Myopopone

A monotypic genus. Myopopone castanea are rare ants that nest in rotten wood or under bark. Single colonies may be composed of several small nests scattered over a small area. They feed on large, soft-bodied insect larvae and may bring their larvae to food sources rather than attempt to move especially large prey back to their nest.

Identification
The mandibles are long and slender, with numerous (always more than 5) teeth which vary greatly in size and are scattered along the inner margins, and with a sharp, pointed tooth at the tip which is only slightly longer than the next longest tooth. The frontal lobes are large and extend well forward of the insertion point of the scapes, and when viewed from the front they cover the underlying clypeus and often form part of the front margin of the head. The antennae have the last few segments distinctly flattened in cross-section. The petiole has distinct front and upper faces but lacks a rear face, and its attachment to the gaster is broad and approximately the same height as the petiole so that the upper surfaces of petiole and gaster are separated by at most a shallow impression.

Although these ants are superficially similar to some Amblyopone, the presence of expanded and projecting frontal lobes and flattened tips of the antennae will separate these genera.

Worker
Worker of M. castanea from Queensland.

Nomenclature

 *  MYOPOPONE [Amblyoponinae]
 * Myopopone Roger, 1861a: 49. Type-species: Myopopone maculata (junior synonym of Amblyopone castanea), by subsequent designation of Bingham, 1903: 33.

Xu and He (2011) - Worker Head nearly rectangular, occipital margin concave, anterolateral corners without spines or denticles. Mandibles elongate and linear, masticatory margin short but distinct, both masticatory and inner margins dentate. Clypeus narrow and transverse, anteri or margin minutely dentate. Frontal lobes large and close together, distinctly broader than the distance between them, and well protruding forward and surpass the anterior margin of clypeus. Antennal sockets complete ly concealed by the frontal lobes. Antennae short, 12-segmented, scapes not surpass occipital corners, antennal clubs distinct and compressed. Eyes reduced and small, well behind the midline of the head. Ocelli absent. Dorsum of alitrunk about at the same level. Promesonotal suture and metanotal groove distinct and notched. Pronotum and propodeum long, mesonotum very short and transverse. Propodeal lobes narrow and reduced. Propodeal spiracles elliptic and vertical, placed at the center of the lateral sides. Metapleural gland bullae small and elliptic. Legs relatively short and robust, tarsi and outer surfaces of middle tibiae with strong spines. Hind tibiae with a curved pectinate spur and a simple spur. Claws simple. Petiolar node large, nearly rectangular, broadly attached to anterior face of the tergite of first gastral segment. Subpetiolar process small. Constriction between the two basal gastral segments distinct. Sting long and strong.

Brown (1960) - In general habitus, to the naked eye, Myopopone workers look very much like those of Amblyopone australis, and they show variation of similar scope. In fact, Myopopone is probably monotypic, and may be regarded as a more than usually aberrant species of Amblyopone. The characters are, however, sufficiently marked and numerous in the worker-female castes to justify the retention of Myopopone as a genus apart from Amblyopone. The head shape is like that of Amblyopone, without the "amblyoponine teeth" at the corners anteriorly, but the lobes of the frontal carinae are large and placed well forward, so as to overreach slightly the concave median lobe or apron of the clypeus (in Amblyopone the lobes never reach the anterior border of the median clypeal lobe). The antennal funiculi are strikingly broadened and flattened, differing in this from Amblyopone. The legs are short and with spiniform processes or spine-like setae developed at several points; in particular, the extensor surface of the middle tibia is provided with a number of sharp peg-like spines, also the metatarsus of the posterior leg. The mandibles are different from those of any given species of Amblyopone, but are not strikingly outside the range of variation seen among Amblyopone species.

The female is winged and is markedly larger and darker than the worker; there are also differences in sculptural detail. The differences between these two castes have been responsible for much of the synonymy at species level. The male is decidedly smaller and more slender than the female, and is typically amblyoponine in its habitus and general characters, with rugulose head and alitrunk and piceous to blackish in color. Notauli present.

Pygidium and subgenital plate both subtriangular, with broadly rounded apices. Parameres rather long, tapered and incurved so that their apices meet or even slightly overlap at the half-retracted position. Volsellae much like those of Amblyopone australis; digitus with a flat, plate-like apical portion, which is convex and tuberculate over its lateral surface; cusp reduced to a vestigial swelling at the base of the digitus, but the heel well developed and bearing a sharp erect tooth. Aedeagus of a peculiar shape. In all castes, the middle and posterior tibiae have two pairs of spurs, one of the posterior pair being larger than its mate, slender, curved, narrowly barbulate and with a peculiar obliquely truncate tip. Antennae stout, but not flattened as in the worker.

Workers and females with 4 maxillary and 3 labial palpal segments. Wings in both sexes similar to those of "complete-veined" Amblyopone species, narrow, glassy, with dark veins; Mf2 usually completely or nearly completely contracted in forewing.