INVESTIGADORES
KRAMARZ Alejandro Gustavo
capítulos de libros
Título:
A new mammal fauna at the top of the Gran Barranca sequence and its biochronological significance
Autor/es:
KRAMARZ, A.; VUCETICH, M.G.; CARLINI, A.; CIANCIO, M; ABELLO, A.; DESCHAMPS, C.; GELFO, G.
Libro:
The Paleontology of Gran Barranca: Evolution and Environmental Change through the Middle Cenozoic
Editorial:
Cambridge University Press
Referencias:
Lugar: Cambridge; Año: 2010; p. 264 - 277
Resumen:
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The top of the stratigraphic sequence of the fossil-bearing Sarmiento Formation at Gran Barranca has yielded a distinctive
assemblage of mammalian taxa. Fossils occur in strata located 25m above the uppermost level bearing typical
Colhuehuapian mammals. This association is represented by fragmentary remains of small to middle-sized
mammals belonging to paucituberculatan marsupials, dasypodids, glyptodonts, tardigrades, hegetotheres, interatheres,
proterotheriids, and hystricognath rodents. Although this fauna contains at least two new rodent species not recorded
in other faunas, it is more similar to that recorded at the lower and middle sections of the Pinturas Formation
in northwest Santa Cruz Province (the Ameghinos Astrapothericulan fauna) than to any other known fossil
mammal assemblage. The strata yielding this fauna (Upper Fossil Zone, UFZ) is estimated to be in Chron C6n (19.7 to
18.7Ma), but the taxic similarity with the younger Astrapothericulan fauna (dated between 17.5 and 16.5 Ma) suggests
that the UFZ is placed at the youngest extreme of the Chron C6n. The Astrapothericulan and the UFZ assemblages
would correspond to a single post-Colhuehuapian pre-Santacrucian biochronological unit (the Pinturan)
which would span from _18.75 to _16.5Ma. This is the youngest faunal unit within the standard sequence of the
middle Cenozoic SALMAs at Gran Barranca. The assignment to this unit of other earlyMiocene faunas elsewhere in
South America (at present poorly o partially known) depends on further descriptions and future findings.