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.

Abstract Extensive subsurface sampling of the Huqf Supergroup in the Sultanate of Oman has yielded microfossil assemblages of Cryogenian, Ediacaran and Early Cambrian age. Microfossils have been recovered from most stratigraphic units in the Huqf, including Marinoan-equivalent horizons of the Ghadir Manqil Formation (Cryogenian Abu Mahara Group), the Masirah Bay, Shuram and Buah formations of the Ediacaran Nafun Group, and the A3 (latest Ediacaran) and A6 (Early Cambrian) cycles of the Ara Group. Despite the extensive recovery of leiosphaerid acritarchs from the Shuram Formation, there is no indication of the large acanthomorphs typical of other early–middle Ediacaran assemblages. This absence suggests a relatively young (post-extinction) depositional age for the Shuram; however, the signal is complicated by local deep-water conditions and the facies-specific distribution of Proterozoic microfossils. A shallower-water sequence of undivided Nafun Group sediments preserves sphaeromorphic acritarchs in association with filamentous microfossils, fragmentary vendotaenids and possible vaucheriacean algae.

Abstract Most of the Precambrian (>538 Ma) fossil record, which includes the time before the onset of macroscopic multicellular life, consists of minute organically preserved remains of soft-bodied micro-organisms, i.e. non-pollen palynomorphs (NPP). These microfossils include single-celled prokaryotic or eukaryotic organisms, filamentous sheets and bacterial cellular aggregates, and occur in marine and lacustrine sediments through most of the Earth's history. Ancient NPP have informed our understanding of one of the biggest evolutionary steps in the history of life: the origin of the eukaryotic cell and the subsequent diversification of eukaryotic life before the evolution of macroscopic forms. The oldest widely accepted eukaryotic microfossils are large cells with opening structures and ornamentation from upper Paleoproterozoic units in China and India. NPP diversify through Meso- and Neoproterozoic Eras, notably recording the oldest multicellular life around 1 billion years ago. In the latest Neoproterozoic, during the advent of animal life, the NPP record allows us to study the cryptic evolution of animals while they were exclusively small and poorly or non-mineralized before the appearance of organisms with hard parts. We review the current understanding of the early eukaryotic evolution and major advances in Precambrian palaeontology through the lens of the NPP record in deep time.