Myopopone castanea

These rare ants, the only species in the genus Myopopone, 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.

Distribution based on Regional Taxon Lists
Australasian Region: Australia. Indo-Australian Region: Borneo, Indonesia, Malaysia, New Guinea, Philippines, Solomon Islands. Oriental Region: Cambodia, India, Sri Lanka, Thailand, Vietnam.

Biology
Wilson (1958) - Both the Karema and Bisianumu collections consisted of workers found under the thick bark of large rotting logs on the floor of rain forests. At Bisianumu workers were clustered with larvae around two large, freshly killed cerambycid larvae on the same log. Since the beetle larvae were well separated from one another, and appeared to be too large for the ants to transport through the preformed galleries under the bark, it is inferred that the ants had transferred their own larvae to feed on the prey after the latter had been attacked and killed. The Myopopone are singularly clumsy and shy ants, and immediately commence searching for cover when exposed to light, abandoning their brood in the process. When handled, however, they are capable of inflicting a painful sting.

Nomenclature

 *  castanea. Amblyopone castaneus Smith, F. 1860b: 105, pl. 1, fig. 6 (w.) INDONESIA (Batjan I.). Mayr, 1867a: 90 (q.); Wheeler, G.C. & Wheeler, J. 1964b: 446 (l.). Combination in Myopopone: Roger, 1862c: 292. Senior synonym of rufula: Roger, 1862c: 292; of picea, rossi, similis, smithi, wollastoni: Wilson, 1958a: 144; of bakeri (and its junior synonym proxima), beccarii, bugnioni, maculata, moelleri, striatifrons: Brown, 1960a: 215. See also: Xu & He, 2011: 232.
 * maculata. Myopopone maculata Roger, 1861a: 50 (w.q.) SRI LANKA. Donisthorpe, 1942c: 29 (m.). Subspecies of castanea: Dalla Torre, 1893: 15; Forel, 1900c: 54; Forel, 1907a: 17; Wheeler, W.M. 1919e: 50. Junior synonym of castanea: Bingham, 1903: 33; Brown, 1960a: 215.
 * rufula. Myopopone rufula Roger, 1861a: 52 (w.) INDONESIA (Batjan I.). Junior synonym of castanea: Roger, 1862c: 292; Brown, 1960a: 215.
 * beccarii. Myopopone beccarii Emery, 1887b: 447 (w.) INDONESIA (Ternate I.). Subspecies of castanea: Dalla Torre, 1893: 15; Emery, 1911d: 26. Junior synonym of castanea: Brown, 1960a: 215.
 * moelleri. Myopopone moelleri Bingham, 1903: 34 (q.) INDIA. Donisthorpe, 1942c: 30 (m.). Junior synonym of castanea: Brown, 1960a: 215.
 * bugnioni. Myopopone castanea var. bugnioni Forel, 1913k: 5 (footnote) (q.m.) SRI LANKA. Subspecies of moelleri: Donisthorpe, 1942c: 31. Junior synonym of castanea: Brown, 1960a: 215.
 * bakeri. Myopopone castanea var. bakeri Viehmeyer, 1916b: 283 (w.) PHILIPPINES. Subspecies of moelleri and senior synonym of proxima: Donisthorpe, 1942c: 31. Junior synonym of castanea: Brown, 1960a: 215.
 * proxima. Myopopone castanea var. proxima Stitz, 1925: 110 (w.) PHILIPPINES. Junior synonym of bakeri: Donisthorpe, 1942c: 31. See also: Wilson, 1958a: 145.
 * striatifrons. Myopopone moelleri var. striatifrons Stitz, 1925: 110 (q.) INDONESIA (Lombok I.). Junior synonym of castanea: Brown, 1960a: 215.
 * picea. Myopopone picea Donisthorpe, 1938e: 498 (w.) BORNEO. Junior synonym of castanea: Wilson, 1958a: 144.
 * wollastoni. Myopopone wollastoni Donisthorpe, 1942c: 29 (q.) NEW GUINEA. Junior synonym of castanea: Wilson, 1958a: 144.
 * smithi. Myopopone smithi Donisthorpe, 1947c: 577 (q.) NEW GUINEA. Junior synonym of castanea: Wilson, 1958a: 144.
 * rossi. Myopopone rossi Donisthorpe, 1948b: 297 (w.) NEW GUINEA. Junior synonym of castanea: Wilson, 1958a: 144.
 * similis. Myopopone similis Donisthorpe, 1949b: 488 (q.) NEW GUINEA. Junior synonym of castanea: Wilson, 1958a: 144.

Worker
Length 41/2 lines. Ferruginous; head wider than the thorax, slightly rounded at the sides, and emarginate behind, finely and distinctly punctured above, anteriorly it is longitudinally striated; the anterior margin fuscous; the antennae short and stout; the flagellum clavate; the mandibles with a row of short, stout, acute teeth on their inner margin; the head has a few scattered erect hairs. Thorax: the prothorax subglobose, strongly punctured in front; the mesothorax short and transverse; the metathorax oblong, parallel, and punctured; the apex transversely striated; the legs short, stout, and pubescent. Abdomen: the basal segment strongly punctured, the second and fullowing segments delicately and very sparingly so; the first and second segments deeply constricted at their margins; the apex pointed and pubescent, the pubescence ferruginous.