Democricetodon sp. 2

Jovells-Vaqué, Sílvia, Ginestí, Montserrrat & Casanovas-Vilar, Isaac, 2017, Cricetidae (Rodentia, Mammalia) From The Early Miocene Site Of Els Casots (Vallès-Penedès Basin, Catalonia), Fossil Imprint 73 (1 - 2), pp. 141-154 : 146

Democricetodon sp. 2

Pl. 1, Fig. 6

1993 Fahlbuschia sp. ; Agustí and Llenas, p. 70 (partim).

M a t e r i a l. 1 m 1 (IPS 45052) (Pl. 1, Fig. 6) from els

Casots level 73.

M e a s u r e m e n t s. L = 1.67, W = 1.08.

D e s c r i p t i o n. m1. This specimen has two roots: a cylindrical one located under the anteroconid and distal one which is flattened. The anteroconid is simple and rounded. The anterior valleys are narrow, specially the anterosinusid, and closed by the well-developed arms of the anterolophulid. The metalophulid is short and reaches the longitudinal ridge anteriorly to the protoconid. The mesolophid is long and reaches the lingual margin of the teeth. The mesosinusid is closed by a low cingulid. The sinusid points markedly forwards and is closed by a low cingulid which emerges from the base of the protoconid and reaches the hypoconid. The hypolophulid is simple and merges with the hypoconid anteriorly. Finally, the posterolophid is thick and reaches the base of the entoconid, thus enclosing the posterosinusid.

D i s c u s s i o n. Agustí and Llenas (1993: 70) reported a few larger-sized lower molars from els Casots 73 that they tentatively attributed to a “primitive form of Fahlbuschia of small dimensions”. Amongst the studied specimens, only the described m1 appears to be above the size range of Democricetodon hispanicus ( Text-fig. 2 ), being slightly larger than the type material of Fahlbuschia decipiens from Bunyol (Valencia; Daams and Freudenthal 1974, Freudenthal and Daams 1988). Van der Meulen et al. (2003) consider Fahlbuschia MEIN et FREUDENTHAL, 1971 a junior synonym of Democricetodon (but see Freudenthal (2006) for a different taxonomic opinion) and propose emended diagnoses for several species of this genus. Their emended diagnosis for D. decipiens stresses its larger size as compared to D. hispanicus and predominantly short mesolophs and mesolophids ( Van der Meulen et al. 2003: 429). The described m1 shows a long mesolophid comparable to that of D. hispanicus specimens from the same site and is slightly larger than D. decipiens, being closer in size to D. moralesi VAN DER MEULEN, PELÁEZ- CAMPOMANES et DAAMS, 2003 or D. koenigswaldi ( Van der Meulen et al. 2003). However, in these species the mesolophid is generally even more reduced than in D. decipiens. Unfortunately, the diagnosis of Democricetodon species requires of sufficient material in order to evaluate the variation in features such as the length of the mesoloph/id or the morphology of the protolophule/ metalophule in the upper molars (see Maridet 2003, Van der Meulen et al. 2003). Clearly the material from els Casots 73 does not allow for such assessment, so it is therefore ascribed to a second, larger-sized Democricetodon species. Further material could clarify its taxonomical attribution and provide valuable biostratigraphic information.

Figures

Text-fig. 2. Length/width scatter plot for the molars of Democricetodon hispanicus and D. decipiens from different Spanish sites. Locality acronyms are as follows: BU = Bunyol; CMV3 = Can Martí Vell 3; CS72 = els Casots level 72; CS73 = els Casots level 73; CS74 = els Casots level 74; LCV1 = Les Cases de la Valenciana 1; SR1 = San Roque 1; SR2 = San Roque 2. Data for SR1 and SR2 taken from Freudenthal and Daams (1988), data for BU taken from Daams and Freudenthal (1974).