''Rastodon'' is an extinct genus of anomodonts. It is the oldest and most
basal
Basal or basilar is a term meaning ''base'', ''bottom'', or ''minimum''.
Science
* Basal (anatomy), an anatomical term of location for features associated with the base of an organism or structure
* Basal (medicine), a minimal level that is nec ...
known genus of
bidentalian
dicynodont
Dicynodontia is an extinct clade of anomodonts, an extinct type of non-mammalian therapsid. Dicynodonts were herbivorous animals with a pair of tusks, hence their name, which means 'two dog tooth'. Members of the group possessed a horny, typica ...
s. Uniquely among dicynodonts, its tusks curve forward.
[ The type and only species is ''R. procurvidens''.
]
Etymology
''Rastodon'' is derived from the Rio do Rasto Formation, where its remains were found, and the Greek word for "tooth". The species name, ''R. procurvidens'', means "curved forward tooth" and describes its uniquely shaped teeth.
Provenance
Only a single specimen of ''Rastodon'' has been discovered so far. It comes from the Rio do Rasto Formation, of the Guadalupian of Brazil.
Description
''Rastodon'' is a fairly typical dicynodont. It bore a beaked head with a single pair of tusks and a keratin
Keratin () is one of a family of structural fibrous proteins also known as ''scleroproteins''. Alpha-keratin (α-keratin) is a type of keratin found in vertebrates. It is the key structural material making up scales, hair, nails, feathers, ...
-covered nasal boss. However, it does possess several distinctive traits, of which its anteriorly
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...
-curved tusks are the most distinctive. Furthermore, its skull is relatively long and shallow compared to its close relatives. Its tusks contacted the lower jaw during propalinal mastication
Chewing or mastication is the process by which food is crushed and ground by teeth. It is the first step of digestion, and it increases the surface area of foods to allow a more efficient break down by enzymes. During the mastication process, th ...
.
Classification
''Rastodon'' is most parsimoniously placed as the basalmost bidental dicynodont, although it may be slightly more derived within Bidentalia.
See also
* List of synapsids
References
{{Taxonbar, from=Q25685697
Anomodont genera
Dicynodonts
Prehistoric synapsids of South America
Permian animals of South America
Permian Brazil
Fossils of Brazil
Paraná Basin
Fossil taxa described in 2016