Hypoponera orba

Nothing is known about the biology of Hypoponera orba.

Identification
Hypoponera orba is similar in size, colour and general appearance to Hypoponera camerunensis and Hypoponera coeca, and the three appear to be closely related. However, camerunensis and coeca occur in leaf litter and rotten wood on the forest floors of Western and Central African countries, mostly in the rainforest zones, where coeca at least is relatively common. Morphologically the three are separated mainly by dimensional characters, but orba also has the margin between the propodeal declivity and its sides more sharply developed than in the other two.

A member of the abeillei group.

Distribution based on Regional Taxon Lists
Afrotropical Region: Eritrea, Ethiopia.

Nomenclature

 *  orba. Ponera orba Emery, 1915g: 7, fig. 4 (w.) ERITREA. Combination in P. (Hypoponera): Santschi, 1938b: 79; in Hypoponera: Bolton, 1995b: 215. See also: Bolton & Fisher, 2011: 81.

Worker
LECTOTYPE (paralectotype in parentheses). Measurements: HL 0.52 (0.54), HW 0.39 (0.40), HS 0.455 (0.470), SL 0.36 (0.36), PrW 0.29 (0.29), WL 0.65 (0.66), HFL 0.34 (0.33), PeNL 0.14 (0.14), PeH 0.30 (0.30), PeNW 0.21 (0.22), PeS 0.217 (0.220). Indices: CI 75 (74), SI 92 (90), PeNI 72 (76), LPeI 47 (47), DPeI 150 (157).

Eyes absent. Scape relatively long (SI 90–92) but when laid straight back from its insertion its apex distinctly fails to reach the midpoint of the posterior margin; SL/HL 0.67–0.69. Funiculus distinctly with 5 enlarging apical segments. Cephalic dorsum very superficially, minutely reticulate-punctate. Pronotal dorsum almost smooth, obviously less strongly and densely sculptured than cephalic dorsum. Mesonotum and dorsum of propodeum almost smooth, shiny, almost entirely devoid of punctulae. Metanotal groove absent from dorsum of mesosoma. Mesonotal-mesopleural suture absent from side of mesosoma. Propodeum with an angular margin between declivity and side. Posterior surface of petiole node without short cuticular ridges that radiate from just above the peduncle. Node of petiole in profile short-nodiform, the anterior and posterior faces weakly converge dorsally; length of node just above anterior tubercle greater than length of dorsum; dorsal surface is almost flat. Subpetiolar process rounded and simple, without an angular differentiated lobe, without a sharply defined ventral tooth or angle. In dorsal view petiole node with posterior face transverse; sides and anterior face form a single convex surface. Maximum width of first gastral tergite in dorsal view 0.34; width of second gastral tergite at its midlength 0.35. Cross-ribs at base of cinctus of second gastral tergite feebly developed and inconspicuous. Sides of second gastral tergite in dorsal view straight and parallel. Midline length of second gastral posttergite, from posterior margin of cinctus to apex, is slightly longer than the maximum width of the segment. Disc of second gastral tergite with densely crowded, small, superficial punctures so that the surface appears microreticulate at lower magnifications. First and second gastral tergites dorsally pubescent and with a number of very short standing setae that project just above the level of the pubescence. Full adult colour yellow.

Type Material
LECTOTYPE worker (by present designation), ERITREA: Ghinda, ix.1914 (F. Silvestri) ; paralectotype worker with same data but 2.ix.1914 (MSNG) [examined]. The original description mentions six worker syntypes. Two are in MSNG, now lectotype and paralectotype; the other four are presumed to be in the Silvestri collection at DEUN, which is not currently available for examination. These should also be regarded as paralectotypes. The lectotype bears an earlier label, “Lectotype Hypoponera orba (Emery). Det. R.W. Taylor, 10.iv.63”, and also has labels by Dr Fabio Penati (MSNG) that correctly state that Taylor’s designation was never published and is therefore invalid.

References based on Global Ant Biodiversity Informatics

 * Bolton, B., and B. L. Fisher. "Taxonomy of Afrotropical and West Palaearctic ants of the ponerine genus Hypoponera Santschi (Hymenoptera: Formicidae)." Zootaxa 2843 (2012): 1-118.
 * Emery C. 1915. Formiche raccolte nell'Eritrea dal Prof. F. Silvestri. Bollettino del Laboratorio di Zoologia Generale e Agraria della Reale Scuola Superiore d'Agricoltura. Portici 10: 3-26.
 * Finzi B. 1939. Materiali zoologici dell'Eritrea raccolti da G. Müller durante la spedizione dell'Istituto Sieroterapico Milanese e conservati al Museo di Trieste. Parte III. Hymenoptera: Formicidae. Atti del Museo Civico di Storia Naturale di Trieste 14: 153-168.
 * Madl M. 2019. Notes on the ant fauna of Eritrea (Insecta: Hymenoptera: Formicidae): type specimens deposited in the Natural History Museum Vienna (Austria) and a preliminary checklist. Ann. Naturhist. Mus. Wien, B 121: 9-18.
 * Wheeler W. M. 1922. Ants of the American Museum Congo expedition. A contribution to the myrmecology of Africa. VIII. A synonymic list of the ants of the Ethiopian region. Bulletin of the American Museum of Natural History 45: 711-1004