Tanycolageus Carpenter, Miles and Cloward, 2005
T. topwilsoni Carpenter, Miles and Cloward, 2005
= Elaphrosaurus "philtippettensis" Pickering, 1995b
= Elaphrosaurus "philtippettorum" Pickering, 1995a
Late Kimmeridgian, Late Jurassic
Brushy Basin Member of the Morrison Formation, Colorado, US
Paratype- ?(USNM 5737; intended holotype of Elaphrosaurus "philtippettensis" and "philtippettorum") distal pubes (Gilmore, 1920)
Comments- The distal pubes USNM 5737 were discovered in 1884 and provisionally referred to Coelurus agilis by Gilmore in 1920 based on their size. Pickering (1995a) listed the name Elaphrosaurus philtippettorum in an unpublished bibliographic manuscript. In that same year, Pickering printed a packet with a description of the taxon as ?Elaphrosaurus philtippettensis, indicating USNM 5737 is the intended type. Both variants on the name are nomina nuda however, as he didn't follow ICZN Article 8.1.3- it must have been produced in an edition containing simultaneously obtainable copies by a method that assures numerous identical and durable copies. Pickering also referred USNM 8414 (two metatarsals) and 8415 (a humerus) without justification. However, there are no characters in the diagnosis except that it shares a straight humerus with Elaphrosaurus and abelisaurids (which does not involve the intended type), and the only characters listed in the description are those which distinguish USNM 8415 from Dryosaurus (identical to those listed by Galton in 1982). It is therefore also a nomen nudum in that it lacks "a description or definition that states in words characters that are purported to differentiate the taxon." Oddly, the intended type is not illustrated, with the only illustration being a humeral figure from Galton's paper. Pickering will also describe the species in his in progress work Mutanda Dinosaurologica. Carpenter et al. (2005) referred USNM 5737 to their new taxon Tanycolagreus because of its straight ventral edge and dorsally placed interpubic fenestra, unlike Coelurus. Additionally, Ornitholestes lacks an interpubic fenestra altogether. Why Pickering referred USNM 5737 to Elaphrosaurus is unknown, as he does not discuss the specimen (except to note it is "elongate, ... lacking a crest on its craniodorsal surface. In lateral view, the distal foot is ventrally convex.") and E. bambergi does not preserve the distal pubis. Furthermore, other ceratosaurs like Ceratosaurus, Kryptops and Carnotaurus have a very distally placed interpubic fenestra, so USNM 5737 is probably not a ceratosaur. Carpenter et al.'s assignment is here retained, though it should be noted Stokesosaurus also has a distally flat pubic boot and proximally placed interpubic fenestra.
unnamed Ceratosauria (Galton, 1982)
Late Kimmeridgian, Late Jurassic
Brushy Basin Member of the Morrison Formation, Colorado, US
Material- ?(USNM 8414) metatarsal III, metatarsal IV (Pickering, 1995)
(USNM 8415) humerus (201 mm) (Galton, 1982)
Comments- The humerus USNM 8415 was discovered in 1883 and initially referred to Dryosaurus, though Galton (1982) described it and referred it to Elaphrosaurus sp. based on the straight shaft and low deltopectoral crest. Pickering (1995b) referred it to his new taxon ?Elaphrosaurus "philtippettensis" without justification. Neither listed any characters to differentiate it from E. bambergi. Carrano and Sampson (2008) thought the specimen was ceratosaurian, but could find no characters shared specifically with Elaphrosaurus. Indeed, the straight shaft is present in all ceratosaurs, while the low deltopectoral crest is present in Limusaurus and abelisaurians as well. The proximal articular surface is wider than Limusaurus, but less so than abelisaurians. The flattened distal condyles are also more derived than Limusaurus, while Spinostropheus is intermediate. The internal tuberosity is well developed as in Ceratosaurus and abelisaurids, but unlike Limusaurus, Elaphrosaurus, Spinostropheus and Masiakasaurus. The deltopectoral crest apex is placed more distally (42%) than Elaphrosaurus, Limusaurus and especially Ceratosaurus and Masiakasaurus, but is more proximal than abelisaurids. Based on these comparisons, I agree the humerus cannot be assigned to Elaphrosaurus.
Ceratosaur humerus USNM 8415 in anterior (A), medial (B), posterior (C), lateral (D), proximal (E) and distal (F) views (after Galton, 1982). Scale = 50 mm.
USNM 8414 was discovered in 1883 and is assigned to Elaphrosaurus sp. on the USNM collections website, though it has not been mentioned in the literature to my knowledge. Pickering (1995b) referred it to his species Elaphrosaurus "philtippettensis" without comment. Until these are illustrated or described, their affinities remain unknown.
References- Gilmore, 1920. Osteology of the carnivorous Dinosauria in the United States National Museum, with special reference to the genera Antrodemus (Allosaurus) and Ceratosaurus. Bulletin of the United States National Museum. 110, 1-154.
Galton, 1982. Elaphrosaurus, an ornithomimid dinosaur from the Upper Jurassic of North America and Africa. Paläontologische Zeitschrift. 56, 265-275.
Pickering, 1995a. Jurassic Park: Unauthorized Jewish Fractals in Philopatry. A Fractal Scaling in Dinosaurology Project, 2nd revised printing. Capitola, California. 478 pp.
Pickering, 1995b. An extract from: Archosauromorpha: Cladistics and osteologies. A Fractal Scaling in Dinosaurology Project. 2 pp.
Carpenter, Miles and Cloward, 2005. New small theropod from the Upper Jurassic Morrison Formation of Wyoming. In Carpenter (ed.). The Carnivorous Dinosaurs. Indiana University Press. 23-48.
Carrano and Sampson, 2008. The phylogeny of Ceratosauria (Dinosauria: Theropoda). Journal of Systematic Palaeontology. 6, 183-236.