Strumigenys minkara

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

Pyramica minkara casent0178315 profile 1.jpg

Pyramica minkara casent0102549 dorsal 1.jpg

Specimen labels

The types were collected from forest in two different Ivory Coast national parks.

Identification

Bolton (2000) - A member of the Strumigenys weberi-group. One of the most distinctive species of the group: head obviously long and narrow in dorsal view, shallow in profile; scape relatively long; disc of postpetiole densely coarsely longitudinally costulate. Hairs on cephalic dorsum between clypeus and highest point of vertex all short and bristly, suberect to erect.

CI and SI in minkara are approached by Strumigenys arahana, some specimens of which may also have weak striolate sculpture on the postpetiole disc. However, specimens of the latter have much more extensive spongiform development on the waist segments, as noted under arahana, and the postpetiole disc sculpture is nowhere near as conspicuously strong and coarse as that seen in minkara.

Bolton (1983) - Of the three known species of this group which have the postpetiolar disc sculptured, minkara is immediately identifiable by its very long narrow head and relatively long scapes.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Ghana, Ivory Coast (type locality), Kenya.


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.

  • minkara. Smithistruma minkara Bolton, 1983: 306, fig. 14 (w.q.) IVORY COAST. Combination in Pyramica: Bolton, 1999: 1673; in Strumigenys: Baroni Urbani & De Andrade, 2007: 124. See also: Bolton, 2000: 339.

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 0.73, HW 0.40, CI 55, ML 0.06, MI 8, SL 0.31, SI 78, PW 0.28, AL 0.68.

Head very long and narrow, CI range of entire type-series 54-58; CI range for all other known species of the weberi-group is 61-68. Mandibles (from a paratype) armed with a high truncated basal lobe which is slightly longer than any of the teeth in the principal row. Distal to the basal lamella is the principal row of 5 relatively large teeth, separated from the lamella by a small diastema. Following these are two slightly smaller teeth, 4 minute denticles and a small apical tooth. Anterior clypeal margin transverse to exceedingly shallowly convex, the lateral clypeal margins very slightly converent anteriorly and with broadly rounded anterolateral angles. Sides and dorsum of clypeus with short curved ground-pilosity and also with numerous much longer stouter curved simple hairs. The long stout simple hairs arising from the lateral clypeal margins are directed outwards from the margin but then curve upwards or forward and upwards. On the dorsum of the clypeus the hairs are shorter centrally than at the sides, directed vertically or slightly curved. In profile the dorsum of the head behind the clypeus with short fine anteriorly curved ground-pilosity which is decumbent, and with stouter longer straighter hairs which are vertical or nearly so, these hairs shorter anteriorly than posteriorly on the head. In full-face view the sides of the head with abundant long simple projecting hairs, most of which are curved or sinuate. Median portion of clypeus from anterior tumulus to frontal lobes smooth or nearly so, the rest of the clypeus irregularly punctate. Dorsum of head coarsely reticulate-punctate, with well developed rugulae between the punctures on the vertex. Occipital concavity bounded on each side by a small flange or tooth in full-face view. Antennal scapes relatively long, narrowest at base but gradually increasing in width through the basal third, then slightly bent and broadened, the evenly curved leading edge with a series of freely projecting curved long simple hairs. Eyes of moderate size, maximum diameter 0.15 X HW. Head flattened in profile, the dorsum depressed and shallowly concave between clypeus and vertex, the eye bulging slightly beyond the ventral margin of the scrobe. Dorsal surfaces of alitrunk (except propodeum), petiole, postpetiole and first gastral tergite with numerous erect irregular to flagellate fine simple hairs, shorter more reclinate forms of which also project from the dorsal (outer) surfaces of the middle and hind tibiae. Dorsum of promesonotum and sides of pronotum strongly longitudinally rugose, the rugae smooth and rounded dorsally but the spaces between them punctate to shagreened and dull. Propodeal dorsum un sculptured except for a few small punctures, the declivity smooth. Pleurae mostly smooth, with a sparse median punctulate patch; the sides of the propodeum irregularly strongly rugose. With the alitrunk in profile the metanotal groove very feebly indicated, the propodeal teeth strong and broadly triangular, without infradental lamellae. Pronotum not sharply marginate laterally and lacking a median dorsal longitudinal carina. Dorsum of petiole node strongly irregularly rugose. Dorsum of postpetiole everywhere very strongly longitudinally costate to rugose, the sculpture very regular and almost sulcate. Basigastral costulae fine and very numerous, extending back almost to the apex of the segment in the centre of the sclerite, less extensive at the sides. Spongiform appendages of pedicel segments massively developed in profile. In dorsal view the petiole node surrounded posterolaterally and posteriorly by a thick spongiform strip. Disc of postpetiole in dorsal view completely surrounded by thick spongiform tissue which is broadest posterolaterally. Base of first gastral tergite with a thick spongiform transverse band which is overlapped by that on the posterior margin of the postpetiole. Colour medium brown.

Paratypes. TL 2.4-2.6, HL 0.70-0.76, HW 0.40-0.44, CI 54-58, ML 0.06-0.08, MI 8-11, SL 0.30-0.33, SI 73-78, PW 0.28-0.29, AL 0.67-0.74 (14 measured).

As holotype but maximum diameter of eye 0.15-0.18 X HW. In some the pleural punctate area is somewhat more extensive than in others and frequently the mesonotum is rather more swollen in profile than is the case in the holotype. One or two vestigial rugulae may be present on the propodeal dorsum, especially towards the sides. The basigastral costulae may cover only about half of the first gastral tergite on the centre of the sclerite.

Type Material

Holotype worker, Ivory Coast: Monogaga, 24.x.1980 (V. Mahnert & J. -L. Perret) (Musee d'Histoire Naturelle Genève). Paratypes. Ivory Coast: 11 workers with same data as holotype; 21 workers and 3 females, Tai Forest, 17.x.1980 (V. Mahnert &J.-L. Perret); 1 worker, Sassandra, 10 km from Monogaga, 16.iii.1977 (J. Lobl); 1 worker, Abidjan, Banco Forest, ii.1963 (W. L. Brown) (MHNG; The Natural History Museum; Museum of Comparative Zoology; Ecole Nationale Superieure Agronomique).

References