Macroleter poezicus (Tverdokhlebova and
Ivakhnenko 1984) Middle Permian ~253 my, ~8 cm skull length, ~75 cm overall length, was considered a parareptile by Tsuji (2006), who nested it between Nyctiphruretus and pareiasaurus like Anthodon. Here, with more taxa, Macroleter was derived from a sister to Bashkyroleter and nested as the sister to Emeroleter and the flattened Lanthanosuchus.
Overall larger than and distinct from the smaller Bashkyroleter, the skull of Macroleter had longer supratemporal and jugal horns, creating a deeper otic notch. The nasals were wider at mid length. The frontals were narrower. The parietals were broader. The premaxilla was shorter with more anterior nares. The maxilla was longer and deeper beneath the orbit. The jugal was taller. A small lateral temporal fenestra appeared the the junction of the postorbital, quadratojugal. The pterygoids contacted one another in twice medially.
In all subsequent sister taxa, such as Nyctiphruretus, Sauropareion and Owenetta, the portion of the quadratojugal below the lateral temporal fenestra is absent and the portion above is very large and in contact with the postorbital process of the jugal. Here in Macroleter it appears that that the suture between the squamosal and quadratojugal extends above the lateral temporal fenestra, as in the "alt" example, rather than to the fenestra as in the Tsuji (2006) interpretation. The area is indeed rugose and difficult to make out. If valid, this provides the morphological link needed to create the cheek morphology in Sauropareion and Owenetta by virtue of the disappearance of the lower temporal bar. |
