INVESTIGADORES
PUJOS FranÇois Roger Francis
artículos
Título:
The pes of Pyramiodontherium bergi (Xenarthra, Tardigrada): the most complete pes of a Tertiary Megatheriinae
Autor/es:
DIEGO, BRANDONI; ALFREDO A., CARLINI; FRANÇOIS, PUJOS; GUSTAVO J., SCILLATO-YANÉ
Revista:
GEODIVERSITAS
Editorial:
Muséum national d’Histoire naturelle de Paris
Referencias:
Lugar: Paris; Año: 2004 vol. 26 p. 643 - 659
ISSN:
1280-9659
Resumen:
    The aim of this paper is to enlarge the description of the only known complete pes of a Tertiary megatherine and make comparisons with those of other members of the sub-family. The complete pes of the specimen type of Pyramiodontherium bergi (Moreno & Mercerat, 1891) Cabrera 1928 (MLP 2-66) is housed in the collection of Departamento Científico de Paleontología de Vertebrados, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Argentina. It was found at the informally named “Araucanense” s. l. levels of Bajo de Andalhuala, Catamarca Province (Late Miocene-Pliocene), Argentina. The elements of the pes show the general characters of other megatherines. However, the astragalar depression is not as deep as in Megatherium americanum Cuvier, 1796; the calcaneum is more slender than Eremotherium laurillardi (Lund, 1842); the navicular has two facets to articulate with the ectocuneiform; there are seven separate tarsal elements (calcaneum, astragalus, navicular, entocuneiform, mesocuneiform, ectocuneiform, and cuboid) while in other megatherines, usually the mesocuneiform and the entocuneiform are fused into a single element termed the mesoentocuneiform complex; the third digit is formed only by the proximal phalanx fused with the second phalanx, and digit IV, unlike Quaternary megatherines, has three phalanges. The presence of separated entocuneiform and mesocuneiform and three phalanges in the digit IV, are interpreted as plesiomorphic condition of the characters present in the Plio-Pleistocene genera. The plesiomorphic character states observed here could be useful to solve the megatherine polytomy proposed by De Iuliis (1996), and indicate more precisely the way the states of the characters were changed.