Jonkeria
Encyclopedia
Jonkeria was a very large herbivorous
(although sometimes thought to be carnivorous - e.g. Colbert 1969 p. 136) dinocephalia
n, from the Tapinocephalus Assemblage Zone
, Lower Beaufort Group
, of the South African Karroo. The overall length was three and a half meters or more (up to 4 or 5 meters), 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
s and large canines
. The cheek teeth were rather small.
The body is robustly built, and the limbs stout. According to Boonstra 1969 p. 38, Jonkeria cannot be distinguished from its relative Titanosuchus
on cranial
grounds, but only in limb length; Jonkeria having short and squat limbs, and Titanosuchus long ones.
About a dozen species have been named, including the type species
, J. truculenta. At least some of the other species were synonymised by Boonstra 1969. There has been no recent review of the genus.
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
(although sometimes thought to be carnivorous - e.g. Colbert 1969 p. 136) dinocephalia
Dinocephalia
Dinocephalia are a clade of large early therapsids that flourished during the Middle Permian, but became extinct leaving no descendants.-Description:...
n, from the Tapinocephalus Assemblage Zone
Tapinocephalus Assemblage Zone
The Tapinocephalus Assemblage Zone is a geological stratum and is the thickest faunal zone of the Beaufort Group, in which has been found a rich variety of early therapsids. The name refers to Tapinocephalus, a genus of large herbivorous dinocephalian synapsids that lived during the Middle Permian...
, Lower Beaufort Group
Beaufort Group
The Beaufort Group is the third of the main subdivisions of the Karoo Supergroup of geological strata in Southern Africa. It follows conformably after the Ecca Group and consists essentially of sandstones and shales, deposited in the Karoo Basin from the Middle Permian to the early part of the...
, of the South African Karroo. The overall length was three and a half meters or more (up to 4 or 5 meters), 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
Incisor
Incisors are the first kind of tooth in heterodont mammals. They are located in the premaxilla above and mandible below.-Function:...
s and large canines
Canine tooth
In mammalian oral anatomy, the canine teeth, also called cuspids, dogteeth, fangs, or eye teeth, are relatively long, pointed teeth...
. The cheek teeth were rather 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
Titanosuchus ferox was a dinocephalian therapsid that lived in the Mid Permian epoch in South Africa. Despite the name, it was not related to crocodiles....
on cranial
Skull
The skull is a bony structure in the head of many animals that supports the structures of the face and forms a cavity for the brain.The skull is composed of two parts: the cranium and the mandible. A skull without a mandible is only a cranium. Animals that have skulls are called craniates...
grounds, but only in limb length; Jonkeria having short and squat limbs, and Titanosuchus long ones.
About a dozen species have been named, including the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
, J. truculenta. At least some of the other species were synonymised by Boonstra 1969. There has been no recent review of the genus.