collections for about a century.

83.6–72.2 million years ago Campanian, Late Cretaceous
Late Cretaceous stages

Latenivenatrix, meaning "hiding huntress", is a genus of large troodontid known from a single species, L. mcmasterae. Along with the contemporary Stenonychosaurus, it is known from non-tooth fossils that were formerly assigned to the now potentially dubious genus Troodon. Although described as separate, it has been considered a junior synonym of Stenonychosaurus.

Under dispute

The validity of Latenivenatrix is contested. Van der Reest and Currie (2017) erected it for large Dinosaur Park Formation troodontid material previously assigned to Troodon formosus, diagnosing it on three characters of the pubis and treating Stenonychosaurus inequalis as a separate, stratigraphically lower taxon. Cullen and colleagues (2021) found extensive overlap between the two in frontal morphospace and in stratigraphic range, judged the putatively autapomorphic frontal and metatarsal characters variable, and concluded that Latenivenatrix mcmasterae is a subjective junior synonym of Stenonychosaurus inequalis; they could not assess the pubic characters, reporting a lack of overlapping material. Varricchio and colleagues (2025) adopt that taxonomy for working purposes while stating that the status of the taxon remains in question, and note that their new material lends some support to its validity. Rivera-Sylva and colleagues (2026) recover Stenonychosaurus and Latenivenatrix as a distinct sister pair and report that variation among Dinosaur Park frontals is consistent with more than one species, while cautioning that the holotypes do not overlap. The species is marked disputed and the genus retained at Troodontinae.

Diagnosis

  1. Pubis retroverted approximately 17 degrees relative to the pubic peduncle of the ilium
  2. Pubic shaft curves anteriorly as it extends distally
  3. Large, moderately pronounced muscle scar on the lateral surface of the pubic shaft, slightly proximal to the pubic boot

Species

Latenivenatrix mcmasterae van der Reest & Currie, 2017 Disputed

Type species

Honors Lynne McMaster van der Reest, the late mother of the first author.

Holotype
CMN 12340 , Canadian Museum of Nature
Material
Partial skeleton: paired frontals and parietals, postorbital, basioccipital, basisphenoid, dorsal and caudal vertebrae, chevrons, ribs, gastralia, ulnae, radius, carpals, manus, femur shaft, astragalocalcanea and partial pedes.
Horizon
upper Dinosaur Park Formation, Campanian, Late Cretaceous , 83.6–72.2 million years ago
Locality
3.1 km north-northeast of the northeastern corner of Dinosaur Provincial Park, Alberta, Canada

References

  1. van der Reest, A. J.; Currie, P. J. (2017). Troodontids (Theropoda) from the Dinosaur Park Formation, Alberta, with a description of a unique new taxon: implications for deinonychosaur diversity in North America. Canadian Journal of Earth Sciences 54(9): 919-935. doi:10.1139/cjes-2017-0031

    Erects the genus for large Dinosaur Park troodontid material and diagnoses it on three characters of the pubis.

    vanderreest2017a
  2. Cullen, T. M.; Zanno, L.; Larson, D. W.; Todd, E.; Currie, P. J.; Evans, D. C. (2021). Anatomical, morphometric, and stratigraphic analyses of theropod biodiversity in the Upper Cretaceous (Campanian) Dinosaur Park Formation. Canadian Journal of Earth Sciences 58(9): 870-884. Canadian Science Publishing. doi:10.1139/cjes-2020-0145

    Finds extensive frontal and stratigraphic overlap with Stenonychosaurus and treats the species as a subjective junior synonym of Stenonychosaurus inequalis.

    cullen2021a
  3. Varricchio, D. J.; Hogan, J. D.; Gardner, J. D. (2025). Troodontid specimens from the Cretaceous Two Medicine Formation of Montana (USA) and the validity of Troodon formosus. Journal of Paleontology 99(1): 219-240. Cambridge University Press (CUP). doi:10.1017/jpa.2024.67

    Adopts that synonymy for working purposes while stating the taxon's status remains in question, and reports material lending some support to its validity.

    varricchio2025a
  4. Rivera-Sylva, H. E.; Aguillón-Martínez, M. C.; Flores-Ventura, J.; Sánchez-Uribe, I. E.; Guzmán-Gutiérrez, J. R.; Longrich, N. R. (2026). A Thick-Skulled Troodontid Theropod from the Late Cretaceous of Mexico. Diversity 18(1). MDPI AG. doi:10.3390/d18010038

    Recovers Stenonychosaurus and Latenivenatrix as a sister pair and finds Dinosaur Park frontal variation consistent with more than one species.

    rivera-sylva2026a
  5. Jasinski, S. E.; Sullivan, R. M. (2026). Dinevenator, a New Genus of Troodontid Dinosaur from the Late Cretaceous of New Mexico. Fossil Studies 4(3). MDPI AG. doi:10.3390/fossils4030021

    Notes the species may be conspecific with Stenonychosaurus inequalis.

    jasinski2026a