FIG. 13. Astrapotherium magnum MACN A 8580 in Cranial Morphology And Phylogenetic Relationships Of Trigonostylops Wortmani, An Eocene South American Native Ungulate

FIG. 13. Astrapotherium magnum MACN A 8580, parasagittal segments through left side of caudal cranium, sequence lateral to medial. In A, inset passes through skull just medial to the complete segment; note small epitympanic sinus and proximity of aditus of extratympanic sinus (see also fig. 27). In B, asterisk marks lambdoidal process of petrosal also seen in inset (see also fig. 14F). In C, D, curved black arrows indicate continuity between frontal sinus and air spaces throughout skull; note relatively small size of braincase. Cobbly appearance of bone and matrix in nasal region is due to artifacts in CT data. Premaxillae missing postmortem in this specimen (but see fig. 4).Published as part of MacPhee, R.D.E., Del Pino, Santiago Hernández, Kramarz, Alejandro, Forasiepi, Analía M., Bond, Mariano & Sulser, R. Benjamin, 2021, Cranial Morphology And Phylogenetic Relationships Of Trigonostylops Wortmani, An Eocene South American Native Ungulate, pp. 1-185 in Bulletin of the American Museum of Natural History 2021 (449) on page 55, DOI: 10.1206/0003-0090.449.1.1, http://zenodo.org/record/541502