Perrichot et al. (2019): Peruvian amber comes from amber-rich grey lignitic clays exposed on the eastern bank of the Amazon River in the Tamshiyacu locality, 30 km upstream of Iquitos in northeastern Peru (Antoine et al., 2006), assigned to the Pebas Formation (Crassoretitriletes zone, middle Miocene, 15-12 Ma; Hoorn, 1994). These clays are typical of the Pebas Mega-wetland System that existed before the onset of the modern Amazon River basin (Wesselingh et al., 2002; Hoorn et al., 2010). The Pebas System consisted of interconnected shallow lakes and swamps, under a marine influence, covering over 1 million km2 in Western Amazonia, and it formed a cradle of speciation for both invertebrates (Hoorn & Vonhof, 2006; Wesselingh et al., 2006; Boonstra et al., 2015) and vertebrates (e.g., Salas-Gismondi et al., 2015; Antoine et al., 2016, 2017). Its unique situation in the Western Amazonia provides the record of an intertropical entomofauna prior to the land connection with Central and North America which occurred in the latest Miocene Pliocene (Gingras et al., 2002; Coates et al., 2004; Antoine et al., 2006; Petrulevičius et al., 2011; Perrichot et al., 2014). Miocene fossil insects are otherwise unknown in South America.
Less than 30 amber chunks have been collected from this deposit; thus the diversity of the fossil arthropod fauna is quite low although significant already (Antoine et al., 2006). Two ants have been found among the hexapods identified. One is only fragmentary, preserved by the head capsule without mouthparts and antennae, and represents an undetermined genus; the other one, complete, is described herein in the subfamily Dolichoderinae.