Strumigenys sharra

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

Pyramica sharra casent0102555 profile 1.jpg

Pyramica sharra casent0102555 dorsal 1.jpg

Specimen labels

Known from a few forest litter-samples.

Identification

Bolton (2000) - A member of the chyatha complex in the Strumigenys emarginata group. Characters of chyatha-complex. Clypeal dorsum densely clothed with large suborbicular hairs; similar hairs evenly distributed over cephalic dorsum behind clypeus and sparsely represented on dorsal alitrunk. In the group this pilosity is duplicated only in Strumigenys cavinasis.

Bolton (1983) - The closest relative of shara is Strumigenys cavinasis which shares the remarkable dense suborbicular pilosity. They can be separated by the following differences:

cavinasis sharra
Head absolutely and relatively shorter, HL 0.52-0.56, CI 63-67. Head absolutely and relatively longer, HL 0.58-0.64, CI 56-63.
Antennal scapes absolutely and relatively shorter, SL 0.22-0.26, SI 63-70. Antennal scapes absolutely and relatively longer, SL 0·26-0.28, SI 73-78.
Posterior margin of postpetiole disc without a row of spatulate to squamate hairs on each side of the midline. Posterior margin of postpetiolar disc with now of 5-6 spatulate to squamate hairs on each side of the midline which project backward over the spongiform strip.
Simple elongate hairs present on the postpetiolar disc. Simple elongate hairs absent from the postpetiolar disc.
Simple elongate hairs present on the basal portion of the first gastral tergite. Simple elongate hairs absent from the basal portion of the first gastral tergite.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Angola, Cameroun, Gabon, Ghana, Ivory Coast (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.

  • sharra. Smithistruma sharra Bolton, 1983: 295, fig. 3 (w.q.) IVORY COAST. Combination in Pyramica: Bolton, 1999: 1673; in Strumigenys: Baroni Urbani & De Andrade, 2007: 127. See also: Bolton, 2000: 305.

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 2.1, HL 0.62, HW 0.38, CI 61, ML 0.06, MI 10, SL 0.28, SI 74, PW 0.24, AL 0.60.

Mandibles with 5 relatively strong teeth following the basal lamella without a diastema. Distal to these main teeth are two slightly smaller teeth, followed by 4 minute denticles and an apical small tooth. Anterior clypeal margin strongly and evenly concave, the concavity involving the entire border between the anterolateral angles. Lateral margins of clypeus feebly convex and convergent anteriorly, fringed with a continuous series of large flattened spatulate to spoon-shaped hairs which project freely and are curved anteriorly. Anterior clypeal margin with a row of 6 broadly scale-like to suborbicular hairs which project out over the mandibles. Dorsum of clypeus and remainder of head densely covered with broadly scale-like to suborbicular hairs which are densest on the clypeus; such hairs also fringe the lateral borders of the head in full-face view. Flagellate hairs or other pilosity absent. Pre ocular laminae broad in full-face view and somewhat divergent anteriorly. Antennal scapes narrow basally, bent at about the basal quarter and suddenly broadened, broadest at about this level and the leading edge evenly rounded with a narrow prominent lamina. Dorsal surface of scape with scale-like hairs but leading edge with a series of freely projecting longer narrower hairs, the longest of which occurs at about the broadest part of the scape. Eyes of moderate size, about 0.11 x HW, smaller than the maximum width of the scape. Dorsum of clypeus and area immediately posterior to it very finely reticulate-punctate, with a granular appearance. Remainder of dorsum similarly sculptured but also with scattered very short low rugulae. Dorsal alitrunk with scattered but conspicuous scale-like hairs, which are also conspicuous on the petiole and postpetiole, though averaging smaller in size. In dorsal view the posterior margin of the postpetiolar disc with a row of 5-6 scale-like to spatulate hairs on each side of the midline which project out over the spongiform tissue; the posterior petiolar margin with a similar row of 4 scale-like hairs (2 on each side of the midline). Standing simple hairs absent from alitrunk, petiole, postpetiole and first gastral tergite; flagellate hairs never developed. Alitrunk not marginate laterally, the pronotum flattened and without a median longitudinal ridge or carina dorsally. With the alitrunk in profile the mesonotum very slightly raised above the level of the pronotum and propodeum. Metanotal groove not impressed but its site marked by the small step-down from the mesonotal to the propodeal dorsum. Propodeal teeth strong, broad basally and slightly upcurved along their length, the infradental lamella very narrow and its outline distinctly concave. Pleurae and sides of propodeum densely punctulate. Pronotal dorsum exceedingly feebly rugulose, the rugulae tending to be irregular but with an overall longitudinal trend. Spaces between the minute rugulae shagreened and dull. Remainder of dorsal alitrunk and petiole dorsum finely punctulate. Disc of postpetiole smooth and shining and first gastral tergite unsculptured except for the basigastral costulae which form an uninterrupted band across the base of the sclerite. Spongiform appendages massively developed in profile. In dorsal view the sides and posterior margin of the petiole node surrounded by continuous thick spongiform material. The postpetiole with an anterior spongiform transverse strip and with the lateral spongiform material projecting beyond the lateral outlines of the disc in dorsal view. Posterior margin of postpetiole disc with a continuous broad spongiform strip which is narrower centrally than at the sides but not broken. Base of first gastral tergite with a transverse spongiform band which is as broad as, and is overlapped by, that on the posterior postpetiolar margin. Colour medium to dark brown.

Paratypes. TL 2.0-2.2, HL 0.58-0.64, HW 0.35-0.38, CI 56-63, ML 0.06-0.08, MI 9-12, SL 0.26-0.28, SI 73-78, PW 0.22-0.26, AL 0.54-0.62 (20 measured).

As holotype but with maximum diameter of eye 0.11-0.15 X HW. In some the longitudinal nature of the minute pronotal rugulae is better shown than in others, which are less regular and like the holotype. The maximum number of scale-like hairs fringing the posterior dorsal margin of the petiole node appears to be 6 (3 on each side of the midline) though the outermost on each side may actually arise on the lateral margin of the node and project backward. The basal lamella of the mandible consists of a high rectangle with concave sides, visible in one of the paratypes.

Type Material

Holotype worker, Ivory Coast: Issoneu, 12.x.1980 (V. Mahnert & f.-L. Perret) (Musee d'Histoire Naturelle Genève).

Paratypes. Ivory Coast: 14 workers and 1 female with same data as holotype; 9 workers, Man, 7.x.1980 (V. Mahnert & f.-L. Perret); 7 workers and 1 female, Dropleu, 10.x.1980 (V. Mahnert & f.-L. Perret); 4 workers, Tai Forest, 17.x.1980 (V. Mahnert &f.-L. Perret) (Musee d'Histoire Naturelle Genève; The Natural History Museum; Museum of Comparative Zoology).

References