Astrapotheria, Lydekker, 1894

Fernández, Mercedes, Zimicz, Ana N., Bond, Mariano, Chornogubsky, Laura, Arnal, Michelle, Cárdenas, Magalí & Fernicola, Juan C., 2021, New Eocene South American native ungulates from the Quebrada de los Colorados Formation at Los Cardones National Park, Argentina, Acta Palaeontologica Polonica 66 (1), pp. 85-97 : 87

Astrapotheria indet.

Fig. 1B .

Material.—IBIGEO-P 66, left maxillary fragment with three broken molariforms, Quebrada Grande, Los Cardones National Park, Casamayoran SALMA, Eocene.

Description.—The three molariforms of IBIGEO-P 66 exhibit long roots that can be easily identified due to the breakage of the maxilla ( Fig. 1B 1 ), and are subrectangular in outline ( Fig. 1B 3 ). Their occlusal surfaces are poorly preserved. Nevertheless, it is possible to recognize the dental enamel distributed in vertically oriented Hunter-Schreger bands ( Fig. 1B 4), which is a remarkable feature in all astrapotheres, which is particularly evident on the slightly undulated fragmented ectoloph of the last tooth. These three molariforms show a closer size to Albertogaudrya (see Carbajal et al. 1977), but the poor preservation of the occlusal surface of the specimen does not allow achieving a more specific taxonomic identification, which is the reason why it is identified as Astrapotheria indet.

Remarks.—During the Eocene, the astrapotheres are represented in Northwestern Argentina by Albertogaudrya ? carahuasensis Carbajal, Pascual, Pinedo, Salfity, and Vucetich, 1977 , which has been collected in levels of the lower section of Lumbrera Fm. at La Comarca de Carahuasi, Salta (Carbajal et al. 1977), and an Astrapotheriidae indet. from the Geste Fm. at Antofagasta de la Sierra ( López 1997).

Figures

Fig. 1. New fossil materials of Litopterna,Astrapotheria, and Notostylopidae from the Quebrada de Los Colorados Formation exposed at Quebrada Grande locality, Los Cardones National Park (Salta Province), Casamayoran SALMA, Eocene. A. cf. Ernestokokenia sp. (IBIGEO-P 65), fragmented left upper cheek tooth in occlusal view.B.Astrapotheria indet.(IBIGEO-P 66), left maxillary fragment with three broken molariforms in lingual (B1) and occlusal (B3) views, and detail showing Hunter-Schreger bands (B4); dashed area in B2 indicates broken or missing dental areas. C. Homalostylops sp. (IBIGEO-P 57b), right m2? in occlusal (C1), lingual (C3), and labial (C4) views. D.?Homalostylops sp. (IBIGEO-P 57a), left m1? in occlusal view. Photographs (A1, B1, B3, B4, C1, C3, C4, D1), explanatory drawings (A2, B2, C2, D2).

Fig. 3. New fossil specimens of Typotheria and Toxodontia from the Quebrada de Los Colorados Formation exposed at Quebrada Grande locality, Los Cardones National Park (Salta Province), Casamayoran SALMA. A, B. Colbertiasp. A. IBIGEO-P 58a, left maxillary fragment with M2–M3 in occlusal view.B. IBIGEO-P 58b, left maxillary fragment with P4–M3 in occlusal view.C–E. Pampahippus secundus Deraco and García-López, 2016. C. IBIGEO-P 62, right trigonid and incomplete talonid of a lower right molar in occlusal view. D. IBIGEO-P 63, fragmented left p3 or p4 in occlusal view. E. IBIGEO-P 64, left m1? in occlusal (E1), labial (E2), and lingual (E3) views. Photographs (A1–E1, E3, E4), explanatory drawings (A2–E2). Dashed area indicates broken or missing dental areas.