Nesodon

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Nesodon[1]
Temporal range: late Oligocene - early Miocene
Nesodon imbricatus.JPG
N. imbricatus skull
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Notoungulata
Family: Toxodontidae
Subfamily: Nesodontinae
Genus: Nesodon
Owen, 1846
Type species
Nesodon imbricatus
Species
  • N. conspurcatus
  • N. cornutus
  • N. imbricatus Owen, 1846
  • N. taweretus Forasiepi et al., 2014
Synonyms

Nesodon ("island tooth")[2] is a genus of Miocene mammal belonging to the extinct order Notoungulata which inhabited southern South America during the Late Oligocene to Miocene living from 29.0—16.3 Ma and existed for approximately 12.7 million years. [3] It had a relatively large size, weighing up to 554 kg (1221 lbs) and reaching 1.5 m in height.[4]

Taxonomy[edit]

Nesodon imbricatus

Nesodon was named by Owen (1846). It was assigned to Toxodontidae by Carroll (1988). It was an early member of the family Toxodontidae, which included the well-known Pleistocene genus Toxodon. Like almost all toxodontids, Nesodon was endemic to South America. In particular, fossils of Nesodon are known from late early Miocene (Santacrucian SALMA) deposits of Argentina and Chile.[5]

Three species of Nesodon are recognized including a larger species, N. imbricatus, and a smaller species, N. conspurcatus.[6] A poorly known and possibly invalid third species, N. cornutus, was similar to N. imbricatus but may have had a small horn on its head. All species of Nesodon were larger than species of the contemporary toxodontid Adinotherium.

The dentition of Nesodon shows features typical of living grazing (grass-eating) mammals, but a study of wear on the enamel of N. imbricatus suggests that it was a browser (leaf eater) that may have supplemented its diet with fruit or bark.[7]

Classification[edit]

Promegatherium nanum and Nesodon.

In 2014, a study identifying a new species of Nesodon, N. taweretus, resolved the families phylogenetic relations. The below cladogram was found by the study:[8]



Pampahippus arenalesi





Rhynchippus spp.




Scarritia canquelensis



Leonitinia gaudri




Toxodontidae

Proadinotherium leptognathum





Adinotherium spp.




Nesodon taweretus



Nesodon imbricatus






Palyeidodon obtusum




Hyperoxotodon speciosus





Nonotherium henningi



Xotodon spp.






Andinotoxodon bolivariensis





Dinotoxodon paranensis



Toxodon platensis





Gyrinodon quassus




Ocnerotherium intermedium



Hoffstetterius imperator








Posnanskytherium desaguaderoi




Pisanodon nazari




Pericotoxodon platignathus





Calchaquitherium mixtum



Mixotoxodon larensis





Paratrigodon euguii



Trigodon gaudri















Notes[edit]

  1. ^ range and species from Croft et al. (2004) pp. 4-5; synonyms from McKenna and Bell (1997), p. 460.
  2. ^ Palmer (1904) p. 457.
  3. ^ Paleobiology Database: Nesodon imbricatus, Basic info.
  4. ^ D.Patterson, Bruce (2012) Bones, Clones, and Biomes: The History and Geography of Recent Neotropical Mammals p.92
  5. ^ Croft et al. (2004), p. 5.
  6. ^ Croft et al. (2004), pp. 7-8.
  7. ^ Townsend & Croft (2008) p. 225.
  8. ^ Forasiepi, A. A. M.; Cerdeño, E.; Bond, M.; Schmidt, G. I.; Naipauer, M.; Straehl, F. R.; Martinelli, A. N. G.; Garrido, A. C.; Schmitz, M. D.; Crowley, J. L. (2014). "New toxodontid (Notoungulata) from the Early Miocene of Mendoza, Argentina". Paläontologische Zeitschrift. doi:10.1007/s12542-014-0233-5. 

References[edit]