Odontomachus simillimus F. Smith, 1858

Satria, Rijal, Kurushima, Hiroaki, Herwina, Henny, Yamane, Seiki & Eguchi, Katsuyuki, 2015, The trap-jaw ant genus Odontomachus Latreille (Hymenoptera: Formicidae) from Sumatra, with a new species description, Zootaxa 4048 (1), pp. 1-36 : 5-11

Odontomachus simillimus F. Smith, 1858

( Figs. 2 , 3 , 4 , 17, 18)

Odontomachus simillimus F. Smith, 1858: 80 , pl. 5, figs 8, 9, queen, type locality: Fiji Islands; Wilson, 1959: 499; Brown, 1976: 165 –166; Fisher & Smith, 2008: 15 ; Sorger & Zettel, 2011: 157 –161, figs. 43–45.

Odontomachus haematodus Linnaeus, 1758 : Wheeler, 1924: 243 (misidentification); Dammermann, 1948: 369 (misidentification) (see Wilson, 1959; Brown, 1976; Yamane, 2013).

Odontomahus haematoda var. breviceps Crawley, 1915: 239 , worker, type locality: Christmas Island. Synonymy by Brown, 1976: 106.

Odontomachus haematodus var. fuscipennis Forel, 1913: 19 , worker, queen, male, type locality: Sri Lanka (Peradenyia). Synonymy by Wilson, 1959: 499.

Ponera pallidicornis F. Smith, 1860: 73 , male, type locality: Indonesia (Makassar). In Euponera (Brachyponera) by Donisthorpe, 1932: 458. In Odontomachus by Brown, 1976: 106. Synonymy by Brown, 1976: 106.

Type materials and images examined. Images of the type material of the following species provided in AntWeb v5.17.5 (http://www.antweb.org) were examined to confirm our species recognition: O. simillimus , queen, Ceylon (CASENT0900650); “ O. haematoda braeviceps ”, worker (CASENT0901486); “ O. haematoda fuscipennis ”, worker (CASENT0907433); “ Ponera pallidicornis ”, male (CASENT0901350).

Non-type materials examined. Indonesia: Sumatra: Aceh: Simeulue Island, Babul Makmur, 15.IX.2012, S. Rijal leg., 4 workers ( SKYC); same loc., 16.IX.2012, S. Rijal leg., 1 worker ( SKYC); West Sumatra: Padang, 24.III.1989, K. Nakamura leg., 89-PD-15 (KN), 1 worker ( SKYC, RSC); same loc., Teluk kabung near Padang, 14.III.1985, Sk. Yamane leg., 1 worker ( SKYC, RSC); Maninjau, 16–18.VIII.1985, Sk. Yamane leg., Sumatra Nature Study (SNS col.), 1 worker ( SKYC); Solok, Mt. Talang, 23–28.X.2010, S. Rijal leg., 3 workers, 1 queen ( SKYC, RSC). Lampung: Krakatau Islands, P. Rakata Besar, 19.VII.1982, Sk. Yamane leg., 8 workers ( SKYC, RSC); same loc., P. Sertung, 08.VII.1982, Sk. Yamane leg., 8 workers ( SKYC, RSC); same loc., P. Rakata kecil, Sk. Yamane leg., 17.VII.1982, 4 workers ( SKYC, RSC); same loc., P. Sertung, Sk. Yamane leg., 08.VII.1982, 2 workers, 1 queens ( SKYC, RSC); same loc., P. Pencang, Sk. Yamane leg., 05.VII.1982, 1 worker ( SKYC). Java: West Java: Jasinga near Bogor, 05.XI.1985, Sk. Yamane leg., 11 workers ( SKYC, RSC); ITB campus (ca. 700 m alt.), 28.XII.2002, Sk. Yamane leg., 4 workers ( SKYC); Bogor, 09.XI.1985, 5 workers ( SKYC); Bogor (botanical garden), 03.VIII.1992, Sk. Yamane leg., 1 worker ( SKYC, RSC); Carita, 03.VIII.1982, Sk. Yamane leg., 1 worker ( SKYC); Yogyakarta: Campus of Gajah Mada Univ. (100 m alt.), 29.XII.2002, Syaukani leg., 3 workers ( SKYC, RSC); same loc., F. Yamane leg., 1 worker ( SKYC); same loc., Sk. Yamane leg., JV02/03-SKY-26, 4 workers ( SKYC); Borobudur near Yogyakarta, 07.I.2003, Sk. Yamane leg., 4 workers ( SKYC, RSC); same loc., F. Yamane leg., 1 worker ( SKYC, RSC); East Java: Surabaya, Taman Binatang, 04.I.2003, F. Yamane leg., 1 queen ( SKYC, RSC); same loc., Syaukani leg., 1 worker ( SKYC, RSC); same loc., Sk. Yamane leg., 2 workers ( SKYC, RSC); Batu, Bumiaji, Air Panas Cargar (1600 m alt.), 03.I.2003, Sk. Yamane leg., 9 workers ( SKYC, RSC). Bali: Denpasar, 09.III.1987, K. Nakamura leg., 1 worker ( SKYC, RSC); W. Bali, Mendaya, Dusun PK Jelati, 05- 06.V.1998, I.K.T. Ginarsa leg., 3 workers ( SKYC, RSC); same loc., Sk. Yamane leg., 3 workers ( SKYC); same loc., 22.X.2012, PKJ-22-12, 6 workers, 1 queen ( SKYC, RSC); same loc., S. Rijal leg., PKJ-12-12, 4 workers ( SKYC, RSC); same loc., S. Rijal leg., PKJ-24-12, 11 workers, 8 queens ( SKYC, RSC); same loc., S. Rijal leg., PKJ-33-12, 4 workers, 1 queen ( SKYC, RSC); Denpasar, 24.IV.1998, I.K.T. Ginarsa leg., 5 workers ( SKYC). Sulawesi: South Sulawesi: Ujung Pandang, Bantimurung, 18.VIII.1992, Sk. Yamane leg., 9 workers ( SKYC). West Nusa Tenggara: W. Lombok, Kopi house near Semaya, 26.X.1998, K. Eguchi leg., EG98-LMB-1042, 4 workers ( SKYC, RSC); Same loc., I.K.T. Ginarsa leg., 1 worker ( SKYC). Irian Jaya (or Papua): Genyem near Jayapura, 02.v.1998, K. Eguchi leg., 1 queen ( SKYC). Malaysia: Borneo: Sabah: Kota Kinabalu, 20.III.1995, Sk. Yamane leg., 4 workers ( SKYC); Near Keningau (210 m alt.), 24.II.1997, Sk. Yamane leg., 1 worker ( SKYC); Sepilok Forest, 29.I.1997, K. Eguchi leg., Eg97-BOR-514, 7 workers ( SKYC); Lahad Datu, Lower Segama, 26.V.2005, Alveron leg., 9 workers ( SKYC); Manggatal, Taman Fajar, 15.X.1996, K. Eguchi leg., 1 queen ( SKYC). Sarawak, Niah N.P., 28.I.1993, Sk. Yamane leg., 1 worker ( SKYC); Bako, Nat. Park, 21–22.IV.1993, Sk. Yamane leg., 3 workers ( SKYC). Malay Peninsula: Selangor: Ulu Gombak, 12.XII.1992. K. Tomiyama leg., 1 worker ( SKYC); same loc., (ca. 250 m alt.), 4.VII.1999, Sk. Yamane leg., 4 workers ( SKYC); Pahang: Endu Rompin N.P., 10.VI.2005, Bakhtiar, Ruslan, Fauzi leg., SEM10 (nesting in soil), 2 workers ( SKYC); Negeri Sembilan: Pasoh, 14.XII.1992. K. Tomiyama leg., 4 workers ( SKYC). Philippines: Luzon, Olongapo, Subic Bay (FZ), 09- 20.XI.2005, S. Onoda leg., 7 workers ( SKYC). Singapore: 4.II.1995, Sk. Yamane leg., 9 workers ( SKYC). Sri Lanka: Central Province: Kandy, Campus of University Peradeniya, 12.IV.2001, Sk. Yamane, 4 workers, 2 queens ( SKYC). Sabaragamuwa: Ratnapura, 11.IV.2001, Sk. Yamane leg., 3 workers, 2 queens ( SKYC). Western Province: Gampaha Dist., Pilikuttuwa, 10.IV.2001, Sk. Yamane leg., 7 workers ( SKYC).

Material used for DNA barcoding. Colony PKJ-24-12 (individual no. RJ20141114-7, accession no. LC056048 ); colony PKJ-33-12 (RJ20141114-4, LC056049 ); colony LMR-01-12 (RJ20141201-5, LC056043 ); colony LW-09-12 (RJ20141201-4, LC056044 ).

Worker measurements and indices. Non-type (n=10): HW 1.72–2.26 mm, HL 2.12–2.73 mm, SL 1.97–2.43 mm, IFLW 0.50–0.65 mm, EL 0.34–0.42 mm, MDL 1.15–1.50 mm, WL 2.66–3.29 mm, PTL 0.46–0.57 mm, PTH 1.02–1.28 mm, CI 76–83, SI 106–116, MDI 52–56, PTHI 212–236.

Worker description. Relatively small (HL 2.12–2.73 mm; WL 2.66–3.29 mm). Head in full-face view slightly longer than broad, with posterior margin strongly concave; median furrow on vertex present as dark line; each side of line weakly humped; frontal lobes followed by weak frontal carinae which are divergent posteriad; minimum distance between margin of ocular ridge and margin of compound eye less than half of major axis of compound eye; mandible relatively stout; masticatory margin with small denticles or edentate; subapical tooth shorter than broad, blunt at apex; palp formula 4, 3. Mesosoma in lateral view stout; pronotum including its anteromedian lobe short, in lateral view with anterodorsal slope steep; mesopleuron with conspicuous anteroventral ridge, with anterodorsal margin distinctly carinate, clearly separated by distinct dorsal carina from mesonotum and metapleuron; propodeum in lateral view with dorsum slightly convex and gradually sloping posteriad, with posterior face steeply sloping; propodeal dorsum without median longitudinal depression. Petiolar node conical, with sharply pointed apical spine; node in lateral view, excluding apical spine almost straight anteriorly and very weakly convex posteriorly; apical spine short and slender, 1/4 as long as petiolar height, sometimes weakly curved posteriad; subpetiolar process anteroposteriorly longer than dorsoventrally high, triangular, directed posteriorly. First gastral tergum in lateral view short, with anterior face long and vertical.

Head in full-face view extensively striate, with area between eye and frontal lobe and area around eye smooth and shiny; frontal lobe finely and faintly striate; extraocular furrow striate; median part of vertex along median furrow striate; lateral face weakly striate; venter of head completely or largely smooth and shiny; median disc of clypeus with rough texture. Pronotal disc in dorsal view densely with concentric striation; mesonotum densely striate transversely; mesopleuron largely smooth and shiny, but with anterior third finely striate; metapleuron moderately striate; lateral face of propodeum with transverse striation which is a little sparser and stronger than mesonotum; dorsum and posterior face of propodeum coarsely and transversely striate. Petiolar node weakly striate anteriorly and laterally; posterior face of node weakly striate or sometimes smooth and shiny.

Vertex with a pair of long erect setae; frontal lobe without seta; pronotal disc and first gastral tergum with long erect setae, as long as setae on vertex. Head (except its venter), mesosoma, petiole and gaster with dense subdecumbent to decumbent pubescence; venter of head with sparse appressed pubescence.

For color pattern see Fig. 2 ; body reddish brown ( Fig. 2 ) to dark brown (nearly black).

Queen measurements and indices. Non-types (n=10): HW 2.07–2.17 mm, HL 2.49–2.69 mm, SL 2.22–2.39 mm, IFLW 0.60–0.68 mm, EL 0.45–0.52 mm, OL 0.08–0.11 mm, MDL 1.31–1.45 mm, WL 3.19–3.29 mm, FWL 6.56–6.86 mm, PTL 0.56–0.60 mm, PTH 1.40–1.48 mm, CI 80–85, SI 102–114, MDI 50–55, PTHI 232–256.

Queen description. In general appearance queen is similar to worker. Vertex near ocelli swollen; ocular ridge faintly developed; distance between lateral ocelli as long as distance between lateral and median ocelli, and 3.5 times as long as major axis of median ocellus; ocelli in lateral view with not protruded dorsad. Mesosoma with main sclerites associated with wing function ( Figs. 3 B, 3C), in dorsal view short and stout; anterodorsal slope of pronotum in lateral view relatively steep; anterodorsal outline of mesoscutum in lateral view relatively gentle; mesoscutum without posteromedian depression; parapsidal furrow very weak and slightly curved; mesopleuron without oblique furrow; propodeum relatively long, in lateral view with dorsum almost straight and sloping gradually posteriad. Wing venation as in Figs. 3 E and 3F. Petiolar node in lateral view, excluding apical spine with anterior face faintly to weakly concave and posterior face faintly convex; apical spine very short and slender, and curved posteriad; subpetiolar process anteroposteriorly longer than dorsoventrally high. First gastral tergum in lateral view relatively short, with anterior face long and vertical.

Head in full-face view extensively striate, with area between eye and frontal lobe, and area around eye smooth and shiny; frontal lobe finely and faintly striate; extraocular furrow striate; median part of vertex along median furrow striate; lateral face weakly striate; venter of head completely or largely smooth and shiny; median disc of clypeus with rough texture. Pronotum weakly striate transversely; mesoscutum with dense longitudinal striation; striation finer on mesoscutum than on pronotum and propodeum; mesopleuron largely smooth and shiny, but with posteriormost part faintly striate; mesoscutellum smooth and shiny; propodeum strongly striate transversely. Petiolar node excluding apical spine entirely striate, but striation on anterior and posterior faces weaker than that on lateral face.

Pair of long erect setae present on vertex near lateral ocelli; frontal lobe without erect seta; pronotal disc and first gastral tergum with long erect setae, as long as setae on vertex near lateral ocelli. Head, mesosoma, petiole and gaster with dense subdecumbent to decumbent pubescence, except mesopleuron very sparsely pubescent.

For color pattern see Fig. 3 ; body reddish brown ( Fig. 3 ) to dark brown (nearly black).

Male measurements and indices. Non types (n=10): HW 1.16–1.28 mm, HL 0.95–1.14 mm, SL 0.17–0.21 mm, EL 0.59–0.68 mm, EW 0.34–0.40 mm, OL 0.15–0.18 mm, OES 0.21–0.26 mm, WL 2.66–2.99 mm, FWL 4.60–5.48 mm, PTL 0.46–0.64 mm, PTH 0.81–0.95 mm, CI 104–129, SI 14–17, PTHI 147–176.

Male description. Size small (HL 0.95–1.14 mm; WL 2.66–2.99 mm). Major axis of median ocellus smaller than minimum distance between lateral ocelli; 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, 3; dorsal outline of clypeus in lateral view strongly convex. Mesosoma in lateral view relatively stout and short; dorsal outline of pronotum in lateral view strongly convex; anterodorsal outline of mesoscutum in lateral view steeply slooping; mesoscutum without median depression; parapsidal furrow weak and almost straight; oblique mesopleural furrow relatively deep and wide; ventrolateral part of katepisternum with weak longitudinal furrow; propodeum in lateral view with its dorsal outline angulate (arrow in Fig. 4 D); metapleuron distinctly separated from propodeum by a suture; wing venation similar to queen (see Figs. 3 E and 3F for queen wings). Petiolar node in lateral view tapering to blunt apex; its anterior slope in lateral view very weakly sinuate, and its posterior slope straight and steeper; subpetiolar process in lateral view anteroposteriorly as long as dorsoventrally high, triangular and thick; petiolar sternum with conspicuously angulate process posteroventraly. First gastral tergum in lateral view short; posterior spine of 8th abdominal tergum long and slender, very weakly curved (but variable in shape within species) (Fig. 18A); pygostyle digitiform, with long setae in apical half; disc of 9th abdominal sternite broader than long, almost as long as apical lobe, with straight basal margin; apical lobe slightly narrower in basal half, with apical margin weakly convex; telomeral apex in lateral view as long as high; distiventral apex of valviceps strongly produced; basiventral corner of valviceps distinctly produced; ventral margin of valviceps with 34–36 denticles.

Head including area between lateral ocelli largely smooth and shiny, with clypeus faintly striate; venter of head faintly striate and shiny. Pronotum largely smooth and shiny, with lateral part faintly striate; mesoscutum faintly rugoso-reticulate and opaque; scuto-scutellar suture with very sparse, weak, longitudinal rugae; mesopleuron with anepisternum smooth and shiny, and katepisternum largely smooth and shiny, but with faint and rough texture in posteriormost part; propodeum including its posterior slope with rough texture. Petiole faintly striate to rugose.

Head, mesosoma, legs, petiole, and gaster with fine dense subdecumbent to decumbent pubescence; apex of mandible, vertex near ocelli, pronotum and gaster with several long erect setae.

For color pattern see in Fig. 4 ; head, mesosoma, legs, petiole, gaster blackish brown; antenna yellowish brown; frons and clypeus largely yellowish brown, with lateral part of clypeus and the areas in front of antennal insertions rather yellow; mandible yellow.

Species recognition. Odontomachus simillimus is easily separated from the other Sumatran species of the genus by the following characteristics of the worker: subapical teeth blunt and short; palp formula 4, 3; pronotal disc and first gastral tergum with several long erect setae. This species is also distinguishable from the other Sumatran species by the following characters of the male: palp formula 6, 3; dorsal outline of clypeus in lateral view much convex; propodeum in lateral view with its dorsal outline angulate; disc of 9th abdominal sternite broader than long, almost as long as apical lobe, with straight basal margin; apical lobe slightly narrower in basal half, with apical margin weakly convex; telomeral apex in lateral view as long as high; vental margin of valviceps with 34–36 denticles; body largely blackish brown, with mandible and small area of clypeus and anterior of head yellowish, and antenna yellowish brown.

Distribution. The majority of the members of the O. haematodus species group are distributed in the New World and one species in Africa, but only O. simillimus is distributed widely in tropical Southeast and South Asia, Melanesia and Madagascar.

Bionomics. Odontomachus simillimus is a common species in gardens and green patches in residential zones, plantations, and secondary forests. Nests are usually found in the soil near the base of living trees, and under shelters (such as stumps, rotten logs and rocks), but sometimes under paved floors around houses.

In Bali, we found two colonies of O. simillimus near the base of living trees in a cacao plantation which coexisted with colonies of the myrmicine Pheidole gighii Emery, 1900 (“compound colony” PKJ-22-12/PKJ-23- 12, PKJ-24-12/PKJ-25-12). However, the coexistence between the two species seems to be occasional because we have not yet found such cases in Krakatau and Sumatra. Any other ant partner of O. simillimus has not yet been found.

Figures

FIGURE 2. Odontomachus simillimus, worker (colony: PKJ- 22 - 12; individual: SEMUT 150102 D): A, head in full-face view; B, mesosoma in dorsal view; C, mesosoma in lateral view, with an arrow indicating mesosoma with its anteroventral ridge; D, petiole and gaster in lateral view.

FIGURE 3. Odontomachus simillimus, queen (colony: PKJ- 27 - 12; individual: SEMUT 150102 C): A, head in full-face view; B, mesosoma in dorsal view; C, mesosoma in lateral view; D, petiole and gaster in lateral view; E, forewing; F, hindwing.

FIGURE 4. Odontomachus simillimus, male (colony: PKJ- 27 - 12; individual: SEMUT 141217 C): A, head in full-face view; B, head in lateral view; C, head in dorsal view; D, mesosoma in lateral view, with an arrow indicating an angulate dorsal outline; E, petiole in lateral view; F, mesosoma in dorsal view; G, gaster in lateral view.