Didelphodon

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Didelphodon
Temporal range: Late Cretaceous,[1] 73–66Ma
Didelphodon Clean.png
The only known Lancian age mammal skeleton, this cast of Didelphodon is in the Rocky Mountain Dinosaur Resource Center in Woodland Park, CO and was collected in Harding County, SD.
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Infraclass: Marsupialia
Order: Didelphimorphia
Suborder: Archimetatheria
Superfamily: Didelphoidea
Family: Stagodontidae
Genus: Didelphodon
Marsh, 1889
Type species
Didelphodon vorax Marsh, 1889
Species

Didelphodon vorax Marsh, 1889
Didelphodon padanicus (Cope, 1892)
Didelphodon coyi Fox & Naylor, 1986

Didelphodon (meaning "two womb tooth") is a genus of stagodont marsupials from the Late Cretaceous of North America.[2]

Description[edit]

Skull cast of Didelphodon in the Rocky Mountain Dinosaur Resource Center in Woodland Park, CO; collected in Harding County, SD.

Although perhaps little larger than a Virginia Opossum, it was one of the largest mammals of the Mesozoic. The teeth have specialized bladelike cusps and carnassial notches, indicating that the animal was a predator; the jaws are short and massive and bear enormous, bulbous premolar teeth which appear to have been used for crushing.[3]

A recently found specimen, located just 40 m (130 ft) away from a Triceratops in a riverbed, shows the anatomy of Didelphodon. Before the find, only a lower jaw and a partial skull were assigned to the species. This new find shows that Didelphodon possessed an otter-like body with a tasmanian devil-like skull. A study that is being prepared by Kraig Derstler, Greg Wilson, Robert Bakker, Ray Vodden and Mike Triebold will describe this new specimen, housed in the Rocky Mountain Dinosaur Resource Center.[2]

Paleobiology[edit]

Fossil evidence suggests Didelphodon was a small predator, perhaps filling the niche that otters do today. A recently found and soon-to-be-described specimen that is almost complete was preserved in a possible burrow surrounded by concretion. It probably had an omnivorous diet, possible for feeding on molluscs, dinosaur eggs, lizards and plants.[2]

Discovery[edit]

A cast of the first Didelphodon mandible to be discovered still containing teeth, now located in the permanent collection of The Children’s Museum of Indianapolis

Three species are known: Didelphodon vorax, D. padanicus, and D. coyi.[3] A specimen was discovered in 2001, Harding County, South Dakota.[2] Didelphodon is known from the Hell Creek Formation of Montana, the Lance Formation of Wyoming, and the Scollard Formation of Alberta, where it is one of the most abundant mammals.[3]

Classification[edit]

Didelphodon is a stagodontid marsupial related to Eodelphis and Pariadens. The genus appears to descend from the Campanian Eodelphis, and in particular appears to be related to Eodelphis cutleri. Pariadens appears to be more primitive than either Eodelphis or Didelphodon, and is probably sister to their group. Didelphimorphia is an order that was named in 1872 by Gill. Previously, in 1821, Gray named the superfamily Didelphoidea to house the families Alphadontidae, Pediomyidae, Peradectidae, and Stagodontidae, which unites Didelphodon with many other genera.[3]

In 2006, a study found only two stagodontids, Didelphodon and Eodelphis. The previously included Pariadens was excluded from the group because its type species, P. kirklandi, lacks any of the families characteristics, so it is classified as Marsupialia incertae sedis. Another species, "P." mckennai even lacks marsupial features and is probably a therian. Another historical stagodontid, Boreodon, which is a nomen dubium. A last final purported stagodontid was Delphodon, which is probably a synonym of Pediomys or Alphadon.[1]

In popular culture[edit]

Didelphodon was featured in a minor role in Walking with Dinosaurs and Prehistoric Planet. In Walking with Dinosaurs, one was eaten by an angry Tyrannosaurus while raiding a nest, and two later fought over a tyrannosaur egg from the same nest. One was also shown feasting on the remains of a young Torosaurus, highlighting how the mammals continue to thrive while the dinosaurs face their demise.

References[edit]

  1. ^ a b Fox, R.C.; Naylor, B.G. (2006). "Stagodontid marsupials from the Late Cretaceous of Canada and their systematic and functional implications". Acta Paleontologica Polonica 51 (6): 13–36. 
  2. ^ a b c d "Didelphodon vorax". Rocky Mountain Dinosaur Resource Center. 2010-12-07. 
  3. ^ a b c d Kielan-Jaworowska, Z.; Cifelli, R.L.; Cifelli, R; Luo, Z.X. (2004). Mammals from the Age of Dinosaurs: Origins, Evolution and Structure. New York: Columbia University Press. pp. 441–462. 
  • Clemens, W. A., Jr. (1979). Marsupialia. Mesozoic mammals: the first two-thirds of mammalian history. J. A. Lilligraven, Kielan-Jaworowska and W. A. Clemens, Jr. Berkeley, University of California Press: 192-220.
  • BBC Online: Science & Nature: Prehistoric Life

Further reading[edit]

  • Fox, R. C., & Naylor, B. G. (1986). A new species of Didelphodon Marsh (Marsupialia) from the Upper Cretaceous of Alberta, Canada: paleobiology and phylogeny. Neues Jahrbuch für Geologie und Paläontologie Abhandlungen, 172, 357-380.