MENUCOA CAZAUI NOV. GEN. ET SP., TRONCO PETRIFICADO DE CYCADALES, PROVINCIA DE RIO NEGRO, ARGENTINA

Bruno Petriella

Abstract


A petrified trunk with an arrnour of leaf bases from the Lower Tertiary (?) of Los Menucos, Río Negro Province, Argentina, is described. The anatomy of Menueoa cazaui is the usual one found in living polyxylic cycad stems. Ccrnparisons have been made with Cycadeoidea, Bueklandia, Michelilloa and living Cycadales. Ir is concluded that: a) there is a close relationship between M. cazaui and the polyxylic genera of the living Cycadales; b) the presense of M. cazaui in the Lower Tertiary (?) of Argentina is a further argument which favours the existence of connections between the southern lands in the past; e) M. cazaui possibly existed in a ternperate to sub tropical region.

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