Pheidole megacephala (Fabricius)

Eguchi, Katsuyuki, 2008, A revision of Northern Vietnamese species of the ant genus Pheidole (Insecta: Hymenoptera: Formicidae: Myrmicinae), Zootaxa 1902 (1), pp. 1-118 : 55-59

Pheidole megacephala (Fabricius)

Figs. 15a–g

Formica megacephala Fabricius, 1793: 36 . Roger 1863b: 30 (combination in Pheidole ). Syntype (s): major, no locality given, not examined.

Myrmica trinodis Losana, 1834: 327 . Roger 1863b: 30 (junior synonym of megacephala ). Syntype (s): “worker”, Italy, not examined .

Formica edax Forskål, 1775: 84 . Emery 1892: 160 (junior synonym of megacephala ), Dalla Torre 1892: 90 (same). Syntype (s): “worker”, Egypt, not examined .

Oecophthora perniciosa Gerstäcker, 1859: 263 . Roger 1863b: 31 (combination in Pheidole ), Emery, 1915 c: 235 (junior synonym of megacephala ). Syntype (s): “worker”, Mozambique, not examined .

Oecophthora pusilla Heer, 1852: 15 . F. Smith 1858: 173 (combination in Pheidole ), Roger 1859: 259 (senior synonym of laevigata Fr. Smith, 1855: 130), Mayr 1870: 981 (senior synonym of laevigata Mayr, 1862: 747), Mayr 1886: 360 (senior synonym of janus), Emery 1915: 235 (subspecies of megacephala ), Wheeler 1922: 812 (junior synonym of megacephala ). Syntypes: major, minor, queen & male, Madeira, not examined.

Myrmica agilis F. Smith, 1857: 71 . Donisthorpe 1932: 449 (combination in Pheidole ). Syn.n. Syntypes: 3 minors, “MALAC” [= Malacca, S. Malay Peninsula], OXUM TYPE HYM: 988 1-3/3, examined.

Myrmica suspiciosa F. Smith, 1859: 148 . Donisthorpe 1932: 455 (junior synonym of megacephala ). Syntype (s): “worker”, Aru I. ( Indonesia), not examined .

Atta testacea F. Smith, 1858: 168 . Mayr 1886: 360 (combination in Pheidole ), Brown, 1981: 530 (junior synonym of megacephala ). Syntypes: major & minor, Brazil, not examined .

Subspecies enumerated in Bolton, 1995: nominal plus costauriensis Santschi, 1914: 443, syntype (s): major, Ghana, not examined; duplex Santschi, 1937a: 220, syntypes: major, minor & queen, Angola, not examined; ilgi Forel, 1907: 82, syntypes: major & minor, Ethiopia, not examined.; impressifrons Wasmann, 1905: 110 (replacement name for impressiceps Wasmann, 1904: 72), syntypes: major, minor & queen, South Africa, not examined; melancholica Santschi, 1912: 164, syntypes: major & minor, Ivory Coast, not examined; nkomoana Forel, 1916: 415, syntypes: major, minor, queen & male, Zaire, not examined; rotundata Forel, 1894: 92, syntypes: major & minor, Mozambique, not examined; scabrior Forel, 1891: 178, syntypes: major & minor, Madagascar, not examined; speculifrons Stitz, 1911: 386, syntypes: major & minor, Tanzania, not examined; talpa Gerstäcker, 1871: 356, syntypes: “worker” & queen, Kenya, not examined. For these forms type material not examined.

Other material examined: S. China: Hong Kong: Victoria Park , Hong Kong I. [K. Eguchi]; Macau: Mong Ha [K. Eguchi]. N . Vietnam: Ha Noi: Hanoi Agric. Univ. ( Gia Lam ) [K. Ogata: 15-min TUS #2]; Quang Ninh: Hoanh Bo [K. Eguchi]. S . Vietnam: Vinh Long (misspelled as “ Vinlong ”): Vinh Long (10°15’N, 105°58’N) [S. Kawaguchi] . Thailand: Trang: Khao Chong Waterfall [Eg 01-VN-761]. W . Malaysia: Penang: beside a building of Univ. Sains Malaysia [C.Y. Lee]. E. Malaysia: Sabah: Kota Kinabalu [Eg97-BOR-376], Tambunan Village [H. Okido], Danam Valley [Eg96-BOR-108] . Indonesia: Kalimantan Timur: Tandjung Isuy [Seyfert & Graindl]; Irian Jaya: Wamena , 1600 m alt. [Eg 98-IRI-674, -675, -676, -703] . Australia: Queensland: S. Mission Beach near Tully [AU01-SKY-12] . Tonga: Tongatapu: Vaini [J.K. Wetterer] .

Worker measurements & indices: Major (n=5). — HL 1.28–1.45 mm; HW 1.25–1.45 mm; CI 98–100; SL 0.71–0.76 mm; SI 52–57; FL 0.94–0.98 mm; FI 68–77.

Minor (n=5). — HL 0.62–0.72 mm; HW 0.55–0.65 mm; CI 88–91; SL 0.67–0.73 mm; SI 111–121; FL 0.68–0.77 mm; FI 118–123.

Worker description

Major. — Head in lateral view roundly convex dorsally, not impressed on vertex, in full-face view shallowly concave posteriorly; frons longitudinally rugose (or rarely almost smooth, only sparsely with short interrupted longitudinal rugulae); vertex and dorsum of vertexal lobe smooth and shining or shagreened; frontal carina absent or present just as weak rugula(e); antennal scrobe absent; median longitudinal carina of clypeus weak or absent; hypostoma at most with a pair of very small or inconspicuous submedian processes in addition to a pair of conspicuous lateral processes; antenna with a 3-segmented club; maximal diameter of eye almost as long as or longer than antennal segment X. Promesonotal dome in dorsal view smooth and shining or shagreened, sometimes with several weak transverse rugulae, in lateral view at most with an inconspicuous mound on its posterior slope; humerus not or weakly produced laterad; the dome at the humeri narrower than at the bottom; mesopleuron, metapleuron and lateral face of propodeum weakly or very weakly punctured. Petiole a little longer than postpetiole (excluding helcium); postpetiole not massive; its anteroventral part weakly swollen. First gastral tergite smooth and shining entirely, or very weakly punctured around its articulation with postpetiole and smooth or shagreened in the remainder.

Minor. — Head smooth and shining; preoccipital carina weak but present dorsally and laterally; median part of clypeus smooth and shining, without a median longitudinal carina; antenna with a 3-segmented club; scape extending beyond posterolateral margin of head by the double length of antennal segment II or more; maximal diameter of eye almost as long as, or sometimes a little shorter than antennal segment X. Promesonotal dome smooth and shining, in lateral view lacking a mound on its posterior slope; humerus in dorso-oblique view not or hardly produced; mesopleuron, metapleuron and lateral face of propodeum punctured weakly; metanotal groove inconspicuous. Petiole almost as long as or a little longer than postpetiole (excluding helcium); postpetiole relatively long but not massive; its anteroventral part weakly swollen.

Recognition: The syntype minors of “ Myrmica agilis ” agree well with minors of Bornean populations (e.g., Eg96-BOR-108) of P. megacephala . I conclude that P. agilis is a juninor synonym of P. megacephala .

P. megacephala is well distinguished from Indo-Chinese species by the combination of the following characteristics: in the major head in full-face view only shallowly concave posteriorly; in the major dorsum of vertexal lobe smooth and shining or shagreened; in the major hypostoma in the middle at most with a pair of very small or inconspicuous submedian processes; in the minor preoccipital carina weak but present dorsally and laterally; posterior slope of promesonotal dome at most with an inconspicuous mound in the major, and without any mound in the minor; in the major and minor anteroventral part of postpetiole weakly swollen.

Distribution & bionomics: Widely distributed in the world tropics and subtropics. For detailed information on biology and ecological and economic impacts of this species see Reimer et al. (1993), Campbell (1994), Hoffmann (1998), Wetterer (1998), Hoffmann et al. (1999), Vanderwoude et al. (2000), etc.

Figures

FIGURE 15a–d, Pheidole megacephala, major, Thailand [Eg01-TH-761] — a, head in full-face view; b, head in lateral view; c, mesosoma and waist in dorsal view; d, mesosoma and waist in lateral view.