Zygosaurus

Last updated

Zygosaurus
Temporal range: Middle Permian
Zygosaurus14DB.jpg
Life restoration of Zygosaurus
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Order: Temnospondyli
Family: Dissorophidae
Clade: Eucacopinae
Genus: Zygosaurus
Eichwald, 1848
Type species
Zygosaurus lucius
Eichwald, 1848

Zygosaurus is an extinct genus of dissorophid temnospondyl from the Middle-Late Permian of Russia. It was described in 1848 by Eduard Eichwald, making it the first dissorophid to be described and is known from a single species, Zygosaurus lucius. [1] The location of the holotype, and only known specimen, is unknown, [2] and although casts are reposited in several institutions, little is known about this taxon beyond qualitative aspects of the skull (e.g., preorbital length twice as long as postorbital length; skull width greatest at mid-length of orbits). [3] The skull was estimated to be around 20 cm in length, making it one of the largest dissorophids, being only slightly smaller than Kamacops . [2]

Related Research Articles

<i>Cacops</i> Extinct genus of amphibians

Cacops, is a genus of dissorophid temnospondyls from the Kungurian stage of the early Permian of the United States. Cacops is one of the few olsoniforms whose ontogeny is known. Cacops fossils were almost exclusively known from the Cacops Bone Bed of the Lower Permian Arroyo Formation of Texas for much of the 20th century. New material collected from the Dolese Brothers Quarry, near Richards Spur, Oklahoma in the past few decades has been recovered, painting a clearer picture of what the animal looked and acted like.

<span class="mw-page-title-main">Dissorophidae</span> Extinct family of temnospondyls

Dissorophidae is an extinct family of medium-sized temnospondyls that flourished during the late Carboniferous and early Permian periods. The clade is known almost exclusively from North America.

<span class="mw-page-title-main">Temnospondyli</span> Ancestors of modern amphibians adapted to life on land

Temnospondyli or temnospondyls is a diverse ancient order of small to giant tetrapods—often considered primitive amphibians—that flourished worldwide during the Carboniferous, Permian and Triassic periods, with fossils being found on every continent. A few species continued into the Jurassic and Early Cretaceous periods, but all had gone extinct by the Late Cretaceous. During about 210 million years of evolutionary history, they adapted to a wide range of habitats, including freshwater, terrestrial, and even coastal marine environments. Their life history is well understood, with fossils known from the larval stage, metamorphosis and maturity. Most temnospondyls were semiaquatic, although some were almost fully terrestrial, returning to the water only to breed. These temnospondyls were some of the first vertebrates fully adapted to life on land. Although temnospondyls are amphibians, many had characteristics such as scales and large armour-like bony plates (osteoderms) that generally distinguish them from the modern soft-bodied lissamphibians.

<i>Platyhystrix</i> Genus of amphibians (fossil)

Platyhystrix is an extinct temnospondyl amphibian with a distinctive sail along its back, similar to the unrelated synapsids, Dimetrodon and Edaphosaurus. It lived during the boundary between the latest Carboniferous and earliest Permian periods throughout what is now known as the Four Corners, Texas, and Kansas about 300 million years ago.

<i>Mastodonsaurus</i> Extinct genus of temnospondyls

Mastodonsaurus is an extinct genus of temnospondyl from the Middle Triassic of Europe. It belongs to a Triassic group of temnospondyls called Capitosauria, characterized by their large body size and presumably aquatic lifestyles. Mastodonsaurus remains one of the largest amphibians known, and may have exceeded 6 meters in length.

<i>Eryosuchus</i> Extinct genus of temnospondyls

Eryosuchus is an extinct genus of capitosauroid temnospondyl from the Middle Triassic of northern Russia. It was a very large predator: the largest specimen known could reach up to 3.5 m (11.5 ft) in length, with a skull over 1 m long.

<i>Kamacops</i> Extinct genus of amphibians

Kamacops is a genus of dissorophid temnospondyls known from the Middle to Late Permian of Russia that was described by Yuri Gubin in 1980. It is known from a single species, Kamacops acervalis, material of which is currently reposited in the Paleontological Institute of the Russian Academy of Sciences. Kamacops is one of the youngest dissorophids, along with Iratusaurus and Zygosaurus from Russia and Anakamacops from China and was one of the largest known dissorophids, with an estimated skull length of 24–30 cm. It is typically recovered as being most closely related to Zygosaurus and to the North American Cacops. A detailed study of the braincase region was performed by Schoch (1999), one of the first to examine this region in dissorophids. This study revealed extensive co-ossification of the braincase.

<i>Aspidosaurus</i> Extinct genus of amphibians

Aspidosaurus is an extinct genus of dissorophoid temnospondyl within the family Dissorophidae.

<i>Anconastes</i> Extinct genus of amphibians

Anconastes is an extinct genus of dissorophoid temnospondyl within the family Trematopidae. It is known from two specimens from the Late Carboniferous Cutler Formation of north-central New Mexico in the southwestern United States. The genus name derives from two Greek roots, ankos and nastes ("inhabitant"), which refers to the type locality of El Cobre Canyon where the specimens were found. The specific name is derived from the Latin word vesperus ("western"). The more complete specimen, the holotype, is a partial skull with articulated mandibles and a substantial amount of the postcranial skeleton. The less complete specimen, the paratype, consists only of the right margin of the skull with an articulated mandible.

Actiobates is an extinct genus of trematopid temnospondyl that lived during the Late Carboniferous. It is known from the Garnett Quarry in Kansas.

<i>Broiliellus</i> Extinct genus of amphibians

Broiliellus is an extinct genus of dissorophoid temnospondyl within the family Dissorophidae. Broiliellus is most closely related to the genus Dissorophus, and both have been placed in the subfamily Dissorophinae. Broiliellus is known from five species from the Early Permian: the type species is Broiliellus texensis, and the other species are Broiliellus brevis,Broiliellus olsoni, Broiliellus arroyoensis, and Broiliellus reiszi. An additional species, Broiliellus novomexicanus, which was originally named Aspidosaurus novomexicanus, is now thought to fall outside the genus as a member of the subfamily Eucacopinae.

<i>Conjunctio</i> Extinct genus of amphibians

Conjunctio is an extinct genus of dissorophid temnospondyl amphibian from the early Permian of New Mexico. The type species, Conjunctio multidens, was named by paleontologist Robert L. Carroll in 1964.

<i>Ecolsonia</i> Extinct genus of amphibians

Ecolsonia is an extinct genus of trematopid temnospondyl. Its phylogenetic position within Olsoniformes has been historically debated, but it is presently considered to be a trematopid.

<i>Dissorophus</i> Extinct genus of amphibians

Dissorophus (DI-soh-ROH-fus) is an extinct genus of temnospondyl amphibian that lived during the Early Permian Period about 273 million years ago. Its fossils have been found in Texas and in Oklahoma in North America. Its heavy armor and robust build indicate Dissorophus was active on land, similar to other members of the clade Dissorophidae that are known from the Late Carboniferous to the Early Permian periods. Dissorphus is distinguished by its small body size, disproportionately large head and short trunk.

Iratusaurus is an extinct genus of dissorophoid temnospondyl within the family Dissorophidae. It was described by Gubin (1980) on the basis of a fragmentary posterior skull. It is estimated to have been comparably large to Kamacops, another Russian dissorophid, but little more can be said about it, and it is rarely mentioned in comparative descriptions and has never been tested in a phylogenetic analysis. Distinguishing features include a large, triangular otic notch and a median crest on the postparietals.

Tersomius is an extinct genus of dissorophoid temnospondyl within the family Micropholidae. It is known from the early Permian of North America.

Parioxys is an extinct genus of temnospondyl amphibian from the Early Permian of Texas.

Scapanops is an extinct genus of dissorophid temnospondyl amphibian known from the Early Permian Nocona Formation of north-central Texas, United States. It contains only the type species Scapanops neglecta, which was named by Rainer R. Schoch and Hans-Dieter Sues in 2013. Scapanops differs from other dissorophids in having a very small skull table, which means that its eye sockets are unusually close to the back of the skull. The eye sockets are also very large and spaced far apart. Scapanops was probably small-bodied with a proportionally large head and short trunk and tail. Like other dissorophids, it probably spent most of its life on land.

<span class="mw-page-title-main">Eucacopinae</span> Extinct clade of amphibians

Eucacopinae is an extinct clade of dissorophid temnospondyls. Eucacopines differ from the other main group of dissorophids, the Dissorophinae, in having more lightly built skeletons and more knobby skulls. The subfamily was originally named Cacopinae, but since the name was already established for a group of living microhylid frogs in 1931, the name was changed to Eucacopinae in 2013. Eucacopinae is a stem-based taxon defined as the most inclusive clade containing the species Cacops apsidephorus but not Dissorophus multicinctus, which belongs to Dissorophinae. According to the most recent phylogenetic analyses of Dissorophidae, Eucacopinae includes the basal ("primitive") species Conjunctio multidens and Scapanops neglecta from the southwestern United States and a more derived ("advanced") group including several species of Cacops and the Russian genera Kamacops and Zygosaurus. Derived eucacopines have two rows of bony plates called osteoderms running down their backs, while the more basal eucacopines have only a single row. Dissorophines also have a double row of osteoderms but probably evolved them independently because the most recent common ancestor of the two groups had a single row of osteoderms.

This list of fossil amphibians described in 2018 is a list of new taxa of fossil amphibians that were described during the year 2018, as well as other significant discoveries and events related to amphibian paleontology that occurred in 2018.

References

  1. Eichwald, Eduard (1848). "Uber die Saurier des kupferfhrenden Zechsteins Russlands". Bulletin de la Société Nationale de Moscou (in Russian). 21: 136–204 via Google Books.
  2. 1 2 Schoch, Rainer R. (2012). "Character distribution and phylogeny of the dissorophid temnospondyls". Fossil Record. 15 (2): 121–137. doi: 10.1002/mmng.201200010 .
  3. Schoch, Rainer R.; Milner, Andrew R. (2014). Sues, Hans-Dieter (ed.). Handbuch der Paläoherpetologie Part 3A2. Temnospondyli. Stuttgart: Verlag Dr. Friedrich Pfeil. ISBN   9783931516260. OCLC   580976.