Description: We present estimates for head and body length (HBL) of fossil rodents. We assembled HBL data and tooth row length data (LTR, UTR) for a large number of extant rodents, and calculated regression lines of HBL on LTR and UTR for all rodents together (all-rodents equation), and for separate taxonomic groups (family equations). In fossil rodents, data for complete tooth rows are scarce, therefore we use the sum of the lengths of the teeth (LRsum, URsum) as a surrogate for tooth row length. The relation between this parameter and real tooth row length (LTR, UTR) is calculated on the basis of a number of populations for which both parameters are available. We estimate HBL of fossil rodents, using LRsum and URsum and the regression lines of extant rodents, and we compare the results for lower and upper tooth row when both are available. For each species we calculate HBL through the all-rodents equation and through the family equation. We consider the amount of difference between these two values as a measure of the reliability of this method.

Description: The paleoecological analysis of Neogene rodent faunas in the Calatayud-Teruel Basin leads to the recognition of three realtively cool, and two relatively warm periods. The humidity curve reveals four wet and four dry periods. The results agree remarkably well with temperature and humidity curves obtained from other geological disciplines.

Description: During the summer holidays of 1960 to 1963 a great many localities of Miocene and Pliocene mammals were discovered in the Southern part of Zaragoza province (Spain).\nRemains of both large and small mammals were found, the latter by sieving clays and marls. This small fauna consists mainly of Cricetodontinae, Gliridae, Sciuridae, Lagomorpha and Insectivora.\nThe object of the present study is the Cricetodontinae. Other families of the same localities will be described by H. de Bruyn of the State University of Utrecht, Netherlands. The localities are situated along the S.W. border of the Calatayud-Teruel basin. Apart from small local faulting and folding along the margin of the basin the sediments are undisturbed. This circumstance and the nearly continuous exposures made it possible to determine the relative stratigraphic position of the sites. With the stratigraphic succession as a directive it proved to be possible to follow the evolution of the Cricetodontinae step by step. The Cricetodon material found in the region falls into four groups. Within each group species are closely related. 1. The group minor (based on Cricetodon minor LARTET, 1851) comprises small species with elongated M1. The oldest member of this group is Cricetodon minor primitivus n. ssp. from the Valtorres locality near Calatayud. This form develops to C. collongensis MEIN, 1958, from Vieux-Collonges (France). The author considers this to be a subspecies of C. minor LARTET. Cricetodon minor collongensis was found in several Spanish localities. The evolutionary development of this form appears to be C. minor minor LARTET on the one side and C. gregarius SCHAUB, 1925 on the other. Representatives of both branches were found in the Calatayud-Daroca region. In the course of time members of the gregarius branch grow gradually larger, whereas in the minor branch they stay of about the same size. 2. The group larteti (based on Cricetodon larteti SCHAUB, 1925) comprises species of medium size. The molars are short and broad, squarishly built, and show definite reduction. The early and middle Miocene ancestors of Cricetodon larteti were now discovered in Spain, namely C. koenigswaldi n.sp. and C. darocensis n.sp. The most notable feature of the evolutionary trend in this group is a gradual increase in size. 3. The group affinis (based on Cricetodon affinis SCHAUB, 1925) comprises species of small and medium size. The molars are squat and show little reduction. C. brevis SCHAUB is synonymous with C. affinis. The type specimen of C. brevis from La Grive-St. Alban (France) is considered to be a small specimen of C. affinis. Cricetodon brevis from Sansan, being markedly different from the above mentioned, had better be named Cricetodon cf. vindoboniensis SCHAUB & ZAPFE, 1953.\nIt is fairly certain that the species from Villafeliche II A (Spain) is identical to the latter. 4. The group sansaniensis (based on Cricetodon sansaniensis LARTET, 1851) comprises large species. The molars have high relief and fat cusps. Only one locality (Manchones) provided sufficient material for analysis. Comparison of this material with finds from France and North-Spain led to the conclusion that there are two identical lines of evolution within the group. These are most probably closely related, though the common ancestor is not yet known. One branch leads from C. meini n.sp. (from Vieux-Collonges) through a somewhat more highly developed member (from Manchones) to C. decedens (from La Grive-St. Alban, and the Valles-Penades). The other branch, which is also known from Vieux-Collonges, though not yet described, leads to sansaniensis from Sansan. Cricetodon sansaniensis from La Grive seems somewhat more developed and might well be called C. rhodanicus DEPERET. The highest developed member of this branch is found in the Valles-Penades (not yet described).\nWith the above mentioned data of the evolutionary trends in the Cricetodontinae it was tried to correlate some of the well-known Miocene localities in France with the sites in the Calatayud-Daroca region (fig. 17). There proved to be a good agreement between miocene Cricetodon fauna of Spain and France, whereas no similarity was found with the North-African fauna from Beni-Mellal (Morocco). Comparison of the living species Cricetus cricetus canescens NEHRING and Mesocricetus auratus (WATERHOUSE) with the Cricetodontinae of Western Europe shows that none of these can be an ancestor of the recent Cricetinae. Certain primitive characters of the dentition of Cricetus have already disappeared in all known Cricetodontinae. The oligocene genus Cricetops from Mongolia is the only one that more or less satisfies the demands one should theoretically make on an ancestor of the Cricetinae. It is probable that the Cricetinae are originally an Asiatic family, arriving in Europe more or less at the same time as Hipparion and crowding out the Cricetodontinae. The common ancestor of Cricetodontinae and Cricetinae is at least of Oligocene age.

Description: The Cricetidae from various new localities in the area of Crevillente are described, and compared with the material published by de Bruijn et al. (1975). Among the material there are two new species: Neocricetodon plinii and N. lucentensis.

Description: Hattomys, a new genus of Cricetidae, is described and three new species H. beetsi, H. nazarii and H. gargantua are attributed to it. Hattomys are very large cricetids, and the evolution of the genus is characterized by a considerable increase in size, and an increasing predominance of ridges over cusps. The supposedly oldest Gargano localities yielded, apart from the lineage H. beetsi-nazarii-gargantua, some scarce material of three other hamster species: a Megacricetodon, a Cricetulodon and a Cricetus. Comparison with the Spanish sequences of rodent faunas shows that the Gargano faunas probably are of late Turolian age, equivalent of the Messinian.

Description: Apart from the common cricetid fauna, the site of Vieux-Collonges contains a number of rare forms: Lartetomys, Melissiodon, Neocometes, and Anomalomys. This scarce material is described and compared with material from other European localities. The stratigraphie position of Vieux-Collonges is discussed briefly. En plus des Cricetodontinae et Cricetinae communs, il existe \xc3\xa0 Vieux-Collonges plusieures esp\xc3\xa8ces d\'autres groupes de Cricetidae, repr\xc3\xa9sent\xc3\xa9es par des mat\xc3\xa9riaux peu nombreux. Il s\'agit de Lartetomys mirabilis, Lartetomys zapfei, Melissiodon aff. dominans, Neocometes similis et Anomalomys sp. Cettes formes sont d\xc3\xa9crites, et leur valeur pour la corr\xc3\xa9lation de Vieux-Collonges avec d\'autres gisements de mammif\xc3\xa8res mioc\xc3\xa8nes est discut\xc3\xa9e.

Description: Eight rodent species from the Upper Oligocene of Pareja are described. The Theridomyidae are represented by Issiodoromys minor and Archaeomys (A.) gervaisi and the Eomyidae by Eomys cf. molassicus. Four cricetid species are described: Heterocricetodon landroveri sp. nov., Eucricetodon margaritae sp. nov., Eucricetodon cf. atavus, and Eucricetodon sp. One new glirid species, Gliravus caracensis, is recognized. The fauna of Pareja is considered to be somewhat older than that of Carrascosa del Campo, and considerably younger than that of Montalb\xc3\xa1n.

Description: Two new species of Pseudocricetodon are described: P. simplex sp. nov. is characterised by a simple dental pattern in the lower molars. It has been discovered almost simultaneously in Oligocene beds near Mart\xc3\xadn del R\xc3\xado (Teruel Basin) and near Alcorisa on the southern border of the Ebro Basin. P. adroveri sp. nov. had previously been described from Vivel del R\xc3\xado as P. aff. thaleri, and is characterised by a complex dental pattern. These two new species change the current ideas on the evolution of the genus Pseudocricetodon.

Description: The various fossiliferous localities at Polg\xc3\xa1rdi are described. One of them has yielded a very rich material of a new species of hamsters, Cricetus polgardiensis. The phylogenetical relationships of the Polg\xc3\xa1rdi hamsters are discussed.

Description: The fauna of Muridae (Rodentia) from the Lower Turolian of Crevillente (Alicante, SE Spain) contains species attributed to the genera Huerzelerimys, Parapodemus, and Occitanomys. The material described allows a detailed biostratigraphy of Upper Miocene deposits of SE Spain. En este trabajo se estudian tres generos de Muridae (Huerzelerimys, Parapodemus y Occitanomys) procedentes de varios yacimientos del Mioceno final de Crevillente (Alicante). Las faunas encontradas permiten precisar la bioestratigrafia de los depositos del Turoliense inferior del SE de Espana.