Paleoecology of the mammalian carnivores (Metatheria, Sparassodonta) of the Santa Cruz Formation (late Early Miocene)

FRANCISCO J. PREVOSTI; MARCOS D. ERCOLI; GUILLERMO F. TURAZZINI

Early Miocene Paleobiology in Patagonia: high-latitude paleocommunities of the Santa Cruz Formation

Cambridge University Press

Año: 2012; p. 1 - 20

South America had an endemic mammalian fauna for much of the Cenozoic, largelyevolved during its long isolation. The predator guild was mainly occupied bymetatherians (Sparassodonta), as well as large terrestrial birds (Phorusrhacidae), agileterrestrial crocodiles (Sebecidae), and giant snakes (Madtsoiidae). Sparassodonta was adiverse clade, recorded from the Paleocene to the Middle Pliocene, with its acme in thelate Early Miocene (Santacrucian Age). In this chapter, we review the paleoecology ofthe sparassodonts known from the Santa Cruz Formation and include new resultsobtained by geometric morphometric analyses. The Santa Cruz Formation containseleven sparassodont species: six Hathliacynidae (Acyon tricuspidatus, Cladosictispatagonica, Sipalocyon gracilis, Sipalocyon obusta, Pseudonotictis pusillus,Perathereutes pungens) and five Borhyaenoidea (Prothylacynus patagonicus, Lycopsistorresi; and three Borhyaenidae: Borhyaena tuberata, Acrocyon sectorius, andArctodictis munizi). These sparassodonts were mainly hypercarnivores exhibitingdifferent locomotor abilities (from scansorial to terrestrial), and a wide range of body3masses (between 1 kg and more than 50 kg). The reconstruction of the Santacrucianpredator guild suggests that there was good ecological separation within thesparassodonts, determined by particular combinations of body size, locomotion and diet.The diversity of sparassodonts recorded in the Santa Cruz Formation (eleven species)and in the Estancia La Costa Member (seven species), is similar to that observed inpresent and past placental hypercarnivore communities.