Scolicia and its producer in shallow-marine deposits of the Miocene Chenque Formation (Patagonia, Argentina): functional morphology and implications for understanding burrowing behavior

CARMONA, NOELIA B.; BROMLEY, RICHARD G.; BELLOSI, EDUARDO; MÁNGANO, M. GABRIELA; PONCE, JUAN JOSÉ; BUATOIS, LUIS A.; ASGAARD, ULLA

ICHNOS-AN INTERNATIONAL JOURNAL FOR PLANT AND ANIMAL TRACES

TAYLOR & FRANCIS INC

Lugar: Londres; Año: 2020 vol. 27 p. 290 - 299

1042-0940

Scolicia is one of the most conspicuous trace fossils in lower shoreface deposits of theMiocene Chenque Formation of Patagonia, Argentina. This ichnotaxon consists of horizontal,sinuous or meandering trace fossils with a laminated backfill and two parallel strings locatedat the base. Abundant body fossils attributed to Brisaster iheringi occur in close associationto these trace fossils. The echinoids are very well preserved, and most of the specimenshave some areas with their spines attached in life position. In particular, preservation of thesubanal tufts of spines, associated to isopores (which are interpreted as being associated tofunnel building tube feet), supports the interpretation that these organisms are the pro-ducers of Scolicia isp. A shaft connecting the burrow with the sediment-water interface wasnot observed in vertical sections of the excavations, although on bedding plane surfaces,some small circular tube outlets are recognized. However, the great diversity and abun-dance of ichnofossils co-occurring in these deposits may preclude adequate identification ofvertical structures. These deposits provide an excellent opportunity to integrate trace fossildata, body fossil information and observations from modern analogues in order to performa morpho-functional analysis of Scolicia.