Hojas de Myrtaceae de la Formación San José (Mioceno Medio), provincia de Tucumán, Argentina

Abstract

Fossil leaves from the San José Formation assigned to Myrtaceae are described herein. They were found at three localities of the quebrada de Amaicha, northwest Tucumán Province. The San José Formation of Middle Miocene age is the basal unit of the Santa Maria Group. The genus Myrciophyllum Engelhart is emended, a new species, Myrciophyllum tucumanensis, and Myrciophyllum sp. 1 and Myrciophyllm sp. 2 are described. The genus has brochidodromous to acrodromous leaves with intramarginal veins, the intersecondary and tertiary veins with admedial branching pattern. Myrciophyllum tucunuinensis sp. nov. has obovate leaves with 5-6 secondary veins, Myrciophyllum sp. 1 has elliptic leaves and Myrcíophyllum sp. 2 lanceolate to elliptic narrow ones, both with 9-10 pairs of secondary veins. The three species are similar to leaves of the extant genus Myrciathes Berg. They resemble extant species from northern Argentina and probably integrated the tree stratum of a neotropical forest, ancestral to the present Yungas Province.