A new early Pliocene murine rodent from the Iberian Peninsula and its biostratigraphic implications

PIÑERO, P.; VERZI, D.H.

Congreso; 2nd Palaeontological Virtual Congress; 2020

In the last years, a murid identified as Paraethomysaff. abaigari, has been repeatedly recognizedin several early Pliocene localities of the IberianPeninsula. We have revised all these occurrencesand suggest that these records correspond to anew species. The sample from Baza-1 (Guadix-BazaBasin, Andalusia, Spain) represents the largestand most complete sample of this novel speciesrecorded thus far. Therefore, we characterize Paraethomyssp. nov. based on this sample. It is amedium-sized representative of the genus, withhigh t6?t9 and low t4?t8 connections in the M1;distal spur in t1 and t3 in the M1 and to a lesserextent in the M2; the t9 is absent in the M2; the m1generally lacks a tma and shows a round islet ofenamel between the anteroconid and the protoconid-metaconid, reduced longitudinal spur, andmoderate labial cingulum with large c1. The newspecies differs from the other described Europeanmembers of Paraethomys mainly in its size,which is intermediate between that of the smallsizedParaethomys meini and the large-sized Paraethomysabaigari. In addition, the size and relativewidth are smaller than those of Paraethomysjaegeri. The grade of development of the posteriorspurs in the t1 and t3 in the M1 and M2 ishigher than that of P. meini and lower than thatof P. abaigari and P. jaegeri. Paraethomys sp. nov.represents a significant biostratigraphic markersince it is restricted to levels of late early Ruscinianage (upper part of the MN14 unit). Thus, thisspecies is useful for establishing divisions withinthe early Ruscinian, and becomes a characteristictaxon for the early Pliocene terrestrial record ofthe Iberian Peninsula.