Gnamptogenys crassicornis

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Gnamptogenys crassicornis
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Ectatomminae
Tribe: Ectatommini
Genus: Gnamptogenys
Species: G. crassicornis
Binomial name
Gnamptogenys crassicornis
(Forel, 1912)

Gnamptogenys crassicornis casent0281843 p 1 high.jpg

Gnamptogenys crassicornis casent0281843 d 1 high.jpg

Specimen Labels

Synonyms

Collected just a few times, nothing is known about this ant's biology.

Identification

Lattke (2004) - Anterior margin of clypeal lamella ending in median convex lobe; scape mostly longitudinally strigulose; occipital lamella well developed, convex at both ends. Dorsum of abdominal segment 4 smooth with scattered punctae, laterally with longitudinally oblique costae and costulae.

Also see the Nomenclature section below.

Distribution

Known from Indonesia and Malaysia.

Distribution based on Regional Taxon Lists

Indo-Australian Region: Indonesia (type locality), 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 crassicornis. 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 not known for this species.

Worker

Nomenclature

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

  • crassicornis. Ectatomma (Stictoponera) binghami subsp. crassicorne Forel, 1912n: 51 (w.) INDONESIA (Sumatra). Lattke, 2004: 107 (q.). Combination in Gnamptogenys: Brown, 1958g: 228. Raised to species: Brown, 1954h: 6. Senior synonym of spiralis: Lattke, 2004: 106.
  • spiralis. Stictoponera spiralis Karavaiev, 1925a: 79 (w.) INDONESIA (Java). Combination in Gnamptogenys: Brown, 1958g: 229. Junior symonym of crassicornis: Lattke, 2004: 106.

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

Brown (1954) - Forel states that the eyes are anterior to the middle of the sides of the head, which if true would separate this form from binghamii very decisively. The other characters cited, however, indicate considerable similarity, and Forel may wen have been mistaken about the eyes. The description of Stictoponera spiralis, the next species following, also claims a similar position for the eyes. Among all the series available to me, I have seen no Stictoponera specimens with the eyes in front of the middle of the sides of the head. In any case, it is very unlikely that crassicornis can be a race of S. binghamii, since the known distribution of the latter straddles the Sumatran type locality of crassicornis. Provisional specific rank is indicated for crassicornis until the type can be re-examined.

Lattke (2004) - The type of Gnamptogenys spiralis is a typical G. crassicornis and shows nothing to distinguish it as a separate species. Brown (1954b) already suspected that it was a synonym of G. crassicornis, based on the description. G. crassicornis is similar to Gnamptogenys binghamii in many aspects and was originally described by Forel (1912b) as a subspecies of G. binghamii. Brown (1954) elevated crassicornis to species based on the anterior position of its compound eyes in comparison with G. binghamii. Even though the eyes are a bit more forward on the head when compared with G. binghamii, the difference is not striking. The following characters of G. binghamii will separate it from G. crassicornis: more evenly convex dorsal margin of the petiolar node when seen laterally, third and fourth antennal segments about as long as wide, no extensive striae or costulae on the sides of the fourth abdominal tergite, such sculpturing, if present, limited to small patch on the anteroventral corner of the segment in lateral view. In G. binghamii the fourth abdominal tergite has evenly convex lateral margins that gradually converge with each other posteriorly when seen dorsally in full-length view. In G. crassicornis the tergite is roughly funnel shaped with the anterolateral margins abruptly converging for a short distance before gradually converging posteriorly. Gnamptogenys coxalis could be confused with G. crassicornis, especially some of the forms with a smooth fourth abdominal tergite, but it has more protuberant occipital lobes and no anteromedian lobe on the clypeal lamella.

Description

Worker

Lattke 2004 Gnamptogenys fig 19-21

Lattke (2004) - Metrics (n = 7): HL 1.38-1.52, HW 1.07-1.18, ML 0.68-0.75, SL 1.10-1.21, ED 0.19-0.23, WL 1.85-1.97 mm. CI 0.76-0.80, SI 0.99-1.06, MI 0.61-0.66, OI 0.18-0.20. Head slightly wider posterad than anterad in frontal view, lateral margins relatively straight, posterior margin broadly concave, anterior margin of clypeal lamella with median convex lobe; frons rugulose-punctate with traces of striae; clypeus longitudinally carinate. Scape mostly longitudinally strigulose; occipital lamella well developed, convex at both ends.

Lateral mesosoma mostly foveolate over smooth background; katepisternum densely foveolate; mesosomal dorsum with round foveolae on smooth background; promesonotal suture faint; longitudinal smooth area present on median promesonotum; propodeal dorsum areolate. Petiolar node with convex dorsal margin in lateral view, dorsum foveolate, subpetiolar process subquadrate in lateral view; postpetiolar dorsum punctate, punctae become more shallow and sparse posterad, posterior margin scrobiculate to strigulose; postpetiolar sternum mostly smooth with low transverse strigulae; dorsum of abdominal segment 4 smooth with scattered punctae, laterally with longitudinally oblique costae and costulae; sternum transversely rugulose. Fore coxa transversely striate in lateral view; fore tarsus opposite strigil with row of stout setae; metacoxal tooth relatively straight, not hooked. Dorsum of thorax and abdominal segments 1-4 with scattered erect to subdecumbent hairs. Coloration uniformly light brown.

Queen

Lattke (2004) - Metrics (n = 2): HL 1.43, 1.47; HW 1.11, 1.11; ML 0.70, 0.73; SL 1.11, 1.16; ED 0.26, 0.29; WL 0.18, 0.19 mm. CI 0.78, 0.75; SI 0.99, 1.04; MI 0.63, 0.66; OI 0.23, 0.26. Striae on frons more noticeable; pronotum foveolate, mesonotum longitudinally strigulose-foveolate; katepisternum foveolate or striate; propodeum densely foveolate, declivity mostly smooth.

Type Material

Lattke (2004) - Holotype worker by monotypy [Indonesia], Sumatra, Indrapura (Tritschler) (Musee d'Histoire Naturelle Genève)[Examined].

Stictoponera spiralis Karavaiev, 1925:79. Holotype worker by monotypy: [Indonesia] Java, Buitenzorg (UASK) [Examined] syn. n.

References

  • Brown, W. L., Jr. 1954h. A review of the coxalis group of the ant genus Stictoponera Mayr. Breviora 34: 1-10 PDF (page 6, Raised to species)
  • 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)
  • Forel, A. 1912o. Einige neue und interessante Ameisenformen aus Sumatra etc. Zool. Jahrb. Suppl. 15("Erster Ba Band: 51-78 (page 51, 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 106, figs. 21, 46b, worker, queen described: senior synonym of spiralis)