Gnamptogenys luzonensis

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Gnamptogenys luzonensis
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Ectatomminae
Tribe: Ectatommini
Genus: Gnamptogenys
Species: G. luzonensis
Binomial name
Gnamptogenys luzonensis
(Wheeler, W.M., 1929)

Gnamptogenys-luzonensisL5x.jpg

Gnamptogenys-luzonensisD5x.jpg

Specimen Label

Nothing is known about the biology of this species.

Identification

Lattke (2004) - This species is similar in appearance to Gnamptogenys epinotalis. Gnamptogenys epinotalis and Gnamptogenys luzonensis are both among the smallest Gnamptogenys, but G. epinotalis has a metanotal sulcus that is lacking in G. luzonensis. The propodeum of G. luzonensis may have partially effaced sculpture, but longitudinal strigulae and foveolae are usually present. The only other known species of the epinotalis group from the Philippines is Gnamptogenys cribrata, which usually has a dark brown mesosoma and a rectangular-shaped petiolar node in lateral view. The posterior mesosomal sides of G. cribrata have more strigulae and undulations, compared with the mostly smooth to longitudinally carinulate cuticle in G. luzonensis. The punctae on the postpetiole of G. cribrata are abruptly impressed anterad and gradually slope posterad compared with the uniformly impressed punctae in G. epinotalis. G. cribrata is on average larger, but there is some overlap at the higher range of dimensions for G. cribrata. Only ergatoid queens are known for this species.

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: Philippines (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Not much is known about the the biology of Gnamptogenys luzonensis. We can speculate that the biology of this species is similar to other species of the genus. Gnamptogenys are predatory ponerine ants that inhabit tropical and subtropical mesic forests. Nesting is typically at ground level in rotten wood or leaf litter. Some exceptions include species that are arboreal, a dry forest species and species that nests in sandy savannahs. Colony size tends to be, at most, in the hundreds. Queens are the reproductives in most species. Worker reproduction is known from a few species in Southeastern Asia. Generalist predation is the primary foraging/dietary strategy. Specialization on specific groups (millipedes, beetles, other ants) has developed in a few species.

Castes

Males are unknown.

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • luzonensis. Rhopalopone luzonensis Wheeler, W.M. 1929g: 30 (w.q.) PHILIPPINES. Combination in Gnamptogenys: Brown, 1958g: 228. See also: Lattke, 2004: 170.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Lattke (2004) - Clypeal lamella bluntly angular laterally and medially projecting as blunt, very obtuse angle; propodeal declivitous face mostly with faint longitudinal undulations. Petiolar node shaped as apically truncated triangle in lateral view.

Description

Worker

Length 1.7 - 1.8 mm.

Head subtectangular, about 1 1/5 times as long as broad, as broad in front as behind, with nearly straight sides, feebly concave posterior border and rather blunt posterior angles. Eyes very minute, imperfectly pigmented, of only two or three facets, situated near the middle of the sides of the head. Mandibles convex, with slightly concave external and straight apical borders, furnished with a large apical tooth and 7 or 8 minute basal denticles. Clypeus convex, its anterior border straight and transverse in the middle, sinuate on each side. Frontal area and groove obsolete. Antennal scapes reaching nearly to the posterior corners of the head; second funicular joint as long as broad; joints 3-8 broader than long, the two basal joints of the club as long as broad, together only 2/3 as long as the terminal joint. Thorax but little longer than the head including the mandibles, slightly broader through the pronotum than through the meso-and epinotum; all three divisions being broader than long and somewhat flattened above, so that their dorsal outline in profile is continuous and nearly straight. Epinotal declivity flattened, somewhat longer than the base, with a minute blunt denticle on each side above. Petiole somewhat broader than long, the node in profile narrowed above but rather thick, its anterior surface convex below, its posterior surface flat, the border thick and rounded, the ventral surface with a large, laterally compressed, sharply truncated, dependent projection, or lamina, provided with a clear circular area, or fenestra in the center. Postpetiole as long as broad, narrower in front than behind where it is nearly twice as broad as the petiole, convex ventrally with a blunt tooth anteriorly. First gastric segment narrower than the postpetiole, slightly longer than broad, also with straight sides, but a little narrower posteriorly than anteriorly. Remaining gastric segments small, deflected downward and forward. Sting large. Legs moderately stout.

Shining, the head and thorax less so than the abdomen. Mandibles with large, scattered, umbilicate punctures; head, thorax, petiolar border and postpetiole with similar but more crowded punctures, except on the petiole and postpetiole. The head is also longitudinally rugose and a similar though more indistinct sculpture is visible on both the dorsal and lateral surfaces of the thorax. Clypeus longitudinally rugulose. Epinotal declivity, scapes, legs and gaster smooth and shining; the gaster, scapes and legs with small, sparse piligerous punctures; fore coxae conspicuously, transversely striate.

Hairs yellow, rather coarse, short and uniformly distributed, arising from the umbilicate and ordinary punctures, erect on the body more oblique but nearly as long on the appendages. Pubescence undeveloped.

Rather rich ferruginous red; mandibles, antennae and legs reddish yellow.

Lattke (2004) - Metrics (n = 6): HL 0.52-0.59, HW 0.43-0.47, ML 0.23-0.30, SL 0.38-0.41, ED 0.03-0.06, WL 0.65-0.72 mm. CI 0.78-0.92, SI 0.82-0.88, MI 0.52-0.65, OI 0.07-0.13. Head with anterior clypeal margin mostly convex in frontal view, lamella laterally bluntly angular and medially projecting as obtuse blunt angle; clypeus with posteromedian longitudinal carinulae, laterally rugulose-punctate, mostly smooth anteromedially; vertex mostly smooth with anterior punctate margin and brief posteromedian longitudinal strigulae; eye approximately four ommatidia in diameter. Pronotal dorsum longitudinally strigulose-punctate, medially impunctate with shallow strigulae; promesonotal suture absent or weakly impressed; lateral pronotal face dorsally longitudinally strigulose to undulate with punctae, ventrally mostly smooth; anepisterum undulate with some punctae; katepisternum longitudinally strigulose; metapleuron posteroventrally with longitudinal carinulae, anterodorsally depressed, mostly smooth; mesometanotum ranging from strigulose to medially smooth with strigulose-punctate sculpturing limited to sides and toward propodeum; propodeal declivity mostly with faint longitudinal undulations, posterolaterally with low triangular ridge, lateral propodeal face longitudinally strigulose. Petiolar node forms apically truncated triangle in lateral view; postpetiolar dorsum mostly smooth with abundant piligerous punctae, punctae usually sparser posterad; postpetiole strigulose-punctate in lateral view, sculpturing denser anterad than posterad; abdominal tergite 4 dorsally like postpetiole but with smaller depressions; fourth abdominal sternite mostly smooth laterally with scattered, scalloped punctae. Dorsum of thorax and abdominal segments 1-4 with scattered erect to subdecumbent hairs. Head, mesosoma, petiole, and gaster ferruginous brown; mandibles, antennae, legs ferruginous.

Queen

(ergatoid). Length 2 mm.

Like the worker but somewhat larger and with very similar but distinctly stouter thorax, broader petiole and decidedly more voluminous postpetiole and gaster. The promesonotal and mesoepinotal sutures are dorsally distinct though not impressed. The eyes are much larger and pigmented and consist of about 10 facets, though these are of unequal size. There are three small but well-developed ocelli. The color of the body is paler and more yellowish ferruginous than in the worker and the integument, especially of the abdomen, is more hairy.

Lattke (2004) - Metrics (n = 1): HL 0.61, HW 0.54, ML 0.28, SL 0.45, ED 0.08, WL 0.78 mm. CI 0.82, SI 0.89, MI 0.55, OI 0.55. Ergatoid. Pronotal dorsum with arching rugulose-punctate sculpturing; mesoscutum with median narrow band of longitudinal carinulae, laterally longitudinally strigulose; scutellum smooth; propodeum rugulose-punctate; mesometapleuron and lateral propodeal face longitudinally strigulose. Punctae on postpetiolar dorsum shallower and smaller in diameter posterad.

Type Material

Described from four workers and a female taken from the same colony at Los Banos, Luzon Island, Philippines.

Lattke (2004) - Syntype workers, queen: Philippines, Luzon Island, Los Baños (Museum of Comparative Zoology) [Examined].

References

  • Brown, W. L., Jr. 1958g. Contributions toward a reclassification of the Formicidae. II. Tribe Ectatommini (Hymenoptera). Bull. Mus. Comp. Zool. 118: 173-362 (page 228, Combination in Gnamptogenys)
  • Lattke, J. E. 2004. A Taxonomic Revision and Phylogenetic Analysis of the Ant Genus Gnamptogenys Roger in Southeast Asia and Australasia (Hymenoptera: Formicidae: Ponerinae). University of California Publications in Entomology 122: 1-266 (page 170, fig. 42 worker, queen described)
  • Wheeler, W. M. 1929h. Ants collected by Professor F. Silvestri in Formosa, the Malay Peninsula and the Philippines. Boll. Lab. Zool. Gen. Agrar. R. Sc. Super. Agric. 24: 27-64 (page 30, worker, queen described)