An early Carboniferous flora from Argentina. Biostratigraphic implications.

SESSAREGO, H.; CÉSARI, S. N.

REVIEW OF PALAEOBOTANY AND PALYNOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 1989 vol. 57 p. 247 - 264

0034-6667

A Lower Carboniferous Aora from the Del Ratón Formation, exposed near Calingasta, San Juan province ofArgentina, is described and illustrated and its biostratigraphic significance is evaluated. The megafossils includeLepidodendropsis eximius (Frenguelli) Sessarego et Césari, Archaeosigillaria conferta (Frenguelli) Menéndez,Diplothmema bodenbenderi (Kurtz) Césari, Eusphenopteris deoonica (Frenguelli) nov. comb., "Hyenia" argentina,"Rhodea" sp. and Telangiopsis sp. The asaociated microAora, described for the first time, includes Verrucosisporitescongestus Playford, Anapiculatisporites amplus Playford et Powis, Dictyotriletes submarginatus Playford, cf.Densosporites spinosu.s Dybová et Jachowicz, Retusol.riletes avonensis Playford, Dibolisporites cf. D. distinctus(Ciayton) Playford and Grandispora debilis Playford.The megafosail species are referable to the Archaeosigillaria Lepidodendropsis biozone, which combines theArchaeosigillaria Zone and Lepidod.endropsis Flora of Archangelsky and Azcuy (1985) and Archangelsky et al. (1986).The plant mega(ossils and associated microAora suggest a Visean ase for this biozone. The presence of an associatedmarine fauna in the stratigraphically equivalent Malimán Formation, having Protocanites scalabrinii Antelo,corrobora tes a Lower Carboniferous age for our biozone. By comparison with others in the world this is the oldestCarboniferous taphoAora in Argentina and probably in the whole o[ South America.The evolutionary significance of the Lepidodendropsis flora is analysed