Massetognathinae is an extinct

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end botanical subfamily names with "-oideae", and zo ...

cynodont Cynodontia () is a clade of eutheriodont therapsids that first appeared in the Late Permian (approximately 260 Megaannum, mya), and extensively diversified after the Permian–Triassic extinction event. Mammals are cynodonts, as are their extin ...

s in the family

Traversodontidae Traversodontidae is an extinct family of herbivorous cynodonts. Traversodonts were primarily Gondwanan, with many species known from Africa and South America. Recently, traversodonts have also been found from Europe and North America. Traversodon ...

. It includes four species from the

Middle Middle or The Middle may refer to: * Centre (geometry), the point equally distant from the outer limits. Places * Middle (sheading), a subdivision of the Isle of Man * Middle Bay (disambiguation) * Middle Brook (disambiguation) * Middle Creek ...

and

Late Triassic The Late Triassic is the third and final epoch (geology), epoch of the Triassic geologic time scale, Period in the geologic time scale, spanning the time between annum, Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch a ...

: '' Massetognathus pascuali'' from Argentina, '' Massetognathus ochagaviae'' and '' Santacruzodon hopsoni'' from southern Brazil, and '' Dadadon isaloi'' from Madagascar. Massetognathines have several distinguishing characteristics, including flattened skulls, small

canine teeth In mammalian oral anatomy, the canine teeth, also called cuspids, dogteeth, eye teeth, vampire teeth, or fangs, are the relatively long, pointed teeth. In the context of the upper jaw, they are also known as '' fangs''. They can appear more fl ...

, and postcanine teeth with three cusps on their outer edges. Massetgognathinae was defined by Kammerer ''et al.'' (2012) as the clade containing all traversodontids more closely related to '' Massetognathus pascuali'' than to '' Gomphodontosuchus brasiliensis'', and is the

sister taxon In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

of the traversodontid subfamily

Gomphodontosuchinae Gomphodontosuchinae is a subfamily (biology), subfamily of Triassic traversodontid cynodonts. It includes the genera ''Gomphodontosuchus'' (the type genus), ''Exaeretodon'', ''Santagnathus'', ''Siriusgnathus'', ''Menadon'', ''Proexaeretodon,'' '' ...

, which was defined by Kammerer ''et al.'' (2008) as all traverodontids more closely related to ''G. brasiliensis'' than to ''M. pascuali''. Below is 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 ...

from Kammerer ''et al.'' (2012) 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 ...

position of Massetognathinae within Traversodontidae:

References

Traversodontidae Middle Triassic first appearances Late Triassic extinctions Prehistoric animal subfamilies Therapsid subfamilies {{paleo-cynodont-stub