''Patriarchus'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

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 interatheriid

notoungulate Notoungulata is an extinct order of ungulates that inhabited South America from the early Paleocene to the end of the Pleistocene, living from approximately 61 million to 11,000 years ago. Notoungulates were morphologically diverse, with forms re ...

s that lived during the

Early Miocene The Early Miocene (also known as Lower Miocene) is a sub-epoch of the Miocene epoch (geology), Epoch made up of two faunal stage, stages: the Aquitanian age, Aquitanian and Burdigalian stages. The sub-epoch lasted from 23.03 ± 0.05 annum, Ma to ...

in what is now

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 ...

. Fossils of this genus have been found in the

Santa Cruz Formation The Santa Cruz Formation is a geological formation in the Magallanes Basin, Magallanes/Austral Basin in southern Patagonia in Argentina and adjacent areas of Chile. It dates to the late Early Miocene epoch, and is contemporaneous with the eponym ...

of Argentina.

Description

It was a small-sized animal, approximately 40 centimeters long, excluding the tail. Its body shape vaguely resembled a

rabbit Rabbits are small mammals in the family Leporidae (which also includes the hares), which is in the order Lagomorpha (which also includes pikas). They are familiar throughout the world as a small herbivore, a prey animal, a domesticated ...

or a

marmot Marmots are large ground squirrels in the genus ''Marmota'', with 15 species living in Asia, Europe, and North America. These herbivores are active during the summer, when they can often be found in groups, but are not seen during the winter, w ...

, and its head ended in a pointed muzzle. ''Patriarchus'' shared many similarities with ''

Protypotherium ''Protypotherium'' is an extinct genus of Notoungulata, notoungulate mammals native to South America during the Oligocene and Miocene epoch (geology), epochs. A number of closely related animals date back further, to the Eocene. Fossils of ''Prot ...

'', with which it is often confused with, and differed from it through certain characteristics of its teeth. The first lower incisor and the lower canine were expanded in their terminal part, labially convex and similar in shape and size; they had a short lingual sulcus, not extending to the base of the teeth and V-shaped in occlusal view. The first lower premolar was bilobed, with a trigonid larger than the thalonid. The inferior dental series between the first incisor and the first premolar was continuous and the teeth did not overlap.

Classification

''Patriarchus palmidens'' was first described in 1889 by

Florentino Ameghino Florentino Ameghino (born Giovanni Battista Fiorino Giuseppe Ameghino; September 19, 1853 – August 6, 1911) was an Argentine naturalist, paleontologist, anthropologist and zoologist, whose fossil discoveries on the Argentine Pampas, especial ...

based on fossilized remains found in Early Miocene terrains from Rio Bote locality of the

in southern

Patagonia Patagonia () is a geographical region that includes parts of Argentina and Chile at the southern end of South America. The region includes the southern section of the Andes mountain chain with lakes, fjords, temperate rainforests, and glaciers ...

. Ameghino described several other species belonging to the genus, ''Patriarchus diastematus'', ''P. furculosus'', ''P. icochiloides'', ''P. leptocephalus'' and ''P. rectus'', but in 1900 the genus was synonymized with a ''Protypotherium''. In 2019 a cladistic analysis revealed sufficient differences between the type species ''Patriarchus palmidens'' and ''Protypotherium'' to allow the re-establishment of the genus ''Patriarchus''. According to this study, the genus ''Patriarchus'' includes only the type species and is a derived member of the family

Interatheriidae Interatheriidae is an extinct family of notoungulate mammals from South America. Interatheriids are known from the Middle Eocene (Mustersan) to the Early Pleistocene (Uquian).McKenna & Bell, 1997Linares, 2004 These animals were principally small- ...

, closely related with ''

Miocochilius ''Miocochilius'' is an extinct genus of small Notoungulata, notoungulate mammals (typotheria, typotheres) native to South America. The genus lived during the Miocene, Middle Miocene epoch (Laventan in the South American land mammal age, SALMA cla ...

''; this clade being the sister group of another clade comprising ''

Cochilius ''Cochilius'' is an extinct genus of interatheriid notoungulate that lived between the Late Oligocene and the lower Miocene in what is now Argentina. Description The skull and skeleton show features also found in other similar contemporary or s ...

'' and '' Interatherium''.

References

{{Taxonbar, from=Q97371620 Typotheres Miocene mammals of South America Neogene Argentina Fossils of Argentina Santacrucian Taxa named by Florentino Ameghino Fossil taxa described in 1889 Prehistoric placental genera Austral or Magallanes Basin Santa Cruz Formation