COPROLITES IN THE NEOGENE OF NORTHWESTERN ARGENTINA

LUNA, CARLOS A.; ZURITA, ALFREDO E.; GALLI, CLAUDIA I.; LANDA RAMIREZ, ENZO M.

Simposio; VII Simposio del Mioceno-Pleistoceno del Centro y Norte de Argentina; 2023

Coprolites are an interesting ichnological proxies for the presence of animals inpaleoecosystems. The morphology and composition of the coprolites can indicate bodysize, diet and other characteristics of the producer. The Palo Pintado Formation (UpperMiocene–earliest Pliocene) comprises fluvial system deposits under a subtropical towarm-temperate and humid climate, and constitutes one of the richest fossiliferous unitsin northwestern Argentina, with abundant vertebrate remains, including mammals,turtles, and caimans. In this contribution, the first record of coprolites for this unit ispresented. The coprolites were recovered isolated, fragmentary, from different levels andcan be divided into two morphotypes, one subcylindrical with flat basal surfaces,compact, with diameters between 18.2–24.6 mm, with subdivisions, coarsely conical atone end. The remaining are also cylindrical to subcylindrical, with larger diameters,between 25–35.4 mm, with constrictions due to peristaltic movements, and presence ofexternal and internal porosity. In one of them, the presence of external moulds of someelements, preliminarily interpreted as seeds and other plant structures, has been observed.The morphology of these coprolites shows similarity with feces of large carnivores suchas felids and canids, however in these there are usually remains belonging to theconsumed prey. Other probable producers based on morphology are crocodilians, inwhich despite their carnivorous diet, remains of bones are not observed due to theircomplete digestion, and in addition, vegetal remains are usually recognized. Therefore,crocodilians seem to be the most probable producer of these structures, consistent withthe paleontological record of the study area.-Subsidized by PIP-2022-11220210100300CO and CIUNSA 2722/0.