Madygenerpeton
Encyclopedia
Madygenerpeton is an extinct genus
of chroniosuchid
reptiliomorph from middle and upper Triassic
deposits of Madygen Formation of Kyrgyzstan
. It was first named by paleontologists Rainer R. Schoch, Sebastian Voigt and Michael Buchwitz in 2010
from a nearly complete skull
and associated osteoderm
s. The type species
is M. pustulatus.
s, or bony plates, overlying its spine. These osteoderms interlock with each other and connect to their associated vertebrae on the spinal column. They are wide and have curved or peaked surfaces. On the upper surface of the front end and the lower surface of the back end of each osteoderm there are facets covered in concentric ridges and furrows. These facets allow the plates to interlock with each other. The relatively narrow width of the osteoderms in Madygenerpeton allow for more lateral flexion in the trunk of than other chroniosuchids, up to 7.5°.
The skull has a parabolic
outline and its surface is covered with pustular ornamentation. This distinctive ornamentation gives the type species its name, M. pustulatus. Unlike other chroniosuchids, Madygenerpeton lacks an antorbital fontanelle
in front of the eyes.The postparietal or posterior area of the skull is concave.
chroniosuchians were likely an adaptation to terrestrial locomotion. The plates made the vertebral column more rigid, allowing it to better cope with stresses from shearing
, torsion
, compression, and tension. However, the increased stability of the vertebral column resulted in less flexibility. In Madygenerpeton, the increased flexibility of the trunk may have been an adaptation to a secondarily aquatic lifestyle. Greater lateral flexion would have enabled lateral undulation useful for swimming.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of chroniosuchid
Chroniosuchidae
The Chroniosuchidae are a family of semi-aquatic reptiliomorp amphibians found in sediments from the upper Permian and the upper Triassic periods, most in Russia. They were generally rather large animals, with long jaws similar to those found in modern crocodiles, and probably lived a similar life...
reptiliomorph from middle and upper Triassic
Triassic
The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...
deposits of Madygen Formation of Kyrgyzstan
Kyrgyzstan
Kyrgyzstan , officially the Kyrgyz Republic is one of the world's six independent Turkic states . Located in Central Asia, landlocked and mountainous, Kyrgyzstan is bordered by Kazakhstan to the north, Uzbekistan to the west, Tajikistan to the southwest and China to the east...
. It was first named by paleontologists Rainer R. Schoch, Sebastian Voigt and Michael Buchwitz in 2010
2010 in paleontology
-Anomalocaridids:-Newly named crustaceans:-Newly named insects:* A new family, Cascopleciidae, is published by Poinar Jr.* A new family of ceraphronoid Hymenopters, Radiophronidae, is published by Ortega-Blanco, Rasnitsyn, and Delclòs....
from a nearly complete skull
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...
and associated osteoderm
Osteoderm
Osteoderms are bony deposits forming scales, plates or other structures in the dermal layers of the skin. Osteoderms are found in many groups of extant and extinct reptiles, including lizards, various groups of dinosaurs , crocodilians, phytosaurs, aetosaurs, placodonts, and hupehsuchians...
s. 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...
is M. pustulatus.
Description
Madygenerpeton, like other chroniosuchids, has osteodermOsteoderm
Osteoderms are bony deposits forming scales, plates or other structures in the dermal layers of the skin. Osteoderms are found in many groups of extant and extinct reptiles, including lizards, various groups of dinosaurs , crocodilians, phytosaurs, aetosaurs, placodonts, and hupehsuchians...
s, or bony plates, overlying its spine. These osteoderms interlock with each other and connect to their associated vertebrae on the spinal column. They are wide and have curved or peaked surfaces. On the upper surface of the front end and the lower surface of the back end of each osteoderm there are facets covered in concentric ridges and furrows. These facets allow the plates to interlock with each other. The relatively narrow width of the osteoderms in Madygenerpeton allow for more lateral flexion in the trunk of than other chroniosuchids, up to 7.5°.
The skull has a parabolic
Parabola
In mathematics, the parabola is a conic section, the intersection of a right circular conical surface and a plane parallel to a generating straight line of that surface...
outline and its surface is covered with pustular ornamentation. This distinctive ornamentation gives the type species its name, M. pustulatus. Unlike other chroniosuchids, Madygenerpeton lacks an antorbital fontanelle
Fontanelle
A fontanelle is an anatomical feature on an infant's skull.-Anatomy:Fontanelles are soft spots on a baby's head which, during birth, enable the bony plates of the skull to flex, allowing the child's head to pass through the birth canal. The ossification of the bones of the skull causes the...
in front of the eyes.The postparietal or posterior area of the skull is concave.
Paleobiology
The tightly interlocking osteoderms along the back of PermianPermian
The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...
chroniosuchians were likely an adaptation to terrestrial locomotion. The plates made the vertebral column more rigid, allowing it to better cope with stresses from shearing
Shear stress
A shear stress, denoted \tau\, , is defined as the component of stress coplanar with a material cross section. Shear stress arises from the force vector component parallel to the cross section...
, torsion
Torsion (mechanics)
In solid mechanics, torsion is the twisting of an object due to an applied torque. In sections perpendicular to the torque axis, the resultant shear stress in this section is perpendicular to the radius....
, compression, and tension. However, the increased stability of the vertebral column resulted in less flexibility. In Madygenerpeton, the increased flexibility of the trunk may have been an adaptation to a secondarily aquatic lifestyle. Greater lateral flexion would have enabled lateral undulation useful for swimming.