Trematosauroidea
Encyclopedia
Trematosauroidea are an important group of Triassic
Temnospondyl
amphibians. They flourished briefly during the Early Triassic, occurring worldwide before declining at the start of the Middle Triassic
, although the group continued until the Late Triassic
. They were medium-sized temnospondyls with wedge-shaped tails, narrow skulls, and, in advanced forms, elongated snouts. The latter feature was probably an adaptation for feeding on fish. The largest and most specialized family, the Trematosauridae
, are the only amphibian
s to have adapted to a marine
life-style.
A temnospondyl ilium
was described in 2004 from the Callovian
Toutunhe Formation
in the Junggar Basin of China
. Although the isolated bone was impossible to identify on the species level, it was referred to Trematosauroidea. The presence of this bone in the Toutunhe Formation extends the range of trematosauroids into the Middle Jurassic
, making it one of only three groups of temnospondyls that survived the Triassic-Jurassic extinction event
(the other two being the Brachyopoidea
and possibly the Capitosauria
).
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...
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. They flourished briefly during the Early Triassic, occurring worldwide before declining at the start of the Middle Triassic
Middle Triassic
In the geologic timescale, the Middle Triassic is the second of three epochs of the Triassic period or the middle of three series in which the Triassic system is divided. It spans the time between 245 ± 1.5 Ma and 228 ± 2 Ma...
, although the group continued until the Late Triassic
Late Triassic
The Late Triassic is in the geologic timescale the third and final of three epochs of the Triassic period. The corresponding series is known as the Upper Triassic. In the past it was sometimes called the Keuper, after a German lithostratigraphic group that has a roughly corresponding age...
. They were medium-sized temnospondyls with wedge-shaped tails, narrow skulls, and, in advanced forms, elongated snouts. The latter feature was probably an adaptation for feeding on fish. The largest and most specialized family, the Trematosauridae
Trematosauridae
Trematosauridae are a family of large temnospondyl amphibians with many members. They first appeared during the Olenekian stage of the Early Triassic, and existed up until around the Carnian stage of the Late Triassic, although by then they were very rare...
, are the only amphibian
Amphibian
Amphibians , are a class of vertebrate animals including animals such as toads, frogs, caecilians, and salamanders. They are characterized as non-amniote ectothermic tetrapods...
s to have adapted to a marine
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...
life-style.
A temnospondyl ilium
Ilium
-Places:* Ilion or, Latinized, Ilium, another name for the legendary city of Troy, hence the title of Homer's Iliad*Ilium , an ancient city in Epirus...
was described in 2004 from the Callovian
Callovian
In the geologic timescale, the Callovian is an age or stage in the Middle Jurassic, lasting between 164.7 ± 4.0 Ma and 161.2 ± 4.0 Ma. It is the last stage of the Middle Jurassic, following the Bathonian and preceding the Oxfordian....
Toutunhe Formation
Toutunhe Formation
The Toutunhe Formation is a Mesozoic geologic formation. Dinosaur remains diagnostic to the genus level are among the fossils that have been recovered from the formation.-See also:* List of dinosaur-bearing rock formations...
in the Junggar Basin of China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
. Although the isolated bone was impossible to identify on the species level, it was referred to Trematosauroidea. The presence of this bone in the Toutunhe Formation extends the range of trematosauroids into the Middle Jurassic
Middle Jurassic
The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from 176-161 million years ago. In European lithostratigraphy, rocks of this Middle Jurassic age are called the Dogger....
, making it one of only three groups of temnospondyls that survived the Triassic-Jurassic extinction event
Triassic-Jurassic extinction event
The Triassic–Jurassic extinction event marks the boundary between the Triassic and Jurassic periods, , and is one of the major extinction events of the Phanerozoic eon, profoundly affecting life on land and in the oceans. In the seas a whole class and twenty percent of all marine families...
(the other two being the Brachyopoidea
Brachyopoidea
Brachyopoidea is a superfamily of temnospondyls that lived during the Mesozoic. It contains the families Brachyopidae and Chigutisauridae. The earliest records of brachyopids are from the Lower Triassic in Australia...
and possibly the Capitosauria
Capitosauria
Capitosauria is a clade of stereospondyl temnospondyls. Capitosauria and its sister taxon Trematosauria are the only major temnospondyl clades that existed during the Mesozoic....
).
External links
- Temnospondyli: Trematosauroidea at PalaeosPalaeosPalaeos.com is a web site on biology, paleontology, cladistics and geology and which covers the history of Earth. The site is well respected and has been used as a reference by professional paleontologists such as Michael J. Benton, the professor of vertebrate palaeontology in the Department of...
- Trematosauroidea at Mikko's Phylogeny ArchiveMikko's Phylogeny ArchiveMikko's Phylogeny Archive is an amateur paleontology website maintained by Mikko Haaramo, a student at the University of Helsinki's Department of Geology, Division of Geology and Palaeontology....
(cladogram)