Strumigenys amnesia

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

Strumigenys amnesia has been collected in primary and old secondary forests (Tang & Guenard, 2023).

Identification

Bolton (2000) – A member of the koningsbergeri complex in the Strumigenys koningsbergeri-group. See Strumigenys chorosa.

Tang & Guenard (2023) - Bolton (2000) noted that workers from Thailand and Sumatra (HL 0.64–0.69, MandL 0.28–0.33, SL 0.35–0.39) were slightly smaller than the type specimens from Malaysia (HL 0.72–0.76, MandL 0.34–0.36, SL 0.42–0.44). The workers from Thailand we measured (HL 0.63–0.66, MandL 0.29–0.30, SL 0.34–0.37) also had morphological measurements that fell within the typical range reported by Bolton.

Keys including this Species

Key to Strumigenys of East Asia

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: 7.35° to 7.35°.


North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

Source: AntMaps

Distribution based on Regional Taxon Lists

Indo-Australian Region: Malaysia (type locality).
Oriental Region: Thailand.

Distribution based on AntMaps

Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.

Biology

Explore Overview of Strumigenys 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.

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Castes

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

amnesia. Strumigenys amnesia Bolton, 2000: 838 (w.) WEST MALAYSIA.

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 2.6, HL 0.74, HW 0.62, CI 84, ML 0.34, MI 46, SL 0.43, SI 69, PW 0.32, AL 0.68. With characters of koningsbergeri-complex. Preocular concavity forms a broad depression on ventral surface of head. Upper scrobe margins constricted and concave above eye, entire eye visible in full-face view but its inner margin only just clear of the line of the scrobe margin. Edge of upper scrobe margin with a few minute tubercles but without a row of triangular teeth and lacking a decidedly jagged appearance. Depression across posterior vertex of head broad and shallow but distinct. Pronotum with a pair of short standing hairs close to anterodorsal margin. Pronotal humeral hair stiff, straight and simple. A single erect pair of hairs on mesonotum. Katepistemum and at least upper half of metapleuron smooth. Bullae of femoral glands absent on middle and hind legs. Lamella on propodeum narrow, its posterior (free) margin usually concave for most of its length but more or less straight in some. Standing hairs on first gastral tergite simple and cylindrical, pointed apically.

Paratypes. TL 2.6-2.7, HL 0.72-0.76, HW 0.63-0.65, CI 85-88, ML 0.34-0.36, MI 47-48, SL 0.42-0.44, SI 66-70, PW 0.32-0.33, AL 0.68-0.72 (3 measured).

Non-paratypic workers from Thailand and Sumatra are slightly smaller. HL 0.64-0.69, HW 0.56-0.61, CI 86-88, ML 0.28-0.33, MI 44-49, SL 0.35-0.39, SI 63-66 (4 measured).

Type Material

Holotype worker (upper of two workers on pin), Malaysia: Pahang, Cameron Highlands, Gunung Jasar, 1720 m., 25.iii.1993, #19b (Lobl & Calame) (Musee d'Histoire Naturelle Genève). Paratypes. 3 workers with same data as holotype (MHNG, The Natural History Museum).

References

Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028. (page 838, worker described)
Khachonpisitsak, S., Yamane, S., Sriwichai, P., Jaitrong, W. 2020. An updated checklist of the ants of Thailand (Hymenoptera, Formicidae). ZooKeys 998, 1–182 (doi:10.3897/zookeys.998.54902).
Tang, K. L., Guénard, B. 2023. Further additions to the knowledge of Strumigenys (Formicidae: Myrmicinae) within South East Asia, with the descriptions of 20 new species. European Journal of Taxonomy 907, 1–144 (doi:10.5852/ejt.2023.907.2327).

References based on Global Ant Biodiversity Informatics

Bolton, B. 2000. The Ant Tribe Dacetini. Memoirs of the American Entomological Institute 65