INVESTIGADORES
CARLINI Alfredo Armando
artículos
Título:
Osteoderm morphology in recent and fossil euphractine Xenarthrans
Autor/es:
11- KRMPOTIC C. M., M. R. CIANCIO, C. BARBEITO, R. C. MARIO, A. A. CARLINI
Revista:
ACTA ZOOLOGICA
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Lugar: STOCKHOLM; Año: 2009 vol. 90 p. 339 - 351
ISSN:
0001-7272
Resumen:
The presence of osteoderms within the integument, forming a carapace, is one
of the most distinctive features of armadillos with the external morphology of
these elements forming the basis of most systematic schemes. This is especially
true for fossil taxa, where these elements are most frequent in the
palaeontological record. A detailed study of osteoderms from the cephalic shield
and different regions of the dorsal armour of Chaetophractus villosus
(Euphractinae, Xenarthra) was made and compared to those of the extant
genus Dasypus (Dasypodinae, Xenarthra), and the extinct genus Eutatus.
Three distinct histological zones were recognized: outer and inner zones
are thin, formed by regular compact bone, the middle zone is thicker, with large
cavities that contain mainly adipose tissue, hair follicles, and sweat and
sebaceous glands. The internal structure of Eutatus (also a member of
Euphractinae) osteoderms is close to that of C. villosus, consistent with the
notion that these taxa are phylogenetically closely related. In contrast, Dasypus
shows marked differences. Dasypus shows hair follicles associated with both
gland types (sweat and sebaceous) and connected to foramina on the external
surface. Although not observed in adult C. villosus, it has been documented
during embryonic development, only to atrophy later in ontogeny. Furthermore,
the presence of red bone marrow is rare in C. villosus, but widespread in
Dasypus novemcinctus osteoderms. These results suggest an early split of both
subfamilies and support the hypothesis that the Euphractinae are more derived
than the Dasypodinae