Ptychotherates bucculentus was named by Srivastava and Nesbitt (2026) [Ptychotherates bucculentus bears the following combination of character states (local autapomorphies indicated with *): supratemporal fossa present on posterior portion of the frontal and dorsal surface of the parietal; tapering dorsal process of the maxilla; maxilla lacking antorbital fossa on its posterior portion ventral to the antorbital fenestra; prefrontal symmetrical in lateral view*; jugal body proportionally dorsoventrally deep* (i.e. more than three times as deep as the jugal posterior process, deeper than the length of postorbital ventral process, and more than half the height of the quadrate main body; Table 1); laterally extensive ventral process (= crista interfenestralis) of the otoccipital; ventral process of squamosal anteroposteriorly wide with a lateral fossa on the posterior part; retroarticular process upturned immediately posterior to glenoid; anterolateral portion of postorbital dorsally overhanging orbit; postorbital dorsolaterally overlapping the squamosal; posttemporal fenestra as wide as foramen magnum; nasal and frontals flat dorsally; serrated and recurved teeth with fine serrations (4–5 per 1 mm in the maxilla, 5–6 per 1 mm in the dentary) with pointed apices of the serrations. Differs from all other archosaurs other than Tawa hallae (GR 241) in the following character states: jugal laterally flat and proportionally tall ventral to the orbit (i.e. deeper than half the length of postorbital ventral process and more than one-third the height of the quadrate main body, Table 1); deep fossa on the posterior edge of the quadrate in posterior view; well-defined fossa on the dorsal surface of the paroccipital process of the braincase; fine serrations on the teeth (4–5 per 1 mm in the maxilla, 5–6 per 1 mm in the dentary) with pointed apices; ventral recess of the parabasisphenoid wide with a centrally located foramen. Differs from Tawa hallae (GR 241) in the following character states: proportionally deeper jugal (i.e. deeper than the length of postorbital ventral process and more than half the height of the quadrate main body; Table 1); labial surface of dentary and maxillary tooth crowns smooth without ridges or grooves; proportionally longer anterior portion of the prefrontal so that the element is symmetrical in lateral view; proportionally shorter ventral process of the prefrontal; more laterally pronounced surangular ridge; surangular with a dorsally arched dorsal margin, as seen in lateral view; possibly deeper dentary; articular groove demarcation on ventral process of the postorbital rounded in transverse cross-section; dorsal articular head of the quadrate more circular in transverse outline. Ptychotherates bucculentus cannot strictly be distinguished from Chindesaurus bryansmalli because the holotypes lack any anatomical overlap. Although it will always be difficult to demonstrate that they are different taxa based on anatomy and they are likely to be closely related, they show distinct stratigraphic separation: specimens referred to Chindesaurus bryans�malli are older than 209.926
0.072 Ma (Ramezani et al. 2011) in the Revueltian holochronozone (Marsh et al. 2019) of Petrified Forest National Park, Arizona, whereas Ptychotherates bucculentus is younger than 211.9
0.7 Ma (Irmis et al. 2007, 2011), possibly up to 5–9 myr younger, and is from the Apachean holochronozone (Lucas 1998; see Locality and age). Ptychotherates bucculentus can be easily differentiated from its contemporary dinosaurs found in the same locality (i.e. Coelophysis Quarry). Ptychotherates bucculentus differs from Coelophysis bauri in many aspects of the skull of the former, including (but not a comprehensive list, see description): postorbital with a broad contact with the frontal; jugal much taller ventral to the orbit and lacking a lateral ridge; quadrate with deep fossa on the posterior edge; maxilla lacking the broad lateral antorbital fossa present in Coelophysis bauri; proportionally larger posttemporal fenestra. Ptychotherates bucculentus differs from Daemonosaurus chauliodus in that the skull of Ptychotherates bucculentus possesses both a proportionally deeper jugal that lacks a lateral ridge and a proportionally much smaller prefrontal (see description for other differences).]. Its type specimen is CM 31368, a skull (a mostly complete and partially articulated skull with a complete braincase and much of the skull roof, as well as some palatal and hemimandibular elements), and it is a 3D body fossil. Its type locality is Ghost Ranch Quarry, which is in a Rhaetian crevasse splay siltstone/conglomerate in the Chinle Formation of New Mexico. It is the type species of Ptychotherates.