Hypoponera rigida Bolton & Fisher, 2011

Bolton, B. & Fisher, B. L., 2011, Taxonomy of Afrotropical and West Palaearctic ants of the ponerine genus Hypoponera Santschi (Hymenoptera: Formicidae)., Zootaxa 2843, pp. 1-118 : 98

Hypoponera rigida Bolton & Fisher sp.n.

HOLOTYPE WORKER. Measurements: HL 0.46, HW 0.34, HS 0.400, SL 0.28, PrW 0.26, WL 0.56, HFL 0.26, PeNL 0.13, PeH 0.24, PeNW 0.17, PeS 0.180. Indices: CI 74, SI 82, PeNI 65, LPeI 54, DPeI 131.

Eyes absent. In full-face view apex of scape, when laid straight back from its insertion, conspicuously fails to reach the midpoint of the posterior margin by a distance that is ca 0.25 × SL; SL/HL 0.61. Reticulate-punctulate sculpture of cephalic dorsum fine and superficial, but distinct; pronotal dorsum with minute scattered punctulae, mostly smooth. Lateroventral surfaces of head with widely separated minute punctulae. With mesosoma in dorsal view the metanotal groove absent. Propodeal declivity separated from sides by weak margins. Mesopleuron unsculptured. Petiole in profile quite low, with the node relatively long in proportion to its height, the anterior and posterior faces almost parallel, the anterior face vertical and the posterior face only very weakly inclined towards it; dorsal surface extremely feebly convex. In profile the anterodorsal and posterodorsal angles of the petiole node are about equally rounded. Subpetiolar process with a low, obtuse, ventral angle. Posterior surface of petiole node without a transverse groove or impression above the peduncle and lacking cuticular ridges that radiate upwards from the posterior petiolar peduncle. In dorsal view the petiole node about one-third broader than long. Maximum width of first gastral tergite in dorsal view about equal to the width of the second tergite at its midlength (ca 0.30). First gastral tergite in dorsal view slightly broader than long, narrower across the anterior margin (ca 0.20) than across the posterior margin (ca 0.30) and with the sides distinctly divergent posteriorly. Base of cinctus of second gastral tergite with distinct cross-ribs. Sides of second gastral segment parallel for most of their length in dorsal view; narrowing extremely feebly only at the cinctus anteriorly and the apex posteriorly. Posttergite of second gastral segment, from posterior margin of cinctus to apex, very slightly broader than long. Disc of second gastral tergite shallowly reticulate-punctate. Full adult colour brown.

Holotype worker, Uganda: nr Queen Elizabeth N.P., 2.x.2006, UG06-SKY-144, bush (S. Yamane) (KUIC). Apical funicular segments of right antenna missing from holotype. Paratype. 1 alate queen with same data as holotype (KUIC).

Known from only a single worker, rigida seems closely related to meridia and abeillei , but is distinctly darker in colour than these. In the key rigida is grouped together with meridia and abeillei as in these three species the anterior face of the petiole node in profile is vertical. In meridia and abeillei the posterior face is also vertical so that the anterior and posterior faces are parallel and the node is columnar. However, in rigida the anterior face is vertical but the posterior face converges very slightly upon it from the level of the anterior tubercle to the dorsal angle. In orba , camerunensis and their relatives, either both faces of the node in profile are inclined and converge dorsally, or it is the posterior face that approaches verticality and is converged upon by the obviously sloped anterior face.