In this paper we present the first descriptions of Triassic blattopterans from Argentina and the second from southern South America. The only previously described species is Triassoblatta cargnini Pinto and Ornellas, 1974 from the Middle to Upper Triassic (Santa Maria Formation) of southern Brazil. A historical summary and lists of previously described insects can be found in Gallego (1997), Gallego and Martins-Neto (1999), Martins-Neto and Gallego (1999, 2001) and Martins-Neto et al. (2003).
In this contribution we describe new Blattoptera from the Los Rastros Formation (Río Gualo, Picos Gemelos and Los Chañares localities, La Rioja Province, Argentina) (figure 1.A). The samples from the Los Rastros Formation were collected in two field trips, one by OFG, A. Arcucci, C. Forster, C. May, and R. Rogers in 1995 and the other by ACM, A. Arcucci and C. Marsicano in 1999.
The terminology adopted here follows Kukalova-Peck (1991), except for the newly proposed abbreviations as follows (figure 2.A):
oMA: the distance from the tegmen base to MA origin;
aml: anal margin length from the tegmen base to CuP distal part;
amh: anal margin hight from CuP origin, at the tegmen base to the anal margin;
d: anal area diagonal, from CuP origin at CuP distal extremity, at the anal margin;
f: height from the main CuP curvature to d, in relation to the tegmen base;
lcm: length from the wing base to the last distal ScP branch;
lrp: length from the distal part of the first RA branch to the last RP branch;
lh: Humeral area length.
The repository and institutional abbreviations used here are, PULR-I: Paleontology Collection, Museo de Ciencias Naturales, Universidad Nacional de La Rioja, La Rioja, Argentina. PZ-CTES: Paleozoological Collection, Facultad de Ciencias Exactas y Naturales y Agrimensura, Universidad Nacional del Nordeste, Corrientes, Argentina.