Microlobiusxylon paranaensis gen. nov. et sp. Nov. (Fabaceae-Mimosoideae) from the Pliocene –Pleistocene of Ituzaingó Formation, Paraná basin, Argentina.

FRANCO, M.J. Y BREA. M

REVISTA BRASILEIRA DE PALEONTOLOGIA

SOC BRASILEIRA PALEONTOLOGIA

Lugar: Rio de Janeiro; Año: 2010 vol. 13 p. 103 - 114

1519-7530

A fossil wood with Fabaceae affinity from the Pliocene-Pleistocene sediments of Ituzaingó Formation is described. The silicified wood was collected at the Toma Vieja fossil locality, Paraná Basin, Argentina. The relationship and comparison with the nearest living relatives (NLRs) are discussed. Wood anatomical characters suggest an affinity with the genus Microlobius C. Presl. In South America, the genus Microlobius occurs in Brazil, Bolivia (Santa Cruz), Argentina (Chaco and Formosa) and Paraguay and is an important extant element of the Paraguay-Paraná system. The presence of this fossil in the Ituzaingó Formation supports the idea that the morphogenus Microlobiusxylon might have been an important component of Seasonally Dry Tropical Forest (SDTFs) during the Pliocene-Pleistocene. Today this forests type has a relict distribution, occurring in isolated localities in the North of Argentina, Southeast of Bolivia and Brazil, but in the past were more widespread to the East and South in America. Microlobiusxylon paranaensis would indicate a temperate-warm climate during the Pliocene-Pleistocene.