Showing papers in "Bulletin of the Museum of Comparative Zoology at Harvard College in 1970"

The Argyrolagidae, extinct South American marsupials

Abstract: 1. The known Argyrolagidae include two genera, for which the names Microtragulus and Argyrolagus are provisionally retained, with certainly four, possibly five or six valid species. M. reigi and A. scagliui are here described as new. The known range is mid or late Pliocene to early or mid Pleistocene in Argentina. 2-0-1-4 2. The dentition is -.„.,. ; incisors en2-0-1-4 larged, procumbent below; all teeth rootless. The skulls have tubular bony snouts in advance of the incisors, a large, covered masseteric origin in the anterior part of the orbit, no distinct temporal fossa, and globular crania with somewhat inflated ear regions. Forelegs are reduced, hindlegs elongate; tibia and fibula are fused distally; metatarsals III and IV are appressed; there are only two digits in the pes; locomotion was bipedal ricochetal. The habitus is remarkably convergent toward some placental, especially kangaroo rats and jerboas. 3. Argyrolagids are marsupials but show no clear affinity with any others known. They probably arose from didelphids independently of other known families and are distinct at the superfamily level, at