Trematosauridae are a family of large
marine temnospondyl
Temnospondyli (from Greek τέμνειν, ''temnein'' 'to cut' and σπόνδυλος, ''spondylos'' 'vertebra') is a diverse order of small to giant tetrapods—often considered primitive amphibians—that flourished worldwide during the Carbo ...
amphibians with many members. They first appeared during the
Induan
The Induan is the first age of the Early Triassic epoch in the geologic timescale, or the lowest stage of the Lower Triassic series in chronostratigraphy. It spans the time between 251.902 Ma and Ma (million years ago). The Induan is sometime ...
age of the
Early Triassic
The Early Triassic is the first of three epochs of the Triassic Period of the geologic timescale. It spans the time between Ma and Ma (million years ago). Rocks from this epoch are collectively known as the Lower Triassic Series, which is a un ...
, and existed until around the
Carnian stage of the
Late Triassic
The Late Triassic is the third and final epoch of the Triassic Period in the geologic time scale, spanning the time between Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch and followed by the Early Jurassic Epoch. ...
, although by then they were very rare. By the
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 in chronostratigraphy. The Middle Triassic spans the time between Ma and ...
they had become widespread throughout
Laurasia and
Gondwana with fossils being found in Europe, Asia, Madagascar, and Australia.
They are one of the most derived families of the
Trematosauroidea
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 ...
superfamily in that they are the only family that have fully marine lifestyles. Long, slender snouts that are characteristic of the trematosaurids, with some members having
rostrums resembling those of modern-day
gavials. Traditionally, two subfamilies within Trematosauridae can be identified, the relatively short-nosed
Trematosaurinae
Trematosaurinae is a subfamily of temnospondyl amphibians within the family Trematosauridae. Like all trematosaurids, they were marine piscivores, resembling crocodiles in their general build. Unlike the long, almost gharial-like snouts of the ...
and the long-nosed
Lonchorhynchinae
Lonchorhynchinae is a subfamily of temnospondyl amphibians within the family Trematosauridae.
Classification
Below is a cladogram from Steyer (2002) showing the phylogenetic
In biology, phylogenetics (; from Greek φυλή/ φῦλον . A third subfamily, Tertreminae">...
. A third subfamily, Tertreminae, was named in 2000 and includes broad-snouted forms like ''Tirraturhinus''. Below is a cladogram from Steyer (2002) showing the phylogenetic relationships of trematosaurids:
. If this analysis is accurate, it renders Trematosauridae one of the longest lived lineages of
, having lasted as recently as the late Jurassic.