Gnamptogenys laevior

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Gnamptogenys laevior
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Ectatomminae
Tribe: Ectatommini
Genus: Gnamptogenys
Species: G. laevior
Binomial name
Gnamptogenys laevior
(Forel, 1905)

Gnamptogenys laevior casent0179966 p 1 high.jpg

Gnamptogenys laevior casent0179966 d 1 high.jpg

Specimen Labels

Synonyms

Little is known about this species despite it being a common ant with a large range.

Identification

Lattke (2004) - This widespread species is variable in size and sculptural features compared with other members of the laevior group. It is usually easily distinguished from other laevior group members by the strigulose to colliculate sculpturing on the fourth abdominal sternite. All other species have mostly smooth sculpturing with scattered foveolae. In G. laevior the degree of coverage of minute rounded elevations forming the colliculate areas can vary from very widespread throughout the body of the ant to present only on the fourth abdominal sternite. Specimens completely lacking minute rounded elevations can be found on the Malay Peninsula, Greater Sundas, northern Borneo, and Sulawesi. Though these specimens were on average smaller than those with minute rounded elevations, some specimens with minute rounded elevations fall within their size range. The single record from Sulawesi (not included in "metrics" above) is smaller (HL 0.82; HW 0.59; WL 1.07 mm) than most G. laevior and has a more evenly convex anterior clypeal margin as well as a convex petiolar process without a posterior angle and with no colliculate areas.

Distribution

Distribution based on Regional Taxon Lists

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

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 laevior. 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

Nomenclature

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

  • laevior. Ectatomma (Stictoponera) laevius Forel, 1905c: 7 (w.) INDONESIA (Java). Lattke, 2004: 203 (q.). Combination in Stictoponera: Emery, 1911d: 48 (spelling emended to laevior); in Gnamptogenys: Brown, 1958g: 228. Senior synonym of avia: Brown, 1954h: 2; of kalabit: Lattke, 2004: 200.
  • avia. Stictoponera laevior var. avia Forel, 1912d: 98 (w.q.m.) INDONESIA (Java). Junior synonym of laevior: Brown, 1954h: 2.
  • kalabit. Gnamptogenys kalabit Brown, 1958g: 308, fig. 43 (w.q.m.) BORNEO. Junior synonym of laevior: Lattke, 2004: 200.

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

Lattke 2004 Gnamptogenys fig 45-49

Lattke (2004) - Anterior margin of clypeal lamella medially projecting as small lobe or very obtuse angle; anterior and ventral pronotal margins usually form pointed angle in lateral view; subpetiolar process usually subquadrate or forming anteriorly projecting lobe with posterior angle. Fourth abdominal sternite with extensive strigose to strigulose sculpturing; fourth abdominal tergite with narrow band of transverse strigulae; colliculate sculpturing usually present, especially on mesosomal sides, petiole and parts of gaster.

The clypeal lamella varies from a medially projecting blunt angle with convergent straight sides, to a feebly medially projecting convexity, with straight to slightly sinuate sides; sometimes one side is straight and the other is slightly concave in the same specimen. The clypeal lamella is evenly convex in specimens from Sulawesi and the Philippines. In frontal view the posterolateral cephalic corners can have the occipital lamella forming a small denticulate point. This feature depends on the degree of development of the lamella, which varies geographically, and on how frontal the view of the head is. Specimens from Luzon Island have smaller and more dispersed cephalic foveolae, with finer strigulae on the clypeus; the anterior pronotal margin lacks transverse strigulae, and the mesosomal sides tend to be smooth. Specimens from the Malay Peninsula have denser foveolae on the head with longitudinal low strigulae and patches of striae along the posterior edges of the foveolae.

Brown (1954b) included G. laevior in his treatise of the coxalis group of Stictoponera in which the only information provided was the characterization of G. laevior as a “small, slender shining species” and the justification of the synonymy of G. avia based on its being a teneral specimen. The specimen of G. avia he examined was apparently not the type but a worker from Poendjak, Java, identified by Forel. In his 1958 revision he did not see a type of G. laevior but based his concept of the species from “satisfactory evidence.” This also explains why Brown (1958) made no reference to G. laevior when comparing features of G. kalabit with other Gnamptogenys in his description of G. kalabit. An examination of the G. kalabit holotype as well as other specimens from the same nest series did not reveal any clear-cut difference from G. laevior. In his description of G. avia Forel (1912a) described two males that he assigns to this species even though they were not associated with any of the females. The larvae of G. laevior are described in Wheeler and Wheeler (1952:122-123, pl. 3, figs. 1-8) as Stictoponera sp.

Description

Worker

Lattke 2004 Gnamptogenys fig 56-57

Lattke (2004) - Metrics (n = 15): HL 0.86-1.23, HW 0.62-0.90, ML 0.37-0.52, SL 0.55-0.81, ED 0.16-0.25, WL 1.16-1.60 mm. CI 0.72-0.82, SI 0.86-0.95, MI 0.53-0.63, OI 0.19-0.34. Head parallel sided in frontal view; posterolateral margins angular to sharply pointed; foveolae on dorsum range from dense, with diameters larger than intervening space, to dispersed, with diameters equal to or less than intervening space; small smooth area present behind frontal lobes; background sculpturing mostly smooth, occasionally with longitudinal strigulae or brief, faint longitudinal striae; frontal lobe mostly smooth with elongate foveolae; median clypeus longitudinally punctate-strigulose, strigulae extend to posterior half of clypeal lamella, rest of lamella smooth, anterior margin of lamella medially projecting as small lobe or open obtuse angle; mandibular dorsum mostly smooth with sparse punctae, base strigulose, strigulae extending up to posterior half, mandibular dorsal surface basally convex; occipital lamella not conspicuously protuberant in lateral view, evenly convex.

Pronotum with anteroventral margins forming angle in lateral view, humeral angle with broad posterior sulcus, pronotal sides foveolate, intervening areas either smooth, colliculate or strigulose or with rows of colliculae; anterior pronotal face usually with transverse strigulae or colliculae, pronotal dorsum can be densely foveolate and with arching strigulae; anepisternum smooth with sparse punctae; katepisternum with broad anteroventral sulcus, ventral third foveolate and elevated, rest smooth to colliculate or strigulose; metapleuron mostly smooth with colliculate to strigulose posterior end; propodeum laterally smooth to slightly undulating with sparse foveolae or punctae, spiracles at same level or slightly raised above rest of integument; propodeal dorsal and declivitous margins in lateral view joined through variably curving convexity, never angular; mesosomal dorsum with mostly smooth median longitudinal strip.

Sides of petiolar node foveolate with intervening space smooth to colliculate; subpetiolar process subquadrate in lateral view or forms anteriorly projecting lobe with posterior angle; sides of postpetiolar tergite foveolate, anterior depressions deeper and wider than posterior ones, intervening cuticle smooth to colliculate, colliculae usually present ventrally; abdominal tergite 4 mostly smooth with sparse punctulae plus varying degrees of ventral strigulae or colliculae in lateral view; sternite posterolaterally with band of minute strigulae or colliculae. Fore coxae with transverse strigae ranging from rough to partially effaced anteriorly. Dorsum of thorax and abdominal segments 1-4 with scattered erect to subdecumbent hairs. Body brown to dark brown, extremities lighter.

Queen

Lattke (2004) - Metrics (n = 2): HL 1.15, 1.22; HW 0.91, 0.95; ML 0.54, 0.51; SL 0.74, 0.82; ED 0.27, 0.31; WL 1.71, 1.75 mm. CI 0.79, 0.78; SI 0.82, 0.87; MI 0.59, 0.53; OI 0.29, 0.33. Pronotum foveolate; mesoscutum with anterior shiny area, posteriorly strigulose-foveolate or only foveolate; axillae rugulose-foveolate; scutellum with median smooth or sparsely foveolate area, laterally foveolate. Propodeal declivity posteriorly smooth, anterior margin finely rugulose.

Male

See Brown (1958:308).

Type Material

Lattke (2004) - Holotype worker by monotypy: Java, Tjibodas (Kraepelin) (Musee d'Histoire Naturelle Genève) [Examined].

Stictoponera laevior var. avia Forel, 1912a:98. Syntype workers: Java, Nongkodjdjar [not examined]. Synonymized by Brown, 1954b:2.

Gnamptogenys kalabit Brown, 1958:308. Holotype: Sabah, Kalabit Country (Mjöberg) (Museum of Comparative Zoology) [Examined]. Syn. Nov.

References

  • Brown, W. L., Jr. 1954h. A review of the coxalis group of the ant genus Stictoponera Mayr. Breviora 34: 1-10 (page 2, Senior synonym of avia)
  • 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)
  • Emery, C. 1911e. Hymenoptera. Fam. Formicidae. Subfam. Ponerinae. Genera Insectorum 118: 1-125 (page 48, Combination in Stictoponera, and spelling emended to laevior)
  • Forel, A. 1905f. Ameisen aus Java. Gesammelt von Prof. Karl Kraepelin 1904. Mitt. Naturhist. Mus. Hambg. 22: 1-26 (page 7, worker described)
  • 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 200, figs. 47a-b, 57a-b; worker, queen described; senior synonym of kalabit)