These animals were part of the family called Metoposauridae, which filled the crocodile-like predatory niches in the late Triassic.

[4] Anaschisma was erected by Branson (1905) from two metoposaurid skulls from the Popo Agie Formation (Carnian) of Wyoming.

The generic name Anaschisma ("ripped up") was not explained but would derive from Ancient Greek ἀνασχίζω [anaskhizo] "rip up, rend", likely alluding to the fragmented state of the original fossils noted by Branson: "The skulls were incased in a hard matrix of arenaceous shale, and had been broken in many pieces."

[5] Moodie (1908) considered A. brachygnatha a junior synonym of A. browni, although Branson and Mehl (1929) retained the two species as distinct.

[8] Chowdhury (1965) synonymized Anaschisma with Metoposaurus and sunk all North American metoposaurids from the Chinle and Dockum into browni.

[19] Other more minor skull traits characterize Anaschisma as well: elongation of the lacrimal, shortening of the prefrontal, reduction of the interclavicle, and the most characteristic is the center lachrymal entering margin of the orbit.

[20] Some researchers believe that Anaschisma has a shorter posterior process of the interclavicle, which may discriminate it from other closely related species, while others believe that there is not enough information to make that distinction.

[21] These dental adaptations enhanced the ability of Anaschisma to capture prey; the teeth are optimized for piercing prey and not allowing it to escape, resisting the bending force applied by the struggling organism, and propagating cracks in the hard parts of the object, such as bone, allowing for easier eating and digestion.

[3] It was not long like the crocodiles of today, but more likely short and strong to enable it to quickly spring up from hiding and capture prey before it escapes.

[3] Anaschisma likely spent a lot of time motionless, waiting for prey, which these short legs were likely an adaptation to.

[5] The hunting style of Anaschisma involved lying at the bottom of a shallow swamp, waiting for a fish, crustacean, smaller amphibian, or even a young phytosaur to wander by.

It is unknown what caused this mass extinction; hypotheses include huge volcanic eruptions (the Central Atlantic magmatic province is a prime example), climate change, oceanic acidification, or an asteroid impact.