Abstract On the Indian subcontinent, Late Proterozoic rocks form part of a continuous sequence grading into Cambrian, postdating the Sturtian glaciation (Cryogenian) and terminated by the Xingkaian/Pan African Orogeny (Late Cambrian). These sequences are restricted to the northwestern part of the Indian Shield, are overlain by Cenozoic sediments of the Indo-Gangetic Plain, and rest unconformably on the oldest platform sequences (Meso—Cryogenian) in many parts of the Lesser and Tethys/Higher Himalaya. Of these, the succession in the Krol Belt, Lesser Himalaya, divided into Baliana, Krol and Tal Groups, is fossiliferous. Changes in faunal composition of acritarchs and cyanobacteria are recorded in the upper part of the Baliana Group, as is the appearance and extinction of forms assigned to the Ediacara fauna in the overlying Krol. Such biotic change is accompanied by a significant depletion in δ 13 C values in the ‘cap carbonates’. Another δ 13 C depletion is recorded in the upper part of the Krol Group along with appearance of spiny acanthomorphic acritarchs, scaphomorphs and hercomorphs, small shelly fossils, a variety of Early Cambrian trace fossils and trilobites in the overlying Tal Group. A review of biota reported from the oldest platform sediments (Vindhyan Supergroup, Karnool, Bhima Groups) suggests a Meso-Cryogenian (pre-Sturtian glaciation) age.

Abstract Evidence of past life found in the Vindhyan Supergroup exhibits extensive diversity and taxonomically unresolved morphological complexities indicating varied biological affinities, advanced life and macroevolutionary dynamics of evolving clades. The megascopic life of the supergroup documents possibly two macroevolutionary modes, demarcated as: (i) the Palaeo-Mesoproterozoic transitional period, which is represented by the fossil assemblages of the Semri and Rewa groups, and exhibits the domination of a diversified prokaryotic cyanobacterial community and moderately diversified megascopic life; (ii) the Neoproterozoic (Bhander groups, Uppermost Vindhyans), represented by the diversified and morphologically complex megascopic eukaryotes, and the emergence of multicellularity among plant and animal clades, viz. structures resembling bryophytes, sporophyte and Ediacara fauna. The overall Vindhyan fossils exhibit episodes of adaptive innovations and the emergence of complex morphologies in separate lineages of evolutionary history, resulting in extensive morphodiversity. The present assemblage can be represented by that of prokaryotes, eukaryotes, possibly a symbiotic association, a Jacutianema -like Neoproterozoic form, specimens possibly of vaucheriacean affinity, mesoscopic intermediate forms inferred as transitional forms of microscopic–megascopic evolution, discs with process-like structures, the emergence of animal life (Ediacaran fauna) and a number of other complex morphologies that have no parallels in time and space. Traditionally and conventionally, the age of the Vindhyan Supergroup is considered to be that of Palaeoproterozoic–Neoproterozoic.