Protophiomys, JAEGER, DENYS & COIFFAIT, 1985

Jaeger, Jean-Jacques, Marivaux, Laurent, Salem, Mustapha, Bilal, Awad Abolhassan, Benammi, Mouloud, Chaimanee, Yaowalak, Duringer, Philippe, Marandat, Bernard, Métais, Eddy, Schuster, Mathieu, Valentin, Xavier & Brunet, Michel, 2010, New rodent assemblages from the Eocene Dur At-Talah escarpment (Sahara of central Libya): systematic, biochronological, and palaeobiogeographical implications, Zoological Journal of the Linnean Society 160 (1), pp. 195-213 : 204-205

GENUS PROTOPHIOMYS JAEGER, DENYS & COIFFAIT, 1985

Type species: Protophiomys algeriensis Jaeger et al., 1985 .

Included species: Protophiomys durattalahensis sp. nov.

Distribution: Late middle Eocene of eastern Algeria (Nementcha mountains) to central Libya (Dur At-Talah desert).

Emended generic diagnosis: Phiomyid with moderately low cusps and crests on cheek teeth, showing upper molars with an incipient or achieved pentalophodont pattern [depending on the degree of development of the mesoloph (-ule)]. Protophiomys differs from Talahphiomys gen. nov. in showing a better development of the transverse crests and less bunodont tubercles on both upper and lower molars. Differs from Phiomys and Metaphiomys in having slightly more bulbous cusps and cuspids, its upper molars characterized by the absence of the metaloph– posteroloph connection, a weak development of the mure, which can be either lacking or incomplete, a very narrow or shallow internal sinus often closed lingually by the remains of an endoloph, and by a tendency to develop a buccal wall because of a mesiodistal enlargement of the paracone, mesostyle, and metacone. Lower molars in Protophiomys have a stronger hypoconulid, and differ also in the development of a lingual wall, which consists of a mesiodistal enlargement of the metaconid by way of its strong and elevated posterior arm, a strong mesostylid, a strong entoconid (that is connected both to the mesostylid and to a long posterolophid). Lower molars in Protophiomys differ also from those in Phiomys in lacking a completely developed mesolophid, and from those in Metaphiomys in lacking the metalophulid II and the anterior cingulid.

Differs from South Asian baluchimyines ( Baluchimys , Lindsaya , Hodsahibia , and Bugtimys , except Lophibaluchia ) in showing a reduction of the central cups (= metaconule) on upper molars, and in lacking the anterior cingulid on lower molars. Differs from Hodsahibia and Bugtimys in showing upper molars with a very narrow lingual sinus, and lower molars lacking the metalophulid II, and in having a lingual enamel wall. Differs from Lophibaluchia in being lower crested, in having a complete metaloph connected to the metaconule, and in lacking the transverse sinus on upper molars.