Gnamptogenys chapmani

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Gnamptogenys chapmani
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Ectatomminae
Tribe: Ectatommini
Genus: Gnamptogenys
Species: G. chapmani
Binomial name
Gnamptogenys chapmani
Brown, 1958

Gnamptogenys-chapmani-5L5x.jpg

Gnamptogenys-chapmani-5D5x.jpg

G. chapmani is relatively widespread but the number of specimens in collections is relatively meager.

Identification

Lattke (2004) - Head with straight, slightly convergent sides in frontal view; occipital lamella evenly convex in lateral view, lacking abrupt angles; posterior clypeal margin with lateral ridges enclosed by lateral foveolae, clypeal ridges converge posteriorly, running parallel briefly before meeting or fading on frons; petiolar node with broadly convex dorsal margin in lateral view. Also see the nomenclature section below.

Distribution

Known from Indonesia, Malaysia, Philippines and Thailand.

Distribution based on Regional Taxon Lists

Indo-Australian Region: Borneo, Indonesia, Malaysia, Philippines (type locality).
Oriental Region: Thailand, Vietnam.

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 chapmani. 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

Male unknown.

Worker

Nomenclature

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

  • chapmani. Gnamptogenys chapmani Brown, 1958g: 305, figs. 19, 44 (w.q.) PHILIPPINES. See also: Lattke, 2004: 187.

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

Lattke (2004) - Brown (1958) described Gnamptogenys chapmani from specimens gathered in different localities. A study of the type material revealed that the worker and female taken on 27 April 1924 represent a different species (Gnamptogenys leiolabia) from the series of workers taken on 19 March 1924, which include the holotype of G. chapmani. Additional specimens mentioned by Brown (1958) from Romblon Island, Philippines, were not examined, but his discussion of intraspecific differences corresponds to differences between G. chapmani and G. leiolabia. The following characters described by Brown (1958) as intraspecific variation are actually attributes of G. leiolabia: narrower head (CI 0.70-0.76) and petiole, smaller and sparser foveolae, and the angular propodeal declivity relative to the mesosomal dorsum. Thus, the queen of G. chapmani described in Brown (1958) corresponds to G. leiolabia. The most easily discernible difference between the two species is the median clypeal area; in G. leiolabia it is mostly smooth down to the lamella, which is broadly concave, almost straight. This median area is bounded by two raised longitudinal crests that stretch from next to the anterior edge of each frontal lobe down to the lateral borders of the lamella.

Specimens vary in the degree of foveolate sculpturing, posteromedian clypeal sculpturing, the angle formed by the ventral and anterior pronotal margins in lateral view, the angle formed by the dorsal and declivitous propodeal margins in lateral view, the shape of the subpetiolar process, and size. When two character states were well defined in some specimens other characters always merged into a continuity, making separation arbitrary.

Description

Worker

Lattke 2004 Gnamptogenys fig 50-51

Lattke (2004) - Metrics (n = 21): HL 0.60-0.84, HW 0.42-0.66, ML 0.23-0.39, SL 0.32-0.56, ED 0.12-0.19, WL 0.73-1.16 mm. CI 0.69-0.81, SI 0.75-0.88, MI 0.52-0.69, OI 0.25-0.35. Head with broadly convex subparallel sides in frontal view; frons ranging from densely foveolate to mostly smooth with irregular rows of foveolae that become denser and more regular laterally, fine median line sometimes impressed from posterior clypeal margin to mid eye height, frons usually mostly smooth; clypeus posteromedially smooth to longitudinally strigulose, strigulae extending onto lamella, posterior clypeal margin with lateral ridges enclosed by lateral foveolae, ridges converge posteriorly, running parallel briefly before fading on frons, or meeting; anterior margin of clypeal lamella mostly convex, with or without slight median convexity; occipital lamella convex, without abrupt angles in lateral view.

Pronotum laterally mostly smooth, usually with scattered punctae dorsally, low longitudinal strigulae or undulations may be present along posterior margin, anteroventral pronotal margins form blunt angle; mesopleuron mostly smooth with scattered punctae, mesopleural sculpture variably impressed; metapleuron mostly smooth and flat, with longitudinal strigulae posteroventrally; propodeum smooth or with low strigulae laterally plus variable amount of foveolae, dorsal and declivitous propodeal margins joined by sharply rounded convexity or blunt angle in lateral view. Dorsum of mesosoma and petiole mostly smooth, foveolae present laterally, sometimes strigulae present laterally; petiolar node foveolate in lateral view, dorsum mostly smooth; subpetiolar process variable, from subquadrate to forming rounded lobe or triangle; postpetiole tergite foveolate over smooth ground sculpture, each depression deeper anteriorly than posteriorly, and progressively smaller in diameter posterad; fourth abdominal tergite laterally with less punctae than postpetiole, some concentrated along posterior edge; fourth abdominal tergite smooth with scattered punctulae, brief strigulae sometimes present along posterior margin. Fore coxa mostly smooth with low transverse strigulae posterad. Dorsum of thorax and abdominal segments 1-4 with abundant erect to subdecumbent hairs. Body ferruginous brown to brown, legs and antennae lighter colored than body.

Queen

Lattke (2004) - Metrics (n = 2): HL 0.78, 0.66; HW 0.61, 0.51; ML 0.32, 0.28; SL 0.52, 0.41; ED 0.19, 0.20; WL 1.22, 0.99 mm. CI 0.77, 0.77; SI 0.86, 0.80; MI 0.53, 0.55; OI 0.31, 0.39. Mesosomal dorsum mostly smooth with sparse foveolae, foveolae on pronotum denser; mesoscutum with faint longitudinal undulations and brief longitudinal fine sulci; mesopleural suture well impressed with minute transverse crests; metapleuron mostly strigulose with small smooth area. Petiolar node with evenly convex dorsal margin in lateral view, curvature not as broad as in worker.

Type Material

Lattke (2004) - Holotype worker: Philippines, Negros Oriental, Cuernos Mountain (Chapman) (National Museum of Natural History) [Examined]. The altitude of the type locality is reported in Brown (1958) as 600m.

References