Protodidelphis, 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 : 9-10

Protodidelphis , sp.

Two isolated lower molars (LIEB-PV 1092, isolated left m?1; LIEB-PV 1142, isolated left m?3) clearly differ from the other Protodidelphis specimens recorded in Paso del Sapo. These came from La Barda and are about twice the size of Protodidelphis , sp. nov. One of them, LIEB-PV 1092, is strongly worn, but the talonid appears to be shorter than in other species of Protodidelphis , and the hypoconid is less projecting labially. The other molar, LIEB-PV 1142, differs in a few details (i.e., more projecting hypoconid, paraconid closer to the metaconid, protoconid more robust), but it is certainly from a different locus in the molar series. However, both molars are assigned to Protodidelphis on the basis of their bunoid pattern, well-developed entoconid, relatively low paraconid, reduced hypoconid, and anterobasal cingulum. Because of the size and morphology of the talonid, they cannot be referred to any Protodidelphis species known up to now, including those listed above.

Family Derorhynchidae Marshall, 1987 Genus Pauladelphys Goin et al., 1999 Pauladelphys , sp. nov. Figure 3E

This new species of Pauladelphys is well represented by dentition, maxillae, and mandibles mostly from Laguna Fría and a few specimens from La Barda. It differs from Pauladelphys juanjoi , from the Antarctic Peninsula, in several features of the molar series. The lower molars have a cristid obliqua more parallel to the dental axis; paraconid less reduced and anteroposteriorly compressed; anterobasal cingulum narrower; labial slope of the entoconid almost flat (LIEB-PV 1123, fragment of right dentary with complete m2; fig. 3E). Upper molars show a larger metaconule; StB less posteriorly placed; paracone farther from the StB. This is a fully tribosphenic taxon in which the molars are sharply crested. All stylar cusps are present; StB is sometimes very large; the centrocrista is V-shaped. The stylar shelf is elevated above the talon basin. The paraconule is present, but small and variably winged; the metaconule is larger and also variably winged. The lower molars also are fully tribosphenic and crested, with the cusps subpyramidal. This new species of Pauladelphys is almost equal in size to the type species of the genus. However, several traits (e.g., StB less displaced posteriorly, less reduced and compressed anteroposteriorly paraconid) suggest that Pauladelphys sp nov. is more generalized that P. juanjoi .

Genus Derorhynchus Paula Couto, 1952

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).