Gnamptogenys biloba

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Gnamptogenys biloba
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Ectatomminae
Tribe: Ectatommini
Genus: Gnamptogenys
Species: G. biloba
Binomial name
Gnamptogenys biloba
Lattke, 2004

Gnamptogenys biloba casent0900590 p 1 high.jpg

Gnamptogenys biloba casent0900590 d 1 high.jpg

Specimen Labels

Gnamptogenys biloba is only known from the holotype worker. Nothing is known about its biology.

Identification

Lattke (2004) - This species shares with Gnamptogenys hyalina and Gnamptogenys leiolabia the two elevated clypeal ridges that define a median depression with effaced sculpturing. No other species of the laevior group have this trait, which defines a clade made up of these three species. Both of the other species have triangular metacoxal teeth. In Gnamptogenys hyalina the clypeal sculpturing is almost glabrous, while in G. biloba, and to a lesser degree in G. leiolabia, there still are some irregularly shaped foveolae and faint strigulae on the clypeus. Among these species the clypeal ridges are most developed in G. biloba. G. leiolabia is quite small (HL < 0.70; WL < 1.00 mm) compared to G. biloba. Gnamptogenys delta also tends toward smoother cuticle on the clypeus and mandibles, but it lacks the pair of clypeal ridges characteristic of G. leiolabia. The compound eyes are normally flattened in the laevior group, but they are more flattened in G. biloba than in any of the other species.

Distribution

Only known from Mt. Tibang in the Nieuenhuis Range of south central Sarawak.

Distribution based on Regional Taxon Lists

Indo-Australian Region: Borneo (type locality), Indonesia, Malaysia.

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 biloba. 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

Queens and males are unknown for this species.

Nomenclature

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

  • biloba. Gnamptogenys biloba Lattke, 2004: 185, figs. 49b, 50 (w.) BORNEO.

Description

Worker

Lattke 2004 Gnamptogenys fig 45-49

Metrics. HL 0.99, HW 0.82, ML 0.45, SL 0.67, ED 0.21, WL 1.32 mm. CI 0.83, SI 0.82, MI 0.56, OI 0.26. Head with subparallel lateral margins in frontal view, anterolaterally with brief, straight to slightly concave margin, forming obtuse angle with lateral cephalic margin; frontal carina straight, frontal lobe convex, elevated convex ridge extends anterad from frontal lobe, defining median clypeal smooth area; clypeus posteriorly strigulose, transverse row of punctae separates clypeal lamella from rest of clypeus, anterior margin of lamella convex; clypeus laterally strigulose, mostly smooth at extreme lateral end; mandible edentate, dorsum smooth with sparse punctae; head laterally with occipital lamella mostly straight anterad, posteriorly convex. Pronotal dorsum posteromedially smooth with foveolae anterolaterally and anterad, humeral angle raised slightly above rest of surrounding surface, pronotum laterally foveolate, ventrally smooth to slightly undulate; anepisternum subquadrate, mostly smooth with some foveolae, dorsal margin concave; katepisternum mostly smooth with posterior strigulae; metapleuron mostly smooth with ventral longitudinal strigulae.

Lattke 2004 Gnamptogenys fig 50-51

Petiole irregularly foveolate in lateral view, subpetiolar process forms anteriorly placed, short projecting lobe, with long concave posterior margin; postpetiole dorsolaterally with scalloped foveolae, deeper and wider anterad than posterad; postpetiolar sternite mostly smooth; postpetiolar sternal margin straight between anterior process and posterior convexity in lateral view; fourth abdominal tergite with lateral scallopings. Fore coxae smooth in lateral view; metacoxal tooth peglike. Sides of thorax and abdominal segments 1-4 with scattered erect to subdecumbent hairs. Mesosomal dorsum devoid of standing hairs. Body mostly ferruginous.

Type Material

Holotype worker. Borneo, Mt. Tibang, 1400m, Mjöberg. Deposited in BMNH.

Etymology

The species name is derived from a conjugation of the Latin word for “lobe,” lobus (m.), and the Latin prefix, bi, meaning “two.” It alludes to the pair of clypeal ridges that are so prominent in this species.

References

  • 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 185, fig. 49b, 50 worker described)