Monomorium destructor (Jerdon)
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|Monomorium destructor (Jerdon)|
Figs. 15, 40-41.
Monomorium destructor r. gracillimum Forel 1913a:437. Syn. under M destructor (Jerdon) HNS : Bolton 1987:324. Myrmica vexator Smith HNS 1861b:47. Syntype [[worker]]"s (lectotype here designated) Indonesia: Ternate Isl. (OXUM) [examined]. Syn. under M destructor (Jerdon) HNS : Donisthorpe 1932:468.
Material examined.- M. basale: Lectotype: [[worker]], Sri Lanka ("Ceylon"), no collector named (BMNH). The ant on the LHS (seen from the rear) on a rectangle containing three syntype workers is designated the lectotype for Monomorium HNS basale, so that the name can be fixed. This and other early collections of Monomorium destructor HNS were given separate species-level names, presumably on the basis of quite minute differences in color or morphology, and, possibly, their provenance. The antennal club in M. basale is described by Smith as "dark fuscous", and the termination of the flagellum in M. vexator HNS as "slightly fuscous", otherwise their respective descriptions by Smith read much the same. Paralectotypes: Two workers on the same card rectangle as the lectotype (BMNH). No attempt has been made to separate the carded specimens, which are damaged and fragile. M. vexator HNS : Lectotype: [[worker]], J. Smith. (OXUM) (The collection locality, which does not appear on the labels but in the publication, is Ternate Island, [Indonesia.]) The middle ant of the three carded syntype specimens is here designated the lectotype to fix the name of this taxon. Monomorium destructor HNS , because of its ubiquity and its allometric variation, has attracted half-a-dozen synonyms. Paralectotypes: Two workers on the same card rectangle as the lectotype (OXUM). Carded specimens as above.
Other material examined: Prov. Antsiranana: 10km NE Antsiranana, 14.ii.1991, G.A. Alpert (145) (MCZ); 15km NE Antsiranana, 14.ii.1991, G. A. Alpert (25); (MCZ); 3 km S Namakia, 19.iii.1993 P. Rabeson (2 [[worker]], 2[[male]]) (MCZ). Prov. Mahajanga: Mahavavy River, 6.2 km 145 SE Mitsinjo 1-5.xii.2002 Fisher et al. (10 [[worker]]); Mahavavy River, 10.6 km 148 SSE Mitsinjo 4.xii.2002 Fisher et al. (9 [[worker]]); P. N. Namoroka, 17.8 km 329 WNW Vilanandro, 12.ii.2002 Fisher et al. (1 [[worker]]).
Worker description.- Head: Head square; vertex planar or weakly concave; frons longitudinally finely striolate anteriad (striolae curving inwards around antennal insertions), smooth and shining posteriad, except for a few transverse rugulae on upper vertex; pilosity of frons consisting mainly of appressed and decumbent setulae with a few erect setae on vertex. Eye large, eye width 1.5x greater than greatest width of antennal scape to moderate, eye width 1-1.5x greatest width of antennal scape; (in full-face view) eyes set below midpoint of head capsule; (viewed in profile) eyes set around midline of head capsule; eye elliptical, curvature of inner eye margin may be more pronounced than that of its outer margin. Antennal segments 12; antennal club three-segmented. Clypeal carinae indicated by multiple weak ridges; anteromedian clypeal margin broadly convex to straight; paraclypeal setae moderately long and fine, curved; posteromedian clypeal margin extending slightly beyond level of posterior margin of antennal fossae. Anterior tentorial pits situated nearer antennal fossae than mandibular insertions. Frontal lobes sinuate, divergent posteriad. Weak psammophore present. Palp formula 2,2. Mandibular teeth three, plus minute, basal denticle or angle; mandibles with sub-parallel inner and outer margins, striate; masticatory margin of mandibles approximately vertical or weakly oblique; basal tooth a small to minute denticle or angle, much smaller than t3 (four teeth present).
Mesosoma: Promesonotum shining and smooth on dorsum, lower mesopleuron strongly punctate; (viewed in profile) promesonotum broadly convex anteriad, convexity reduced posteriad; promesonotal setae seven to twelve; standing promesonotal setae a mixture of well-spaced, distinctly longer, erect and semi-erect setae which are curved distally and often paired, interspersed with much shorter, incurved, decumbent setae; appressed promesonotal setulae well-spaced over entire promesonotum. Metanotal groove strongly impressed, with distinct transverse costulae. Propodeum uniformly finely striolate, some punctation on metapleuron; propodeal dorsum flat throughout most of its length; propodeum smoothly rounded or with indistinct angle; standing propodeal setae variable in number and arrangement, when present usually one prominent pair at propodeal angles or at midlength, with other shorter setae very sparse or absent; appressed propodeal setulae well-spaced and sparse; propodeal spiracle equidistant from metanotal groove and declivitous face of propodeum. Vestibule of propodeal spiracle distinct in some specimens. Propodeal lobes present as vestigial flanges or small strips of cuticle only.
Petiole and postpetiole: Petiolar spiracle lateral or laterodorsal and situated within anterior sector of petiolar node or just at front of node; node (viewed in profile) conical, vertex rounded; appearance of node shining and smooth throughout; ratio of greatest node breadth (viewed from front) to greatest node width (viewed in profile) between 1:1 and 3:4; anteroventral petiolar process absent or vestigial; ventral petiolar lobe absent; height ratio of petiole to postpetiole between 1:1 and 3:4; height -length ratio of postpetiole between 4:3 and 3:4; postpetiole shining and smooth; postpetiolar sternite without anterior lip or carina, or this structure vestigial.
Gaster: Pilosity of first gastral tergite consisting of well-spaced, erect and semi-erect setae interspersed with a few appressed setulae.
Mesosoma: Color yellow-orange to brownish-orange, gaster chocolate with or without yellowish area on anterior sector of first gastral tergite. Worker caste monophasically allometric, i.e., with variable size, but not morphology among workers from same nest.
Other worker measurements (non-types): HML 1.31-1.92 HL 0.49-0.76 HW 0.38-0.68 CeI 78-89 SL 0.39-0.52 SI 76-103 PW 0.25-0.40 (n=20).
Queen description.- Head: Head rectangular; vertex weakly concave or planar; frons shining and smooth except for piliferous pits and striolae around antennal sockets, frontal carinae and below the eyes, and fine rugulae near posterior margin of vertex; frons consisting mainly of decumbent setae, with two longitudinal, parallel rows of erect setae straddling the midline. Eye elongate, elliptical and oblique; (in full-face view) eyes set above midpoint of head capsule; (viewed in profile) eyes set posteriad of midline of head capsule.
Mesosoma: Anterior mesoscutum smoothly rounded, thereafter more-or-less flattened; pronotum, mesoscutum and mesopleuron shining and mainly smooth, vestigial striolae, if present, confined to anterior katepisternum; length -width ratio of mesoscutum and scutellum combined between 7:3 and 2:1. Axillae a strip of thin cuticle separating mesoscutum and scutellum, each individual axilla indistinct. Standing pronotal/mesoscutal setae a mixture of well-spaced, distinctly longer, erect and semi-erect setae which are curved distally, interspersed with much shorter, incurved, decumbent setae; appressed pronotal, mescoscutal and mesopleural setulae abundant, particularly on mesoscutum. Propodeum shining and smooth, with a few weak striolae on metapleuron; always smoothly rounded; propodeal dorsum convex; standing propodeal setae consisting of one pair anteriad, with or without another pair posteriad; propodeal spiracle nearer metanotal groove than declivitous face of propodeum; propodeal lobes present as vestigial flanges only, or absent.
Wing: Wing not seen (queen dealated).
Petiole and postpetiole: Petiolar spiracle lateral and situated slightly anteriad of petiolar node; (viewed in profile) node conical, vertex rounded; appearance of node shining and smooth; ratio of greatest node breadth (viewed from front) to greatest node width (viewed in profile) about 1:1. Anteroventral petiolar process absent or vestigial; height ratio of petiole to postpetiole between 4:3 and 1:1; height -length ratio of postpetiole between 4:3 and 1:1; postpetiole shining, with vestigial sculpture; postpetiolar sternite with anterior and posterior margins convergent, forming a narrow wedge.
Gaster: Pilosity of first gastral tergite consisting mainly of appressed setae with a few erect and semi-erect setae.
General characters: Color of foreparts tawny-yellow, gaster brown. Brachypterous alates not seen. Ergatoid or worker-female intercastes not seen.
Queen measurements: HML 3.22-3.46 HL 0.83-0.84 HW 0.76-0.80 CeI 92-95 SL 0.60-0.62 SI 78 PW 0.68-0.89 (n=2).
Remarks.- Monomorium destructor HNS is very similar to the closely related Monomorium robustior HNS , but is lighter in color and the eyes tend to be less elongate. Workers within nests also show more allometric variation than is found in M. robustior HNS . Samples of this tramp species have been taken in tropical dry forest in north and north-western Madagascar in the Antsiranana and Mahajanga Provinces, where they have been collected under stones, from a dead branch and by sweeping. Populations also may be expected to occur generally in severely damaged habitats in these regions.
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