Saskomomys, Perry & Dutchak & Theodor, 2023

Perry, Jonathan M. G., Dutchak, Alex R. & Theodor, Jessica M., 2023, New primates from the Eocene of Saskatchewan: Revision of the primates from the Cypress Hills Formation with description of new taxa, Palaeontologia Electronica (a 20) 26 (2), pp. 1-19 : 11-13

Saskomomys , new genus

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Type species. Saskomomys lindsayorum , new species. Figure 10 . Tables 2 and 3.

Diagnosis. Differs from Omomys in being smaller in occlusal area of all compared teeth and in the following: p4 with indistinct metaconid, crest emitting from protoconid buccally oriented, linguallyseated paraconid, and short talonid that rises quite dorsally at its distal end; m1 and m2 narrower; m3 broader, with more rounded cusps, with paraconid located centrally; M1 less well-developed hypocone shelf; M2 more convex mesial margin and deeper notch at distal margin; M3 less triangular (i.e., more extensive hypocone shelf), relatively less extensive expansion of the base of the protocone lingually, lingual cingulum continuous or nearly so. Differs from Chumashius in having no distinct metaconid on p4, crest running from protoconid runs buccally rather than distobuccally, less lingually projecting paraconid; m1 and m2 narrower, less well-developed buccal cingulid; m3 hypoconulid lobe more isolated (i.e., constricted at its mesial end), trigonid longer at lingual side and more rounded mesially; M2 narrower (especially at protocone), greater extent of hypocone, more distinct conules, more distinct buccal cingulum. Differs from Dyseolemur in having less basal inflation and crenulation on the lower molars and in lacking a metastylid and the fovea separating the metastylid from the metaconid; m3 has more isolated hypoconulid lobe; M1 and M2 have smaller hypocone, conules, and buccal cingulum, with less-distinct crests emitting from the conules lingually; M3 has less-distinct buccal cingulum and is more triangular in outline (narrower at protocone than at buccal cusps). Differs from Ekwiiyemakius in having a shorter and broader p3 and m3; more constriction mesial to the hypoconulid lobe on m3; M1 buccal notch is more pronounced (deeper and narrower); M1 and M2 trigon basin and hypocone shelf are broader; M3 is longer (mesiodistal dimension).

Etymology. Prefix ‘ Sask– ’ in reference to the distribution of the taxon in the province of Saskatchewan. Suffix ‘– omomys ’ (Greek, “shoulder-mouse”) refers to omomyoid primates generally.

Figures

FIGURE 10. Stereo pairs of upper molars of Saskomomys lindsayorum from the Swift Current Creek locality. A: RSM P3450.1470, a left M1. B: RSM P3450.1471, a right M3. Scale bar is 1 mm long.