Strumigenys paranax

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Strumigenys paranax
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Strumigenys
Species: S. paranax
Binomial name
Strumigenys paranax
Bolton, 1983

Strumigenys paranax casent0900627 p 1 high.jpg

Strumigenys paranax casent0900627 d 1 high.jpg

Specimen Labels

Nothing is known about the biology of Strumigenys paranax.

Identification

Bolton (1983, 2000) - A member of the dextra complex in the Strumigenys arnoldi-group. Of the four dextra-complex species in which only a single preapical tooth is present on the left mandible, Strumigenys irrorata is identified by its possession of only a single preapical tooth on the right mandible also, and Strumigenys katapelta by its possession of intercalary small teeth between the teeth of the apical mandibular fork. Of the two species remaining, which have 2 pre apical teeth on the right mandible and lack intercalary teeth, Strumigenys dextra is recognized by having a long fine flagellate hair at each of the pronotal humeri, whilst paranax has a stout straight strongly clavate hair in this position.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Cameroun (type locality), Gabon.


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.

  • paranax. Strumigenys paranax Bolton, 1983: 383 (w.) CAMEROUN. See also: Bolton, 2000: 595.

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 1.8, HL 0.47, HW 0.34, CI 72, ML 0.19, MI 40, SL 0.25, SI 74, PW 0.23. AL 0.46.

Mandibles slender and shallowly curved along their external borders, tapering gradually from base to apex. Apical fork of each mandible of2 teeth, without intercalary teeth or denticles. Left mandibular blade with only 1 preapical tooth (the proximal), right mandible with 2 pre apical teeth present. Upper scrobe margins gradually divergent, the eyes partially visible in full-face view. Eyes small, with only 4 ommatidia, their maximum diameter less than the maximum width of the scape. Preocular notch absent, the ventral surface of the head without a transverse preocular groove or impression. Antennal scapes shallowly curved in the basal third, only slightly broadened medially; the leading edges equipped with a row of apically curved spoon-shaped hairs which are slightly smaller than those fringing the upper scrobe margins. Ground-pilosity of head reduced and sparse, consisting of inconspicuous small flattened hairs. Upper scrobe margins with a double or triple row of large spoon-shaped hairs which are curved anteriorly and, are much more conspicuous than the ground-pilosity. Dorsum of head. with standing hairs arranged in a transverse row of 4 close to the occipital margin and a more anteriorly situated pair. Cephalic dorsum reticulate-punctate. Pronotal humeri each with a single straight stout hair which is clavate apically, without the elongate fine flagellate hair usually seen in this position. Mesonotum with a single pair of short broadly clavate standing hairs. Ground-pilosity of dorsal alitrunk consisting of small flattened hairs, which are closely applied to the surface, similar to those found on the head. Metanotal groove a transverse line on the dorsum, weakly impressed in profile. Mesonotum in profile not sharply depressed behind the level of the pair of hairs, instead the dorsum of the mesonotum forming a more or less even slope to the metanotal groove. Propodeal teeth small and triangular, subtended by infradental lamellae. Sides of alitrunk smooth except for peripheral punctures round the pleurae and propodeum. Dorsum of pronotum with widely spaced longitudinal rugulae, the remainder of the dorsal alitrunk reticulate-punctate. Petiole node punctate, the postpetiole smooth. Spongiform appendages of pedicel segments small, the petiole with only a very narrow ventral strip and the ventral spongiform lobe of the postpetiole smaller than the exposed area of the postpetiolar disc in profile. Basigastral costulae short but sharply defined, arising across the width of the tergite rather than radiating from each side of a broad central clear area. Petiole, postpetiole and gaster dorsally with stout clavate standing hairs. Colour brownish yellow.

Paratypes. TL 1.7-1.8, HL 0.45-0.46, HW 0.32-0.34, CI 70-74, ML 0.17-0.19, MI 37-41, SL 0.24-0.25, SI 73-75, PW 0.22-0.24, AL 0.42-0.46 (4 measured).

As holotype but some have the mesonotal dorsum shallowly concave in profile.

Type Material

Holotype worker, Cameroun: Nkoemvon, 1979 (D. Jackson) (The Natural History Museum). Paratypes. Gabon: 1 worker, Ile aux Singes, IS 1-4 (1. A. Barra) (Museum of Comparative Zoology). Cameroun: 1 worker, Fo Tabe, 19.i.1937 (no collector's name) (BMNH).

References