Tiuclaenus robustus Muizon & Cifelli 2000
- Dataset
- New remains of kollpaniine “ condylarths ” (Panameriungulata) from the early Palaeocene of Bolivia shed light on hypocone origins and molar proportions among ungulate-like placentals
- Rank
- SPECIES
Classification
- kingdom
- Animalia
- phylum
- Chordata
- class
- Mammalia
- order
- Condylarthra
- family
- Hyopsodontidae
- genus
- Tiuclaenus
- species
- Tiuclaenus robustus
description
DESCRIPTION A right mandible fragment bearing m 2 - 3 (MHNC 13875) has been referred to Tiuclaenus robustus (Fig. 10 B, C) essentially because, although structurally similar to the other species of Tiuclaenus (T. minutus and T. cotasi), it differs from them in its size, distinctly larger, and in its greater massiveness. Furthermore, as is observed on the holotype (a mandible fragment with m 2 - m 3, MHNC 1233), m 3 of MHNC 13875 is proportionally shorter than in T. minutus and T. cotasi being barely longer than m 2. An interesting feature of this specimen is the morphology of the roots of m 2 and m 3, which are long extending ventrally on more than 2.5 the height of the crown (Fig. 10 C). Furthermore, the apices of the roots are markedly splayed with their posterior edges extending posteriorly, providing the extremity of the root a characteristic hammer-shape. Although the ventral edge of the dentary is partly broken, this morphology gives the impression that the root had to develop posteriorly because it was abutting the ventral edge of the mandibular canal.
diagnosis
DIAGNOSIS. — See Muizon & Cifelli (2000).