Stenopelix
From Greek stenos, "narrow", combined with Greek pelyx, "pelvis" — means "narrow pelvis", referring to the characteristic narrow hips
Stenopelix is a genus of basal ceratopsian from the Early Cretaceous (late Berriasian stage, approximately 140 million years ago) of Germany. The genus is based on a partial skeleton lacking the skull, and its classification is based on characteristics of the hips.
Under dispute
Stenopelix valdensis has been placed variously as a basal pachycephalosaur, a basal marginocephalian, and a basal ceratopsian; Fonseca and colleagues (2024) recover it within Chaoyangsauridae, with Yinlong; Yu and colleagues (2020) also recovered it within Chaoyangsauridae but discounted that placement as unreliable given its ambiguous status.
Diagnosis
- Weakly biconcave vertebral bodies only slightly longer than high or wide
- Pelvis with narrow elongate form, width less than half length, ilium extending posteriorly into stalk-like process
- Pubis and ischium as broad rib-shaped bones; ischium notably narrow and elongate without fan-like expansion
- Four toes with phalangeal count 3.4.5.6; all toes possessing claw phalanges of equal perfection
- Claw phalanges straight and pyramidal, not flat or curved
- Forearm only half the length of the shank; no osteoderms discernible despite skeleton completeness
Species
Stenopelix valdensis Meyer, 1857
Type species
Named for the Wealden Formation (Latinized as 'Valdensis' from 'Weald'), the geological unit in which the holotype was found in Germany.
- Holotype
- GZG 741/2 , Geo Wissenschaftliches Zentrum der Universität Göttingen
- Material
- Saurian skeleton with skull and front trunk and tail tip broken away; pelvis and hind limbs best preserved; approximately 39–40 caudal vertebrae preserved.
- Horizon
- upper Obernkirchen Sandstein Bed, Obernkirchen Member, Bückeberg Formation, Berriasian–Valanginian, Early Cretaceous , 143.1–132.6 million years ago Covers every bed that may have yielded the type specimen.
- Locality
- Bückeburg/Hexenteich quarry, Lower Saxony, Germany Hornung and colleagues (2012) place the type quarry in the upper Obernkirchen Sandstone, but caution in the same paper that correlating the beds at Harrl hill with those of the central Bückeberge is weakly supported. The stages follow the whole Bückeberg, which the same paper gives as "middle Berriasian through early Valanginian", rather than the bed alone.
References
- Meyer, H. V. (1857). Beiträge zur näheren Kenntniss fossiler Reptilien [Contributions to the detailed knowledge of fossil reptiles]. Neues Jahrbuch für Mineralogie, Geognosie, Geologie und Petrefakten-Kunde 1857: 532-543. meyer1857a
-
Yu, C.; Prieto-Márquez, A.; Chinzorig, T.; Badamkhatan, Z.; Norell, M. (2020). A neoceratopsian dinosaur from the Early Cretaceous of Mongolia and the early evolution of Ceratopsia. Communications Biology 3: 499:1-8. doi:10.1038/s42003-020-01222-7
Recovered Stenopelix within Chaoyangsauridae but discounted the placement as unreliable, noting its ambiguous status (often placed outside Ceratopsia).
yu2020a -
Fonseca, A. O.; Reid, I. J.; Venner, A.; Duncan, R. J.; Garcia, M. S.; Müller, R. T. (2024). A comprehensive phylogenetic analysis on early ornithischian evolution. Journal of Systematic Palaeontology 22: 2346577. doi:10.1080/14772019.2024.2346577
Recovered Stenopelix within Chaoyangsauridae, with Yinlong.
fonseca2024a -
Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Ornithischians. Princeton University Press.
Treats Stenopelix as a chaoyangsaurid.
jones2026a -
Hornung, J. J.; Böhme, A.; van der Lubbe, T.; Reich, M.; Richter, A. (2012). Vertebrate tracksites in the Obernkirchen Sandstone (late Berriasian, Early Cretaceous) of northwest Germany — their stratigraphical, palaeogeographical, palaeoecological, and historical context. Paläontologische Zeitschrift 86(3): 231-267. Springer. doi:10.1007/s12542-012-0131-7
Places the type quarry at Bückeburg/Hexenteich in the upper Obernkirchen Sandstone, and sets that bed within the Obernkirchen Member of the Bückeberg Formation.
hornung2012a