"Megalosaurus" “phillipsi” Welles, Powell and Pickering vide Pickering, 1995
Kimmeridgian, Late Jurassic
Kimmeridgian Clay, England
Material- (OUM J29886) tibia (740 mm) (Huene, 1926)
....(OUM J13586) metatarsal II (360 mm), incomplete metatarsal III, incomplete metatarsal IV (Phillips, 1871)
Diagnosis- (from Pickering, DML 2002) cnemial crest more laterally angled.
(suggested) metatarsal II transversely narrower in proximal view; a wide lateral flare to the ventral rim of the lateral ligament pit on metatarsal II.
Other diagnoses- Pickering has listed his intended diagnosis for this species online (DML, 2002). Of his listed characters, the tibia does not seem noticably straighter in "phillipsi" than in Megalosaurus or Torvosaurus. The fibular crest begins at a similar position proximally. I cannot confirm the presence of a pit in the astragalar facet in M. bucklandii, and the "concavity of the distal end is wider" in Torvosaurus and "Brontoraptor" as well. The latter is also true of the medial malleolus, which "does not extend so far below the medial end." The tibia is equally robust in "Brontoraptor", Torvosaurus tanneri and T? sp. ML 430 from Portugal, which also share the transversely expanded lateral condyle. While the fibular crest extends more distally than in M. bucklandii, it does not do so more than "Brontoraptor" or ML 430.
Comments- OUM J29886 is intended as the holotype, though Huene (1926) felt they belonged to the same individual.
Phillips (1871) illustrated the metatarsus as Megalosaurus in figure 68. Huene (1926) later illustrated both the tibia and metatarsus as Megalosaurus bucklandi, incorrectly stating they derive from the Stonesfield Slate (Pickering, DML 2002). Huene also lists the metatarsals again as Megalosaurus sp. under entry 54 of his list, which also get listed as ?Megalosaurus sp. by him in 1932. Pickering (1995) first mentioned the name Megalosaurus phillipsi in an unpublished bibliographic manuscript. It was later used in the comparative section of another unpublished manuscript (Welles and Pickering, 1999). This paper was largely extracted from the European megalosaur manuscript Welles and Powell worked on in the 1970s but never published, specifically the Megalosaurus redescription section. Pickering intends to publish an updated version of the megalosaur manuscript as Mutanda Dinosaurologica, and has posted small excerpts including the diagnosis of "phillipsi" online (DML, 2002). In any case, the name is a nomen nudum as Pickering didn't follow ICZN Article 7 Recommendation 7a, Article 8a or Recommendation 8A. Curiously, Benson's (2010) recent redescription of Megalosaurus does not even mention the specimen, though it does lack the only character in his diagnosis of M. bucklandii for which it can be checked- complementary groove and ridge structures on the articular surfaces between metatarsals II and III.
Metatarsal II is of equal robusticity to Megalosaurus, unlike Torvosaurus' apomorphically massive element. It apomorphically shares the medial flare to the ventral rim of the collateral ligament pit with Torvosaurus though. It differs from both in being transversely narrower proximally and having a wide lateral flare to the ventral rim of the opposite collateral ligament pit. In proximal view, Megalosaurus and "phillipsi" both have a posterior concavity on metatarsal II, and share a convex anterior edge, as in the outgroup. Distally, it is primitively deeper than in either Megalosaurus or Torvosaurus. Metatarsal III is primitively more medially bowed than either, and is again less robust than Torvosaurus'. Proximally, metatarsal III is closer to Torvosaurus in having an apomorphic highly concave lateral margin and lacking the apomorphic sinuous medial margin of Megalosaurus. It has a primitively blunter posteromedial corner than either of them. Distally, the lateral condyle is apomorphically narrower as in Torvosaurus. Metatarsal IV has an apomorphically concave lateral edge as in Megalosaurus, unlike the sinusoidal edge of Torvosaurus. The distal shaft width is intermediate, and the articular end plesiomorphically expands transversely less than in Megalosaurus.
Ignoring the symplesiomorphies then, "phillipsi" shares five apomorphic states with Torvosaurus, and only one with Megalosaurus. It also shares these apomorphies with "Brontoraptor" and ML 430 where known, and shares the distally projecting fibular crest uniquely with those two specimens. I conclude Welles, Powell and Pickering were correct to refer "phillipsi" to their more inclusive version of Megalosaurus, but if Torvosaurus is separated as most modern workers do, it would be better referred to that genus. "Brontoraptor" has been recently assumed to be synonymous with Torvosaurus, and if so the features "phillipsi" shares with the former to the exclusion of the latter may be individual variation or incorrectly illustrated for "Brontoraptor". However, the fact Portuguese tibia ML 430 has the same characters suggests this may not be the case. Whether ML 430 should be referred to "phillipsi" is an interesting question, as they are both from Late Jurassic Europe. While the distally extensive fibular crest might suggest so, the broadly flared medial malleolus and laterally straight lateral malleolus of ML 430 resemble Torvosaurus more, while the medially narrow astragalar facet is more like Megalosaurus than any torvosaur. Both "phillipsi" and ML 430 are best referred to Torvosauridae.
References- Phillips, 1871. Geology of Oxford and the Valley of the Thames. Clarendon Press, Oxford.
Huene, 1926. The carnivorous Saurischia in the Jura and Cretaceous formations, principally in Europe. Revista del Museo de La Plata. 29, 35-167.
Huene, 1932. Die fossile Reptil-Ordnung Saurischia, ihre Entwicklung und Geschichte. Monographien zur Geologie und Palaeontologie. 4(1), viii + 361 pp.
Pickering, 1995. Jurassic Park: Unauthorized Jewish Fractals in Philopatry. A Fractal Scaling in Dinosaurology Project, 2nd revised printing. Capitola, California. 478 pp.
Welles and Pickering, 1999. Megalosaurus bucklandii. Private publication of Stephen Pickering. An extract from Archosauromorpha: Cladistics & Osteologies. A Fractal Scaling in Dinosaurology Project. 119 pp.
Benson, 2010. A description of Megalosaurus bucklandii (Dinosauria: Theropoda) from the Bathonian of the UK and the relationships of Middle Jurassic theropods. Zoological Journal of the Linnean Society. DOI 10.1111/j.1096-3642.2009.00569.x
Pickering, in prep. Mutanda Dinosaurologica.