Eomys Schlosser 1884
Description
Genus Eomys Schlosser, 1884
TYPE SPECIES. — Eomys zitteli Schlosser, 1884 by monotypy.
REMARKS
Ŋe few eomyid teeth are assigned to Eomys based on their uninterrupted mure or ectolophid, contrary to Eomyodon Engesser, 1987, Rhodanomys Depéret & Douxami, 1902 or Pseudotheridomys Schlosser, 1926, and on the well-marked cusps contrary to the three latter genera.
Eomys aff. zitteli Schlosser, 1884 (Fig. 14 A-D)
MATERIAL AND MEASUREMENTS (in mm). — One P4 SPV 180: 0.92 × 0.99; one M1-2 SPV 181: 0.86 × 1.08; one p4 SPV 185: 1.00 × 0.89; one ml-2 SPV 184:1.04 × 1.09; one digested lower tooth row m1-m3 SPV 183.
DESCRIPTION AND DISCUSSION
Ŋese isolated teeth are brachydont. P4 has a weak antesinus, a reduced anterosyncline due to the direct connection of the paracone nearly to the labial end of the anteroloph, and a short mesoloph. On M1-2, the protoloph is present and the anterosyncline longer than in P4. Ŋe mesoloph is halflong.
Teeth are of greater size than those of Eomys antiquus Aymard, 1853. Ŋe size of the two molars falls into the variations of the small population of Eomys aff. zitteli from Mas-de-Pauffié (Comte & Vianey-Liaud 1987), the two premolars being a little smaller. Ŋe morphology of the teeth of Saint Privat-des-Vieux is also close to that seen in Eomys zitteli.
A fragment of a left dentary bearing m1-3 is much damaged, pecularly m1. It belongs to a species of smaller size (notably its width) than Eomys zitteli. Ŋe measurements (m1: [0.99 × 0.71 mm]; m2: [0.97 × 0.90 mm]; m3: [0.81 × 0.83 mm]) are of the same order as those of the corresponding teeth in Eomys antiquus and Eomys minor Comte & Vianey-Liaud, 1987. Ŋe occurrence of a form close to Eomys zitteli (supposed to be derived from Eomys antiquus) at Saint Privat-des-Vieux as well as at Mas-de-Pauffié, would lead to refer this small form to another species, Eomys minor. However, the presence of a long mesolophid on m2 does not match the morphology (no mesolophids) of the type of Eomys minor. As the variability of the latter is obviously unknown, we could refer the specimen of Saint Privat-des-Vieux to Eomys minor, known in the locality Belgarric1 (Tarn-et- Garonne, MP 25) and La Blache (Maridet et al. 2010), but it could better represent an extreme variant of E. aff. zitteli.
However, new eomyids were collected in Mas-de- Pauffié:two upper teeth (M2 [0.79 × 1.09 mm] and M3 [0.77 × 0.98 mm]; Fig. 14E, F) can be more clearly referred to Eomys minor. Ŋeir sizes are compatible with that of the lower teeth of E. minor. Ŋe mesoloph is short on M2, and this morphology can correspond to lower molars without mesolophid; such upper teeth are also described from La Blache.
Notes
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Linked records
Additional details
Identifiers
Biodiversity
References
- ENGESSER B. 1987. - New Eomyidae, Dipodidae, and Cricetidae (Rodentia, Mammalia) of the Lower Freshwater Molasse of Switzerland and Savoy. Eclogae Geologicae Helvetiae 80: 943 - 994.
- MARIDET O., HUGUENEY M. & HEISSIG K. 2010. - New data about the diversity of Early Oligocene eomyids (Mammalia, Rodentia) in Western Europe. Geodiversitas 32 (2): 221 - 254. http: // dx. doi. org / 10.5252 / g 2010 n 2 a 3