Ankylomyrma

This genus was described from a single Ankylomyrma coronacantha worker. This remains the only known species of this genus. The type specimen was found via canopy fogging. Additional workers have only been found a few times in collections from vegetation beating and litter sampling. Nothing is known about their biology.

Identification
The combination of the 12 segmented antenna, prominent eyes that are situated at the posterolateral corners of the head, the enlarged first gastric tergite that forms a large subspherical ball, and the forward projection of the well developed sting set this genus apart from other Myrmicinae.

Bolton (1981): DIAGNOSIS OF WORKER. Monomorphic arboreal myrmicine ants. Mandibles with 5 sharply defined large triangular teeth, the mandibles almost entirely concealed by the c1ypeus when closed. Palp formula 5, 3, the palpomeres very long (apical maxillary palpomere equal in length to apical antennal segment). Clypeus very large, projecting forwards over the mandibles as a broad shelf. Median portion of clypeus raised, broad posteriorly and broadly inserted between the widely separated frontal lobes. Frontal lobes concealing antennal insertions, prolonged back by a pair of irregular frontal carinae which run past the inner margins of the eyes to the occipital margin. Frontal carinae forming dorsal margins of a weak scrobe which is bounded below by a ridge running from below the eye to the mandibular insertions. Eyes large, situated at extreme posterolateral corners of head, within the scrobal area as defined by the frontal carinae and ridge. Antennae 12-segmented, without a strongly defined club, the flagellomeres increasing in size apically. Occipital margin bounded by a broad transverse lamella which projects into a series of dentiform processes; occiput behind the lamella broad and flat. Promesonotum swollen, large and convex, without sutures but with 4 pairs of roughly triangular teeth or prominences. Propodeum short and strongly bispinose. Metapleural lobes absent. Mesopleuron divided by a broad transverse suture and a broad suture separating meso- and metapleuron present. Petiole strongly bispinose, with a broad anterior peduncle which grades into the node. Gaster consisting almost entirely of the massively enlarged and strongly vaulted first tergite. The first sternite is visible as a narrow collar fringing the ventral portion of the forward-pointing orifice of the tergite; remaining gastral segments very small and telescoped inside. Sting strongly developed and projecting anteriorly below the pedicel segments.

Distribution
Known from Cameroon, Central African Republic, Ghana and Gabon.

Description
From Bolton (1981)

Worker: Mandibles dentate; palp formula 5, 3. Clypeus of the Meranopline pattern, raised medially and projecting as a bluntly bilobed shelf over the basal borders of the mandibles. Antennae 12- segmented, without a distinctly differentiated club, the funicular segments gradually increasing in size distally. Eyes well developed, situated at the posterolateral corners of the head; ocelli absent. Frontal carinae prolonged backwards to the occipital margin and forming the dorsal margins of a weak antennal scrobe. Scrobe bounded below by a ridge running from below the eye to the mandibular insertions. Occipital margin of the head fringed with a continuous transverse lamella which projects posteriorly into numerous spiniform and dentiform processes, and behind which the occiput is vertical.

Dorsum of alitrunk devoid of sutures. On the sides the promesonotal suture is visible to the height of the spiracle. A transverse suture is present dividing the mesopleuron into an- and katepisterna, and the suture separating the meso- and metapleurae is developed. A broad, longitudinal groove is present on the metapleuron just above the hind coxa, leading posteriorly to the orifice of the metapleural gland. Promesonotum with four pairs of tubercles or broad teeth; propodeum with a pair of spines. Petiole with a short, broad peduncle, armed above with a pair of spines; postpetiole unarmed.

Gaster consisting almost entirely of the massively enlarged and extremely strongly vaulted first tergite. The first gastral sternite is reduced to a narrow, fringing rim around the forward-pointing orifice of the tergite, and the remaining gastral segments are telescoped inside. The sting is well developed and projects anteriorly, below the pedicel.

Queen and male unknown.