Reigitherium
| Reigitherium Temporal range: Late Cretaceous,
| |
|---|---|
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Clade: | †Meridiolestida |
| Clade: | †Mesungulatoidea |
| Family: | †Reigitheriidae Bonaparte, 1990 |
| Genus: | †Reigitherium Bonaparte, 1990[1] |
| Species: | †R. bunodontum
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| Binomial name | |
| †Reigitherium bunodontum Bonaparte, 1990
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Reigitherium was a mammal that lived during the Late Cretaceous, in the (Late Campanian-Maastrichtian). Its fossils have been found in the Los Alamitos and the La Colonia Formations of Argentina.
Description
[edit]The original specimen of Reigitherium was a fragmentary single molar tooth, with a lot of the surface detail damaged.[1] It was mistakenly identified as an upper left molar, but new material - including a whole tooth row of this species - clarifies that it was a lower right tooth.[2]
Reigitherium was a small mammal with simple premolars that increased in size along the tooth row to an enlarged fourth premolar. The molar teeth them decreased in size along the tooth row.
Taxonomy
[edit]Reigitherium has proven difficult to classify until recently, because the original fossil material was sparse, damaged, and difficult to identify. It was initially thought to be a dryolestid mammal when described in 1990.[1] Ten years later, Pascual et al. argued that it was a docodont based on the wear patterns they interpreted on the teeth.[3]
In 2011, Rougier et al. argued again for it being a dryolestoid, within Meridiolestida, an order of Gondwanan dryolestoids.[4] More complete fossils have now supported this analysis[2]
A recent phylogenetic study finds it to be the sister taxon to Peligrotherium.[2] Although the latter is much larger than Reigitherium, they share many tooth and skull characteristics that indicate they are closely related.
References
[edit]- ^ a b c Bonaparte, J. F. New Late Cretaceous mammals from the Los-Alamitos formation, Northern Patagonia. National Geographic Research 6.1 63-83.
- ^ a b c Harper T, Parras A, Rougier GW. 2018. Reigitherium (Meridiolestida, Mesungulatoidea) an enigmatic Late Cretaceous mammal from Patagonia, Argentina: morphology, affinities, and dental evolution. Journal of Mammalian Evolution.
- ^ Pascual R., Goin F.J., Gonzalez P., Ardolino A. & Puerta P.F. (2000) A highly derived docodont from the Patagonian Late Cretaceous Geodiversitas 22 (3) Documento pdf Archived 2012-04-14 at the Wayback Machine.
- ^ Guillermo W. Rougier; Sebastián Apesteguía; Leandro C. Gaetano (2011). "Highly specialized mammalian skulls from the Late Cretaceous of South America". Nature. 479 (7371): 98–102. Bibcode:2011Natur.479...98R. doi:10.1038/nature10591. PMID 22051679. S2CID 4380850. Supplementary information
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