Paleontologists have discovered a new species of the extinct armadillo genus Parutaetus from fossilized osteoderms found in the Paraná state of southern Brazil.
Named Parutaetus oliveirai, this ancient armadillo lived between 42 and 39 million years ago during the Middle to Late Eocene epoch.
The new species belongs to Euphractinae, a highly diverse subfamily within the armadillo family Dasypodidae, which includes both extinct and living armadillos.
According to Tabata Klimeck and her colleagues, Parutaetus oliveirai is one of the early-divergent members of this subfamily.
“The paleontological record of armadillos is primarily represented by their osteoderms,” the researchers noted, as cited by SciNews.
These bony plates are common in South American fossil sites dating back to the Late Paleocene or Early Eocene.
The oldest confirmed Euphractinae fossils were previously discovered in Middle-Late Eocene deposits in Argentinian Patagonia and the Middle Eocene Upper Lumbrera Formation in northwestern Argentina. Parutaetus was first described in 1902 with the type species Parutaetus chicoensis from Patagonia.
Eight fossilized osteoderms of Parutaetus oliveirai were unearthed in the Guabirotuba Formation near Curitiba, Paraná. The formation, part of the Curitiba Sedimentary Basin, represents deposits from a semi-arid environment shaped by temporary rivers and alluvial fans.
“These geological characteristics indicate a semi-arid climate with rainy periods that transported sediment to form the basin,” the researchers explained.
Distinct Features
The osteoderms of Parutaetus oliveirai exhibit several unique features that distinguish it from other species in the genus:
Increased Surface Glandular and Piliferous Foramina: These openings likely played a role in skin structure or sensory function.
Flat Articulation Areas: The osteoderms lack a groove in the middle portion, unlike related species.
Larger Size: The overall size of the osteoderms is greater than those of other Parutaetus species.
The researchers suggest that these traits may be adaptations to global cooling during the Middle-Late Eocene, which significantly influenced South American fauna.
The discovery of Parutaetus oliveirai adds to the limited knowledge about mammal diversity in southeastern South America during the Eocene epoch.
“This new species broadens our understanding of armadillo evolution and the adaptations of mammals to environmental changes during this period,” the team concluded.
The findings were published in the Journal of Vertebrate Paleontology.
