The first Ordovician micromorphic linguliform brachiopods are described from the Province of Mendoza of west-central Argentina. The focus of the study is on carbonate successions exposed in the San Rafael Block, south of the famous Precordillera of San Juan, La Rioja and Mendoza representing the largest area of the so-called Cuyania Terrane. In the San Rafael region, the lingulate brachiopod faunas occur in two successive assemblages. The older assemblage was recovered from the uppermost part of the Ponon Trehue Formation (Lenodus variabilis Biozone; Darriwilian), and is dominated by Numericoma rowelli sp. nov. It has an affinity to contemporaneous faunas from the Antelope Valley Limestone (Whiterockian) at Meiklejohn Peak in central Nevada. The second, younger assemblage was recovered from the lower Lindero Formation (upper Darriwilian-basal Sandbian; Pygodus serra and P. anserinus Biozones) and is mainly dominated by the new genus Mendozotreta, with its type species M. devota (Krause & Rowell), and Conotreta cf. multisinuata Cooper, Rhysotreta corrugata Cooper, Scaphelasma septatum Cooper, Ephippelasma minutum Cooper and Biernatia minor Cooper. In addition, the fauna includes Elliptoglossa sylvanica Cooper, Rowellella margarita Krause & Rowell and Paterula cf. perfecta Cooper. This second lingulate microbrachiopod assemblage is closely comparable to the coeval microbrachiopod fauna from the Pratt Ferry Formation of Alabama.
2016. Vol. 49, 31-50 p.