Llistrofus is readily identified by the presence of a large temporal emargination, a feature shared with Hapsidopareion lepton that unites the Hapsidopareiidae.
Carroll & Gaskill (1978) differentiated Llistrofus from Hapsidopareion by four features: (1) postorbital contacting the tabular; (2) postparietal contacting the squamosal; (3) frontals entering the orbit; and (4) presence of a quadratojugal.
Bolt & Rieppel (2009) revised the diagnosis following additional preparation of the holotype's skull and list three features (only one of which is shared with the previous work): (1) skull length approximately twice that of Hapsidopareion; (2) frontals entering the orbit; and (3) cultriform process of the parasphenoid offset from the basal plate by a narrow base.
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.
Llistrofus is readily identified by the presence of a large temporal emargination, a feature shared with Hapsidopareion lepton that unites the Hapsidopareiidae. Carroll & Gaskill (1978) differentiated Llistrofus from Hapsidopareion by four features: (1) postorbital contacting the tabular; (2) postparietal contacting the squamosal; (3) frontals entering the orbit; and (4) presence of a quadratojugal. Bolt & Rieppel (2009) revised the diagnosis following additional preparation of the holotype's skull and list three features (only one of which is shared with the previous work): (1) skull length approximately twice that of Hapsidopareion; (2) frontals entering the orbit; and (3) cultriform process of the parasphenoid offset from the basal plate by a narrow base. 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.
Llistrofus