Pristerodon
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''Pristerodon'' is an extinct
genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
of
dicynodont Dicynodontia is an extinct clade of anomodonts, an extinct type of non-mammalian therapsid. Dicynodonts were herbivores that typically bore a pair of tusks, hence their name, which means 'two dog tooth'. Members of the group possessed a horny, t ...
therapsid from the Late Permian of South Africa, Zambia and India.


Paleobiology


Brain and senses

''Pristerodon'' were among the earliest land animals able to hear airborne sound as opposed to hearing via ground vibrations. A South African specimen studied with neutron tomography has shown evidence of an
eardrum In the anatomy of humans and various other tetrapods, the eardrum, also called the tympanic membrane or myringa, is a thin, cone-shaped membrane that separates the external ear from the middle ear. Its function is to transmit changes in pres ...
on its lower jaw with the implication that it was hearing impaired during the act of chewing. The specimen had a 3mm cavity for
cochlea The cochlea is the part of the inner ear involved in hearing. It is a spiral-shaped cavity in the bony labyrinth, in humans making 2.75 turns around its axis, the modiolus (cochlea), modiolus. A core component of the cochlea is the organ of Cort ...
which transformed sound frequency ranges into nerve impulses sent on to the brain.


Ecology

''Pristerodon'' has been found in the Kundaram Formation of India, Usili Formation of
Tanzania Tanzania, officially the United Republic of Tanzania, is a country in East Africa within the African Great Lakes region. It is bordered by Uganda to the northwest; Kenya to the northeast; the Indian Ocean to the east; Mozambique and Malawi to t ...
, the Upper Madumabisa Mudstone Formation of Zambia, and the Teekloof Formation and Abrahamskraal Formation of South Africa.


Phylogeny

''Pristerodon'' in a
cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...
modified from Angielczyk and Rubidge (2010) showing the
phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...
relationships of
Dicynodont Dicynodontia is an extinct clade of anomodonts, an extinct type of non-mammalian therapsid. Dicynodonts were herbivores that typically bore a pair of tusks, hence their name, which means 'two dog tooth'. Members of the group possessed a horny, t ...
ia:


See also

*
List of therapsids This list of therapsids is an attempt to create a comprehensive listing of all Genus, genera that have ever been included in the Therapsida excluding mammals and purely vernacular terms. The list includes all commonly accepted genera, but also gene ...


References


External links


The main groups of non-mammalian synapsids at Mikko's Phylogeny Archive
Dicynodontia Lopingian synapsids of Africa Fossils of South Africa Fossils of Zambia Lopingian synapsids of Asia Fossils of India Fossil taxa described in 1868 Taxa named by Thomas Henry Huxley Anomodont genera Permian India {{anomodont-stub