A fossil termite nest from the Marplatan stage (late Pliocene) of Argentina: palaeoclimatic indicator

A new fossil termite nest, Tacuruichnus farinai n. ichnogen. n. ichnosp., is described from the Barranca de Los Lobos Formation (late Pliocene) of Buenos Aires province (Argentina). The preserved part of the nest is cup-shaped, being composed of a wall, 10 cm thick, bearing a net of anastomosed tunnels, and surrounding a central cavity filled with sediments. The exterior shows the remains of a peripheral tunnel system. The morphology of Tacuruichnus farinai closely resembles the hypogeal part of extant Cornitermes cumulans nests. C. cumulans is the southern species of the genus, which presently inhabits northern Argentina, about 1000 km north of the ichnofossil locality, in areas with an annual rainfall of more than 1500 mm and mean temperatures of more than 21 degrees C. This new evidence is congruent with the warm and wet conditions postulated elsewhere for the Marplatan stage based upon other kinds of data, and contributes to a more precise statement of its palaeoclimatic conditions. (C) 1997 Elsevier Science B.V.