Strumigenys bryanti

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Strumigenys bryanti
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Strumigenys
Species: S. bryanti
Binomial name
Strumigenys bryanti
Wheeler, W.M., 1919

Strumigenys bryanti casent0280733 p 1 high.jpg

Strumigenys bryanti casent0280733 d 1 high.jpg

Specimen Labels

Nothing is known about the biology of Strumigenys bryanti.

Identification

Bolton (2000) - A member of the doriae complex in the Strumigenys doriae-group. Closest related to Strumigenys hekate (see under Strumigenys doriae), from which it separates as follows.

S. bryanti: Mandible without trace of preapical dentition. Humeri of pronotum evenly broadly rounded in dorsal view. Mesonotum in profile forming a long convex arc that slopes steeply down to the propodeum, the latter on a much lower level. First gastral tergite without dense short grey pubescence between the main pilosity.

S. hekate: Mandible with two minute preapical denticles. Humeri of pronotum distinctly angulate in dorsal view. Mesonotum in profile forming a short, flat, shallowly sloping surface, the propodeum only on a slightly lower level. First gastral tergite with a dense coat of short grey pubescence between the main pilosity.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: Borneo (type locality), Indonesia, Malaysia.


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.

  • bryanti. Strumigenys bryanti Wheeler, W.M. 1919e: 95 (q.) BORNEO. See also: Brown, 1954f: 164; Bolton, 2000: 774.

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 4.2, HL 1.10, H W 0.71, CI 65, ML 0.58, MI 53, SL 0.70, SI 99, PW 0.42, AL 1.16. Mandible without trace of preapical dentition. In anterior view apical fork of mandible forming a V-shape or very narrow-based U-shape, the dorsal fork tooth conspicuously longer than the ventral. Propodeal teeth invisible in profile or visible as a vague outline, either fully embedded in, or replaced by, spongiform tissue. Lateral spongiform lobe of petiole a short thick collar, restricted to posterior margin of node, not extending forward to the level of the spiracle on the peduncle. Dorsolateral margin of head with 5 or more long fine hairs and a number of shorter simple hairs that freely project laterally; apicoscrobal hair usually slightly longer than any of the other main projecting hairs, its length about 0. 60 X SL. With head in profile erect hairs that arise from the dorsum in front of the highest point of the vertex are much shorter than the longest hairs that arise between the highest point and the occipital margin; the longest of the latter is shorter than the maximum depth of the head capsule. Longest hairs on first gastral tergite about equal to length of tergite from base of limbus to apex and somewhat greater than the maximum depth of the first gastral segment in profile.

Queen

Brown (1954) - Holotype, alate: Differs significantly in proportions, especially of the mandibles, and also in other minor details, from Strumigenys ulcerosa and Strumigenys doriae, but for the most part very similar to. at least the first of these. TL 4.63, HE 1.08, ML 0.60, WL 1.25 mm. CI 69, MI 56; occipital-pronotal overlap 0.1 ram., subtracted from TL. Antennal scapes straight, slender, L 0.70, very feebly incrassate in the apical half; uniculus slender, L 0.88 (segment V 0.40, IV 0.31, II -III 0.08, I 0.09-0.10 mm.).

Mandibles with apical fork of two slender spiniform teeth, the dorsal tooth virtually straight in its apical half, the ventral tooth parallel to the dorsal and about half as long, its extreme tip gently deflected venrad; a single minute, acute intercalary denticle present. The dorsal apical tooth is about 0.17 mm. long, or slightly more. Shaft of mandible straight, broad, depressed, slightly narrowed toward base; external border feebly convex, inner border straight, except for brief weakly concave apical and basal stretches, and with dorsal and ventral subcultrate margins. The gentle preapical .concavity, just at the point where it joins the straight section of the inner border, bears a very low, obtuse vestige of a translucent angle, just barely perceptible at higher magnifications and then only in certain views. This insignificant vestige is probably homologous with the preapical ooth or angle in the majority of Indo-Australian Strumigenys species. The reduction of the preapical tooth can be followed in the series Strumigenys koningsbergeri, Strumigenys formosensis, Strumigenys bryanti, although his series probably does not represent the actually evolved lineage.

The secretory pits and lacunae are arranged much as in the worker of Strumigenys ulcerosa, but those on the thoracic sclerites are somewhat restricted by the different development of these areas accompanying the presence of the wings. Scutum intricately and rather deeply rugulose-punctulate. Scutellum with similar sculpture; punctulation of mesokatepisternum partially effaced, the surface here more or less smooth and shining. Basal costulae of gaster short and fine.

Head with moderate growth of fine, subreclinate ground hairs, fewer moderately long, fine erect hairs, and fewer still very long, outstanding, fine flagellate hairs, the latter concentrated along the dorsolateral and posterior occipital borders. Scape hairs very fine, reclinate. Alitrunk with numerous long, fine erect hairs, the same, becoming longer and flagelliform on both nodes and gastric dorsum (L up to 0.55 ram.), where some are as long as or nearly as long as the maximum depth of the gaster itself. Legs with very long, fine erect hairs, becoming extremely long and tapered, but fewer, on the posterior surfaces of the metatarsi, where they are often nearly as long as the elongate metatarsus itself. Also present on legs, alitrunk, both nodes and underside of head is a dense pile of very fine, short reclinate hairs, inconspicuous except on humeral borders, propodeum and petiolar node; forming a large anteroventral pad at the base of the gaster. The long flagelliform hairs are considerably longer than those of ulcerosa.

Type Material

Bolton (2000) - Holotype queen, MALAYSIA: West Sarawak, Mt Matang (G.E. Bryant) (Museum of Comparative Zoology) [examined].

References