Strumigenys arahana

AntWiki: The Ants --- Online
Strumigenys arahana
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Strumigenys
Species: S. arahana
Binomial name
Strumigenys arahana
(Bolton, 1983)

Strumigenys arahana casent0900096 p 1 high.jpg

Strumigenys arahana casent0900096 d 1 high.jpg

Specimen Labels

Nothing is known about the biology of Strumigenys arahana.

Identification

Bolton (1983) - A member of the Strumigenys weberi-group. Six species of the group combine the characters of having the postpetiolar disc without dense costulate sculpture and having the metanotal groove unimpressed. Of these only arahana has the spongiform tissue behind the petiole node very densely and massively developed. In dorsal view the spongiform material is thicker than the length of the node in arahana, whereas in the five other species (Strumigenys fenkara, Strumigenys malaplax, Strumigenys placora, Strumigenys synkara, Strumigenys tolomyla) it is decidedly narrower than the length of the node, in some being merely a lamella.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Cameroun (type locality).

Distribution based on AntMaps

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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.
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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.
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Biology

Explore-icon.png 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.

  • arahana. Smithistruma arahana Bolton, 1983: 300 (w.) CAMEROUN. Combination in Pyramica: Bolton, 1999: 1673; in Strumigenys: Baroni Urbani & De Andrade, 2007: 115. See also: Bolton, 2000: 336.

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 2.5, HL 0.65, HW 0.40, CI 61, ML 0.05, MI 8, SL 0.28, SI 70, PW 0.30, AL 0.64 .

Anterior clypeal margin transverse, the anterolateral angles rounded and the lateral margins feebly divergent posteriorly. Outline of preocular laminae shallowly convex in full-face view, broadest at about their midlength and slightly convergent both anteriorly and posteriorly. Lateral margins of clypeus with simple projecting hairs, the shorter of which are curved anteriorly and the longer of which curve upwards or forwards and upwards. Clypeal and cephalic dorsa equipped with simple fine ground-pilosity, the hairs of the ground-pilosity short and arched forward so that their apices are in contact or nearly in contact with the surface. Projecting above the ground-pilosity are longer stouter simple hairs which are erect or nearly so. On the clypeal dorsum most of these hairs curve forward then upward but the posteriormost clypeal row are shallowly sinuate and are also the longest. Behind the clypeus similar erect curved to sinuate hairs are present, none of which are longer than the posterior clypeal row. Close to the occipital margin are a few hairs which are angled and have their apical portions narrowly flagellate. In full-face view the sides of the head with numerous projecting simple hairs. Antennal scapes slightly bent in the basal third, broadest at about the midlength, the leading edge with anteriorly projecting simple hairs most of which are upcurved in their distal halves. Dorsum of head coarsely and very densely reticulate-rugulose everywhere, the clypeus less strongly sculptured. Promesonotum not marginate, the pronotal dorsum without a median longitudinal carina. Metanotal groove not impressed. Propodeal teeth broad and triangular, short, the infradental lamellae vestigial and represented only by a narrow rim; outline of the propodeal declivity in profile distinctly concave. Sides of pronotum and propodeum coarsely rugose, the pleurae smooth. Mesopleuron with a dense vertical band of fine punctulae close to its junction with the metapleuron but otherwise the pleurae only with very widely scattered fine punctulae. Promesonotal dorsum coarsely and densely rugose, the propodeal dorsum smooth except for a few feeble anteriorly situated punctures. Dorsal alitrunk with numerous fine simple hairs. Spongiform appendages of pedicel segments massively developed in profile. Outline of petiolar ventral process concave at about its midlength, the ventral postpetiolar lobe very large indeed. In dorsal view the petiole node rugose and distinctly broader than long, with a very thick posterior ruff of dense spongiform material, the thickness of which is greater than the length of the exposed dorsum of the node. Laterally the spongiform tissue laps around the sides of the node almost to the anterolateral angles. Disc of postpetiole in dorsal view completely surrounded by dense thick spongiform material, the disc uneven and with scattered punctures, not glassy smooth as is usual in the weberi-complex but lacking the strong costulae characteristic of the minkara-complex. Anterior margin of postpetiolar disc bordered by a dense spongiform strip, the sides with dense spongiform tissue which is narrowest anteriorly and extremely broad posterolaterally. Posterior spongiform strip broad and with a narrow median cleft. Base of first gastral tergite with a broad very finely and densely spongiform transverse strip, the tergite posterior to this with short basigastral costulae. Dorsal surfaces of petiole, postpetiole and gaster with numerous fine simple hairs. Colour dull brownish yellow to light brown.

Paratype. TL 2.6, HL 0.70, HW 0.43, CI 61, ML 0.06, MI 9, SL 0.30, SI 70, PW 0.32, AL 0.70.

As holotype but disc of postpetiole less noticeably punctate.

Type Material

Holotype worker, Cameroun: nr Yaounde, sample D2 (G. Terron) (Ecole Nationale Superieure Agronomique). Paratype. 1 worker, Cameroun: nr Yaounde, sample 2419 (G. Terron) (The Natural History Museum).

References

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