THE PAPILIOPHYLLIDAE (LOWER DEVONIAN RUGOSA): THEIR SYSTEMATICS AND REINTERPRETED BIOSTRATIGRAPHIC VALUE IN NEVADA

Abstract

Field work has greatly increased the number of well-dated papiliophyllid corals available from Nevada. The established range of the family is expanded from Pragian and lower Emsian to Pragian and almost the entire Emsian. Ranges of species are calibrated against Johnson faunal intervals and a revised Pragian and lowermost Emsian conodont zonation proposed by Murphy for Nevada. Study of all reposited material has led to some revision of every member of the family. Eurekaphyllum, previously imperfectly known from a single specimen of vague stratigraphic origin, is shown to be a useful upper Emsian index. Nine reported occurrences of the family in Europe and Asia are re-examined and, except for a possible occurrence on Novaya Zemlya, all are rejected. The three named genera of the family are apparently endemic to the southwestern North American craton. Papiliophyllum elegantulum asymmetricum new subspecies, P. murphyi new species and Eurekaphyllum vescum new species are described by Pedder.