Found in the Cretaceous Arcadia Park Formation from the TXI Quarry in Midlothian, Texas.   It is Prionocyclus bosquensis according to Jim Kennedy, Professor Emeritus of Natural History at Oxford. He also first described the species. See his paper describing this and other species: Kennedy, W. J. 1988. Late Cenomanian and Turonian ammonite faunas from northeast and central Texas. Palaeontological Association, Special Papers in Paleontology, 39: 131 pp.