Proticia venezuelensis n. g. and sp., based on a partial mandible from rocks attributed to the Trujillo Formation, Paleocene to early Eocene, exposed on the southern flank of the Sierra de Baragua, State of Lara, is described. Proticia is the second colombitheriid pyrotherian to be recorded; it is possibly ancestral to the later Colombitherium. The early pyrotheres are briefly reviewed, and Carolozittelia and Griphodon retained in the Pyrotheriidae; Archaeolophus and Carolozittelia may have been based on different parts of the same animal. Some account of the skull of Pyrotherium is given, and evidence that the group constituted a suborder of the Notoungulata is presented Includes bibliographical references (p. 419-422) Proticia venezuelensis n. g. and sp., based on a partial mandible from rocks attributed to the Trujillo Formation, Paleocene to early Eocene, exposed on the southern flank of the Sierra de Baragua, State of Lara, is described. Proticia is the second colombitheriid pyrotherian to be recorded; it is possibly ancestral to the later Colombitherium. The early pyrotheres are briefly reviewed, and Carolozittelia and Griphodon retained in the Pyrotheriidae; Archaeolophus and Carolozittelia may have been based on different parts of the same animal. Some account of the skull of Pyrotherium is given, and evidence that the group constituted a suborder of the Notoungulata is presented Fieldiana series has been published as Geological Series by Field Columbian Museum (1895-1909) and Field Museum of Natural History (1909-1943), and as Fieldiana: Geology by Chicago Natural History Museum (1945-1966) and Field Museum of Natural History (1966-)