Palaeodiet of Miocene Producers and Depositional Environments: Inferences from the First Evidence of Microcoprolites from India

Abstract

This paper reviews research on coprolites from India, providing the first evidence of microcoprolites from the early Miocene (Aquitanian) Khari Nadi Formation sedimentary succession, exposed about 1.5 km northeast of the village of Kotada, Kachchh (Kutch) District, Gujarat State, western India. Morphometric and size comparisons (in a statistical framework) with known coprolites from the Mesozoic-Cenozoic successions of India (including those recorded herein) and globally suggest that fishes were the likely producers of the Kotada coprolites. Scanning electron microscopy confirms the presence of fish dental remains within the coprolites, while both Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) reveal the phosphatic nature of the microscopic coprolite specimens (recorded herein) hinting that the producer(s) were predominantly carnivorous (ichthyophagous) in their diet. Furthermore, X-Ray Fluorescence (XRF) analysis of the host and associated lithologies allows us to deduce that the Kotada coprolites were deposited in a shallow marine environment, with possible aerial exposure of the host lithology occurring at some point after deposition. To the best of our knowledge, the present report is the first record of microscopic fish coprolites from India, as well as being the first from the Aquitanian of India and the oldest Neogene record from India.

Oldest Asian Record of Snapping Shrimps (Malacostraca: Alpheidae) from the Kutch Basin, Western India and Associated Biota: Biostratigraphic, Paleoenvironmental and Paleoecological Significance

“…In accordance with Young (1998), the FAD of Reticulofenestra haqii lies within the NN2 zone (19.00-22.82 Ma) of Martini (1971). Overall, the presence of Sphenolithus disbelemnos, Cyclicargolithus floridanus and Reticulofenestra haqii designates an Aquitanian (early Miocene) age to the fossiliferous unit belonging to the KNFm studied in the present investigation (see also Kapur et al, 2020).…”

“…Interestingly, Kohda et al (2017) observed that A. bellulus consumes fecal matter (as a primary food source) of the goby Amblyeleotris japonica, which the fish drops exclusively inside the alpheid burrow(s). Noteworthy also is that Kapur et al (2020) recorded numerous microcoprolites (linked to ichthyophagous fishes) from the same sediments that yielded the microfossils recorded in the present investigation.…”

“…The crystalline structure of the calcite matched with the ICDD PDF-4 (2019) mineral database with reference ID: 04-008-0213, 01-072-4582. The geochemical data (XRF analysis) of the host (KOT-1) and associated lithologies (KOT-2, KOT-3) were initially presented by Kapur et al (2020) and their interpretations reflected the preservation state of recovered fish microcoprolites that were deposited in a shallowmarine environment but subsequently exposed to an oxidizing environment. The XRF analysis of the host (KOT-1, SiO 2 : 52.4) and associated lithologies (KOT-2, SiO 2 : 49.8 and KOT-3, SiO 2 : 45.9) shows that SiO 2 is the major constituent followed by Al 2 O 3 and Fe 2 O 3 .…”

Palaeobiological and geochemical aspects of reptilian coprolites from a Maastrichtian Deccan volcano-sedimentary intertrappean deposit of central India

“…The observed porous structures are generally considered as a reminiscence of escaping gases during the process of decomposition of the faecal matter (Lamboy et al 1994;PurnachandraRao & Lamboy 1995;Northwood 2005;Kapur et al 2020;Sagar et al 2022). The microspherulites (i.e., egg-like mineral spheres) are commonlyascribed to mineral pseudomorphs of sulphur-producing bacteria (Hollocher et al 2010;Owocki et al 2013;Bajdek et al 2016;Kapur et al 2020;Sagar et al 2022). Additional biotic remains observed within the Lotkheri coprolites include remains of freshwater sponge spicule morphotype Acanthoxea (Fig.…”

“…recovery of coprolite ichnofossils within DVSS. Thus, much emphasized are the MaastrichtianType-A coprolite morphotype (linked to titanosaurid dinosaurs) limited to an infratrappean (Lameta Formation) horizon at Pisdura locale, central India (Matley 1939;Prasad et al 2005;Khosla et al 2015; also refer to Table 1 in Kapur et al 2020).…”