BIOGEOGRAPHIC TRENDS OF THE BLASTOID FAMILY SCHIZOBLASTIDAE

The blastoid family Schizoblastidae provides a unique insight into cryptic faunal revival. Initially radiating in the Early Mississippian, schizoblastid genera include Acentrotremites, Auloblastus, Lophoblastus, Orbiblastus, and Schizoblastus, which are primarily restricted to Burlington-age mounds occurring on carbonate platform slopes in restricted epeiric seaways. Schizoblastid genera dwindled as Mississippian climate shifted and mounding environments disappeared, going unrecorded until the Middle Permian, when Deltoblastus radiates along coastal platform fringes along the southern and western Tethys. Deltoblastus dominates what appears to be an ideal environment, before suddenly going extinct. This study analyzes multiple dispersal methods and environmental cues between the Early Mississippian and Middle Permian, seeking to understand this perplexing family.