When Taxonomy relies on Taphonomy: implications of digestion in taxonomic identifications of armadillo species

MARIN-MONFORT, MARÍA DOLORES; GARCÍA-MORATO, SARA; MONTALVO, CLAUDIA; BARASOAIN, DANIEL; ZARACHO, ELBA; CHATELLENAZ, MARIO; GARRONE, MARIANA; ZURITA, ALFREDO; FERNÁNDEZ-JALVO, YOLANDA; TOMASSINI, RODRIGO

Madrid

Congreso; 6th ICAZ Taphonomy Working Group Meeting (ICAZ-TWG), 9th TAPHOS International Meeting on Taphonomy and Fossilization; 2022

Museo Nacional de Ciencias Naturales (MNCN-CSIC)

Agents and processes involved in the taphonomic history may produce distortions or loss of macro- and microscopic original features, which can result in taxonomic misidentifications, even with phylogenetic implications. This situation affects to some fossil representatives of the order Cingulata (e.g., armadillos, glyptodonts, peltephilids, and pampatherids), whose taxonomic and phylogenetic proposals are mainly based on different morphological features of the carapace osteoderms (e.g., shape, ornamentation pattern, number, size, and location of foramina). In this context, it is worth noting that the preservation features may, in some cases, provide additional evidence to the taxonomic identification. In this work we analyze a sample of 99 scats of the felid Puma concolor, collected at the Northeastern region of Argentina (Corrientes Province), of which 23 contain 185 osteoderms from different portions of the armour of the armadillo dasypodid Dasypus novemcinctus. We evaluate the macroscopic modifications resulting from digestion, including breakage pattern, and alteration of articular and broken edges, exposed dorsal surface, bone tissues, and original ornamentation pattern. Modifications in the original ornamentation pattern, is observed in a high percentage of the osteoderms analyzed (sometimes around 100%; Figure 1); likewise, an analytical evaluation reflects an evident enlargement of the dorsal foramina in some mobile osteoderms. Analysis of the effects caused by the digestion on armadillo osteoderms is studied here for the first time. The results obtained show that, in general, the original features of the osteoderms are affected by corrosion effects generating, in some cases, non-real morphological patterns. Variability in digestion intensity, even when they have been produced by the same predator, also produces variability in the intensity of distortion. This study highlights the relevance of taphonomic analysis to differentiate original characters from digestion in order to avoid potential taxonomic misinterpretations in this group of mammals.