“…It led to the publication of a monograph (Campbell, 2004), mainly focusing on mammals, that described rodents (Frailey and Campbell, 2004), marsupials (Goin and Candela, 2004), a possible gondwanathere , bats (Czaplewski and Campbell, 2004), and notoungulates (Shockey et al, 2004). It also yielded cingulate xenarthrans, described by Ciancio et al (2013), and the earliest and basalmost South American primate described thus far (Bond et al, 2015). In the absence of any temporal constraint other than mammalian biochronology (which has been difficult given that most Santarosan taxa are unique to that site), the age of this locality remains unclear: it may be either "?late Eocene" (e.g., Bond et al, 2015) or, more probably, early Oligocene (Shockey et al, 2004;Croft et al, 2009: 197;Antoine et al, 2012;Kay, 2015).…”