mammals

Former Ichnoplanet students Martín Farina, Verónica Krapovickas and co-authors have published a study on mammalian trackways from the Neogene Vinchina (Middle to Late Miocene) and Toro Negro (Late Miocene to Early Pleistocene) formations, in the La Rioja Province Vinchina Basin, Argentina!

Northwestern Argentina has an outstanding ichnological record of the Cenozoic vertebrate faunas. This study reports five mammalian trackways and the diversity of the trackmakers responsible. Of the four ichnospecies identified, three are new. The trackways come from deposits interpreted as floodplains of both meandering and anastomosed fluvial systems.

Pichipoda is a novel ichnogenus that has a didactyl to monodactyl manus and tridactyl mesaxonic pes impressions with robust digits with blunt tips. Two ichnospecies are assigned to Pichipoda, including P. manganae and P. vizcainoi. P. manganae (P. manganaei) is the largest ichnospecies of Pichipoda and has a didactyl manus, and the manus of P. vizcainoi shows an almost monodactyl morphology. Tridactylonicha marsicanae is another novel ichnogenera and ichnospecies, described by a tridactyl to didactyl paraxonic manus and tridactyl mesaxonic pes impression with long, slender, and pointed tips of the toe impressions. Dolichotichnus marae has tetradactyl paraxonic manus and tridactyl mesaxonic pes impressions.

Pichipoda manganae. Figure 2 from De La Fuente et al., 2025.

P. manganae and P. vizcainoi are interpreted as being produced by armadillos, with P. vizcainoi being attributed most likely to tolypeutines. Before this study, ichnofossils attributable to fossil armadillos were unknown, meaning this is the beginning of our understanding of the trace fossil record of this group and can help us to ask further paleobiological questions. T. marsicanae is interpreted as being produced by hegetotheriids, a family belonging to the extinct group of South American ungulates, the Notoungulata. D. marae is most likely produced by dolichotines, a group of caviid rodents.

Astute readers will notice the etymology of P. manganae honours our very own Dr. Gabriela Mángano, which we here at Ichnoplanet firmly endorse. The contributions Dr. Mángano has made to ichnology are unmatched, and it is fitting that these newly described trace fossils act as a reflection and reminder of her great career.

Congratulations to the authors, including Martin and Verónica, on this amazing study. We know the continued research into the small mammal trackways of Cenozoic Argentina is filling in an important gap in our understanding of vertebrate faunas within South America, and we await what new discoveries have to say.

Read the paper in the Journal of South American Earth Sciences here.

Written by Jack Milligan

Dr. Buatois was featured in a new Nature article, where he commented on recent work done by the Palaeoburrows Project based at the Federal University of Rio Grande do Sul in Porto Alegre, Brazil.

In conjunction with the University of the Extreme South of Santa Catarina (UNESC) in Criciúma, Brazil, paleontologists and archaeologists have been studying a series of massive caves that have had multiple architects and inhabitants during the Pleistocene. The caves are found within a consolidated eolian sandstone unit of the early late Cretaceous Botucatu Formation (100 Ma). This makes the sandstone soft enough to burrow through and consolidated enough that the caves wouldn’t collapse.

A giant palaeoburrow in southern Brazil, known as the Armadillo’s Den. Image credit to Rafael Lange for Nature https://www.nature.com/articles/d41586-025-00216-x

The walls of the caves preserve large claw-like markings, as well as inscriptions and graffiti by ancient and modern humans, respectively. The large claw-like marks on the walls of the cave point to the original inhabitants of the cave, proposed to be giant ground sloths. They would construct these burrows for multiple reasons, including potentially to sharpen their claws and to seek refuge from megafaunal predators.

These would be not only the largest palaeoburrows, but the largest trace fossils known so far. From this research, a novel ichnogenera and two novel ichnospecies were named, Megaichnus minor and Megaichnus major. These palaeoburrows are so far known from Brazil and Argentina, and are attributed to giant ground sloths like Scelidotherium and Glossotherium. Work is ongoing to refine the classification scheme for palaeoburrows, conservation, and opportunities for international collaboration on future studies.

Paleoartist Renato Pereira Lopes’ reconstruction of several extinct ground sloths and armadillos and schematic representations of the dimensions of some caves found in South America. Artist credit to Renato Pereira Lopes as seen in Nature https://www.nature.com/articles/d41586-025-00216-x

Paleoartist reconstruction of extinct giant ground sloths and armadillos by Renato Pereira Lopes.

You can read the original study in Ichnos and the news feature in Nature.

Written by Jack Milligan

A diverse and dynamic research group, leaving their own tracks around the globe.

Tag: mammals

Pichipoda manganaei, a new armadillo trackway from the Neogene of Argentina.

Giant ground sloths made massive paleoburrows in Brazil