Meranoplus castaneus

A few of the paltry number of specimens know for this species are noted as being from rainforest in Sabah. One was collected from the trunk of a tree and another from low vegetation.

Identification
Schödl (1998) - This species may only be mistaken for the related Meranoplus bellii, from which it can readily be separated by the mesonotum posteriorly overhanging the propodeum, in profile by the narrower postpetiole, and by the gastral microreticulation. Furthermore the range of its distribution is different. From all remaining species it is separable by the bidentate petiole.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Borneo, Brunei Darussalam, Indonesia, Malaysia. Oriental Region: Thailand.

Nomenclature

 *  castaneus. Meranoplus castaneus Smith, F. 1857a: 81, pl. 2, fig. 7 (q.) BORNEO. Forel, 1910a: 29 (w.). Senior synonym of cordatus: Forel, 1912n: 61; of hammaceros, javanus: Schödl, 1998: 378.
 * cordatus. Meranoplus cordatus Smith, F. 1857a: 82, pl. 2, fig. 5 (w.) BORNEO. Junior synonym of castaneus: Forel, 1912n: 61.
 * hammaceros. Meranoplus castaneus subsp. hammaceros Forel, 1912n: 60 (w.) INDONESIA (Sumatra). Junior synonym of castaneus: Schödl, 1998: 378.
 * javanus. Meranoplus bellii subsp. javanus Karavaiev, 1935a: 98, fig. 22 (w.) INDONESIA (Java). Junior synonym of castaneus: Schödl, 1998: 378.

Worker
Schödl (1998) - TL: 4.5 - 5.1, HL: 0.98 - 1.14, HW: 1.05 - 1 18 CI- 100 - 112 SL: 0.75 - 0.83, SI: 65 - 73, PML: 0.76 - 0.94, PW: 1.03 - 1.2, PMI: 125 - 135 AL- 1 13 - 1.25 (10 measured).

Mandibles striate, armed with five teeth, the basal tooth occasionally reduced to a denticle. Mid-portion of clypeus feebly concave, partly carinulate, anterior margin of clypeus entire. Frontal triangle apparent, glossy, with a faint shagreening. Head above antennal scrobes trapezoid, evenly narrowed towards clypeus; ventral part of head (below antennal scrobes) wider, more rectangular, thus genae distinctly prominent and visible from above. Antennal scrobes shagreened, with longitudinal and transverse carinulae. Genae rugulose. Compound eyes situated well behind middle of lateral sides of head, but not close to posterior corners. Maximum diameter of eye 0.25 - 0.28, with 16-17 ommatidia in the longest row. Promesonotum slightly wider than long, overhanging sides of alitrunk laterally; propodeum overhung by a sinuate, translucent lamella, which is situated between the posterior teeth of the promesonotal shield. Anterior pronotal corners provided with stout anterolaterally projecting teeth. Promesonotal suture sometimes inconspicuously discernible, at its level small, translucent, lateral fenestrae on each side of the shield near or at the lateral margins. Behind the fenestra with a posteriorly directed, stout tooth and one additional arcuate tooth at the posterolateral corner of the mesonotum. Declivity of propodeum glabrous throughout, with occasional longitudinal striae. In about middle of its length propodeum provided with two slender, only little diverging, lateral spines. An arcuate suture between dorsum of alitrunk and propodeum is visible right below the posterior mesonotal margin, when viewed from behind.

Petiole in lateral view tapered, when viewed from behind, distinctly bidentate. Anterior face of petiole glabrous, posterior face with rugae or carinulae. Postpetiole nodiform, in profile with a ventral tooth and one additional acute tooth at the posterior dorsum. First gastral tergite shagreened throughout.

Dorsum of head anteriorly feebly rugulose, posteriorly reticulate-rugulose, width of meshes ca. 25 - 50 jam. Secondarily head covered with distinct shagreening. Promesonotal shield and postpetiole reticulate-rugulose above, shining, without shagrening, width of meshes ca. 25 - 60 μm. Dorsal surface near posterior mesonotal margin rugose! Entire dorsum of individuals covered with dense pubescence of suberect to erect, on head ca. 100 - 150 μm, on alitrunk ca. 150 - 200 μm, on gaster ca. 150 - 250 μm, apically arcuate hairs, and few longer outstanding hairs (ca. 0.3 - 0.4 mm), which distinctly surpass the pubescence.

Colour of body usually of a uniformly greyish brown.

Type Material
Schödl (1998) - Holotype queen (examined): "SAR. 6 \ castaneus Sm \ 9 Meranoplus castaneus Smith. TYPE. J.P.L.S.Lond. v.ii,1858,p.42. \ Ann.Mag.Nat.Hist. vol.x,pp. 441-476, 1932. \ Meranoplus castaneus Smith H.St.J.Donisthorpe del. 9.V.1932 9 \ Holotype \ TYPE HYM : 1038 Meranoplus castaneus SMITH HOPE DEPT. OXFORD". Type locality: Sarawak, Borneo, E-Malaysia.

Meranoplus castaneus

Holotype queen in. Labelled “Sar. 6.”

Meranoplus cordatus

Holotype worker in. Labelled “Sar. 3.”

References based on Global Ant Biodiversity Informatics

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 * Tanaka H. O., S. Yamane, and T. Itioka. 2012. Effects of a fern-dwelling ant species, Crematogaster difformis, on the ant assemblages of emergent trees in a Bornean tropical rainforest. Ann. Entomol. Soc. Am. 105(4): 592-598.
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