Proviverrine hyaenodontids (Creodonta: Mammalia) from the Eocene of Myanmar and a phylogenetic analysis of the proviverrines from the para-tethys area

摘要

Recent expeditions in the Pondaung Formation have revealed an assemblage of hyaenodontid creodonts from the late middle Eocene of Myanmar. Among the three proviverrines known from the fauna, Kyawdawia lupina gen. et sp. nov. is represented by the most complete dental materials. Kyawdawia is similar to the proviverrines known from the Eocene and middle Miocene of India-Pakistan and from the late Eocene to middle Miocene of Africa, in that it has a short protocone and strong buccal cingulum on M1-2, a small metaconid on m2-3 and a well-basined talonid on p4-m2. In addition, it lacks an anterior accessory cusp on p4 and the distinction between the hypoconulid and entoconid on the lower molars. It is unique among the Afroasian proviverrines in lacking a protocone 1obe on P4 and in having a broader paracone relative to the metacone on M1-2. This species is one of the largest proviverrines and was estimated to be the size of a red wolf. The type specimen includes postcranial materials. The well-developed deltopectoral crest, supracondylar ridge and medial epicondyle of the humerus and the relatively short gracile tibia suggest some digging adaptations, while the two well preserved caudal vertebrae indicate the presence of a long tail. The cladistic analysis of 14 proviverrines from Europe and Afroasia based on dental morphologies supports the monophyly of proviverrines from Africa and South and Southeast Asia. This group must have originated from the European forms by the early Eocene and dispersed into South and Southeast Asia. Kyawdawia is phylogenetically closest to Masrasector from the late Eocene to early Oligocene of Egypt and Oman, and the second closest to Paratritemnodon from the middle Eocene of India-Pakistan. The other two Pondaung proviverrines, Yarshea cruenta and an indeterminate proviverrine, are also close to these genera.