Validation of the species Stephanomys progressus, a murid (Rodentia) from the early Pleistocene of Spain

Abstract

The genus Stephanomys (Muridae, Rodentia) is one of the most common elements in the late Miocene to Early Pleistocene mammal faunas from the Ibero-Occitan region. Its geographic distribution is limited to this area with only two mentions in the late Miocene of Italy (de Giuli, 1989) and Algeria (Coiffait et al., 1985). The genus has been subject of numerous studies, some of them suggesting different interpretations on the phylogenetic relationships between the various described species (Gmelig-Meyling and Michaux, 1973; Cordy, 1978; Adrover, 1986; Bachelet and Castillo-Ruiz, 1990; Aguilar et al., 1993). The most extensive and significant study of the genus is the Ph.D. dissertation of Cordy (1976), who studied in detail several samples of Stephanomys, analyzed the changes observed in successive populations and defined four species (S. medius, S. michauxi, S. thaleri and S. progressus), which are considered as nomina nuda because this work was never published. Only one of these species, S. thaleri from the French locality of Seynes, was validated later by López-Martinez et al. (1998).

Chronological context, species occurrence, and environmental remarks on the Gelasian site Pedrera del Corral d’en Bruach (Barcelona, Spain) based on the small-mammal associations

“…The molars of Stephanomys progressus are slightly larger than those from Pedrera del Corral d'en Bruach. In addition, the M2 of S. progressus shows a clearly lessdeveloped t9 than the studied M2 does (Cordy 1976;Minwer-Barakat et al 2011). The Moreover, the large size ( as S. progressus.…”

“…We have revised some specimens of Stephanomys from Almenara-Casablanca 1 stored at the Institut de Paleoecologia Humana i Evolució Social (Tarragona, Spain) in order to clarify their determination. We have found that this material fits better with S. balcellsi than with S. progressus, as all the available M2s develop a t9, a diagnostic character that differentiates S. balcellsi from S. progressus (see Minwer-Barakat et al 2011). There is therefore an inconsistency in the identification of the descendant of S. balcellsi in the older site of Almenara-Casablanca 4.…”

“…The genus Stephanomys is a common murid in the Late Miocene to Early Pleistocene rodent faunas of the Iberian Peninsula and France. The anagenetic evolutionary line Stephanomys minor -Stephanomys balcellsi -Stephanomys progressus underwent an increase in size, stephanodonty and crown height through the Pliocene andearliest Pleistocene(Cordy 1976;Aguilar et al 1993a;Renaud et al 2005;Minwer- Barakat et al 2011). The descendant of S. balcellsi, i.e.…”

“…The descendant of S. balcellsi, i.e. S. progressus, is the most recent representative of the genus(Minwer-Barakat et al 2011). The oldest records of S.…”

Updating the Europe–Africa small mammal exchange during the late Messinian

“…However, some slight differences exist between S. dubari and S. numidicus , such as the occasional presence of an anterocentral cuspid (tma) in M 1 of S. numidicus (67% in the type population from Argoub Kemellal 1) and the size of M 2 and M 2 , which are slightly larger in S. numidicus . The Stephanomys lineage shows morphological and biometrical changes throughout the late Miocene, Pliocene and early Pleistocene, including an increase in size, an increase in crown height and better development of longitudinal connections in both upper and lower molars (Minwer‐Barakat et al ., , ). The transition between S. ramblensis and S. dubari can be recognized in the Granada Basin (García‐Alix et al ., ), where an increase in both size and height of the longitudinal connections can be seen in teeth from older to more recent sites.…”