Deltatheroida

Deltatheroida
Temporal range: Aptian–Maastrichtian

Early-Late Cretaceous

Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Subclass: Theria
(unranked): Metatheria
Order: †Deltatheroida
Gregory and Simpson, 1926
Families & Genera

Deltatheroida is an extinct group of basal metatherians that lived in the Cretaceous and were closely related to marsupials. Their fossils are restricted to Central Asia and North America. This order can be defined as all metatherians closer to Deltatheridium than to Marsupialia.

These mammals possessed tritubercular lower molars and these were not tribosphenic and were quite primitive. This is awkward because tribosphenic molars are commonly found in most therian mammals (there exist some exceptions such as anteaters and some whales, which have no teeth at all).

When they were first identified in the 1920s, they were believed to be placentals and possible ancestors of the "creodonts" (a polyphyletic group of extinct carnivorous mammals from the Paleogene and Miocene), but this was later disproven. Nonetheless, deltatheroideans do converge on hyaenodontids, oxyaenids, carnivorans, dasyuromorphs and sparassodonts in many details of their dental anatomy, suggesting a carnivorous lifestyle.[3][4] Oxlestes and Khuduklestes in particular are among the largest mammals of the Mesozoic,[4] though at least the former's status as deltatheroideans is questionable.[5]

At least some deltatheroideans were sabertoothed predators.[6]

Taxonomy

Species list of Deltatheroida[7][8]

†Deltatheroida Kielan-Jaworowska 1982 [Deltatheralia Marshall & Kielan-Jaworowska 1992; Holarctidelphia Szalay 1993]

See also

References

  1. ↑ Averianov, A.; Archibald, J.D. (2005). "Mammals from the mid-Cretaceous Khodzhakul Formation, Kyzylkum Desert, Uzbekistan". Cretaceous Research. 26 (4): 593–608. doi:10.1016/j.cretres.2005.03.007.
  2. ↑ Guillermo W. Rougier; Brian M. Davis; Michael J. Novacek (2015). "A deltatheroidan mammal from the Upper Cretaceous Baynshiree Formation, eastern Mongolia". Cretaceous Research. 52, Part A: 167–177. doi:10.1016/j.cretres.2014.09.009.
  3. ↑ CHRISTIAN DE MUIZON and BRIGITTE LANGE-BADRÉ, Carnivorous dental adaptations in tribosphenic mammals and phylogenetic reconstruction, Article first published online: 29 MAR 2007 DOI: 10.1111/j.1502-3931.1997.tb00481
  4. 1 2 Zofia Kielan-Jaworowska, Richard L. Cifelli, Zhe-Xi Luo (2004). "Chapter 12: Metatherians". Mammals from the Age of Dinosaurs: origins, evolution, and structure. New York: Columbia University Press. pp. 425–262. ISBN 0-231-11918-6.
  5. ↑ Guillermo Rougier, New specimen of Deltatheroides cretacicus (Metatheria, Deltatheroida) from the Late Cretaceous of Mongolia, BULLETIN OF CARNEGIE MUSEUM OF NATURAL HISTORY 36(DEC 2004):245-266 · SEPTEMBER 2009
  6. ↑ S. Bi, X. Jin, S. Li and T. Du. 2015. A new Cretaceous metatherian mammal from Henan, China. PeerJ 3:e896
  7. ↑ Mikko's Phylogeny Archive Haaramo, Mikko (2007). "†Deltatheroida – deltatherids". Retrieved 30 December 2015.
  8. ↑ Paleofile.com (net, info) . "Taxonomic lists- Mammals". Retrieved 30 December 2015.
  9. ↑ Guillermo W. Rougier; Brian M. Davis; Michael J. Novacek (2015). "A deltatheroidan mammal from the Upper Cretaceous Baynshiree Formation, eastern Mongolia". Cretaceous Research. 52, Part A: 167–177. doi:10.1016/j.cretres.2014.09.009.
  10. ↑ S. Bi, X. Jin, S. Li and T. Du. 2015. A new Cretaceous metatherian mammal from Henan, China. PeerJ 3:e896

Further reading

Zofia Kielan-Jaworowska, Richard L. Cifelli, and Zhe-Xi Luo, Mammals from the Age of Dinosaurs: Origins, Evolution, and Structure (New York: Columbia University Press, 2004), 444-448.


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