Incertae sedis, Tejedor & Goin & Gelfo & López & Bond & Carlini & Scillato-Yané & Woodburne & Chornogubsky & Aragón & Reguero & Czaplewski & Vincon & Martin & Ciancio, 2009

Tejedor, Marcelo F., Goin, Francisco J., Gelfo, Javier N., López, Guillermo, Bond, Mariano, Carlini, Alfredo A., Scillato-Yané, Gustavo J., Woodburne, Michael O., Chornogubsky, Laura, Aragón, Eugenio, Reguero, Marcelo A., Czaplewski, Nicholas J., Vincon, Sergio, Martin, Gabriel M. & Ciancio, Martín R., 2009, New Early Eocene Mammalian Fauna from Western Patagonia, Argentina, American Museum Novitates 3638, pp. 1-43 : 9

Family Incertae sedis

Gen. et sp. nov. 3 Figure 3C

Several upper and lower molars of this new taxon were collected at both localities of Paso del Sapo. The molars are brachydont and bunodont. Upper molars (e.g., LIEB-PV 1097, a left M3; fig. 3C) have a robust protocone, StB and StD relatively conical, vestigial ‘‘StC’’, poorly developed ectoflexus, and conules not winged. The centrocrista is linear and low. As in peradectians, there is no difference between the relative height of the stylar shelf and the trigon basin. The lower molars have a reduced anterobasal cingulum and a reduced hypoconulid, and they lack a postcingulum. Trigonid and talonid are subequal in length. The talonid basin is wide and entoconid and hypoconid are subequal in height and development; the hypoconulid is small. The wide trigon and talonid basins and the robust protocone suggest a strong adaptation toward grinding. Judging from this morphology, this new taxon exhibits an omnivorous, or omnivorous-frugivorous adaptation.

Family Protodidelphidae Marshall 1987 Protodidelphis , sp. nov. Figure 3D

This new species of Protodidelphis is well represented by several lower and upper isolated teeth from La Barda. It differs from other species of the genus mostly in its smaller size and less bunoid aspect. The upper molars (e.g., LIEB-PV 1097, a left M3; fig. 3D) have a well-developed metaconule and the crest joining the StB and StD is straight, unlike the Itaboraian species of the genus. The lower molars have a hypoconulid slightly more developed in m3–4 than in other Protodidelphis species. The overall crown surface is simple and devoid of cluttering crests; the stylar region is not specialized for ‘‘crowding’’ against the paracone and metacone; the centrocrista is linear and there is no special elevation of the stylar shelf relative to the talon surface. The lower molars have normal trigonid vs. talonid proportions; the paraconid is not reduced or otherwise specialized as to size or location; the metaconid and entoconid do not develop strong opposing crests; the entoconid is basically conical and isolated; the hypoconulid is located near, but isolated from the entoconid, and connected to the hypoconid.

Figures

Fig. 3. Marsupials from Laguna Fría (LF) and La Barda (LB). A, Peradectidae gen. et sp. nov., LIEB- PV 1031 (LF); B, Caroloameghiniidae gen. et sp. nov., LIEB-PV 1098 (LF); C, Peradectoidea gen. et sp. nov., LIEB-PV 1097, left M3 (LB); D, Protodidelphis sp. nov., LIEB-PV 1091, left M?3 (LB); E, Pauladelphys sp. nov., LIEB-PV 1123, m2 in a fragment of right dentary (LF); F, cf. Itaboraidelphys sp., LIEB-PV 1064, an isolated right m2 or m3 (LF); G, Paucituberculata gen. et sp. nov. 1, LIEB-PV 1135, a left maxillary fragment with M2–3 and part of M4 (LF); H, Sparassodonta, Hathliacynidae, gen. et sp. nov. LIEB-PV 1036, M?3 in a maxillary fragment (LF); I, Eomicrobiotherium sp., LIEB-PV 1040, a right m?3 (LF); J, Palangania sp., LIEB-PV 1106, left M?3 (LB); K, Gashternia ctalehor, LIEB-PV 1132, a right M4 (LB).