Asmithwoodwardia, 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 : 23

Asmithwoodwardia , sp. nov.

Figure 7B, C

This taxon is represented by an m1 or m2 (LIEB-PV 1613) from La Barda. It differs from Asmithwoodwardia scotti and A. subtrigona in labiolingual width and in the arrangement of the talonid cusps. The hypoconulid is central and posteriorly placed, while the hypoconulid of A. scotti and A. subtrigona are closer to the entoconid in m1–2. In the trigonid, a small paraconid is appressed against the mesiolabial side of the metaconid.

Asmithwoodwardia subtrigona Ameghino (1901) is represented by several isolated teeth from Laguna Fría and a larger sample from La Barda (fig. 7B, C). It is a small South American ungulate with a bunodont dentition and controversial systematic position. Asmithwoodwardia is represented by two species: A. scotti , from the Itaboraian of Brazil ( Paula Couto, 1952), and A. subtrigona , from the Vacan subage (Lower Casamayoran SALMA,?middle Eocene; Cifelli, 1983b) from Patagonia ( Ameghino, 1901; Simpson, 1948). However, McKenna and Bell (1997) suggested that Ernestokokenia , a larger Patagonian ungulate, is a junior synonym of Asmithwoodwardia (contra Simpson, 1948; Muizon and Cifelli, 2000). A. scotti is well represented by isolated teeth and an almost complete skull associated with the lower jaw. Instead, the type of A. subtrigona (MACN 10723) consists of two isolated teeth, an upper and a lower molar. Simpson (1948) regarded the upper molar of A. subtrigona as an M2 or possibly M3, while Paula Couto (1952) suggested that it was an M1 or M2. The specimens from La Barda are comparable to A. subtrigona and lead us to confirm that the type specimen is an M3 ( Gelfo and Tejedor, 2004). This taxon differs from A. scotti in its larger size, and in exhibiting conspicuous postparaconular and premetaconular cristae; the M3 is less transversally elongate, and it has a hypocone in M3. Despite the mentioned differences, the development of the hypocone of M3s in primitive bunodont ungulates seems highly variable.

Family Sparnotheriodontidae ( Soria, 1980b)

The Sparnotheriodontidae are considered basal forms of the Order Litopterna ( Soria, 1980b, 1989, 2001; Hoffstetter and Soria 1986; López, 1999). However, the systematic position of this family is also controversial. It has been referred to the Order Notoungulata ( Soria, 1980a; Marshall et al., 1983), Order Condylarthra ( Cifelli, 1983b; Mones, 1986), or placed as a subfamily of the Macraucheniidae ( McKenna and Bell, 1997) .

Gen. et sp. indet. G Figure 7D

Several specimens clearly referrable to the Sparnotheriodontidae were collected in Laguna Fría, including a right maxillary fragment (MLP 66-V-12-2; fig. 7D) with three molariforms (P4–M2?), right M3 (MLP 66-V- 12-1), and a broken left M1 or M2 (LIEB-PV 1615). These remains are comparable in size to Victorlemoinea labyrinthica Ameghino (1901) with some morphological differences (e.g., more reduced hypocone in the first molars and shorter lingual crest of the metaconid) indicating a possible attribution to a different taxon, probably related to Notolophus arquinotiensis Bond et al. (2006) .

Figures

Fig. 7. South American native ungulates from Laguna Fría (LF) and La Barda (LB). A, LIEB-PV 1612, Didolodontidae, gen. et sp. nov., right m2–3; B, Asmithwoodwardia subtrigona, LIEB-PV 1636, left M2; C, Asmithwoodwardia subtrigona, LIEB-PV 1617, right m2; D, Spartnotheriodontidae, Gen. et sp. indet. G, MLP-66-V-12-2, right maxillary fragment with three molariforms (P4–M2?) (LF); E, Henricosbornia lophofonta, LIEB-PV 1633, right maxilla with P4–M2 (LB); F, Othnielmarshia lacunifera, LIEB-PV 1618, right maxilla with M1–3 (LF); G, Edvardotrouessartia sola, LIEB-PV 1619; right maxilla with P2–4 (LF); H, Isotemnus sp., LIEB-PV 1646, right maxilla with P4–M3 (LF); I, Isotemnus sp., LIEB-PV 1659, left m2 (LF). Scale bar 5 1 mm.