May 2006 ARCHIBALD ET AL.: EOCENE BULLDOG 507 comorph subfamily, the ; it is easily sep- and general habitus, including petiole morphology, arable from the , differing strongly in and large size. many characters (Bolton 1994: Figs. 3 and 4). Forewing morphology of Y. orbiculata (Figs. 2, Grimaldi et al. (1997) placed the Late 16M) agrees with the combination of character states (Ϸ97 Ma: Turonian) genus Brownimecia Grimaldi, consistent within the subfamily (above). The closed Agosti and Carpenter from New Jersey amber in the cells 1 ϩ 2r, rm, and mcu are present (3r cannot be (as then deÞned), based primarily on the conÞrmed closed, wing apex not preserved); cell rm is slight constriction between AIII and AIV, Þnding this hexagonal and mcu pentagonal; cu-a joins MϩCu here also suggestive of Myrmeciinae (Grimaldi and Engel within a veinÕs width proximad the branching of M.f1 2005). Furthermore, AIII is bell-shaped, and its max- and Cu.f1; 1m-cu is faintly preserved but is apparently imum height seems slightly but not distinctly less than subparallel with M.f1, joining Cu proximad its con- that of AIV. This genus clearly differs from the Myr- nection with M; and cell cua is apparently closed meciinae in other characters and is currently consid- (Cu.f2 is faintly preserved). ered to constitute the monotypic subfamily Browni- The propodeum is rounded in lateral aspect, with- meciinae, likely close to the poneromorph group of out spines or projections, as in all Myrmeciinae except subfamilies (Bolton 2003). , which bears small, blunt, paired The Cretaceous Armaniinae also bear a bell-shaped propodeal teeth. Petiole morphology is close to that AIII, Ͻ 0.80 the maximum height of AIV (cf. Armania of P. janzeni. robusta Dlussky; Dlussky 1984: Fig. 1). Myrmeciines Y. bartletti. The only specimen of this is are easily separated from them by a number of char- more poorly preserved, in low contrast to the sur- acter states, e.g., the Armaniinae have a notably short rounding matrix. Only portions of the forewing are female scape, a distinctive petiole shape, and biden- preserved, and some of the gaster caudad AIII is tate mandibles without masticatory margin. The max- slightly deformed. Preserved morphology agrees with imum height of AIII seems about equal to that of AIV that of the Myrmeciinae: elongate-triangular mandi- in , which is also otherwise distinct bles (as in , Prionomyrmex); cu-a joins from Myrmeciinae by a suite of character states, e.g., Cu at, or extremely close to the separation of MϩCu; the short female scape, and many others (Wilson et al. cell rm is closed (crossvein 2rs-m present); the petiole 1967, Wilson 1987). is close in shape to that of P. longiceps (cf. Mayr 1868: Presence of a sting combined with lack of constriction Fig. 75); and AIII is bell-shaped; and a sting is present between AIII and AIV. Nothomyrmecia has both a sting and well developed. and no constriction between AIII and AIV, a condition Although the correct size of AIV in life cannot be it shares with few other extant ants (i.e., Aneuretus, determined, because it is somewhat crushed, the Asphinctopone Santschi, Anochetus Mayr, and Odon- shape of AIII, and its size in proportion to the pre- tomachus Latreille), none of which are closely related. served general morphology conforms to that of Myr- In some ponerines, however, the constriction between meciinae, and in particular to other species of Ypre- AIII and AIV is sufÞciently weak that its presence siomyrma. Compound eye morphology cannot be could likely not be conÞdently established in com- determined by low-contrast preservation. The great pression fossils. However, in these, the shape and overall similarity of all preserved characters to relative size of AIII is distinctly ponerine as described other species of Ypresiomyrma further makes place- above. Some genera of other subfamilies also bear ment in this genus, and therefore the Myrmeciinae, stings and have little constriction between these seg- conÞdent. ments, e.g., Brown, Gotwald and Le´vieux Y. rebekkae. Rust and Andersen (1999) supported (Apomyrminae); F. (); and Chelio- assignment of this species to the extant ponerine genus myrmex Mayr (Ecitoninae); however, in those cases, Pachycondyla by its large, robust mandibles and the other morphological characters of the head, meso- positions of the compound eyes and antennae, similar soma, wing, petiole, or a combination differ strongly in particular to some extant African species of the from those of the Myrmeciinae. genus. In our opinion, this species is clearly not a Species of the extinct, Eocene (easily member of the genus Pachycondyla and not a poner- distinguished, e.g., head small, less than half length, ine. width of mesosoma; legs short relative to mesosoma; AIV has sharply deÞned and distinct presclerites, M.f1 and 1m-cu convergent anteriorly, not parallel); over half the length of AIII, as in Myrmeciinae, the and the Cretaceous Armaniinae and Sphecomyrminae poneromorph subfamilies, and Cerapachyinae also lack a constriction between AIII and AIV and bear (Baroni Urbani et al. 1992, Rust and Andersen 1999). a sting. This is visible on the paratype Danekr¾ 93 (Figs. 5B, Ypresiomyrma. Y. orbiculata. Assignment of Y. or- 17B) due to postmortem expansion of the gaster. Rust biculata to the Myrmeciinae is conÞdent by a combi- and Andersen (1999) excluded Cerapachyinae by py- nation of wing venation; mandibles large, elongate- gidium morphology in this subfamily, it is large and triangular and multidentate; AIII bell-shaped, ßattened dorsally, with short spines or teeth (Bolton distinctly smaller than AIV (AIII/AIV height ϭ 0.70), 2003). Details of the pygidial morphology are not or without a constriction between AIII and AIV; with a are only indistinctly preserved on almost all of the well-developed sting; the compound eye apparently fossils of Y. rebekkae that we examined, although it large (convexity cannot be conÞrmed as preserved); seems smoothly rounded in lateral aspect in Danekr¾