Abstract

TORO, Blanca A.  and  BRUSSA, Edsel D.. New systematic insights about the graptolites of the "Rusconi Collection" from the lateordovician Empozada Formation, Precordillera of Mendoza, Argentina. Ameghiniana [online]. 2007, vol.44, n.1, pp.231-240. ISSN 1851-8044.

The holotypes, paratypes and the best preserved material of twenty graptolite taxa proposed by Rusconi, and deposited in the "Juan Cornelio Moyano" Natural and Anthropological Sciences Museum of Mendoza were reviewed. The fossils, which were collected from sedimentary deposits of the Empozada Formation that crop out in the San Isidro area, located in the Precordillera close to Mendoza city, were compared with the specimens collected by the authors in the same unit. This paper deals with the reasons why the following taxa are invalid: Desmograptus australis (Rusconi), Tetragraptus bueyensis (Rusconi), Dichograptus quebradensis (Rusconi), Pterograptus longissimus (Rusconi), Cryptograptus crassispinus (Rusconi), Mendograptus inversus (Rusconi), Monograptus bayensis (Rusconi), Glyptograptus cuyanensis (Rusconi), Glyptograptus cuyunchensis (Rusconi) and Janograptus simplicidentatus (Rusconi); in addition, reasons for the doubtful classification of the following taxa are discussed: Janograptus alfaensis (Rusconi), Janograptus australis (Rusconi) and Janograptus bueyensis (Rusconi). Moreover, the descriptions of reassigned taxa such as: Thamnograptus sp., Climacograptus tubuliferus Lapworth, Orthoretiolites aff. hami Whittington, Hallograptus sp. and Plegmatograptus sp. are given. Corynoides sp. and Dicellograptus cf. minor Toghill are reported and described for the first time for the Empozada Formation. Finally, new information about the recognized graptolite assemblages and their biostratigraphic implications is also discussed.

Keywords : Ordovician graptolites; Rusconi Collection; Empozada Formation; Mendoza; Argentina.