Dissorophidae
Encyclopedia
Dissorophidae is an extinct family
of medium-sized, temnospondyl
amphibians that flourished during the Late Pennsylvanian and early Permian periods in what is now North America and Europe. Despite being amphibians, they seem to be well developed for life on land, with well-developed limbs, solid vertebrae, and a row of armour plates of dermal bone, which both protected the animal and further strengthened the backbone.
A well known genus is Cacops
, a squat solid animal from the late Early Permian (Artinskian
age) Clear Fork
group of Texas, with a relatively huge head, and a row of armor plates along the back. In the similar but slightly larger and more specialised genus, Platyhystrix
, whose fossil remains are known from the Cutler Group of Utah, Coloardo, and New Mexico, the armor developed into a sort of ridge or sail.
Not all Dissorophids were squat-bodied big headed animals. Fayella
, from the late Artinskian
of Oklahoma, was lightly built with long limbs, obviously relying on speed rather than armour plating as a defense against predators.
There are a number of related forms which seem to have been more aquatic, which are known from the Late Permian of Russia
and the Early Triassic of Gondwana
.
It has been suggested that the Dissorophidae may be close to the ancestry of modern amphibians (Lissamphibia
), as it is closely related to another family called Amphibamidae
that is often considered ancestral to this group.
from Reisz et al. (2009):
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
of medium-sized, temnospondyl
Temnospondyli
Temnospondyli is a diverse order of small to giant tetrapods—often considered primitive amphibians—that flourished worldwide during the Carboniferous, Permian, and Triassic periods. A few species continued into the Cretaceous. Fossils have been found on every continent...
amphibians that flourished during the Late Pennsylvanian and early Permian periods in what is now North America and Europe. Despite being amphibians, they seem to be well developed for life on land, with well-developed limbs, solid vertebrae, and a row of armour plates of dermal bone, which both protected the animal and further strengthened the backbone.
A well known genus is Cacops
Cacops
Cacops is a genus of dissorophid temnospondyl that is known from the Early Permian of the central United States.It was about long and well adapted to a terrestrial lifestyle, with a heavily built skull, strong legs, a short tail, and a row of armor plates along its back...
, a squat solid animal from the late Early Permian (Artinskian
Artinskian
In the geologic timescale, the Artinskian is an age or stage of the Permian. It is a subdivision of the Cisuralian epoch or series. The Artinskian lasted between 284.4 ± 0.7 and 275.6 ± 0.7 million years ago...
age) Clear Fork
Clear Fork
Clear Fork may refer to a location in the United States:*Clear Fork in Tennessee*Clear Fork in Kentucky and Tennessee*Clear Fork Mohican River in Ohio*Clear Fork, West Virginia, a town...
group of Texas, with a relatively huge head, and a row of armor plates along the back. In the similar but slightly larger and more specialised genus, Platyhystrix
Platyhystrix
Platyhystrix was a temnospondyl amphibian with a distinctive sail along its back, similar to the unrelated synapsids, Dimetrodon and Edaphosaurus...
, whose fossil remains are known from the Cutler Group of Utah, Coloardo, and New Mexico, the armor developed into a sort of ridge or sail.
Not all Dissorophids were squat-bodied big headed animals. Fayella
Fayella
Fayella is an extinct genus of dissorophoidean temnospondyl amphibian within the family Dissorophidae....
, from the late Artinskian
Artinskian
In the geologic timescale, the Artinskian is an age or stage of the Permian. It is a subdivision of the Cisuralian epoch or series. The Artinskian lasted between 284.4 ± 0.7 and 275.6 ± 0.7 million years ago...
of Oklahoma, was lightly built with long limbs, obviously relying on speed rather than armour plating as a defense against predators.
There are a number of related forms which seem to have been more aquatic, which are known from the Late Permian of Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
and the Early Triassic of Gondwana
Gondwana
In paleogeography, Gondwana , originally Gondwanaland, was the southernmost of two supercontinents that later became parts of the Pangaea supercontinent. It existed from approximately 510 to 180 million years ago . Gondwana is believed to have sutured between ca. 570 and 510 Mya,...
.
It has been suggested that the Dissorophidae may be close to the ancestry of modern amphibians (Lissamphibia
Lissamphibia
The subclass Lissamphibia includes all recent amphibians and means smooth amphibia.Extant amphibians fall into one of three orders — the Anura , the Caudata or Urodela , and the Gymnophiona or Apoda .Although the ancestry of each group is still unclear, all share certain common characteristics,...
), as it is closely related to another family called Amphibamidae
Amphibamidae
Amphibamidae is an extinct family of dissorophoid euskelian temnospondyls. The earliest amphibamids such as Amphibamus are known from Early Permian strata in the United States, while the last known amphibamid, Micropholis, is known from the Early Triassic Karoo Basin of South Africa...
that is often considered ancestral to this group.
Phylogeny
Below is a cladogramCladogram
A cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational...
from Reisz et al. (2009):