Analysis of millerettid parareptile relationships in the light of new material of Broomia perplexa Watson, 1914, from the Permian of South Africa

Abstract

Synopsis A second specimen of the poorly known millerettid Broomia perplexa is reported. It consists of a cranium and partially articulated postcranium. As indicated by its small size (ca. 35% shorter skull than the holotype) and unfused pelvis and limbs, the new specimen is a sub‐adult individual. Comparison with the holotype reveals only minor differences that are ascribed to ontogenetic or individual variation. Accordingly we consider the new specimen to represent the second record of Broomia, discovered 90 years after the description of the holotype. A preliminary phylogenetic analysis of millerettid inter‐relationships identifies Broomia as a millerettid related to the genus Millerosaurus. The enigmatic parareptile Eunotosaurus africanus is nested within Millerettidae as the sister taxon of Milleretta rubidgei. Whereas millerettids are well known from the latest Permian Dicynodon Assemblage Zone of the Beaufort Group of South Africa, Broomia and Eunotosaurus are found in the Middle Permian Tapinocephalus Assemblage Zone. The new Broomia specimen not only complements our knowledge of this early millerettid but also shows, in addition to recent findings in the same area, that the lowermost Beaufort Group is at least 1200 m thick in this area compared with ca. 2500 m in the western part of the Karoo Basin.