On the identity of † Protrechina Wilson:

Wilson (1985) described a genus putatively close to Paratrechina sensu lato (∼ Prenolepis genus group) from mid-Eocene Claiborne amber (Arkansas, 40.4–37.2 Ma; Saunders et al., 1974). This genus, † Protrechina, supposedly differs from Paratrechina s. l., Lepisiota Santschi and Brachymyrmex Mayr – among other, unstated formicines – by the absence of standing macrosetae on the mesosomal dorsum, a state similar to that observed for Metalasius gen.nov. as noted below. The genus has been variably treated as a lasiine (Bolton, 1994, 1995; LaPolla & Dlussky, 2010), a ‘prenolepidine’ (Hölldobler & Wilson, 1990), or as incertae sedis in the subfamily where it remains at present (Wilson, 1985; Dlussky & Fedoseeva 1988; Bolton, 2003; Ward et al., 2016). The type specimen of † Protrechina carpenteri Wilson, at the Museum of Comparative Zoology (Harvard), should be reexamined to evaluate its tribal, and perhaps generic, placement. This would be particularly valuable given the approximately mid-Eocene origin of the Prenolepis genus group here inferred (Fig. 4; Table 5); such a study will be facilitated by use of micro-CT (e.g., Hita-Garcia et al., 2017; Barden et al., 2017b; Boudinot et al., in press), given the poor condition of the specimen reported by LaPolla & Dlussky (2010).