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Description

A selection of temnospondyls known as metoposauroids, to scale.

Fossil assemblages create the opportunity for palaeontologists to investigate multiple individuals of the same species. Inferences can be made on life history when there are individuals from different age groups, while one gains a better understanding of how the animal looked like in life due to having full skeletons. Catastrophic conditions may vary from being covered in sandstorms, mudslides or covered by snow or ice. Several species of large temnospondyls from the Late Triassic appear to be commonly caught under these circumstances.

Judging by their weak limbs, metoposauroids were predominately aquatic animals. Related to the marine trematosauroids (see All at sea - Trematosaurs ), the flattened plagiosauroids (see Flip-top lid - Plagiosaurs ) and the big headed brachyopoids (including Monster snot otters - Chugutisaurids ), metoposauroids were major predators in freshwater environments. In form they didn't look dissimilar from the distantly related living giant salamanders, having a long low flattened skull filled with sharp teeth. Compared to other large aquatic predatory temnospondyls, such as the capitosaurs (see Crocomanders 1 - Capitosaurs (revised) ) the metoposauoids had eyes placed further forward. The two groups lived alongside each other in the same environments, but were able to separate niches. Capitosaurs appear to have been more mobile, patrolling the surface water, while metoposauroids were sluggish bottom-dwelling ambush hunters. They were able to remain submerged due to the dense large shoulder clavicles.

Across the South-west USA, Portugal and Morocco, several mass graves of metoposaurids (Anashima, Metoposaurus, Dutuitosaurus) have been found. Most death assemblages have been shown to be a result of disarticulated skeletons deposited together by river currents. However with Duituitosaurus, the 70+ individuals died in-situ suggestive that this was due to a dried out pool. As a result the articulated specimens provide an accurate guide to the appearance of metoposaurids. It had a relatively longer tail indicating it was a more active hunter than other metoposauroids. Historically Anaschisma was incorrectly reconstructed with a long tail as it was known from incomplete skeletons, although other material suggests it actually relatively short. Confusingly Anaschisma has had a variety of names, including Koskinonodon, Buettneria, Borborophagos + a species of Metoposaurus. These have since been synonomised, while the juvenile specimens of Apachesaurus are possibly the same species.

Metoposauroids as with most temnospondyls died out at the end of the Triassic.

* Note: illustration modified to reflect comments regarding size of Dutuitosaurus.

Description

A selection of temnospondyls known as metoposauroids, to scale.

Fossil assemblages create the opportunity for palaeontologists to investigate multiple individuals of the same species. Inferences can be made on life history when there are individuals from different age groups, while one gains a better understanding of how the animal looked like in life due to having full skeletons. Catastrophic conditions may vary from being covered in sandstorms, mudslides or covered by snow or ice. Several species of large temnospondyls from the Late Triassic appear to be commonly caught under these circumstances.

Judging by their weak limbs, metoposauroids were predominately aquatic animals. Related to the marine trematosauroids (see All at sea - Trematosaurs ), the flattened plagiosauroids (see Flip-top lid - Plagiosaurs ) and the big headed brachyopoids (including Monster snot otters - Chugutisaurids ), metoposauroids were major predators in freshwater environments. In form they didn't look dissimilar from the distantly related living giant salamanders, having a long low flattened skull filled with sharp teeth. Compared to other large aquatic predatory temnospondyls, such as the capitosaurs (see Crocomanders 1 - Capitosaurs (revised) ) the metoposauoids had eyes placed further forward. The two groups lived alongside each other in the same environments, but were able to separate niches. Capitosaurs appear to have been more mobile, patrolling the surface water, while metoposauroids were sluggish bottom-dwelling ambush hunters. They were able to remain submerged due to the dense large shoulder clavicles.

Across the South-west USA, Portugal and Morocco, several mass graves of metoposaurids (Anashima, Metoposaurus, Dutuitosaurus) have been found. Most death assemblages have been shown to be a result of disarticulated skeletons deposited together by river currents. However with Duituitosaurus, the 70+ individuals died in-situ suggestive that this was due to a dried out pool. As a result the articulated specimens provide an accurate guide to the appearance of metoposaurids. It had a relatively longer tail indicating it was a more active hunter than other metoposauroids. Historically Anaschisma was incorrectly reconstructed with a long tail as it was known from incomplete skeletons, although other material suggests it actually relatively short. Confusingly Anaschisma has had a variety of names, including Koskinonodon, Buettneria, Borborophagos + a species of Metoposaurus. These have since been synonomised, while the juvenile specimens of Apachesaurus are possibly the same species.

Metoposauroids as with most temnospondyls died out at the end of the Triassic.

* Note: illustration modified to reflect comments regarding size of Dutuitosaurus.