Dasypodidae and Chlamyphoridae (Xenarthra, Cingulata) armadillos from the Río Bermejo Formation (Late Pleistocene), Formosa Province, Argentina
Late Pleistocene vertebrate fossils have been recorded at multiple localities in Formosa Province, specifically between the localities of General Mansilla and El Colorado. The fossiliferous levels belong to the Río Bermejo Formation, represented by swamp-like deposits associated with oxbow lakes fro...
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| Autores principales: | , , , , |
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| Formato: | Reunión |
| Lenguaje: | Inglés |
| Publicado: |
Asociación Paleontológica Argentina
2025
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| Materias: | |
| Acceso en línea: | http://repositorio.unne.edu.ar/handle/123456789/59274 |
| Aporte de: |
| Sumario: | Late Pleistocene vertebrate fossils have been recorded at multiple localities in Formosa Province,
specifically between the localities of General Mansilla and El Colorado. The fossiliferous levels belong
to the Río Bermejo Formation, represented by swamp-like deposits associated with oxbow lakes
from an ancient river channel. Absolute dating (14C) of this formation at the Villa Escolar area
indicates a Late Pleistocene to earliest Holocene (ca. 10–20 ka BP) age. The faunal assemblage of
this unit stands out for its high diversity of mammals, which includes representatives of
Notoungulata, Litopterna, Proboscidea, Artiodactyla, Carnivora, and Xenarthra. Within Xenarthra,
Cingulata is particularly well represented including remains of glyptodonts, pampatheres, and
armadillos. Since there are no studies focusing on armadillos, and previous contributions only
reached a genus level, this study aims to refine our knowledge about their taxonomy and diversity.
The analyzed materials include several isolated and articulated osteoderms of the carapace of
Dasypodidae and Chlamyphoridae, which are housed at the collection of the Museo Provincial de
Ciencias Naturales de Villa Escolar (Formosa, Argentina). The taxa identified are restricted to
Propraopus sulcatus (Dasypodidae, Dasypodinae) and Chaetophractus villosus (Chlamyphoridae,
Euphractinae). The specimens PVE-F72 (one fixed and one mobile osteoderm), PVE-F101 (one fixed
and one mobile osteoderm), PVE-F105 (three fixed and four mobile osteoderms), PVE-F108 (two
semimobile osteoderms), PVE-F122 (six articulated fixed osteoderms and four broken mobile
osteoderms), and PVE-F157 (articulated fragments of the caudal armor) are assigned to P. sulcatus
for having both fixed and mobile osteoderms exhibiting a typical Dasypodinae ornamentation pattern,
dorsal foramina restricted to the anterior half of the osteoderm, and a much larger size than Dasypus
spp. The specimen PVE-F54 (articulated fragments of the caudal armor and dorsal carapace and
several associated fixed and mobile osteoderms) is assigned to C. villosus for having an
ornamentation pattern of fixed osteoderms including an additional peripheral figure placed anteriorly
to the central figure, a character only present in this species. This fossil diversity is much lower than
expected, since the living association of armadillos in Formosa Province, which includes a total of
seven genera recorded, is one of the largest in South America. In this context, it is hypothesized that
there is a taphonomic or sample bias in the fossil diversity recorded so far from the Río Bermejo
Formation that is probably not reflecting the real diversity of the formation, which is expected to be
higher. |
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