Right ulna, proximal portion in cranial and distal views of radio and ulna. A Tympanoctomys aureus B Tympanoctomys barrerae C Tympanoctomys kirchnerorum D Tympanoctomys loschalchalerosorum. lcp, lateral coronoid process; mcp, medial coronoid process; ol, olecranon; r, radio distal surface; rn, radial notch; ul, ulnar distal surface; ulptc, ulnar lateral proximal trochlear crest; umptc, ulnar medial proximal trochlear crest. Scale bars 1 mm.