Gnamptogenys cribrata

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Gnamptogenys cribrata
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Ectatomminae
Tribe: Ectatommini
Genus: Gnamptogenys
Species: G. cribrata
Binomial name
Gnamptogenys cribrata
(Emery, 1900)

Gnamptogenys cribrata casent0616422 p 1 high.jpg

Gnamptogenys cribrata casent0616422 d 1 high.jpg

Specimen Labels

Synonyms

This species has small colonies with one queen and an average of 27 workers.

Identification

Lattke (2004) - Mesosomal dorsum varies from mostly smooth with punctae to longitudinally strigulose-punctate to densely punctate, usually with longitudinal median smooth area extending from posterior pronotum to part of propodeal dorsum; dorsal postpetiolar surface with scalloped punctae, not strigulose. Dorsum of fourth abdominal segment mostly smooth with scattered scalloped punctulae, frequently with longitudinal costulae that extend anterad from posterior margin up to three-fourths the length, usually less, of tergite.

The lighter-colored specimens of G. cribrata may look superficially like Gnamptogenys epinotalis because of their body color, but G. epinotalis has uniformly round punctae on the postpetiole that are not scalloped. Other characters of G. epinotalis not present in G. cribrata are a narrow sulcus around the katepisternum, a metanotal sulcus, and longitudinal costulae on most of the posterior end of the lateral mesosomal face. G. cribrata keys out along with Gnamptogenys luzonensis in the last couplet of the key.

Distribution

Southeast Asia and New Guinea.

Distribution based on Regional Taxon Lists

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

Distribution based on specimens

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The above specimen data are provided by AntWeb. Please see Gnamptogenys cribrata for further details

Biology

Lattke (2004) - No ergatoid queens were seen among the four queens examined (from northern Borneo) of this species; all were either winged or previously alated individuals. This is the most widespread species of the epinotalis group and also the most commonly collected. Most of the specimens were found in forested areas beneath logs, one was in bamboo leaf mold, and another was from a soil core.

The abstract of Ito and Gobin (2008) provides the following details about the biology of this species: We describe colony composition and reproductive and behavioural characteristics of Gnamptogenys cribrata. Colonies are monogynous, composed of one dealate queen and an average of 27 workers. This species shows the unusually low number of two ovarioles (1 – 1) in both queens and workers. The queen shows larval hemolymph feeding. Workers laid two distinctive types of egg depending on social environment: in the presence of a queen workers laid small trophic eggs which were not eaten by the queen. In the queenless condition, workers laid eggs that looked similar to a queen’s egg, but did not develop into a larva.

Castes

Worker

Males are unknown.

Queen

Nomenclature

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

  • cribrata. Rhopalopone cribrata Emery, 1900c: 311 (w.) NEW GUINEA. Lattke, 2004: 164 (q.). Combination in Gnamptogenys: Brown, 1958g: 228. Senior synonym of dammermani, diehlii: Lattke, 2004: 162.
  • diehlii. Ectatomma (Mictoponera) diehlii Forel, 1901e: 372 (w.) BORNEO. Combination in Rhopalopone: Emery, 1911d: 35; in Gnamptogenys: Brown, 1958g: 228. Junior synonym of cribrata: Lattke, 2004: 162.
  • dammermani. Rhopalopone dammermani Wheeler, W.M. 1924b: 240 (w.) INDONESIA (Sebesi I.). Combination in Gnamptogenys: Brown, 1958g: 228. Junior synonym of cribrata: Lattke, 2004: 162.

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

Lattke (2004) - When Wheeler (1924:240) described G. dammermani, he compared it to G. malaensis and separated the two species based on the slight size and color differences of G. dammermani, as well as the presence of propodeal denticles. The examined syntype of G. diehlii is lighter colored than that of G. dammermani and has overall less sculpturing, but darker-colored specimens (previously considered G. diehlii) are known from Thailand. The syntype of G. diehlii has a prominent spiracle on the fourth abdominal segment, but the conspicuousness of the spiracle seems to be an effect of the lighter coloring, and intermediate stages have been found in specimens previously considered G. dammermani. The development of the propodeal denticles, lobes, or ridges varies and does not correlate with any other potentially diagnostic character.

Compared with the forms known as G. dammermani and G. diehlii the syntypes of G. cribrata have more regular costulate sculpturing on the clypeus and the anterior margin of the clypeal lamella is more evenly convex, with much reduced lateral angles as well as a reduced median lobe. G. cribrata also has a very reduced anterior shelf on the petiole when seen laterally. The costulae are partially effaced in a specimen from Manus Island, and the same exemplar has an anterior petiolar shelf. Other specimens have the longitudinal clypeal strigulae much more regular and uniformly parallel, a condition closely approaching the regular carinulae in the forms known as G. cribrata. The extent of development of the anterior lobe of the clypeal lamella as well as the lateral angles of the lamella will vary. Intermediate morphologies can be found in ants previously regarded as G. dammermani. In short, no characters were found that could justify keeping G. dammermani, G. diehlii, and G. cribrata as different species from each other.

Description

Worker

Lattke 2004 Gnamptogenys fig 38-40

Lattke (2004) - Metrics (n = 10): HL 0.62-0.72, HW 0.48-0.58, ML 0.24-0.30, SL 0.40-0.51, ED 0.03-0.06, WL 0.68-0.89 mm. CI 0.73-0.81, SI 0.82-0.90, MI 0.49-0.57, OI 0.07-0.11. Anterior margin of clypeal lamella usually with bluntly angular sides in frontal view and slight convex median projection, median projection variable as well as lateral angles; clypeus longitudinally strigulose with broad median smooth longitudinal sulcus, sometimes carinulate. Lateral pronotal face longitudinally strigulose-punctate, frequently with smooth ventral strip; mesopleuron strigulose; metapleuron posteroventrally strigulose, anterodorsally depressed and mostly smooth; mesosomal dorsum varies from punctate over smooth ground sculpture to longitudinally strigulose-punctate to densely punctate (especially on propodeum), usually with longitudinal median smooth area extending from posterior pronotum to part of propodeal dorsum; promesonotal suture reduced to brief, feebly impressed line; metanotal sulcus usually absent, rarely present as vaguely impressed very fine line; propodeal declivity ranging from smooth to longitudinally strigulose, with or without low posterolateral denticles or lobes; propodeal dorsal margin meets declivitous margin through single convexity or blunt angle in lateral view, lateral propodeal face mostly smooth.

Petiolar dorsum ranging from mostly smooth to densely punctate, node punctate in lateral view; postpetiolar dorsum mostly smooth with abundant shallow piligerous punctae forming scalloped surface, each depression with abruptly impressed anterior margin and gradually sloped posterior margin; sternum usually transversely strigulose-punctate to densely punctate, sometimes punctate over mostly smooth ground sculpture; postpetiole punctate in lateral view, with each puncture more deeply impressed anterad than posterad; dorsum of abdominal tergite 4 similar to postpetiole but with finer, sparser depressions, frequently with longitudinal costulae that extend anterad from posterior margin up to three-fourths the length, usually less, of tergite; fourth abdominal sternite punctate over smooth to strigulose ground sculpture. Dorsum of thorax and abdominal segments 1-4 with scattered erect to subdecumbent hairs. Head, mesosoma, petiole, and gaster brown; mandibles, antennae, legs ferruginous brown; lighter-colored specimens frequently found.

Queen

Lattke (2004) - Metrics (n = 1): HL 0.67, HW 0.54, ML 0.27, SL 0.46, ED 0.11, WL 0.82 mm. CI 0.80, SI 0.85, MI 0.50, OI 0.20. Pronotum varies from punctate with scabrosity to strigulose-punctate in lateral view, anterior surface punctate with smooth cuticle between punctae; anepisternum punctate with undulations or strigulae; katepisternum longitudinally strigulose; mesoscutum longitudinally rugose-punctate, medially mostly impunctate; metanotum strigulose-punctate; propodeal declivity with more longitudinal strigulae than worker; lateral propodeal surface strigulose. Petiole more compressed than in worker.

Type Material

Lattke (2004) - Syntype workers: New Guinea (Museo Civico di Storia Naturale, Genoa) [One syntype examined].

Ectatomma (Mictoponera) diehlii Forel, 1901a:372. Syntype workers: Borneo, Sarawak (Haviland) (Musee d'Histoire Naturelle Genève) [Examined] Syn. nov.

Rhopalopone dammermani Wheeler, W.M., 1924:240. Holotype worker by monotypy: Indonesia, Sebesi Island. (Dammerman) (Museum of Comparative Zoology) [Examined]. Syn. nov.

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)
  • Emery, C. 1900b. Formicidarum species novae vel minus cognitae in collectione Musaei Nationalis Hungarici quas in Nova-Guinea, colonia germanica, collegit L. Biró. Publicatio secunda. Természetr. Füz. 23: 310-338 (page 311, worker described)
  • Ito, F. & Gobin, B. 2008. Colony composition and behaviour of a queen and workers in the Oriental ectatommine ant Gnamptogenys cribrata (Emery) 1900 in West Java, Indonesia. Asian Myrmecology, 2, 103-107.
  • 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 162, fig. 39 worker, queen described; senior synonym of diehlii, dammermani)