Abstract

FRABCO, María Jimena. Fossil woods of Anacardiaceae from Ituzaingó Formation (Pliocene - Pleistocene), Toma Vieja, Paraná, Entre Ríos, Argentina. Ameghiniana [online]. 2009, vol.46, n.4, pp.587-604. ISSN 1851-8044.

Two petrified woods from Ituzaingó Formation (Pliocene- Pleistocene) are described and assigned to Anacardiaceae. The specimens were found in Toma Vieja fossiliferous locality, Paraná, Entre Ríos, Argentina. The presence of a combination of characters in each one allowed to distinguish this family from other dicotyledonous and to assign the material to two morfotaxa: Astroniumxylon parabalansae Franco et Brea and a new morphospecies of Astroniumxylon Brea et al. The petrified woods show great affinity with the genera Astronium Jacq., while Astronium balansae Engl. and Astronium urundeuva (Allemão) Engl. are the most related species. The comparison with the nearest living relatives suggests that the fossils might have been a component of Neotropical Dry Forests with strongly seasonal climate. These current forests develop in South America and are relict in isolated localities in the North of Argentina, Southeast of Bolivia and Brazil, but that in the past they were more extended to the South and East of the American continent. Anacardiaceae family was a very important component during the Cenozoic in southernmost South America. This evidence is supported by diverse and abundant fossil record of Anacardiaceae.

Keywords : Fossil woods; Anacardiaceae; Pliocene-Pleistocene; Ituzaingó Formation; Argentina; Entre Ríos.