Morphodiversity, complexity and macroevolution: revealed by the megascopic life of the Palaeo-Neoproterozoic Vindhyan Supergroup, India

Abstract

AbstractEvidence 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.