INVESTIGADORES
CIANCIO Martin Ricardo
artículos
Título:
When xenarthrans had enamel: insights on the evolution of their hypsodonty and paleontological support for independent evolution in armadillos
Autor/es:
CIANCIO, MARTÍN R.; VIEYTES, EMMA C.; CARLINI, ALFREDO A.
Revista:
NATURWISSENSCHAFTEN
Editorial:
SPRINGER
Referencias:
Lugar: Berlin; Año: 2014 vol. 101 p. 715 - 725
ISSN:
0028-1042
Resumen:
All xenarthrans known to date are characterized by having permanent
teeth that are both high crowned and open rooted, i.e., euhypsodont, and
with a type of hypsodonty different from that of the rest of
Placentalia: dentine hypsodonty. Also, most xenarthrans lack enamel;
however, its presence has been reported in the fossil armadillo Utaetus buccatus and in living Dasypus.
Considering the divergence of Xenarthra from other eutherians that
possessed enameled teeth, the absence of enamel is a derived character.
Diverse specializations are known in the dentition of xenarthrans, but
the primitive pattern of their teeth and dentitions is still unknown.
Here, we describe the mandible and teeth of a fossil armadillo, Astegotherium dichotomus (Astegotheriini, Dasypodidae), from the early Middle Eocene of Argentine Patagonia,
with teeth showing both true enamel and closed roots. It is the oldest
xenarthran with mandibular remains exhibiting protohypsodonty and is
therefore likely representative of ancestral cingulates and xenarthrans
generally. Astegotherium supports a recent
hypothesis based on molecular data that enamel loss occurred
independently not only within xenarthrans but also within dasypodid
armadillos.