Patranomodon

Patranomodon Temporal range: Middle Permian–Late Permian PreЄ Є O S D C P T J K Pg N
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Synapsida
Order:	Therapsida
Suborder:	Anomodontia
Genus:	Patranomodon
Species:	P. nyaphulii

Patranomodon (from Greek, patra meaning “father”, “father of anomodonts”) is an extinct genus belonging to the group of anomodontia.^[1] Rubidge and Hopson named this anomodont after discovering its skull.^[2] Anomodontia is a group of terrestrial organisms that roamed the land on four limbs. Other genus belonging to the same group of anomodontia include Suminia, being the most complete basal anomodont, however Patranomodon being the most primitive.^[3][4] Patranomodon is the sister taxon to Dicynodon, which belongs to the group of Dicynodontia.^[2] Dicynodontia is known to be a carnivore unlike the Patranomodon, whom feeds on plant material. It is also a sister taxa to Galechirus, Galeops, and Galepus.^[5] Patranomodon believed to range in the Karoo of Southern Africa, however it is proposed that anomodonts ranged from the European continent (known as today) to the southern region of Africa as well as China and India.^[2] This is because the continents that we know today as Europe, Asia, and Africa, were connected in one very large land mass. This land mass was walk-able for many terrestrial organisms, and was called Pangaean. Patranomodon roamed this planet during the middle to late Permian era, which were about 268 to 265 million years ago.^[2] These land dwelling creatures belong to a group of Synapsida Therapsida.^[5]

Description and Paleobiology

Derived from only one nearly completed skull, Patranomodon nyaphulii is the most primitive genus of anomodontia based on its morphological features compared to its sister taxon, Dicynodontia.^[6] Patranomodon have a short exposure of their palatine and premaxilla, in which creates a shorter face compared to other anomodontons.^[6] This gives the Patranomodon a shorter facial structure, shorter in length as well as small in size. They also have a reduced tabular, a slit-like interpterygoid vacuity, three sacral vertebrae, as well as a screw-shape jaw.^[6] Patranomodon has many features indicating its herbivorous behaviors. The division of the external adductor muscles in the jaw into two separate components, the medial and lateral side, as well as using a propalinal jaw movement while feeding on plant material.^[7] This feature is important for the diet of the anomodont because being able to grind down tough plant matter is necessary for survival. The teeth formation of the Patranomodon allows crushing and grinding to occur with the way the jaws connect and move. Other aspects include widening of the palatal areas for breaking down plant matter in feeding, widening of the external adductors, the higher raised jaw hinge, reduction in the number of teeth as well as the size, and acquiring a horn that covers to the jaw.^[7] A key feature of the anomodontia is its raised zygamatic arch. This feature allows for jaw muscles to connect and form as powerful jaws began to develop further. The teeth of the Patranomodon fit perfectly together when the upper and lower jaw came together and the mouth is closed. They also possessed a complete set of teeth. The conversion from its ancestor being a carnivore to Patranomodon being herbivore occurred rapidly when compared to the longevity of the species of anomodonts.^[7] Sister taxa to the Patranomodon and the anomodonts were believed to be carnivorous, consuming other organism as their diet. The relative size of these terrestrial organisms is about the size of your average day mongoose.^[8] The average size of a mongoose is about 15 inches long, which means these species is relatively small compared to the average human.^[9] This is based on the small skull of the Patranomodon that was found.

Geological/paleoenvironment

Cast of Anomodont

The environment during the late Permian era, in which Patranomodon roamed the land, was typically aquatic based with lots of precipitation focusing on the mountains and plateaus of terrestrial habitats.^[10] Rainfall occurred very often during this era. There were times of warm humid greenhouse like climate with soil erosion and stagnation in the wetlands, which may have lead up to the mass extinctions in the middle to late Permian era.^[11] These environmental conditions created harsh living habitats for terrestrial creatures, in which had died off. The mass extinction affected most of the terrestrial and aquatic species, however, the terrestrial species evolved greatly after the mass extinction. Patranomodon was one of the early terrestrial species that evolved from the full aquatic environments. Flash floods were mainly the reason why there were sediment depositions as well as overflowing rivers from melting ice caps.^[12] Fossilization requires specific factors that allow preservation of the hard tissues such as bone. In Southern Africa, where Patranomodon lived during the late Permian era, there was probably migration occurring because of the progressive climatic drying and the shrinking of the basin. The migration occurred in a northward direction to warmer environments.^[13] Evidence for migration also found in the distribution of fossils of certain anomodonts northward from the southern cape of Africa. The Beaufort Group, where Patranomodon was found in the fossil record, dominated most of the basin with fluvial sedimentation.^[13] During the Permian era, Europe, Africa, Asia, America and Antarctica were merged into one large super continent called Pangea. Scattered fossils of Anomodonts also supported this huge land mass as well as migration from one end of the land mass to the other. The fluvial sedimentations refers to the sediment that was created by streams and rivers that deposit into landforms, thus preserving the fossil skull of Patranomodon. These streams and rivers were most likely formed by ice masses such as glaciers.

Historical Information and Discovery

Patranomodon Holotype

The skull fossil of Patranomodon was found in the Eodicynodon Assembleage Zone of South Africa, belonging to the lowest biozone of the beaufort group.^[6] The beaufort group time period extends from the middle of the Permian to the early Triassic era.^[14] It is one of the three main subdivisions of the Karoo Supergroup in what is known today as southern Africa. Rubidge and Hopson was the first to discover the skull of Patranomodon, in which was later named by these paleobiologists as well. These paleobiologist also was the first to publish literature on the Patranomodon in 1990, and many other literature following that. The most abundant remains of the Patranomodon were found on the Eastern Cape of Southern Africa, however, fossil parts were also found in Europe, China, as well as India, which indicated migration occurring among these terrestrial creatures.^[15] Paleontologist, Nyaphuli, collected the fossil of this creature in Southern Africa, and gave it the species name of "Patranomodon Nyaphuli".^[5] The length of the skull that was discovered was only 5 centimeters in length, predicting its body to be a total of only 30 centimeters.^[2] This is 11 inches when converted. The relative size of Patranomodon is really small when compared to an average adult human. The discovery of the Patranomodon nyaphuli was an important group because it led to the evolution of larger dominant herbivores by the end of the Permian and into the early Triassic era.^[6] Patranomodon was one of the earliest terrestrial herbivores as well as being the most primitive anomodont. Using the information that was gather from the skull of Patranomodon as well as fossils from its sister taxa, the group of paleontologist led discoveries to major advances in to understanding the phylogenetic relationships between Synapsida, even though major taxonomic information is still relatively missing.^[16]

See also

• Anomocephalus
• List of synapsids
• Therapsida
• Permian Extinction
• Beaufort Group

References

External links