''Jonkeria'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of dinocephalians. Species were very large and

omnivorous An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nut ...

(although there is some dispute to this, e.g. Colbert 1969 p. 136), from the

Tapinocephalus Assemblage Zone The ''Tapinocephalus'' Assemblage Zone is a tetrapod assemblage zone or biozone which correlates to the middle Abrahamskraal Formation, Adelaide Subgroup of the Beaufort Group, a fossiliferous and geologically important geological Group of the ...

, Lower

Beaufort Group The Beaufort Group is the third of the main subdivisions of the Karoo Supergroup in South Africa. It is composed of a lower Adelaide Subgroup and an upper Tarkastad Subgroup. It follows conformably after the Ecca Group and unconformably underli ...

, of the South African Karoo.

Description

The overall length was or more (up to ), the skull about 55 cm long. The skull is nearly twice as long as wide, and the snout is elongated and provided with sharp

incisor Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, wher ...

s and large

canines Canine may refer to: Zoology and anatomy * a dog-like Canid animal in the subfamily Caninae ** ''Canis'', a genus including dogs, wolves, coyotes, and jackals ** Dog, the domestic dog * Canine tooth, in mammalian oral anatomy People with the surn ...

. The cheek teeth were small. The body is robustly built, and the limbs stout. According to Boonstra 1969 p. 38, ''Jonkeria'' cannot be distinguished from its relative ''

Titanosuchus ''Titanosuchus ferox'' ("Fierce titan crocodile") is an extinct species of dinocephalian therapsids that lived in the Middle Permian epoch in South Africa. Along with its close relatives, ''Jonkeria'' and ''Moschops'', ''Titanosuchus'' inhabited ...

'' on

cranial Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position pro ...

grounds, but only in limb length; ''Jonkeria'' having short and squat limbs, and ''Titanosuchus'' long ones. Evidence of femoral

osteomyelitis Osteomyelitis (OM) is an infection of bone. Symptoms may include pain in a specific bone with overlying redness, fever, and weakness. The long bones of the arms and legs are most commonly involved in children e.g. the femur and humerus, while the ...

has been described in a

fossilised A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved i ...

specimen Specimen may refer to: Science and technology * Sample (material), a limited quantity of something which is intended to be similar to and represent a larger amount * Biological specimen or biospecimen, an organic specimen held by a biorepository ...

of ''J. parva''. The authors attributed the cause of the pathology, characterised by bony spicules growing perpendicular to nonpathological fibrolamellar bone tissue, to a bacterial infection resulting from an attack by a

predator Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...

, as evidenced by puncture marks on the

femur The femur (; ), or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates wit ...

Classification

About a dozen

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

have been named, including the

type species In 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 species that contains the biological type specime ...

, ''J. truculenta''. At least some of the other species were synonymised by Boonstra 1969. There has been no recent review of the genus.

References

* Boonstra, L. D. 1969, "The Fauna of the Tapincephalus Zone (Beaufort Beds of the Karoo)," Ann. S. Afr. Mus. 56 (1) 1-73, pp. 35–38 * Colbert, E. H., (1969), ''Evolution of the Vertebrates'', John Wiley & Sons Inc (2nd ed.) * von Zittel, K.A (1932), ''Textbook of Paleontology'', C.R. Eastman (transl. and ed), 2nd edition, Macmillan & Co. vol.2, p. 255 {{Taxonbar, from=Q942270 Tapinocephalians Prehistoric therapsid genera Guadalupian synapsids of Africa Fossil taxa described in 1917 Taxa named by Egbert Cornelis Nicolaas van Hoepen

Description

Classification

See also

References