1. Microwear of other groups(Townsend & Croft, 2008; McGrath et al., in prep.) Santa Cruz toxodonts (larger notoungulates) were “dirty” browsers Semi-arid forest or shrubland Paleobotany (Brea et al., 2012) Evidence from phytoliths, fossilized wood and leaves, microcharcoal Mixed habitat of open semi-arid forests and humid warm-temperate forests Seasonal precipitation limited plant growth Composition of animal community (Kay et al., 2012) Based on proportion of arboreal species, frugivorous species, average body size, presence of certain amphibians and reptiles 1000-1500 mm of precipitation per year Mixture of temperate humid and semi-arid forests Geologic (Blisniuk et al., 2005; Kay et al., 2012) Paleosols, Andes uplift Seasonal rainfall higher than today Reconstructing the Paleoenvironment of the Santa Cruz Formation, Argentina Using Typothere (Notoungulata: Mammalia) Microwear Andrew J. McGrath Dept. of Paleobotany and Paleoecology, Cleveland Museum of Natural History, 1 Wade Oval Dr., Cleveland, OH 44106 I would like to thank the Kirtlandia Society for providing the funding necessary for this project. I would also like to thank Dr. Darin Croft, Dr. Denise Su, and Paulette Hughes for their assistance and support. What is Enamel Microwear? Results Acknowledgements Typotheres Santa Cruz Formation Sample tooth (Moschus moschiferus) showing pits (black) and scratches (white) Browser--Arabian Camel (Camelus dromedarius) Mixed Feeder--Grant’s Gazelle (Nanger granti) Grazer--Waterbuck (Kobus ellipsiprymnus) Conclusions Other Evidence ProtypotheriumPachyrukhos HegetotheriumInteratherium 400 µm Vizcaíno et al., 2012 Southeastern Argentina (Santa Cruz province) ~18-16 Ma (Early Miocene) Santacrucian SALMA (South American Land Mammal Age) Among the best-known Miocene sites in South America Studied since 19 th century >70 mammal species described Protypotherium australe from Scott, 1932 Members of extinct South American ungulate order Notoungulata Eocene-Pleistocene (56 Ma-13 Ka) Filled niches of large rodents, rabbits, small ungulates ~6 families currently recognized In this study: Hegetotherium (Hegetotheriidae) Interatherium (Interatheriidae) Pachyrukhos (Hegetotheriidae) Protypotherium (Interatheriidae) Small markings left by food on teeth Pits and scratches are primary features Other features can provide additional information Markings influenced by differences in diet Grazer (primarily grass) Browser (primarily leaves) Fruit Browser Can reveal environmental conditions Precipitation? Seasonal? Fossilized Nothofagaecae from Brea et al., 2012 Mixed habitat of trees, grasses, shrubs Microwear, paleobotanic, ecologic, geologic evidence Grasslands and grass-filled woodlands Pachyrukhos and Protypotherium were likely grazers Low-lying bushes likely present Interatherium and Hegetotherium were likely non-arboreal browsers Semi-arid conditions High pit counts likely caused by dust settling on leaves Related to seasonal rainfall? Similar to modern Chilean chaparral Grazer Mixed Feeder Fruit Browser Browser Rooter Interatherium Hegetotherium Protypotherium Pachyrukhos Compared to 59 modern ungulates Photos taken at 35x magnification