Family Bairdiidae Sars, 1888

Preliminary remarks

The classification of ornate Bairdiidae is complex and still disputed mainly because of the difficulty to unravel the taxonomic significance of their lateral ornamentation features. As detailed in Forel & Grădinaru (2020), the revision of their classification requires the addition of new characters to avoid producing another classification system that would only be a new point of view further complicating the current situation. The peak of diversity of ornate Bairdiidae occurred in the Late Triassic but they were already present in the Permian (see Forel & Crasquin 2020 and references therein for a review) as illustrated for instance by the material described herein from the Middle Permian of the Guadalupe Mountains. Specifically, the confusion and instability of the conceptions of Petasobairdia Chen, 1982 and Praelobobairdia Kozur, 1991 have recently been described and discussed in Forel & Grădinaru (2020). Herein, we follow the view that Praelobobairdia is a junior synonym of Petasobairdia, as was first introduced by Becker (2001).