CAUDAL TUBES TAPHONOMY OF THE NEOGENE GENUS ELEUTHEROCERCUS (CINGULATA, GLYPTODONTIDAE) AND ITS TAXONOMIC IMPLICATIONS

NUÑEZ, A.; TOMASSINI, R.L.; MARÍN-MONFORT, M. D.; MIÑO BOILINI, A. R.; BONINI, R.; ZURITA, A.E.

Congreso; 4th Virtual Palaeontological Congress; 2023

Eleutherocercus is a glyptodont Doedicurinae genus with records inthe Late Miocene-Late Pliocene of southern South America. It includessix species, most of them recognized on the basis of morphologicalcharacteristics of the dorsal carapace and caudal tube. One interestingaspect to highlight in this taxon is the notable difference between theornamentation pattern of the carapace and the caudal tube. Very wellpreservedspecimens evidence that the osteoderms of the carapacehave a smooth surface with numerous large foramina, representing theoriginal pattern. On the contrary, for caudal tubes two ornamentationpatters were described: Type A represented by a “rosette” pattern, whichincludes a central figure surrounded by several small figures, and Type Brepresented by a smooth surface pattern with large foramina arrangedin a circular disposition. Recent studies on living and fossil cingulatessuggested that the original ornamentation pattern can be modifiedby taphonomic processes. Here, the study of several well-preservedcaudal tubes reflects that the “rosette” pattern represents the originalornamentation in Eleutherocercus. Likewise, we infer that the Type Bornamentation is the result of taphonomic alterations, which generatedthe degradation of the figures that compose the original “rosette” patternand the enlargement of the foramina. Considering that some speciesof Eleutherocercus (e.g., E. tucumanus (MACN2893) and E. paranensis(MACN6253)) have been defined based on Type B ornamentationpattern, their taxonomic assignment should be reviewed. We finallyremark on the importance of taphonomy as a complementary disciplineto avoid systematic and phylogenetic misinterpretations.