Eomorphippus bondi, Wyss & Flynn & Croft, 2018

Wyss, André R., Flynn, John J. & Croft, Darin A., 2018, New Paleogene Notohippids and Leontiniids (Toxodontia; Notoungulata; Mammalia) from the Early Oligocene Tinguiririca Fauna of the Andean Main Range, Central Chile, American Museum Novitates 2018 (3903), pp. 1-44 : 4-5

Eomorphippus bondi , species novum

Figure 1

HOLOTYPE: SGOPV 3046 : partial skull preserving orbital rims, portions of both zygomatic arches, rostrum, and LI1–C, P3–M3; RI1–C, P3, M1–3.

PARATYPE: SGOPV 2891 , partial left lower dentition including i1–3 and p2–m3, plus remnants of the right dentition, including i1 and molds and external (labial) slivers of some posterior cheekteeth .

TENTATIVELY REFERRED SPECIMEN: SGOPV 3085, labiolingually crushed right?p4–m1.

TYPE LOCALITY: The type, paratype, and tentatively referred specimen all derive from volcaniclastic sediments currently mapped as belonging to the Abanico (= Coya-Machalí) Formation in the Tinguiririca River valley (~35° S), in the Andean Main Range of central Chile, some 7 km west of the international boundary. (Geologic maps dating from before the late 1980s mistakenly identified these deposits as belonging to the Cretaceous Colimapu Formation; Charrier et al., 1996.) All specimens described below were recovered from 35°–50° west-dipping strata, north of an unnamed 2738 m pass (indicated on the topographic sheet; Anonymous, 1985), approximately 3 km south of the town of Termas del Flaco, at what is termed the “main locality” in Charrier et al. (1996: fig. 6) .

AGE: Early Oligocene (to potentially late Eocene), Tinguirirican SALMA. The diverse Tinguiririca Fauna recovered from near Termas del Flaco, of which the notohippids are an important constituent, formed the basis for the formalized Tinguirirican SALMA (Flynn et al., 2003), which lies temporally between the Mustersan and Deseadan of the classical SALMA sequence. An extensive series of isotopic dates (summarized in Flynn et al., 2003) have been generated for strata hosting and underlying the Tinguiririca Fauna, indicating that E. bondi and its contemporaries described below are no younger than ~31.5 million years old (early Oligocene) and could be ~1–2 million years older (Bradham et al., 2015).

ETYMOLOGY: In honor of Mariano Bond, for his enormous and influential contributions to the understanding of notoungulate phylogenetics and taxonomy.

DIAGNOSIS: Eomorphippus bondi generally resembles E. obscurus , differing from the latter mainly in being roughly 20% larger in most dental dimensions, in having a slightly smaller upper canine, and in having an I3 that is substantially wider than both I1 and I2.

Figures

FIGURE 1. Photographs of cast, and line drawings of holotype of Eomorphippus bondi, SGOPV 3046, a partial skull bearing left I1–3, C, P3–M3 and right I1–3, P3, M1–3, in A, left lateral, B, C, occlusal, and D, anterior views (opposite page). Horizontal ridge in anterior view is a seam from the two-piece mold. Note hypsodonty of the incisors and narrowness of molars. Paratype of Eomorphippus bondi, SGOPV 2891, showing partial left lower dentition including i1–3 and p2–m3, in E, occlusal and F,labial views (above; photograph of cast).