83 PALEONTOLOGIA I EVOLUCIÓ, memòria especial nº3 (2009), p. 83-84 Paloma LÓPEZ-GUERRERO 1 , Israel GARCíA-PAREDES 2, 3 & M. ángeles áLVAREZ-SIERRA 1 Preliminary geometric morphometric analysis of Cricetodon and Hispanomys upper molars (Rodentia, Mammalia) The rodent genera Cricetodon Lartet 1851 and Hispanomys Mein & Freudenthal 1971 (Tribe Cri- cetodontini) are very important for the biochronol- ogy and biostratigraphy of the Middle and Late Miocene from the Iberian Peninsula. Both genera are especially abundant in the localities of the Ca- latayud-Daroca Basin (Zaragoza, Spain). In this basin, the stratigraphical distribution of Cricetodon is from local biozone E (MN 5) to G3 (MN 7/8) and Hispanomys is from local biozone G3 to I (MN 9) (DAAMS &FREUDENTHAL, 1988; áLVAREZ SIERRA et al., 2003; LÓPEZ-GUERRERO et al., 2008). The dental morphology of both genera shows several differences that can be used as diagnostic characters. However, we found some dificulties to distinguish between both genera in the localities from the biozone G3. One of the observed differ- ences is that Cricetodon from biozones E, F, G1 and G2 have a straight outline in the upper irst molars whereas Hispanomys from local biozones H and I have a trilobe outline on the labial part. 1. Universidad Complutense de Madrid, Facultad de Geología, Departamento de Paleontología. C/ José Antonio Novais, 2. 28040 Madrid (Spain). PL-G: palomalopez@geo.ucm.es; MAAS: masierra@geo.ucm.es 2. Nationaal Natuurhistorisch Museum-Naturalis. P.O. Box 9517. 2300RA Leiden (The Netherlands). IG-P: paredes@naturalis.nl 3. Museo Nacional de Ciencias Naturales-CSIC. C/ José Gutiérrez Abascal, 2. 28006 Madrid (Spain). This study examined the differences in the shape of the upper irst molars of Cricetodon and Hispanomys from different Middle and Late Mio- cene localities by means of a geometric morpho- metric analysis. we applied a landmark based methodology proposed by MARTINÓN-TORRES et al. (2006) and GÓMEZ-ROBLES et al. (2007) to quantify the differences in the relative position of the main cusps combined with the changes in the outline of the teeth in occlusal view. Principal Component Analysis, Cluster analysis and sig- niicance tests have been performed in order to evaluate if there is a satisfactory separation and grouping of the analyzed specimens according to their generic assignation. The results are compared with the classical metrical and morphological studies and they are discussed with regard to the ability of this method- ology for the taxonomic assignment of the Cricet- odon and Hispanomys upper irst molars from the biozone G3 of the Calatayud-Daroca Basin.