REVISION OF DIAGNOSTIC FEATURES OF THE TRILOBITE GENUS BHARGAVIA (ELLIPSOCEPHALOIDEA) FROM THE PARAHIO VALLEY (SPITI), NORTHWEST HIMALAYA, INDIA

摘要

In the light of additional material from the Cambrian successions of the Parahio valley (Spiti), the Ellipsocephalinae trilobite genus Bhargavia is rediagnosed. We also record the lowest occurrence of this taxon at 12.1 m above the Oryctocephalus indicus Zone (Cambrian Series 3, Stage 5). Earlier, the type species of Bhargavia prakritika was known from Kaotaia prachina Zone (Stage 5) at 233.4 m above the inferred O. indicus level. The present discovery, thus, indicates the lowest stratigraphic level of this taxon, which is equated with the upper part of the Plagiura Zone of Great Basin. Discovery of complete specimens of Bhargavia prakritika permits elaboration of its diagnostic characters, which earlier were based on cranidia and pygidia.