Issue


December 1985
Vol. 15, Fasc. 3
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Print ISSN: 0031-0247
Online ISSN: 2274-0333
Frequency: biannual

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Palaeovertebrata Vol. 15, Fasc. 3:December 1985

Table of contents


Articles


Evolution of the Rhizomyine zygoma
Lawrence J. Flynn, Mohammed Sarwar and Jean-Jacques Jaeger
Keywords: parallel evolution; Rhizomyidae; Rodentia; Siwalik; zygoma
 
  Abstract

    Cranial anatomy of a late Miocene rhizomyid, Brafhyrhizomys cf. B. pilgrimi, provides new evidence on the origin of the dorsal, round infraorbital foramen of living rhizomyines. Primitive rhizomyids retain a myomorphous keyhole foramen with a long ventral slit that retracts upward during the evolutionary history of the Rhizomyidae. The primitive condition of the elongated ventral slit is represented by Kanisamys sivalensis. Among later burrowers the foramen shows progressive dorsal migration, the ventral slit terminating midway up the snout in B.tertracharax and B. choristos ; well above the midline of the snout in Brachyrhizamys cf. B. pilgrimi. Apparently this transformation began earlier among Rhizomyinae than among Tachyoryctinae and continued to a more derived stage in rhizomyines. ln living Rhizomyx the ventral slit is absent and only a high round hole remains at the anterior end of the zygomatic arch. 


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Crivadiatherium iliescui n. sp., nouvel Embrithopode (Mammalia) dans le Paléogène ancien de la dépression de Hateg (Roumanie).
Constin Radulesco and Jean Sudre
Keywords: Embrithopods; Late Eocene; Paleobiogeography; Romania
 
  Abstract

    The investigations undertaken at Crivadia (Hateg Depression, Hunedoara District, Romania), the type locality of Crivadiatherium mackennai RADULESCO el al. (Radulesco, Iliesco et lliesco, 1976), led to the discovery of remains of a new Embrithopod. Close to the above mentioned species, but larger in size, this animal is here described as a new species of Crivadiatherium, C. iliescui. ln addition, the comparison made between the forms indicated above and Palaeaamasía kansui OZANSOY from the Eocene deposits of Anatolia (Ozansoy, 1966; Sen et Heintz, 1979) showed that the latter species included a heterogeneous material; this permitted us to distinguish the form in the Anatolian locality Ciçekdag-Arabin Kôyü under the name Palaeoamasia sp. The geographical distribution and diversity of the Embrithopod species under discussion (Balkan, Anatolia) support the idea of an eurasiatic origin of this group and seem to suggest the existence during the Eocene of a particular faunal province in south-eastern Europe. 


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Nouvelle quantification de l'Hypsodontie chez les Theridomyidae : l'exemple de Theridomys ludensis nov. sp.
Monique Vianey-Liaud
Keywords: dental morphology; evolution; Hypsodonty; Oligocene; Theridomyidae
 
  Abstract

    A new example of parallelism in the dental pattern ofthe Theridomyidae is illustrated by the description ofa new species: Theridomys Iudensis from the standard level of Antoingt (middle Oligocene). Considering the occurence ofthis parallelism phenomenon. the use of numerous qualitative and quantitative criteria is essential to characterize the different stages ofthe different evolutive lineages. Thus, a new simple parameter is proposed (CHY = H+l/0,5 L) to estimate hypsodonty of the medium hypsodont Rodentia. 


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