INVESTIGADORES
BOSCAINI Alberto
artículos
Título:
The Dermal Armor Of Mylodontid Sloths (Mammalia, Xenarthra) From Cueva Del Milodón (Última Esperanza, Chile)
Autor/es:
TOLEDO, NÉSTOR; BOSCAINI, ALBERTO; PÉREZ, LEANDRO M.
Revista:
JOURNAL OF MORPHOLOGY
Editorial:
WILEY-LISS, DIV JOHN WILEY & SONS INC
Referencias:
Año: 2021 vol. 282 p. 612 - 627
ISSN:
0362-2525
Resumen:
Dermal ossifications (osteoderms, dermal ossicles, osteocutes) appear independently in various tetrapod lineages. In mammals, however, dermal ossifications are only present in some members of Xenarthra. This clade includes Cingulata (armadillos and their relatives), and Pilosa, which in turn includes Vermilingua (anteaters) and Folivora (sloths). In extant xenarthrans, osteoderms are invariably present in cingulates whereas they are absent in pilosans. Among extinct sloths, however, a limited number of taxa display dermal ossifications. Records of mummified skins of ground sloths bearing osteoderms found in ?Cueva del Milodón? (Southern Chile), with a late Pleistocene age, allowed us to analyze their micro- and macroscopic morphology. The main goal of this study is to closely examine a portion of a mylodontid skin portion using radiography. The arrangement, morphology and internal structure of the ossicles are analyzed and the results are discussed in the context of previous research. The results we obtained indicate that ossicles show both a diversity of shapes and sizes, and the integument has four different patterns of arrangement of these: areas without ossicles, disorganized ossicles, rows, and mosaic areas. The latter has two variants, with clusters of ossicles forming rosettes or stars. Thin sections of the ossicles allowed us to recognize and describe anatomical features of the bone and its mode of growth. Finally, paleobiological and functional considerations of the dermal armor are discussed along with its phylogenetic and chronological implications.