[3] Llistrofus is readily identified by the presence of a large temporal emargination, a feature shared with Hapsidopareion lepton that unites the Hapsidopareiidae.

[2] Gee et al. (2019) further revised the diagnosis based on additional material from Richards Spur and listed 11 features: (1) frontals entering the orbit; (2) prefrontal entering the naris; (3) premaxilla contributing to ventral narial margin; (4) postfrontal excluded from the temporal emargination; (5) postorbital contacting the tabular; (6) denticles on the vomer; (7) teeth on the palatine smaller than the marginal teeth; (8) absence of a pterygoid-premaxilla contact; (9) a splenial that contributes to the symphysis; (10) presence of a Meckelian foramen; and (11) presence of a retroarticular process.

[1] Using high-resolution micro-CT scans of three skulls of the coeval Hapsidopareion, Jenkins et al. (2025) identified that the characters used to distinguish Llistrofus from it are actually shared by both taxa.

Due to its larger size, they identified Llistrofus as representing a more mature ontogenetic stage of Hapsidopareion, and argued that the former should be regarded as a junior synonym of the latter.

The results of their phylogenetic analyses are displayed in the cladogram below, where they found recumbirostrans to be a clade along the amniote stem:[4] Limnoscelis Captorhinidae Protorothyris Amniota Pantylus Hapsidopareion (including Llistrofus) Odonterpetidae Molgophidae Brachystelechidae Huskerpeton Proxilodon Gymnarthridae Rhynchonkidae Ostodolepididae