autapomorphy for Tatuidris described by Keller (2011) was the position of the antennal socket, which, in this genus, sits upside-down on the roof of the frontal lobe. Such position of the antennal sockets is easily recognizable when ants are viewed with head in full-face view as small “blisters”. A closer examination of this character among other ant genera suggests that Phalacromyrmex, an ant genus traditionally associated with Tatuidris, may present this character as well (Figure 14). Here I hypothesize that further re-examination of this character as well as analysis of molecular characters of Phalacromyrmex will likely shed light on the origin and phylogenetic status of Tatuidris. FIGURE 14. Lateral-diagonal view of head of Phalacromyrmex sp., from Brazil, showing position of antennal sockets on head capsule. In Phalacromyrmex, the antennal socket is located up-side down in a way similar to that of Tatuidris. Photo courtesy of R. Feitosa. Acknowledgements Frank Azorza, Michael Branstetter, Stefan Cover, Thibaut Delsinne, Augusto Enriquez, Brian Fisher, Justine Jacquemin, Jack Longino, Bill Mackay, Patricia Rojas, Alex Smith and Phil Ward loaned valuable specimens. Additionally, specimens collected in the Area de Conservacion de Guanacaste were under the support of a Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant to M. Alex Smith and under permits ACG-PI-001-2010 and ACG-PI-035-2010. Stefan Cover, Gary Alpert, Allison Schellhammer and an Ernst Mayr travel grant in Animal Systematics (Harvard University) provided logistic and financial support that made possible a visit to the MCZC. Details on the first live observations of Tatuidris specimens by Thibaut Delsinne are kindly acknowledged. Brian Fisher facilitated the use of the Auto-Montage figures from the portal www.antweb.org. Jack Longino facilitated images from the Ants of Costa Rica portal. Rodrigo Feitosa provided generously and readily images of Phalacromyrmex. This work was greatly improved by careful edition of two THE ANT GENUS TATUIDRIS Zootaxa 3503 © 2012 Magnolia Press · 79.