Polydolopimorphia is an extinct order of

metatheria Metatheria is a mammalian clade that includes all mammals more closely related to marsupials than to placentals. First proposed by Thomas Henry Huxley in 1880, it is a more inclusive group than the marsupials; it contains all marsupials as wel ...

ns, closely related to extant

marsupials Marsupials are a diverse group of mammals belonging to the infraclass Marsupialia. They are natively found in Australasia, Wallacea, and the Americas. One of marsupials' unique features is their reproductive strategy: the young are born in a ...

. Known from the

Paleocene The Paleocene ( ), or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), ...

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58South 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 ...

and the

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. ...

, they were a diverse group during the Paleogene, filling many niches, before declining and becoming extinct at the end of the

Neogene The Neogene ( ,) is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period million years ago ( Mya) to the beginning of the present Quaternary Period million years ago. It is the second period of th ...

. It is divided into two suborders, Bonapartheriiformes, and Polydolopiformes Most members are only known from jaw fragments, which have their characteristically generally

bunodont The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name ''molar'' derives from Latin, ''molaris dens'', meaning "millstone tooth ...

teeth. The morphology of their teeth has led to proposals that polydolopimorphians may be crown group marsupials, nested within

Australidelphia Australidelphia is a superorder of marsupials encompassing about three-quarters of all living marsupial species, including all those native to Australasia and one South American species, the monito del monte. Unlike other American marsupials, wh ...

, though this proposal, has been questioned, with other analyses finding them outside of crown-group Marsupialia. The

monophyly In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent comm ...

of the group has been questioned, due to the possibility of the characteristic bunodont teeth emerging convergently in unrelated groups, rather than reflecting a true

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 ...

relationship. The group contained

omnivorous An omnivore () is an animal that regularly consumes significant quantities of both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize ...

frugivorous A frugivore ( ) is an animal that thrives mostly on raw fruits or succulent fruit-like produce of plants such as roots, shoots, nuts and seeds. Approximately 20% of mammalian herbivores eat fruit. Frugivores are highly dependent on the abundance ...

and

herbivorous A herbivore is an animal anatomically and physiologically evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat n ...

forms.

Taxonomy

Taxonomical subdivision of the Polydolopimorphia:Polydolopimorphia
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 * Suborder Bonapartheriiformes ** Family Bonapartheriidae *** Genus '' Bonapartherium'' *** Genus '' Epidolops'' ** Family Argyrolagidae *** Genus '' Anargyrolagus'' *** Genus '' Argyrolagus'' *** Genus '' Hondalagus'' *** Genus '' Klohnia'' *** Genus '' Microtragulus'' *** Genus '' Proargyrolagus'' ** Subfamily Chulpasiinae *** Genus '' Chulpasia'' *** Genus '' Thylacotinga'' ** Family Prepidolopidae *** Genus '' Incadolops'' *** Genus '' Perrodelphys'' *** Genus '' Punadolops'' ** Family Rosendolopidae *** Genus '' Hondonadia'' *** Genus '' Rosendolops'' * Suborder Polydolopiformes ** Family Polydolopidae Along with: * Enrico de Lazaro
Three New Species of Extinct Marsupials Identified
sci-news, Jan 26, 2021 *** Genus '' Amphidolops'' *** Genus '' Antarctodolops'' *** Genus '' Archaeodolops'' *** Genus '' Hypodolops'' *** Genus '' Kramadolops'' *** Genus '' Pliodolops'' *** Genus '' Polydolops'' *** Genus '' Pseudolops'' ** Family Sillustaniidae *** Genus '' Sillustania'' *** Genus '' Roberthoffstetteria'' *''incertae sedis'' ** Genus '' Prepidolops'' ** Genus '' Wamradolops'' ** Genus '' Bobbschaefferia''

References

{{Taxonbar, from=Q3805917 Metatheria Danian first appearances Piacenzian extinctions Eocene mammals of Antarctica