A new species, R. piojoensis, was described by Colin D. Sumrall, Susana Heredia, Cecilia M. Rodríguez and Ana I. Mestre in 2012, from 116 specimens collected from the Los Espejos Formation in the Loma de Los Piojos locality near San José de Jáchal, Argentina.
San Francisco | San Diego | San Salvador | San Antonio | San Pedro Sula | San Juan | San Diego Padres | San Francisco Giants | San Sebastián | San Francisco 49ers | San Francisco Chronicle | San Francisco Museum of Modern Art | San Francisco Bay Area | University of California, San Diego | San Jose | San José | San Francisco Bay | San Francisco Opera | San Marino | San Lorenzo | San José, Costa Rica | San Miguel de Tucumán | San Fernando Valley | San Diego Chargers | San Miguel | San Francisco Symphony | San Diego State University | José Carreras | Grand Theft Auto: San Andreas | University of California, San Francisco |