A KATAGMICHNUS FROM THE ITABORAÍ BASIN (MCT-1 FISSURE, LOWER EOCENE), BRAZIL: ICHNOLOGICAL AND PALEOECOLOGICAL IMPLICATIONS

Carneiro et al. – A Paleogene Katagmichnus in Brazil

Resumen

Katagmichnus myelus is an ichnotaxon described for the Quaternary of Argentina to identify large and deep grooves on bones. A similar tooth mark was identified in a metatherian dentary from the Itaboraí Basin, Brazil, having a larger and deeper form compared to other groove-like marks observed in the same locality. This specimen was initially identified as cf. Linichnus serratus mostly due to its discrete serrations and evidently larger size. Here, we reidentified this tooth mark as a new species of Katagmichnus, K. sarcophagicus isp. nov., tracing back the occurrence of this ichnogenus to the Paleogene of Brazil. Katagmichnus is inferred to be made by bladed, blunt, or larger teeth compared to other teeth of a dental series (e.g., a plaugiaulacoid premolar or carnassial teeth). The larger size of Katagmichnus resulted from its larger area of contact with the bone substrate or by gnawing, resulting in a comparatively broader groove than that of Linichnus.