Strumigenys emdeni

AntWiki - Where Ant Biologists Share Their Knowledge
Jump to navigation Jump to search
Strumigenys emdeni
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Strumigenys
Species: S. emdeni
Binomial name
Strumigenys emdeni
Forel, 1915

Strumigenys emdeni casent0280760 p 1 high.jpg

Strumigenys emdeni casent0280760 d 1 high.jpg

Specimen Labels

The only non-type specimen yields the only details about this ant's biology. It was collected from a tropical evergreen forest.

Identification

Bolton (2000) - A member of the emdeni complex in the Strumigenys horvathi-group. The three species emdeni, Strumigenys enanna and Strumigenys semirex are closely related. S. emdeni has a longer, more slender head than the other two, with more convex upper scrobe margins. In addition the striking broad ground-pilosity of the cephalic dorsum is very obviously repeated on the promesonotum and the disc of the postpetiole is sculptured.

In the other two species the head is shorter and broader, with straighter upper scrobe margins. The ground-pilosity of the cephalic dorsum is not repeated on the promesonotum, which in dorsal view looks quite bare in comparison to the head. The disc of the postpetiole in both species is smooth. S. semirex is larger than enanna and has extensive smooth patches laterally on the alitrunk; this area is entirely reticulate-punctate in enanna.

These three species together are quickly separable from the fourth member of the emdeni-complex, Strumigenys nummula, as this last species has a short, straight pronotal humeral hair and three pairs of erect hairs on the mesonotal dorsum.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Australasian Region: Australia (type locality).

Distribution based on AntMaps

AntMapLegend.png

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

Worker

Nomenclature

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

  • emdeni. Strumigenys emdeni Forel, 1915b: 41 (w.) AUSTRALIA. Combination in Labidogenys: Brown, 1948e: 103; in Strumigenys: Taylor & Brown, D.R. 1985: 87. See also: Bolton, 2000: 974.

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

Description

Worker

Bolton (2000) - TL 2.5-2.9, HL 0.69-0.80, HW 0.49-0.58, CI 70-74, ML 0.22-0.26, MI 30-34, SL 0.29-0.35, SI 58-66, PW 0.29-0.33, AL 0.69-0.76 (12 measured).

Characters of emdeni-complex. Inner margin of mandible with a narrow translucent cuticular lamella that commences at mandible base and peters out just proximal of the curved-spiniform preapical tooth; maximum width of lamella distinctly less than half the length of the preapical tooth. Outer curvature of eyes not visible in full-face view, eyes completely concealed by upper scrobe margins. Ventrolateral margin of head in front of eye very shallowly concave. With head in profile the scrobe strongly developed behind the level of the eye, deep, clearly defined and with sharp dorsal, ventral and posterior margins. Dorsal surfaces of head and promesonotum densely clothed with orbicular ground-pilosity. Posteriorly on mesonotum these hairs may be more elevated than elsewhere but there are no erect hairs anywhere on the cephalic and alitrunk dorsa. Pronotal humeral hair absent. First gastral tergite with numerous erect stiff hairs that are slightly thickened or flattened apically, or weakly remiform. Dorsum of head and alitrunk reticulate-punctate but sculpture m uch concealed by ground-pilosity. Side of alitrunk entirely reticulate to reticulate-punctate, without a smooth area on katepisternum. Disc of postpetiole reticulate-shagreenate to reticulate-punctate.

Type Material

Bolton (2000) - Syntype workers, AUSTRALIA: Queensland, Atherton (E. Mjoberg) (Musee d'Histoire Naturelle Genève) [examined].

References

  • Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028. (page 974, fig 529 redescription of worker)
  • Brown, W. L., Jr. 1948e. A preliminary generic revision of the higher Dacetini (Hymenoptera: Formicidae). Trans. Am. Entomol. Soc. 74: 101-129 (page 103, Combination in Labidogenys)
  • Emery, C. 1924f [1922]. Hymenoptera. Fam. Formicidae. Subfam. Myrmicinae. [concl.]. Genera Insectorum 174C: 207-397 (page 321, catalogue)
  • Forel, A. 1915b. Results of Dr. E. Mjöbergs Swedish Scientific Expeditions to Australia 1910-13. 2. Ameisen. Ark. Zool. 9(1 16: 1-119 (page 41, worker described)
  • Taylor, R. W.; Brown, D. R. 1985. Formicoidea. Zool. Cat. Aust. 2:1- 149: 1-149, 30 (page 87, revived combination)