Mesotheriidae
| Mesotheriidae Temporal range:
| |
|---|---|
| |
| Mesotherium cristatum | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | †Notoungulata |
| Suborder: | †Typotheria |
| Family: | †Mesotheriidae Alston, 1876 |
| Subfamilies & genera[2] | |
|
† Mesotheriinae
| |
Mesotheriidae ("Middle Beasts") is an
Characteristics
Mesotheriids were small to medium-sized notoungulates; larger forms were approximately the size of a
Behavior
A biomechanical study of the skeleton of three mesotheriid genera (Trachytherus, Plesiotypotherium, and Mesotherium) spanning the temporal range of the family indicates that most or all mesotheriids were adapted for digging. Mesotheriids likely dug for roots and tubers and were most similar in their diet and behavior to living wombats, although no living group is perfectly analogous.[3] Extensive burrowing was considered possible but unlikely given the relatively large size of most mesotheriids.
Geographic and temporal distribution
As with almost all other notoungulates, mesotheriids are known only from the Cenozoic of South America.[4] Unlike some other families, mesotheriid fossils are not found across the continent. Instead, mesotheriids are most abundant and diverse in faunas from middle latitudes in Bolivia and Chile, particularly the Altiplano.[5] Mesotheriid fossils are rare in high latitude Patagonian faunas and absent entirely from tropical faunas in northern South America.
The earliest secure records of the family come from the late Oligocene, when the family is represented by the genus Trachytherus from Argentina and Bolivia.[6] The family reached its greatest diversity in the Miocene,[5] and mesotheriids persisted into the middle Pleistocene, in the form of the type genus, Mesotherium.[4] Mesotheriidae was one of only three notoungulate families to persist into the Quaternary, the others being Hegetotheriidae and Toxodontidae.
Classification
Within the order Notoungulata, Mesotheriidae is placed in the
McKenna and Bell recognized three subfamilies within Mesotheriidae:
Classification of Mesotheriidae:[11]
Family †Mesotheriidae
- Subfamily †Fiandraiinae[12]
- Subfamily †Trachytheriinae
- †Trachytherus (?l. Eocene-l. Oligocene[13])
- †Trachytherus (?l. Eocene-l. Oligocene[13])
- Subfamily †Mesotheriinae
- †Eotypotherium (e. Miocene[14])
- †Altitypotherium (e. Miocene[14])
- †Microtypotherium (m./l. Miocene)
- †Eutypotherium (m. Miocene)
- †Caraguatypotherium (m.-l. Miocene[15])
- †Plesiotypotherium (l. Miocene)
- †Rusconitherium (e. Miocene[16])
- †Typotheriopsis (l. Miocene)
- †Pseudotypotherium (l. Miocene-?m. Pleistocene)
- †Mesotherium (e.-m. Pleistocene)
- †Hypsitherium[17] (e. Pliocene)
Notes
- ^ First appearance from Reguero and Castro (2004) with age of fauna following Shockey and Flynn (2007); last appearance from McKenna & Bell (1997).
- ^ Compiled from McKenna & Bell (1997), Reguero and Castro (2004), and Shockey et al. (2007).
- ^ a b c d e Shockey et al., 2007
- ^ a b c McKenna and Bell, 1997
- ^ a b c Flynn et al., 2005
- ^ a b Reguero and Castro, 2004
- ^ a b Cifelli, 1993
- ^ Simpson, 1967
- ^ Croft and Anaya, 2006
- ^ a b Billet et al., 2007
- ^ Trachytheriinae following Billet et al. (2008); Mesotheriinae following Anaya and MacFadden (1995) and Shockey et al. (2007). Temporal ranges following McKenna and Bell (1997) except where noted.
- ^ Inclusion tentative following Flynn et al. (2005).
- ^ a b FAD following Cerdeño et al. (2006) and Shockey and Flynn (2007).
- ^ a b Following Croft et al. (2004).
- ^ Following Flynn et al. (2005).
- .
- ^ Recognized as valid by McKenna and Bell (1997), this genus has not been evaluated in recent studies.
References
- Billet, G.A., Muizon, C. de, and Quispe, B.M. 2008. Late Oligocene mesotheriids (Mammalia, Notoungulata) from Salla and Lacayani (Bolivia): implications for basal mesotheriid phylogeny and distribution. Zoological Journal of the Linnean Society 152:153-200.
- Billet, G.A., Patterson, B., and Muizon, C. de. 2007. The latest archaeohyracids representatives (Mammalia, Notoungulata) from the Deseadan of Bolivia and Argentina; pp. 39–43 in E. Díaz-Martínez and I. Rábano (eds.), 4th European Meeting on the Palaeontology and Stratigraphy of Latin America. Instituto Geológico y Minero de España, Madrid. ISBN 978-84-7840-707-1 [1]
- Cerdeño, E., González Riga, B., and Bordonaro, O. 2006. Primer hallazgo de mamíferos en la Formación Mariño (Mioceno) en Divisadero Largo (Mendoza, Argentina). Ameghiniana 43:205-214. [2]
- Cifelli, R. L. 1993. The phylogeny of the native South American ungulates. pp. 195–216 in F. S. Szalay, M. J. Novacek and M. C. McKenna (eds.) Mammal Phylogeny, Volume 2, Placentals. Springer-Verlag, New York. ISBN 0-387-97853-4
- Croft, D.A., and Anaya, F. 2006. A new middle Miocene hegetotheriid (Notoungulata: Typotheria) and a phylogeny of Hegetotheriidae. Journal of Vertebrate Paleontology 26:387-399.
- Croft, D.A., Flynn, J.J. and Wyss, A.R. 2004. Notoungulata and Litopterna of the Early Miocene Chucal Fauna, Northern Chile. Fieldiana Geology 50(1):1-52. [3]
- Flynn, J. J., Croft, D.A., Charrier, R., Wyss, A.R., Hérail, G., and García, M. 2005. New Mesotheriidae (Mammalia, Notoungulata, Typotheria), geochronology and tectonics of the Caragua area, northernmost Chile. Journal of South American Earth Sciences 19:55-74.
- McKenna, Malcolm C., and Bell, Susan K. 1997. Classification of Mammals Above the Species Level. Columbia University Press, New York, 631 pp. ISBN 0-231-11013-8
- Reguero, M.A., and Castro, P.V. 2004. Un nuevo Trachytheriinae (Mammalia, †Notoungulata) del Deseadense (Oligoceno tardío) de Patagonia, Argentina: implicancias en la filogenia, biogeografía y bioestratigrafía de los Mesotheriidae. Revista Geológica de Chile 31:45–64. [4]
- Shockey, B.J., Croft, D.A., and Anaya, F. 2007. Analysis of function in the absence of extant functional homologues: a case study using mesotheriid notoungulates (Mammalia). Paleobiology 33:227-247.
- Shockey, B.J., and Flynn, J.J. 2007. Morphological diversity in the postcranial skeleton of Casamayoran (?middle to late Eocene) Notoungulata and foot posture in notoungulates. American Museum Novitates 3601:1-26. [5]
- Simpson, G.G. 1967. The beginning of the age of mammals in South America. Part 2, Systematics : Notoungulata, concluded (Typotheria, Hegetotheria, Toxodonta, Notoungulata incertae sedis), Astrapotheria, Trigonostylopoidea, Pyrotheria, Xenungulata, Mammalia incertae sedis. Bulletin of the American Museum of Natural History 137:1-259. [6]