Protadelomys lugdunensis, Hartenberger. We, 1969

Vianey-Liaud, Monique & Hautier, Lionel, 2022, Revision of the genus PRotadelomYS, a middle Eocene theridomyoid rodent: evolutionary and biochronological implications, Swiss Journal of Palaeontology (8) 141 (1), pp. 1-98 : 40

Comparisons between P. lugdunensis from the different localities and P cartieri

As the materiel of P. lugdunensis from Egerkingen most of the lower teeth of P. lugdunensis from Lissieu display obliquely aligned postprotocristid–ectolophid. Te main difference with the lower teeth of P. cartieri , as defined by Stehlin and Schaub (1951), corresponds to the absence of a mesoconid associated to a disruption of the distal ectolophid distally in P. cartieri . Te P4 are only slightly less reduced in P. lugdunensis than in P. cartieri , and the m3 are only slightly longer.

We have not confirmed that the lower p4 of P. lugdunensis from Laprade are less molarized than those of P.lugdunensis as previously considered (Sudre et al., 1990: 20). Tey have similar length and the protoconid is weak as in typical P. lugdunensis from Lissieu. Te P4 are not significantly narrower than typical P. lugdunensis ( Table 8), but similar in size to P. cartieri . Extra-ridges and granules are variably present as for the teeth from Lissieu, and the M3 are not significantly smaller than the M3 from Lissieu ( Tables 2, 3, 8). Tese features cannot support the idea that the teeth from Laprade, are more “primitive” than those from Lissieu (Sudre et. al.: 20), bearing in mind their limited number. It would rather be the opposite, some dental categories (p4, m1, m2) in Laprade being actually significantly larger than specimens from Lissieu ( Table 8), while dental size increase was often observed through the evolutionary history of these lineages (e.g., Escarguel, 1998; Vianey-Liaud & Marivaux, 2017).

In addition with the differential development of extra-ridges and granules, most of the morphological differences observed between P. lugdunensis and? P. alsaticus involve the lower teeth: in P. lugdunensis , the cusps seem more bulged, the entolophid is more continuous, the postprotocristid is fused to the mesoconid area (no distinct pre, meso and postmesoconid elements).