Strumigenys londianensis

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Strumigenys londianensis
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Strumigenys
Species: S. londianensis
Binomial name
Strumigenys londianensis
(Patrizi, 1946)

Strumigenys londianensis casent0900593 p 1 high.jpg

Strumigenys londianensis casent0900593 d 1 high.jpg

Specimen Labels

Brown (1954) state this is a forest species. Little else is known about its biology.

Identification

A member of the londianensis complex in the Strumigenys rogeri -group.

Bolton (1983) - A relatively large and easily recognized species, londianensis is known only from Kenya. Together with its close relative Strumigenys sarissa, Strumigenys londianensis is characterized by its distinctive mandibular dentition, deep preocular notch and detached dye. The only species coming close to londianensis and sarissa is Strumigenys bernardi, but this is a smaller species with relatively long mandibles which lacks intercalary teeth in the apical fork. The other two are separated as follows.

londianensis sarissa
HW 0.62-0.70, HL 0.84-0.92. HW 0.50-0.60, HL 0.72-0.82.
Some hairs on leading edge of antennal scape curved basally. All hairs on leading edge of antennal scape curved apically.
Vertex of head in profile with a single pair of stout clavate standing hairs, the cephalic ground-pilosity short and broadly spatulate. Vertex of head in profile without standing hairs, the cephalic ground-pilosity elongate, dense and narrowly spatulate.
Pronotal humeri with stout straight hairs which are clavate apically. Pronotal humeri with elongate fine flagellate hairs.
Anterior pronotal margin between the humeral hairs without other standing hairs. Anterior pronotal margin between the humeral hairs with a pair of stouter standing hairs; rarely with two pairs.
Propodeum without triangular teeth. Propodeum with triangular teeth.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Afrotropical Region: Ethiopia, Kenya (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.

  • londianensis. Proscopomyrmex londianensis Patrizi, 1946: 295, figs. 1, 2 (w.) KENYA. Combination in Strumigenys: Arnold, 1948: 227; Brown, 1949d: 15. See also: Brown, 1954k: 14; Bolton, 1983: 377; Bolton, 2000: 602.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

Bolton (1983) - TL 3.5-4.2, HL 0.84-0.92, HW 0.62-0.70, CI 74-77, ML 0.44-0.47, MI 51-52, SL 0.52-0.58, SI 82-87, PW 0.38-0.44, AL 0.82-0.94 (8 measured).

Apical fork of left mandible with a small intercalary tooth between the upper and lower fork teeth; right apical fork without an intercalary tooth. Blade of left mandible with a single spiniform preapical tooth present (the proximal); blade of right mandible with 2 pre apical teeth, a larger proximal and a smaller distal tooth which is situated close to the apical fork and may be hidden by the opposing left apical fork when the mandibles are fully closed. Upper scrobe margins not bordered by a continuous projecting lamina, close together on anterior third of head, the eyes clearly visible in full-face view. Upper scrobe margins concave immediately behind the convex frontal lobes, with a pinched-in appearance. Behind this the scrobe margins shallowly concave above the eyes and then diverging posteriorly. Preocular notch deep and strongly developed, the anterior portion of the eyes detached from the side of the head. Preocular notch continued onto the ventral surface of the head as a conspicuous broad transverse impression. Antennal scapes roughly cylindrical, very slightly broadened in the median third and with a characteristic arrangement of strong hairs projecting from the leading edge. The basalmost 1-3 (usually 2) projecting hairs are curved apically, the next 3-4 are curved basally and the distalmost 3-4 are curved apically. Ground-pilosity of head short, broadly spatulate to scale-like everywhere and curved anteriorly. In profile the vertex usually with a single pair of stout standing hairs which are weakly clavate, but these are easily lost by abrasion. Dorsum of head reticulate-punctate. Pronotal humeri each with along stout straight hair which is remiform to weakly clavate apically. Mesonotum with a single pair of shorter stout straight hairs which are somewhat more strongly clavate apically; the dorsal alitrunk otherwise without standing pilosity but with sparse narrowly spatulate appressed ground-pilosity. In profile the posterior portion of the mesonotum sharply depressed below the level of the anterior portion and pronotum, forming a single surface with the propodeum. Metanotal groove absent. Propodeum without differentiated angular teeth, instead the infradental lamellae merely bulge slightly and form blunt angles dorsally. Sides of alitrunk mostly punctate but with some smooth shining areas on the pleurae. Dorsal alitrunk predominantly punctate but the pronotum generally with a few posteriorly divergent rugulae superimposed on the punctures. Petiole node weakly punctulate dorsally, the postpetiole generally smooth but sometimes with the weakest vestiges of punctulate sculpture visible Spongiform appendages of petiole represented by a thin ventral strip and a narrow posterior collar on the node. Postpetiole in profile with moderately well-developed ventral and lateral spongiform lobes and in dorsal view with a very narrow anterior and posterior spongiform strip. Basigastral costulae short and sparse, radiating from the narrow basal spongiform strip of the first tergite. Petiole, postpetiole and gaster dorsally with stout strong hairs which are clavate apically. Colour light brown, gaster darker.

Type Material

Bolton (1983) - Syntype workers, KENYA: Londiani, q. 2260 m.s.m., 4.ix.1943 (S. Patrizi); and Mau Forest, 16.i.1946 (Meneghetti) (The Natural History Museum; Museum of Comparative Zoology) [examined].

References

  • Arnold, G. 1948. New species of African Hymenoptera. No. 8. Occas. Pap. Natl. Mus. South. Rhod. 2: 213-250 (page 227, Combination in Strumigenys)
  • Bolton, B. 1983. The Afrotropical dacetine ants (Formicidae). Bulletin of the British Museum (Natural History). Entomology. 46:267-416. PDF (page 377, redescription of worker)
  • Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028. (page 602, redescription of worker)
  • Brown, W. L., Jr. 1949f. Revision of the ant tribe Dacetini. I. Fauna of Japan, China and Taiwan. Mushi 20: 1-25 (page 15, redescription of worker)
  • Brown, W. L., Jr. 1954k. The ant genus Strumigenys Fred. Smith in the Ethiopian and Malagasy regions. Bull. Mus. Comp. Zool. 112: 1-34 (page 14, redescription of worker)
  • Patrizi, S. 1946. Contribuzioni alla conoscenza delle formiche e dei mirmecofili dell'Africa orientale. Boll. Ist. Entomol. Univ. Studi Bologna 15: 292-296 (page 295, figs. 1,2 worker described)