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| Erectopus | ||||||||||||||||||||
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| Erectopus superbus Heune, 1932 |
Erectopus is an allosauroid theropod from the Lower Cretaceous of France. The material comprising the type series was discovered in the late 19th Century from the Phosphate-bearing beds of La Penthèive (Mammilatum Zone; lower Albian) at Louppy-le-Château in eastern France, which have also produced remains of plesiosaurs, ichthyosaurs, and crocodiles. The bones originally resided in the private collections of Louis Pierson and were first described by H. E. Sauvage in 1882. It was Sauvage who made them the basis for a new taxon, Megalosaurus superbus. In 1932, the material was redescribed by Friedrich von Huene (1875-1969), who argued that it could not be included within the genus Megalosaurus and placed the Pierson theropod in a second new taxon, Erectopus sauvagei. Subsequently, the Pierson collection was dispersed after the death of its owner and the holotype was long believed lost to science. However, casts of some of the bones have been located in the Muséum National d'Histoire Naturelle (MNHN, Paris), and the anterior part of a left maxilla, described by Sauvage in 1882, was found through a Parisian fossil dealer in the late 20th Century and purchased by Christian de Muison, a paleontologist at the MNHN. The casts and the incomplete maxilla allowed for a reevaluation of Erectopus (Allain, 2005), which determined that the correct taxonomic name for the material is E. superbus. The recovered maxilla has been designated a lectotype, and the casts of Pierson's specimen has become the plastotype for the taxon. The plastotype includes a partial right manus, the left femur, left calcaneum, the proximal and distal halves of the right tibia, and right metatarsal II. The etymology of Erectopus is based on the structure of the foot (Latin erectus = "upright" + Greek pous = "foot").
Based on the morphology of the distal end of the tibia and the inferred morphology of the astragalus, Allain (2005, p. 83) placed Erectopus superbus within the Allosauroidea and regarded it as carnosaurian. It is the third youngest carnosaur known from the European Lower Cretaceous, after the "Montmirat theropod" (Valangian) of southern France and Neovenator salerii (Barremian) from the Isle of Wight.
Diagnosis
Allain (2005 pp. 75-76) diagnoses Erectopus superbus as follows: "Rounded anterior ramus of maxilla; slender neck of femur; posterior curvature of proximal half of femur; anterodorsal edge of calcaneum dorsally projected; calcaneum twice as long as deep vertically; posteromedial process of for tibia on articular surface of astragalus; length of second metatarsal equal to half the length of femur; lateral margin of proximal end of second metatarsal regularly concave."
References
- Allain, R. 2005. The enigmatic theropod dinosaur Erectopus superbus (Sauvage, 1882) from the Lower Albian of Louppy-le-Château (Meuse, France). in Carpenter, K. 2005. The Carnivorous Dinosaurs, Indiana University Press: 72-86.
- Huene, F. 1926. The carnivorous Saurischia in the Jura and Cretaceous formations, principally in Europe. Revista del Museo de la Plata 29: 35-167.
- Huene, F. 1932. Die fossile Reptil-Ordnung Saurischia, ihre Entwicklung und Geschichte. Monographien zur Geologie und Palaeontologie, ser. 1: 1-361.
- Sauvage, H. E. 1882. Recherches sur les reptiles trouvés dans le Gault de l'est du Bassin de Paris. Mémoires de la Société géologique de France 4: 439-442.
