A new fairy armadillo (Cingulata, Chlamyphorinae) from the upper Miocene of Argentina: first fossil record of the most enigmatic Xenarthra

ABSTRACT

Recent molecular analyses suggest that the evolutionary history of Cingulata (Xenarthra) could be more complex than believed previously. An ancient divergence was proposed for armadillos, recognizing two large monophyletic groups: Dasypodidae (including Dasypodinae) and Chlamyphoridae (including Euphractinae, Tolypeutinae, and Chlamyphorinae). Extant Chlamyphorinae (fairy armadillos) are among the most bizarre, elusive, and unknown mammals of the world. Here, we report the first accurate fossil record of this enigmatic xenarthran from the upper Miocene of the Argentine Pampas in southern South America, which represents a new genus and species (Chlamyphractus dimartinoi, gen. et sp. nov.). The phylogenetic analysis reflects the monophyly of the chlamyphorines. It is well supported by several unambiguous synapomorphies and includes the new fossil taxon as a sister group of the two extant species. This new taxon represents the most basal lineage among Chlamyphorinae and increases its diversity. The morphology of the forelimb suggests that it would have been a good digger, although, unlike extant species, it would not have had ‘fully’ subterranean habits.

View correction statement:

Chlamydophractus, new name for Chlamyphractus Barasoain et al., 2020 (Xenarthra, Chlamyphorinae), non Chlamyphractus Castellanos, 1940 (Xenarthra, Glyptodontidae)

ACKNOWLEDGMENTS

We thank N. Sánchez (MMH) and curators M. Díaz (CML) and P. Teta (MACN) for access to specimens in their care. P. Cuaranta and H. Smichowski helped with the illustrations and figures. Reconstruction of the new taxon (Fig. 10) was drawn by P. Cuaranta. C. Luna prepared the fossil specimen. J. Baez and R. Mauriño contributed with some photographs. F. Cuadrelli made valuable observations and comments on previous issues of the manuscript. We also thank the anonymous reviewers and editor J. Meachen, whose comments and suggestions greatly improved the manuscript. This work was partially supported by the scientific projects PICT 0765/17 and G06 Facultad de Ciencias Exactas y Naturales, Universidad Nacional de La Pampa.

ORCID

Daniel Barasoain http://orcid.org/0000-0002-0266-0913

Rodrigo L. Tomassini http://orcid.org/0000-0001-8143-1723

Claudia I. Montalvo http://orcid.org/0000-0002-6336-4237