Strumigenys radix

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

Strumigenys radix casent0280759 p 1 high.jpg

Strumigenys radix casent0280759 d 1 high.jpg

Specimen Labels

Despite their being more than ten collections of this ant, the only recorded biological record is of one specimen being found in open forest.

Identification

Bolton (2000) - Within the Strumigenys emmae-group only this species and Strumigenys anchis have two distinct preapical teeth on each mandible. The latter is immediately separated from radix as the ventrolateral margin of the head of anchis, in front of the eye, has a broad, deep U-shaped concavity. Some samples of Strumigenys emmae have a minute denticle on the inner mandibular margin distal of the spiniform preapical tooth but in those the scapes are much flattened and expanded in their median third, the lateral margins of the postpetiole disc are margined with spongiform tissue in dorsal view (and the disc usually has some sculpture) , and the hairs on the first gastral tergite are sparser and not so strongly expanded apically.

Identification Keys including this Taxon

Distribution

Distribution based on Regional Taxon Lists

Australasian Region: Australia (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.

  • radix. Strumigenys radix Bolton, 2000: 953 (w.q.) AUSTRALIA.

Type Material

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 1.7, HL 0.47, HW 0.36, CI 77, ML 0.14, MI 30, SL 0.24, SI 67, PW 0.23, AL 0.44. Exposed length of fully closed mandible less than width of anterior clypeal margin. Mandible with two preapical teeth; a long spiniform proximal tooth and an acute conical distal tooth that is about one-third the length of the proximal. Antenna with 4 segments; second funicular segment longer than broad. Cephalic dorsum with broadly spoon-shaped to suborbicular hairs; upper scrobe margin fringed with similar hairs and with a remiform to clavate apicoscrobal hair. Occipital margin of head without erect hairs. Leading edge of scape flattened and very obtusely angled near the midlength, without a convex lobe in the median third of its length. Pronotal humeral hair large, curved remiform; a similar pair present on mesonotum. Ground-pilosity of promesonotal dorsum spoon-shaped. Promesonotal dorsu m finely reticulate-punctate. Disc of post petiole somewhat swollen, entirely smooth; sides of disc in dorsal view not margined by projecting spongiform tissue. First gastral tergite with numerous short thick remiform hairs that are strongly expanded apically. Basigastral costulae at least equal in length to postpetiole disc.

References

  • Bolton, B. 2000. The ant tribe Dacetini. Mem. Am. Entomol. Inst. 65: 1-1028 (page 953, worker described)