Takumi Maekawa, James F. Jenks
Paleontological Research 29 (1), 1-23, (13 December 2024) https://doi.org/10.2517/prpsj.2400141
KEYWORDS: conodont, Crinoid ossicles, Crittenden Springs, Smithian, Thaynes Formation
We document the occurrence of Early Triassic (Olenekian) crinoid ossicles in exotic blocks contained within the black limestone unit of the Thaynes Formation, which overlies the Dinwoody Formation at the classic Crittenden Springs Smithian ammonoid locality. Crinoid ossicles include two species, i.e., Holocrinus sp. and Articulata ord., fam., gen. et sp. indet. Furthermore, two co-occurring, age diagnostic conodonts, i.e., Neospathodus pakistanensis and Ns. posterolongatus, constrain the age of the crinoids from the early Smithian to the earliest middle Smithian. This discovery represents the third report of Smithian Holocrinidae in the Panthalassan area and it provides important data for the study of crinoid recovery during the Early Triassic.