FIGURE 12. From top to bottom: 'Plesiotypotherium' minus, holotype; Microtypotherium cf. M. choquecotense (here referred to 'P.' minus); Microtypotherium choquecotense, holotype; Plesiotypotherium achirense, holotype. Note the two lingual sulci in 'P.' minus and P. achirense. Scale bar = 2 mm. Compiled from Villarroel, 1974a and 1978.