The Earliest Known Fossil Ant (First Southern Hemisphere Mesozoic Record) (Hymenoptera: Formicidae: Myrmeciinae)

Social insects are scarce in Cretaceous deposits. Sphecomyrma freyi Wilson & Brown (1967) was the first fossil ant assigned to the Mesozoic. The wingless holotype and paratype were found embedded in amber at Cliffwood, New Jersey, U.S.A. (Magothy Formation). This formation was at the time referred to the lower part of the Upper Cretaceous (Turonian--Coniacian), presumably deposited not long after mid-Cretaceous times, about 100 million years ago (Wilson et al., 1967). S. freyi was described as the typespecies of the only genus of a new subfamily of Formicidae, Sphecomyrminae. These deposits have been recently redated as Santonian or even early Campanian, circa 80 million years ago (Zherikhin, 1978 apud Dlusskyi, 1983). Dlusskyi (1975 apud Dlusskyi, 1983) described Cretomyrma and Paleomyrmex, respectively, from a worker and a male, found in fossil tars at Yantardakh, .Tamyr Peninsula (extreme north-central Siberia), both of approximately the same age as Sphecomyrmafreyi (Late Santonian) and assigned to the Sphecomyrminae. Four other Cretaceous genera, described in the same publication (Cretopone, Petropone, Archaeopone and Dolichomyrma)were found in southern Kazakstan (Kzyl-Dzhar) in considerably older beds (Turonian). The first three genera named were originally considered to belong to the extant subfamily Poiaerinae. Dlusskyi (1983) studied 13 very well preserved impressions tentatively interpreted as ants, found in the Ten’ki district of the Magadan region (extreme eastern Siberia), Ol’skaya Formation