Bone‐bearing coprolites from the Upper Triassic of India: ichnotaxonomy, probable producers and predator–prey relationships

Abstract

Multiple spiral and non‐spiral cylindrical coprolites with profuse bone inclusions were recovered from a metoposaurid‐dominated bonebed in the Upper Triassic Tiki Formation of India. The spiral coprolites are assigned to two new ichnotaxa based on amphipolar and heteropolar micropolar coilings. The non‐spiral coprolites are internally devoid of any spiral structure, mostly cylindrical, except for a few, which are ellipsoidal. All of these coprolites contain randomly scattered inclusions of partly digested and undigested skeletal fragments. Based on external and internal morphology, and the type of inclusions, the probable producers of these coprolites are considered to have been carnivorous and/or piscivorous, and included different types of chondrichthyans, dipnoans and actinopterygians, as well as various semiaquatic and terrestrial tetrapods. A web‐like interconnectedness is evident, which highlights dynamic and highly diverse animal communities inhabiting the terrestrial, semiaquatic and aquatic realms and dissolution of the inter‐realm boundaries in the Upper Triassic Tiki palaeoecosystem.

Laurussian-Aspect of the Coprolite Association From the Upper Triassic (Carnian) of the Argana Basin, Morocco

“…3A, 6) from the middle/upper Permian Rio do Rasto Formation (Brazil) and is characterized by a coil limited to the very end of the coprolite. It is also similar to the coprolites collected from the Upper Triassic Tiki Formation of India identified as Rewacopros jaini (Rakshit and Ray 2022, fig. 6).The Irohalene and Indian coprolites have the same sizes, are slightly flattened, and the spires present less than a quarter of the length of coprolite.…”

“…In a recent study coprolites similar to MC1 (Fig. 5N-5U) were attributed to xenacanthid sharks (Rakshit and Ray 2022;Fig. 12).…”

“…The presence of spiral coprolites may suggest a more diversified ichthyofauna than the body fossils represented largely by sarcopterygians. The early sarcopterygians could produce an amphipolar coprolite but usually produce elongated coprolites similar to MK (Jain 1983;Hunt and Lucas 2012b;Rakshit and Ray 2022) The spiral coprolites are dominantly produced by chondrichthyans but also could be produced by actinistians, lungfish, and a few osteichthyans. Heteropolar coprolites (like MC) are characteristic of some cartilaginous fish with spiral intestine valves such as sharks, rays and lungfish (McAllister 1987;Hunt et al 1994;Sumner 1994;Northwood 2005).…”

“…Microspiral heteropolar coprolites are common in the Middle–Late Triassic of Laurussia and also occur in India (Jain 1983; Rakshit and Ray 2022) and Morocco (Hunt et al 2013). This morphology extends back to the late Carboniferous and occurs in many late Paleozoic ichnofaunas (Hunt and Lucas 2013).…”

“…Discussion.— Triangular cross sectioned coprolites have also been reported from the Late Triassic sediments of Poland (Qvarnström et al 2019, p. 6, fig. 3) and India (Rakshit and Ray 2022, fig. 8W–8AB, morphotype NSC-V).…”