T22 Topics in Paleoecology: Modern Analogues and Ancient Systems I

Sunday, 19 October 2014
8:00 AM - 12:00 PM
223/224

INTEGRATIVE STUDIES OF LATE TRIASSIC VERTEBRATE COPROLITES FROM POLAND

Paper number: T22-5
Program: Technical Sessions
Time: 9:00 AM – 9:15 AM

Authors

Abstract

Coprolites of Late Triassic vertebrates from southern Poland have been investigated using various analytical methods, including XRD, inorganic and organic geochemistry, microscopy and palynology. The coprolites are geochemically excellently preserved as attested by the immature character of organic matter. Most specimens are elongated, usually rod-like in shape, beige in color and measure from a few up to 16 cm in length. Single specimens possess spiral morphology. The coprolite groundmass is phosphatic (francolite) containing large amounts of tiny (up to 3 µm) spherical, coccoid structures resembling bacterial cells. The organic matter of bacterial origin is also confirmed by specific biomarkers (e.g., series of mid-chain methyl-alkanes and cycloalkanes). The fossil inclusions comprise bone, teeth and scale remains showing different degree of digestion. Some are penetrated by tiny canals, probably of fungal origin. Interestingly, majority of coprolites also contain numerous plant remains (cuticles, tracheids, miospores) and sparse arthropod cuticles. The plant remains are very well-preserved, showing almost no sign of digestion.

On one hand, the presence of vertebrate remains inside the phosphatic coprolite groundmass points to carnivorous animals as possible culprits. On the other hand, the presence of rich plant remains attest for herbivory. Biomarkers (e.g., sterols and steradienones distribution) also confirmed the mixed carnivorous-herbivorous diet. It is very probable, that the usual diet of the coprolite producers was composed of meat, but occasionally they fed on fresh plants, mainly foliage but also wood. It is also possible that the plant remains were swallowed accidentally by some of the carnivores, e.g., during meat-eating in aquatic environment. It is known that the stomach contents of wild alligator may contain residual plant material. Although the exact nature of the coprolite producers remains a mystery, a semi-aquatic, mid- to large-sized archosaurs and large capitosauroid temnospondyls are probable culprits.

The research is supported by the MNiSW grant N N307 066040