Odontomachus minangkabau

Odontomachus minangkabau inhabits secondary and primary lowland forests, and nests in the soil near the base of living trees.

Identification
Satria et al. (2015) - Odontomachus minangkabau is morphologically most similar to Odontomachus rixosus and Odontomachus pararixosus. However, it is distinguishable from the latter two by the following characteristics of the worker: large size: HL 3.13–3.55 mm, WL 4.15–4.65 mm (vs. small size: HL 2.40–3.03 mm, WL 3.35–4.00 mm in latter two); masticatory margin of mandible with 11–14 denticles (vs. less than 10 denticles in latter two); SI 153–161 (vs. SI 131–150 in latter two); median part of vertex along median furrow faintly striate transversely (vs. smooth and shiny or with rough texture in latter two); colors of head, mesosoma, petiole and gaster darker than in the latter two. Furthermore, Odontomachus minangkabau is easily distinguished from O. rixosus by the following characteristics of the male: first gastral tergum in lateral view long (vs. short in the latter); apical lobe of 9th abdominal sternum slightly narrowed in basal half, with apical margin weakly convex (vs. gently tapering to almost truncate apex in the latter); telomeral apex in lateral view much longer than high (vs. longer than high in the latter); ventral margin of valviceps with 28−29 denticles (vs. 21−22 denticles in the latter); head, pronotum, mesoscutum and mesopleuron pale yellowish (vs. yellowish to yellowish brown in the latter).

Distribution
Sumatra

Distribution based on Regional Taxon Lists
Indo-Australian Region: Indonesia.

Nomenclature

 *  minangkabau. Odontomachus minangkabau Satria, et al. 2015: 28, figs. 14-18 (w.q.m.) INDONESIA (Sumatra).

Worker
Holotype and paratypes (n=10): HW 2.05–2.34 mm, HL 3.13–3.55 mm, SL 3.30–3.65 mm, IFLW 0.56–0.64 mm, EL 0.42–0.50 mm, MDL 1.85–2.00 mm, WL 4.15–4.65 mm, PTL 0.78–0.86 mm, PTH 1.25–1.40 mm, CI 65–69, SI 153–161, MDI 53–61, PTHI 158–173.

Relatively large (HL 3.13–3.55 mm, WL 4.15–4.65 mm). Head in full-face view much longer than broad, with posterior margin weakly concave; median furrow on vertex present as dark line; neither side of line swollen; frontal lobes followed by strong frontal carinae which are nearly parallel; minimum distance between margin of ocular ridge and margin of compound eye less than half of major axis of compound eye; mandible elatively slender; masticatory margin with 11–14 denticles; subapical tooth 2.5 times as long as broad, with truncate apex; palp formula 4, 4. Mesosoma in lateral view relatively slender; pronotum including its anteromedian lobe long, in lateral view with anterodorsal slope gentle; mesopleuron without anteroventral ridge, with anterodorsal margin weakly carinate, clearly separated by distinct dorsal carina from mesonotum and metapleuron; propodeum in lateral view with dorsum almost straight, and gradually sloping posteriad, with posterior face relatively gently sloping; propodeal dorsum anteriorly without median longitudinal depression. Petiolar node conical; node in lateral view, excluding apical spine with anterior face weakly convex or weakly and bluntly angulate and posterior face weakly convex; apical spine short and stout, less than 1/4 as long as petiolar height, sometimes weakly curved posteriad (but shape variable within species); subpetiolar process anteroposteriorly as long as dorsoventrally high, lobate, directed ventrally. First gastral tergum in lateral view long, with anterior face relatively short and vertical.

Head in full-face view largely smooth and shiny, but with a striate area bordered by frontal carinae and ocular ridges; frontal lobe with rough texture and shiny; faint striation extended from extraocular furrow through part of temporal ridges till part of posterolateral face of vertex; median part of vertex along median furrow faintly striate transversely; lateral face of head largely smooth and shiny, with its posterior third faintly striate; venter of head smooth and shiny; median disc of clypeus smooth and shiny. Pronotal disc and mesonotum densely and weakly striate transversely; posterolateral face of pronotum partly smooth and shiny; mesopleuron largely smooth and shiny, with its anterior 1/3 and posteriormost part finely striate; metapleuron and propodeum with transversal striation which is a little sparser and stronger than that of pronotum and mesonotum. Petiolar node largely smooth and shiny, but with its basal area faintly striate.

Vertex with a pair of long erect setae; frontal lobe sometimes with a seta; pronotal disc without long erect setae; first gastral tergum without erect setae. Head, mesosoma, petiole and gaster with fine appressed pubescence which is sparse and very short on head and sparse and extremely short on gaster.

Body dark reddish brown, with head paler; coxae and femora yellowish brown; tibiae and tarsi reddish brown.

Queen
Paratype (n=1): HW 2.36 mm, HL 3.29 mm, SL 3.35 mm, IFLW 0.65 mm, EL 0.54 mm, OL 0.15 mm, MDL 1.80 mm, WL 4.80 mm, FWL unmeasurable (due to the paratype dealated) PTL 0.88 mm, PTH 1.61 mm, CI 72, SI 142, MDI 55, PTHI 183.

Non-type (n=1): HW 2.37 mm, HL 3.30 mm, SL 3.50 mm, FLW 0.66 mm, EL 0.52 mm, OL 0.15 mm, MDL 1.72 mm, WL 4.70 mm, FWL 9.50 mm, PTL 0.88 mm, PTH 1.60 mm, CI 72, SI 147, MDI 52, PTHI 182.

In general appearance queen is similar to worker. Vertex near ocelli not swollen; ocular ridge clearly developed; distance between lateral ocelli shorter than distance between lateral and median ocelli, and as long as major axis of median ocellus; ocelli in lateral view protruded dorsad. Mesosoma with main sclerites associated with wing function, in dorsal view long and slender; anterodorsal slope of pronotum in lateral view gentle; anterodorsal outline of mesoscutum in lateral view relatively steep; mesoscutum with very weak median longitudinal depression; parapsidal furrow very weak and slightly curved; mesopleuron with fine, oblique furrow; propodeum in lateral view relatively long, with its dorsum almost straight and sloping gradually posteriad. Wing venation as in Figs. 15E and 15F. Petiolar node in lateral view, excluding apical spine with anterior and posterior faces weakly convex; apical spine relatively stout and slightly curved posteriad; subpetiolar process anteroposteriorly as long as dorsoventrally high. First gastral tergum in lateral view long, with anterior face relatively short and vertical.

Head in full-face view largely smooth and shiny, but with striate area bordered by frontal carinae and ocular ridges; frontal lobe with rough texture and shiny; faint striation extending from extraocular furrow through part of temporal ridges to posterolateral face of vertex; median part of vertex along median furrow faintly striate transversely; lateral face of head largely smooth and shiny, with its posterior third faintly striate; venter of head smooth and shiny; median disc of clypeus smooth and shiny. Pronotum densely and finely striate transversely; mesoscutum weakly and longitudinally striate; mesopleuron largely smooth and shiny, with anterior third and posteriormost part faintly striate; mesoscutellum smooth and shiny; propodeum strongly and sparsely striate transversely. Petiolar node largely smooth and shiny, with its basal area faintly striate.

Pair of long erect setae present on vertex near ocelli; frontal lobe, pronotal disc, and 1st gastral tergum without erect setae. Head, mesosoma, petiole and gaster with sparse, subdecumbent to decumbent pubescence which is extremely short in gaster; mesopleuron with very sparse subdecumbent to decumbent pubescence.

Head mesosoma, petiole and gaster reddish brown (Fig. 15) to dark brown; femora yellowish brown; tibiae reddish brown.

Male
Paratypes (n=5): HW 1.41–1.44 mm, HL 1.21–1.24 mm, SL 0.28–0.29 mm, EL 0.85–0.89 mm, EW 0.45–0.49 mm, OL 0.21–0.23 mm, OES 0.18–0.21 mm, WL 3.28–3.40 mm, FWL 6.17–6.46 mm, PTL 0.68–0.71 mm, PTH 0.95–1.07 mm, CI 115–119; SI 15–17, PTHI 139–157.

Size large (HL 1.21–1.24 mm, WL 3.28–3.40 mm). Major axis of median ocellus as long as minimum distance between lateral ocellli; antenna 13-merous; scape very short, 1/3 as long as 3rd antennomere; 2nd antennomere 1/2 as long as scape; 3rd to 13th antennomeres each extremely long; palp formula 6, 4; dorsal outline of clypeus in lateral view straight. Mesosoma in lateral view relatively slender and long; dorsal outline of pronotum in lateral view almost straight; anterodorsal outline of mesoscutum in lateral view gentle; mesoscutum without median depression; parapsidal furrow weak and almost straight; oblique mesopleural furrow relatively shallow and narrow; ventrolateral part of katepisternum without furrow; propodeum in lateral view with its dorsal outline roundly convex; metapleuron separated from propodeum indistinctly by suture; wing venation similar to queen. Petiolar node in lateral view tapering gently to bluntly pointed apex; its anterior slope weakly convex, and posterior slope straight; subpetiolar process in lateral view anteroposteriorly as long as dorsoventrally high, lobate and slender; petiolar sternum without posteroventral process. First gastral tergum in lateral view long; posterior spine of 8th abdominal tergum long and slender, weakly curved; pygostyle with long setae in its apical third; disc of 9th abdominal sternum much broader than long, with posterolateral corner expanding laterad and posterolateral corner distinctly angled; apical lobe much longer than disc and slightly narrowed in basal half, with apical margin weakly convex; telomeral apex in lateral view much longer than high; distiventral apex of valviceps strongly produced; basiventral corner of valviceps distinctly produced; ventral margin of valviceps with 28–29 denticles.

Head including area between lateral ocelli entirely smooth and shiny. Pronotum in lateral view smooth and shiny; mesoscutum in dorsal view smooth and shiny; scuto-scutellar suture with sparse, strong, longitudinal striation; mesopleural anepisternum and katepisternum smooth and shiny; metapleuron smooth and shiny; propodeum in dorsal view with rough texture and shiny. Petiole smooth and shiny.

Head, mesosoma, legs, petiole and gaster with fine dense subdecumbent to decumbent pubescence; mandible, vertex near ocelli and gaster except 1st gastral tergum with several long erect setae.

Body basically pale yellow; antennae, area around ocelli, anteromedian and lateral parts of mesoscutum, metanotum and dorsum of propodeum blackish; tibiae, petiole and gaster yellowish brown.

Type Material
Holotype, worker, secondary forest within the campus of Andalas University, Padang, West Sumatra, Indonesia [RS01-PDG-14, Robby J. leg., 22.ix.2014] ; paratypes: 17 workers, 1 queen, 5 males, same data as holotype (MZB,, & ).

Etymology
The specific epithet is named after the Minangkabau ethnic group indigenous to West Sumatra, Indonesia (type locality of this species).

References based on Global Ant Biodiversity Informatics

 * Herwina H., R. Satria, Yaherwandi, and Y. Sakamaki. 2018. Subterranean ant species diversity (Hymenoptera: Formicidae) in educational and biological research forest of universitas andalas, Indonesia. Journal of Entomology and Zoology Studies 6(1): 1720-1724.
 * Satria R., H. Kurushima, H. Herwina, S. Yamane, and K. Eguchi. 2015. The trap-jaw ant genus Odontomachus Latreille (Hymenoptera: Formicidae) from Sumatra, with a new species description. Zootaxa 4048(1): 001-036.