Strumigenys retothra

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Strumigenys retothra
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Strumigenys
Species: S. retothra
Binomial name
Strumigenys retothra
Bolton, 2000

Strumigenys retothra casent0900861 p 1 high.jpg

Strumigenys retothra casent0900861 d 1 high.jpg

Specimen Labels

Known from a few rainforest collections, one from a tree trunk and the other from a rotten log.

Identification

Bolton (2000) - A member of the Strumigenys loriae-group. In the type-series the postpetiole disc is smooth, but the non-paratypic series from near Wau has fine punctulate sculpture on the disc. However, this series retains the other diagnostic features listed above.

For notes on broader relationships within the group see under Strumigenys kyroma. Whether retothra shows polymorphism similar to that seen in Strumigenys loriae cannot be confirmed as only few workers are known; all are large and about the same size. If they represent the upper end of the size range of retothra workers then the species differs from all its close relatives (kyroma, loriae, Strumigenys festigona) by its lack of standing hairs on the pronotum, except for the humeral pair, and lack of a well developed projection on the side of the head in front of the preocular impression, at least in individuals within the same size range (HW ca 1.00-1.30).

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: New Guinea (type locality).


Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Strumigenys were once thought to be rare. The development and increased use of litter sampling methods has led to the discovery of a tremendous diversity of species. Many species are specialized predators (e.g. see Strumigenys membranifera and Strumigenys louisianae). Collembola (springtails) and other tiny soil arthropods are typically favored prey. Species with long linear mandibles employ trap-jaws to sieze their stalked prey (see Dacetine trap-jaws). Larvae feed directly on insect prey brought to them by workers. Trophallaxis is rarely practiced. Most species live in the soil, leaf litter, decaying wood or opportunistically move into inhabitable cavities on or under the soil. Colonies are small, typically less than 100 individuals but in some species many hundreds. Moist warm habitats and micro-habitats are preferred. A few better known tramp and otherwise widely ranging species tolerate drier conditions. Foraging is often in the leaf litter and humus. Workers of many species rarely venture above ground or into exposed, open areas. Individuals are typically small, slow moving and cryptic in coloration. When disturbed individuals freeze and remain motionless. Males are not known for a large majority of species.

Castes

Nomenclature

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

  • retothra. Strumigenys retothra Bolton, 2000: 865 (w.) NEW GUINEA.

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

Description

Worker

Holotype. TL 4.4, HL 1.32, HW 1.20, CI 91, ML 0.60, MI 45, SL 0.80, SI 67, PW 0.46, AL 1.20. Closely related to Strumigenys kyroma; answering the description of that species except as follows.

1 Preapical tooth on mandible short and blunt, inclined toward the apicodorsal tooth.

2 In full-face view side of head in front of preocular impression merely forms a broadly rounded low blunt tumulus.

3 Pronotum without a pair of standing hairs on its dorsum close to the anterior margin (i.e. the humeral hairs are the only ones present on the pronotum).

4 Bulla of femoral gland on hind leg minute or invisible, much smaller than the conspicuous bulla of the hind tibial gland.

5 Head, alitrunk, waist segments and gaster uniformly dark brown to blackish brown. Legs dull brownish yellow, much lighter than body and strongly contrasting with it.

Paratype. TL 4.3, HL 1.32, HW 1.17, CI 89, ML 0.58, MI 44, SL 0.80, SI 68, PW 0.48, AL 1.20.

Type Material

Holotype worker, Papua New Guinea: 6 km. 5 Telefomin, 5.11°S, 141.38°E, 4.vii.1980, 1500 m., on tree trunk, gully rainforest, #4672 (P. S. Ward) (The Natural History Museum). Paratype. 1 worker with same data as holotype (University of California, Davis).

References

  • Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028. (page 865, worker described)