Advertisement

Naturwissenschaften

, Volume 93, Issue 5, pp 242–245 | Cite as

An abelisaurid from the Late Cretaceous of Egypt: implications for theropod biogeography

  • Joshua B. SmithEmail author
  • Matthew C. Lamanna
Short Communication

Abstract

Recent paleogeographic scenarios postulate the isolation of continental Africa during the Late Cretaceous. The absence of abelisaurid theropods from Upper Cretaceous African strata was offered as support of hypothesized African isolation with the acknowledgement that the paucity of African abelisaurids may be mostly an issue of sampling. Here we report on a shed theropod tooth from the Upper Cretaceous (Maastrichtian, ∼70 Ma) Duwi Formation of Egypt. The tooth was referred to the Malagasy abelisaurid “Megalosauruscrenatissimus (=Majungasaurus crenatissimus) in 1921. A discriminant function analysis was run to test for morphological congruence between the Egyptian tooth and the dentitions of 24 theropod taxa. The analysis correctly classified 96.6% of the teeth in the sample and assigned the tooth to Majungasaurus. As current paleogeographic reconstructions posit Madagascar had attained its current position relative to Africa before the Late Cretaceous, it is unlikely that the Egyptian tooth actually pertains to Majungasaurus. Nevertheless, its classification as an abelisaurid supports its referral to the clade. This tooth thus constitutes defensible evidence of an abelisaurid from the post-Cenomanian Cretaceous of mainland Africa. Combined with recent discoveries of abelisaurids in Niger and Morocco, the result indicates that Abelisauridae was a diverse group in Africa during the Cretaceous, existing in multiple places for at least ∼25 Ma and weakens support for hypotheses of an isolated Africa during the Late Cretaceous.

Keywords

Cretaceous Late Cretaceous Maastrichtian Discriminant Function Analysis Crown Height 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

Acknowledgements

We thank R. Buccheri, G. A. Cacace, and P. Sereno for specimen access; D. W. Krause for informing us about the tooth; and J. Amend, S. Novak, and L. Halliday for logistical assistance. This article was supported by funds from Washington University. The acknowledgements for J.B. Smith et al. (2005b) are relevant but are not repeated for reasons of brevity.

Supplementary material

114_2006_92_MOESM1_ESM.gif (21 kb)
S2

Theropod dental anatomy and variables used in this study (modified from Smith et al. 2005).A, Crown in lateral view showing apical length (AL, measured along line segment AG (points A,B, and G defined by Smith et al. 2005)); crown angle (CA, angle GAB); crown base length (CBL, measured along line segment AB at the base of the enamel); crown height (CH, measured from apex to the base of the enamel along line segment GB); mesial apical (MA), mesial midcrown (MC), and mesial basal (MB) denticle densities (measured along the mesial carina); distal apical (DA), distal mid-crown (DC), and distal basal (DB) denticle densities (measured along the distal carina). B, the crown in (A) in basal view showing CBL and crown base width (CBW, measured perpendicular to CBL)

(23 kB)

114_2006_92_MOESM2_ESM.pdf (123 kb)
(PDF 125 kb)

References

  1. Buffetaut E, Martill, D, Escuillié F (2004) Pterosaurs as part of a spinosaur diet. Nature 430:33PubMedCrossRefGoogle Scholar
  2. Buffetaut E, Escuillié F, Pohl B (2005) First theropod dinosaur from the Maastrichtian phosphates of Morocco. Kaupia 14:3–8Google Scholar
  3. Carrano MT, Sampson SD, Forster CA (2002) The osteology of Masiakasaurus knopfleri, a small abelisauroid (Dinosauria: Theropoda) from the Late Cretaceous of Madagascar. J Vertebr Paleontol 22:510–534CrossRefGoogle Scholar
  4. Farlow JO, Brinkman DL, Abler WL, Currie PJ (1991) Size, shape, and serration density of theropod dinosaur lateral teeth. Mod Geol 16:161–198Google Scholar
  5. Gemmellaro M (1921) Rettili maëstrichtiani d’ Egitto. Giornale di Scienze Naturali ed Economiche 32:339–351 (Palermo)Google Scholar
  6. Gradstein FM, Ogg JG, Smith AG (2005) A geologic time scale 2004. Cambridge Univ. Press, Cambridge, p 611Google Scholar
  7. Hay WW, DeConto R, Wold CN, Wilson KM, Voigt S, Schulz M, Wold-Rossby A, Dullo WC, Ronov AB, Balukhovsky AN, Söding E (1999) An alternative global Cretaceous paleogeography. In: Barrera E, Johnson CC (eds) Evolution of the Cretaceous ocean/climate system. Geol Soc Amer 332:1–47 (special paper)Google Scholar
  8. Krause DW (2001) Fossil molar from a Madagascan marsupial. Nature 412:497–498PubMedCrossRefGoogle Scholar
  9. Krause DW, Prasad GVR, Koenigswald Wv, Sahni A, Grine FE (1997) Cosmopolitanism among Gondwanan Late Cretaceous mammals. Nature 390:504–507CrossRefGoogle Scholar
  10. Krause DW, Rogers RR, Forster CA, Hartman JH, Buckley GA, Sampson SD (1999) The Late Cretaceous vertebrate fauna of Madagascar: implications for Gondwanan paleobiogeography. GSA Today 9:1–7Google Scholar
  11. Krause DW, Sampson SD (2006) Overview of the history of discovery, taxonomy, phylogeny and biogeography of Majungasaurus crenatissimus. In: Sampson SD, Krause DW (eds) Majungasaurus crenatissimus (Theropoda: Abelisauridae) from the Late Cretaceous of Madagascar. Soc Vertebr Paleontol Mem (in press)Google Scholar
  12. Lamanna MC, Martínez RD, Smith JB (2002) A definitive abelisaurid theropod dinosaur from the early Late Cretaceous of Patagonia. J Vertebr Paleontol 22:58–69CrossRefGoogle Scholar
  13. Mahler L (2005) Record of Abelisauridae (Dinosauria: Theropoda) from Cenomanian Morocco. J Vertebr Paleontol 25:236–239CrossRefGoogle Scholar
  14. Marko PB, Jackson JBC (2001) Patterns of morphological diversity among and within arcid bivalve species pairs separated by the Isthmus of Panama. J Paleontol 75:590–606CrossRefGoogle Scholar
  15. Novas FE, Agnolin FL, Bandyopadhyay S (2004) Cretaceous theropods from India: a review of specimens described by Huene and Matley (1933). Rev Mus Argent Cienc Nat 6:67–103Google Scholar
  16. Rauhut OWM, Claderaa G, Vickers-Rich P, Rich TH (2003) Dinosaur remains from the Lower Cretaceous of the Chubut group, Argentina. Cretac Res 24:487–497CrossRefGoogle Scholar
  17. Russell DA (1996) Isolated dinosaur bones from the Middle Cretaceous of the Tafilalt, Morocco. Bull Mus Natl Hist Nat 18(S 4):349–402 (Paris)Google Scholar
  18. Sampson SD, Krause DW, Dodson P, Forster CA (1996) The premaxilla of Majungasaurus (Dinosauria: Theropoda), with implications for Gondwanan paleobiogeography. J Vertebr Paleontol 16:601–605Google Scholar
  19. Sampson SD, Witmer LM, Forster CA, Krause DW, O’Connor PM, Dodson P, Ravoavy F (1998) Predatory dinosaur remains from Madagascar: implications for the Cretaceous biogeography of Gondwana. Science 280:1048–1051PubMedCrossRefGoogle Scholar
  20. Sereno PC, Wilson JA, Conrad JL (2004) New dinosaurs link southern landmasses in the Mid-Cretaceous. Proc R Soc Lond B 271:1325–1330CrossRefGoogle Scholar
  21. Smith JB (2005) Heterodonty in Tyrannosaurus rex: implications for the taxonomic and systematic utility of theropod dentitions. J Vertebr Paleontol 25:865–887CrossRefGoogle Scholar
  22. Smith JB, Krause DW (2006) Dental morphology and variation in Majungasaurus crenatissimus (Theropoda: Abelisauridae) from the Late Cretaceous of Madagascar. In: Sampson SD, Krause DW (eds) Majungasaurus crenatissimus (Theropoda: Abelisauridae) from the Late Cretaceous of Madagascar. Soc Vertebr Paleontol Mem (in press)Google Scholar
  23. Smith JB, Lamanna MC Lacovara KJ, Dodson P, Smith JR, Poole JC, Giegengack R, Attia Y (2001) A giant sauropod dinosaur from an Upper Cretaceous mangrove deposit in Egypt. Science 292:1704–1706PubMedCrossRefGoogle Scholar
  24. Smith JB, Novak SE, Issawi B (2005a) More travels in Stromer’s footsteps: Late Cretaceous vertebrates from the Nile Valley, Egypt. J Vertebr Paleontol 25:116ACrossRefGoogle Scholar
  25. Smith JB, Vann DR, Dodson P (2005b) Dental morphology and variation in theropod dinosaurs: implications for the taxonomic identification of isolated teeth. Anat Rec A 285:699–736Google Scholar
  26. Storey M, Mahoney JJ, Saunders AD, Duncan RA, Kelley SP, Coffin MF (1995) Timing of hot-spot related volcanism and the breakup of Madagascar and India. Science 267:852–855PubMedCrossRefGoogle Scholar
  27. Stromer E, Weiler W (1930) VI. Beschreibung von Wirbeltier-Resten aus dem nubischen Sandstein Oberägyptens und aus ägyptischen Phosphaten nebst Bemerkungen über die Geologie der Umgegend von Mahamîd in Oberägypten. Abh Bayer Akad Wiss Math-Nat Abt NF 7:1–42Google Scholar
  28. Wilson JA, Sereno PC, Srivastava S, Bhatt DK, Khosla A, Sahni A (2003) A new abelisaurid (Dinosauria, Theropoda) from the Lameta Formation (Cretaceous, Maastrichtian) of India. Cont Mus Paleontol Univ Mich 31:1–42Google Scholar

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  1. 1.Earth & Planetary SciencesWashington UniversitySt. LouisUSA
  2. 2.Vertebrate PaleontologyCarnegie Museum of Natural HistoryPittsburghUSA

Personalised recommendations