MURIDAE (RODENTIA) FROM THE PLIOCENE OF TOLLO DE CHICLANA (GRANADA, SOUTHEASTERN SPAIN) RAEF MINWER-BARAKAT 1 , ANTONIO GARCÍA-ALIX 2 , ELVIRA MARTÍN-SUÁREZ 3 , and MATTHIJS FREUDENTHAL 4 Departamento de Estratigrafía y Paleontología, Universidad de Granada, 18071 Granada, Spain; 1 rminwer@ugr.es; 2 agalix@ugr.es; 3 elvirams@ugr.es; 4 mfreuden@ugr.es ABSTRACT—In the continental deposits of the area of Tollo de Chiclana (Guadix Basin, south-eastern Spain), several new fossiliferous Pliocene localities yield a rich rodent and insectivore fauna. Of the various rodent families that occur in these sites, Muridae are the most abundant and diversified. Eleven species belonging to seven different genera (Occitanomys, Stephanomys, Castillomys, Paraethomys, Apodemus, Rhagapodemus, and Micromys) have been recog- nized. In this paper we describe the Muridae from these localities, which have great biostratigraphical and paleoecological interest. The presence of certain taxa and the changes in the abundance of the various taxonomic groups indicate a decrease in temperature and a change in the biotopes from Late Ruscinian through Middle Villafranchian in the area of Tollo de Chiclana. INTRODUCTION This paper describes the Muridae from several fossiliferous Pliocene localities in the continental deposits of the area of Tollo de Chiclana (Guadix Basin, south-eastern Spain). This basin was established as an intramontane basin in the late Miocene (Fernández et al., 1996; Soria et al., 1998), after the main tec- tonism that formed the large structures of the Betic Orogen. The oldest sedimentary infilling in this basin was deposited in a phase of marine sedimentation during the Tortonian. The upper part of the infilling represents a stage of exclusively continental sedi- mentation that lasted from latest Tortonian until the late Pleis- tocene. The localities studied are situated in the central part of the basin, where clays and silts corresponding to distal fluvial sedi- mentation alternate with lacustrine carbonates (Viseras, 1991; Fernández et al., 1996). Vertebrate fossils are found in swamp deposits. Six new fossiliferous localities, which are stratigraphi- cally superposed, have been identified. From oldest to youngest these include Tollo de Chiclana 1 (TCH-1), 1B, 3, 13, 10, and 10B; the latter two are stratigraphic equivalents. The sequence contains remains ascribed to the following genera of Muridae: Occitanomys, Stephanomys, Castillomys, Paraethomys, Apode- mus, Rhagapodemus, and Micromys, accompanied by other ro- dents and insectivores. The geologic age of the fossils is based on faunal comparison with similar taxa of known age from other areas. The nomenclature used in the descriptions of the teeth is that of Van de Weerd (1976). Length and width have been measured as defined by Martín Suárez and Freudenthal (1993). Specimens are curated at the Departamento de Estratigrafía y Paleon- tología de la Universidad de Granada, Spain. SYSTEMATIC PALEONTOLOGY Family MURIDAE Gray, 1821 Subfamily MURINAE Gray, 1821 Genus STEPHANOMYS Schaub, 1938 STEPHANOMYS BALCELLSI Gmelig Meyling and Michaux, 1973 (Fig. 1A–F) Occurrence-TCH-10, TCH-10B. Description of the Material from TCH-10B Lower First Molar—These teeth are high crowned and con- siderably broader posteriorly than anteriorly. The anteroconid is markedly asymmetrical. The tma is small and connected to the lingual lobe of the anteroconid, except for one specimen in which it is large and central. The protoconid is posterior with respect to the metaconid, as is the hypoconid with respect to the entoconid. The longitudinal connecting crests and the labial cingulum are high. The c1 is narrow and comma-shaped, isolated in young specimens, and connected anteriorly to the hypoconid with more advanced wear. It continues as a broad, well-developed enamel crest that reaches the anterior face of the protoconid. In three of ten specimens there is a small accessory cuspid connected to the posterolabial face of the labial lobe of the anteroconid. In two of them there is another cuspid, posteriorly attached to the other accessory cuspid or in front of the termination of the labial cin- gulum. The posterior heel is low, crest shaped, and connects the posterior face of the hypoconid to the posterolingual face of the entoconid. It is higher near the hypoconid. There are two roots. Lower Second Molar—The anterolabial cuspid protrudes over the outline of the tooth. Like m1, the protoconid is poste- rior with respect to the metaconid, as is the hypoconid with respect to the entoconid. The longitudinal crest is well devel- oped. The labial cingulum is formed by a small c1 connected to the labial face of the hypoconid, and by an enamel crest that reaches the anterior face of the protoconid. The posterior heel is low and crest shaped, connecting the base of the hypoconid to the posterolingual face of the entoconid. There are two roots. Lower Third Molar—The anterolabial cuspid is protuberant and connected to the anterolabial part of the protoconid. In one specimen of seven, a small enamel fold can be seen behind this anterolabial cuspid, attached to the labial side of the protoconid. The posterior complex, shifted towards the lingual side of the tooth, joins the posterior part of the metaconid. There is no c1. There are two divergent roots, the posterior one more inclined. M1—These teeth are high crowned, with narrow cusps and well-developed crests. The t1bis and t2bis are always present; the former is larger and longer than the latter. The t1 and t3 are symmetrical, like t4 and t6. The t4 has a small posterior spur. The t9 is similar in size to t3 and t6. The t12 is well defined; in one specimen it is divided into two parts. There are three roots. Journal of Vertebrate Paleontology 25(2):426–441, June 2005 © 2005 by the Society of Vertebrate Paleontology 426