Dryolestida

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Dryolestida
Temporal range: Jurassic-Paleogene Bathonian–Paleocene
Possible early Miocene record
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
(unranked): Holotheria
Subclass: Theriiformes
(unranked): Trechnotheria
Superorder: Dryolestoidea
Order: Dryolestida
Prothero, 1981
Families & Genera

See text

Dryolestida is an extinct order of mammals; most of the members are known from the Jurassic to Paleogene, with one possible member, Necrolestes, surviving as late as early Miocene.[1] It has been suggested that these mammals are either the possible ancestors of therian mammals or an offshoot from the same evolutionary line. It is also believed that they developed a fully mammalian jaw and also had the three middle ear bones. Other than that, not much is known about them, this is because their fossils are made up mostly of jaw and tooth remains.

The Dryolestids were formerly considered part of Pantotheria and/or Eupantotheria. The clade Quirogatheria, erected by José Bonaparte in 1992, is often used as a synonym for Dryolestida. Originally, Quirogatheria was meant to include Brandoniidae, but this family is now included with the Dryolestids.

Classification[edit]

Classification modified after Rougier & Gaetano, 2011.[2]

A phylogenetic analysis conducted by Rougier et al. (2012) indicated that meridiolestidans might not be members of Dryolestida but instead slightly more closely related to the placental mammals, marsupials and amphitheriids. Paurodontids were also recovered as not belonging to Dryolestida, but instead as a sister group of Meridiolestida in this analysis.[1] An analysis conducted by Averianov, Martin and Lopatin (2013) did not recover meridiolestidans as members of Dryolestida as well, but it found them to be the sister group of spalacotheriid "symmetrodonts" instead. However, paurodontids were recovered as members of Dryolestida in this analysis.[3] On the other hand, an analysis conducted by Chimento, Agnolin and Novas (2012) did recover meridiolestidans as members of Dryolestida.[4]

References[edit]

  1. ^ a b c Guillermo W. Rougier, John R. Wible, Robin M. D. Beck and Sebastian Apesteguía (2012). "The Miocene mammal Necrolestes demonstrates the survival of a Mesozoic nontherian lineage into the late Cenozoic of South America". Proceedings of the National Academy of Sciences of the United States of America 109 (49): 20053–20058. doi:10.1073/pnas.1212997109. 
  2. ^ Guillermo W. Rougier, Sebastián Apesteguía and Leandro C. Gaetano (2011). "Highly specialized mammalian skulls from the Late Cretaceous of South America". Nature 479: 98–102. doi:10.1038/nature10591.  Supplementary information
  3. ^ Alexander O. Averianov, Thomas Martin and Alexey V. Lopatin (2013). "A new phylogeny for basal Trechnotheria and Cladotheria and affinities of South American endemic Late Cretaceous mammals". Naturwissenschaften. in press. doi:10.1007/s00114-013-1028-3. 
  4. ^ Nicolás R. Chimento, Federico L. Agnolin and Fernando E. Novas (2012). "The Patagonian fossil mammal Necrolestes: a Neogene survivor of Dryolestoidea". Revista del Museo Argentino de Ciencias Naturales, nueva serie 14 (2): 261–306. 

Further reading[edit]

  • Kielan-Jaworowska, Zofia; Cifelli, Richard L; Luo, Zhe-Xi (2004). Mammals from the Age of Dinosaurs: Origins, Evolution, and Structure. New York: Columbia University Press. pp. 14, 379–393. ISBN 978-0-231-11918-4. 
  • The Illustrated Encyclopedia of the Prehistoric World page 344