Baracidris meketra, Bolton, B., 1981

Bolton, B., 1981, A revision of six minor genera of Myrmicinae (Hymenoptera: Formicidae) in the Ethiopian zoogeographical region., Bulletin of the British Museum (Natural History) Entomology 43, pp. 245-307 : 252-253

Type-species: Baracidris meketra sp. n.

Diagnosis of worker. Minute monomorphic myrmicine ants. Outline shape of head as in Figs 13, 14. Mandibles narrow, the apical (masticatory) margin armed with 5 teeth which decrease in size from apical to basal, the two basalmost teeth small. Basal borders of mandibles unarmed; the mandibles enclosing a space between their basal borders and the anterior clypeal margin when their apical margins are overlapping. Palp formula 2, 2, the first maxillary palpomere small (worker and queen of meketra dissected). Median portion of clypeus sharply raised centrally and in the form of a narrow longitudinal ridge which runs from the anterior margin to the frontal lobes. Anterior clypeal margin projecting medially ( meketra ) or in the form of a truncated lobe ( sitra ). Lateral portions of clypeus unmodified, not prominent not raised into a wall in front of the antennal insertions. Frontal lobes small, very closely approximated, almost touching anteriorly and separated only by the extremely narrow strip of the median clypeus which is inserted between them. The frontal lobes end immediately behind the antennal fossae; frontal carinae and antennal scrobes are absent. Antennae with 12 segments, the flagellum ending in a strong 2 - segmented club of which the apical segment is much the larger. Scapes short, when laid back on the head conspicuously failing to reach the occipital margin. Eyes minute and inconspicuous, situated approximately at the midlengths of the sides of the head. Alitrunk and pedicel segments as in Fig. 12. Promesonotum fused and forming a single long shallow convexity in profile. Metanotal groove impressed. Propodeum short, much shorter than the promesonotum, armed with a pair of blunted, broad but short, triangular teeth. Metapleural lobes very broad and rounded, strongly prominent, linked to the propodeal teeth above by a lamella. Petiole nodiform with a short, thick anterior peduncle; in dorsal view the peduncle about as broad as the node. Postpetiole with a strongly projecting blunt or truncated ventral process in profile; cylindrical in dorsal view. Standing hairs absent from dorsal surfaces of head and body, present only on the clypeus and gastral apex.

Known from two species, the minute ants of the genus Baracidris seem to be endemic in the wet forest zones of West and Central Africa where they inhabit the leaf-litter and topsol layers. The genus most closely related to Baracidris is Adelomyrmex Emery whose known distribution includes the Neotropics, New Guinea, Fiji and Samoa. One of the African species was wrongly referred to Adelomyrmex in an earlier publication (Bolton, 1973 a). Adelomyrmex shares a number of diagnostic characters with Baracidris , particularly in having similarly constructed antennae of 12 segments ending in a large 2 - segmented club. Differences separating the genera may be tabulated as follows.