''Ecteninion'' 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 meat-eating

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 that lived during the

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 ...

(

Carnian The Carnian (less commonly, Karnian) is the lowermost stage (stratigraphy), stage of the Upper Triassic series (stratigraphy), Series (or earliest age (geology), age of the Late Triassic Epoch (reference date), Epoch). It lasted from 237 to 227.3 ...

) in

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

. The

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

''Ecteninion lunensis'' was named by R.N. Martinez, C.L. May, and C.A. Forster in 1996. The holotype of ''E. lunensis'' is PVSJ 422, it's known from a nearly complete skull of about in length. It was found in the Cancha de Bochas Member of the

Ischigualasto Formation The Ischigualasto Formation is a Late Triassic geological formation in the Ischigualasto-Villa Unión Basin of southwestern La Rioja Province, Argentina, La Rioja Province and northeastern San Juan Province, Argentina, San Juan Province in northw ...

in the Ischigualasto-Villa Unión Basin in northwestern

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

.''Ecteninion''
at

Fossilworks Fossilworks was a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database, a large relational database assembled by hundreds of paleontologists from around the world. History Fossilworks was cr ...

.org It has been interpreted as a basal eucynodont. The

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

is in the collection of the Universidad Nacional de San Juan.

Body size

Although specimens larger than the holotype are present in the

, they are notably smaller than

Trucidocynodon ''Trucidocynodon'' is an extinct genus of ecteniniid cynodonts from the Upper Triassic (Carnian) of Brazil. It contains a single species, ''Trucidocynodon riograndensis''. Fossils of ''Trucidocynodon'' were discovered in outcrops of the Upper Sa ...

from the

Santa Maria Formation The Santa Maria Formation is a sedimentary rock formation found in Rio Grande do Sul, Brazil. It is primarily Carnian in age (Late Triassic), and is notable for its fossils of cynodonts, " rauisuchian" pseudosuchians, and early dinosaurs and othe ...

Phylogeny

''Ecteninion'' 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 ...

after Hopson & Kitching (2001):Hopson, J. A. and Kitching, J. W. (2001). A probainognathian cynodont from South Africa and the phylogeny of non-mammalian cynodonts. ''Bulletin of the Museum of Comparative Zoology'' 156(1):5-35 Cladogram after Stefanello ''et al''. (2023):

Body size

Phylogeny

References

Further reading