''Dicynodon'' (from

Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

'' δίς'' "two" and '' κυνόδους'' "canine teeth", often translated to "two canine-teeth" or "two dog-teeth") is a genus of

dicynodont Dicynodontia is an extinct clade of anomodonts, an extinct type of non-mammalian therapsid. Dicynodonts were herbivores that typically bore a pair of tusks, hence their name, which means 'two dog tooth'. Members of the group possessed a horny, t ...

therapsid that lived in southern and

eastern Africa East Africa, also known as Eastern Africa or the East of Africa, is a region at the eastern edge of the Africa, African continent, distinguished by its unique geographical, historical, and cultural landscape. Defined in varying scopes, the regi ...

during the

Late Permian Late or LATE may refer to: Everyday usage * Tardy, or late, not being on time * Late (or the late) may refer to a person who is dead Music * ''Late'' (The 77s album), 2000 * Late (Alvin Batiste album), 1993 * Late!, a pseudonym used by Dave Groh ...

period. It is the namesake for the Dicynodontia, being the first genus named and recognised from the group by

palaeontologist Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure geolo ...

Richard Owen Sir Richard Owen (20 July 1804 – 18 December 1892) was an English biologist, comparative anatomy, comparative anatomist and paleontology, palaeontologist. Owen is generally considered to have been an outstanding naturalist with a remarkabl ...

in 1845, and embodies many of their typical characteristics. It was a

herbivore 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 ...

, with a

tortoise Tortoises ( ) are reptiles of the family Testudinidae of the order Testudines (Latin for "tortoise"). Like other turtles, tortoises have a shell to protect from predation and other threats. The shell in tortoises is generally hard, and like o ...

-like beak and was almost entirely toothless, except for the pair of prominent canine tusks that gave it its name. Over a hundred species of ''Dicynodon'' have been named and placed under ''Dicynodon'' since 1845, and the genus was for a long time treated as a

wastebasket taxon Wastebasket taxon (also called a wastebin taxon, dustbin taxon or catch-all taxon) is a term used by some taxonomists to refer to a taxon that has the purpose of classifying organisms that do not fit anywhere else. They are typically defined by e ...

. A study in 2011 revised every species referred to ''Dicynodon'', and concluded that the only valid species were 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 ...

''D. lacerticeps'' and its close relative ''D. huenei''. The remaining species were either dubious ('' nomina dubia''), referrable to unrelated valid genera, or valid species but representing a

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

grouping, or

evolutionary grade A grade is a taxon united by a level of morphological or physiological complexity. The term was coined by British biologist Julian Huxley, to contrast with clade, a strictly phylogenetic unit. Phylogenetics The concept of evolutionary grades ...

, of Permian dicynodontoids (a

subclade In genetics, a subclade is a subgroup of a haplogroup. Naming convention Although human mitochondrial DNA (mtDNA) and Y chromosome DNA (Y-DNA) haplogroups and subclades are named in a similar manner, their names belong to completely separate syst ...

of dicynodonts that includes ''Dicynodon'', ''

Lystrosaurus ''Lystrosaurus'' (; 'shovel lizard'; proper Ancient Greek is ''lístron'' ‘tool for leveling or smoothing, shovel, spade, hoe’) is an extinct genus of herbivorous dicynodont therapsids from the late Permian and Early Triassic epochs (arou ...

'', and other closely related Triassic dicynodonts). These species were elevated to their own genera, reviving many names previously

synonymous A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

with ''Dicynodon'' and establishing several new ones. A 2019 study named another new species of ''Dicynodon'' from

Tanzania Tanzania, officially the United Republic of Tanzania, is a country in East Africa within the African Great Lakes region. It is bordered by Uganda to the northwest; Kenya to the northeast; the Indian Ocean to the east; Mozambique and Malawi to t ...

, ''D. angielczyki''. The same study, however, simultaneously transferred ''D. huenei'' to the genus '' Daptocephalus'', thus still leaving ''Dicynodon'' with only two species.

Description

''Dicynodon'' was a medium-sized and advanced member of the Dicynodont group. It had an average length of , although size differed among species. Its fossil remains have been found in sediments of latest Permian age in South Africa and Tanzania. The

is ''Dicynodon lacerticeps'' Owen, 1845. A large number of species have since been placed in this genus, some of which turned out to be synonyms of other species, others have been moved to different genera.

Species

Two species of ''Dicynodon'' are currently recognized: the

''D. lacerticeps'' from South Africa and the species ''D. angielczyki'' from Tanzania. Since the genus was first named, over 160 species have been assigned to ''Dicynodon''. A 2011 study of the genus found 11 of these species to be valid, although most are now assigned to other dicynodont genera. Below is a list of all species that have ever been assigned to ''Dicynodon''. Since their naming, most have been considered as synonymous with other dicynodont species. Names in bold are still referable to ''Dicynodon''.

References

* * Lucas, S. G., 2005, ''Dicynodon'' (Reptilia: Therapsida) from the Upper Permian of Russia: biochronologic significance: In: ''The Nonmarine Permian''; edited by Lucas, S. G., and Zeigler, K. E., New Mexico Museum of Natural History & Science, Bulletin 30, p. 192-196.

External links

Dicynodon
- Mikko's Phylogeny archive (list of species and cladogram) {{Taxonbar, from=Q577736 Bidentalia Lopingian synapsids of Africa Taxa named by Richard Owen Fossil taxa described in 1845 Changhsingian genera

Description

Species

See also

References

External links