[6] Subsequently, in 2016, a study conducted by Paul Penkalski and Tatiana Tumanova indicated that PIN 3142/250 is not referable to Saichania due to significant anatomical differences, but instead represents a new species of Tarchia, T. teresae.

[7] In 2021, Jin-Young Park and team named a new species of Tarchia, T. tumanovae, known from the holotype MPC-D 100/1353 which consists of a partial skeleton with associated skull.

Tarchia had previously been distinguished from Saichania on the basis of its relatively larger basicranium, an unfused paroccipital process-quadrate contact and, based on PIN 3142/250, the fact that the premaxillary rostrum is wider than the maximum distance between the tooth rows in the maxillaries.

In addition, it differs from both Saichania and Minotaurasaurus in that it lacks postocular caputegulae (or small, polygonal bony plates behind the orbit) and has a proportionally high occiput in caudal view.

[7] Minotaurasaurus Zaraapelta Saichania T. kielanae T. teresae Pinacosaurus The rocks in which Tarchia fossils were found likely represent eolian dunes and interdune environments, with small intermittent lakes and seasonal streams.

[8] Instead of oral processing, ankylosaurids living in dry environments such as Tarchia may have relied more on hindgut fermentation for digestion or, alternatively, consumed succulent plants that did not require complex chewing.

These ankylosaurids may have also been restricted to simple orthal pulping and might have had to deal with more grit during feeding compared to ankylosaurs that lived in tropical to subtropical climates, as indicated by the microwear pits.

[15] Park et al. (2021) suggested that there was a shift from bulk feeding to selective feeding in Mongolian ankylosaurines during the Campanian and Maastrichtian stages which may have either been caused by the change in habitat, as the climate changed from semi-arid and arid to humid, or interspecific competition with saurolophine hadrosaurids that immigrated from North America to Central Asia during the Campanian stage.

[8] One skull of Tarchia shows tooth marks identified as belonging to the tyrannosaurid, Tarbosaurus, indicating the theropod hunted the ankylosaurid.