Strumigenys inusitata

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Strumigenys inusitata
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Strumigenys
Species: S. inusitata
Binomial name
Strumigenys inusitata
(Lattke, 1992)

Strumigenys inusitata casent0281990 p 1 high.jpg

Strumigenys inusitata casent0281990 d 1 high.jpg

Specimen Labels

Known from a few litter samples from a mature wet forest and a low sclerophyl forest.

Identification

Bolton (2000) - A member of the Strumigenys splendens-group. The remarkable crested development of the clypeus immediately diagnoses inusitata among all the Neotropical species. Only the unrelated Strumigenys euryale from Borneo shows a similar but obviously convergently acquired feature. Coupled with this unique clypeal development the lack of a lateral spongiform lobe on the petiole node but presence of a subspongiform crest on its peduncle, lack of a ventral lobe on the postpetiole and lack of basal spongiform tissue on the first gastral sternite makes inusitata immediately recognisable within the group.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Neotropical Region: Brazil, Venezuela (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.

  • inusitata. Trichoscapa inusitata Lattke, 1992b: 142, fig. 1 (w.) VENEZUELA. Combination in Smithistruma: Bolton, 1995b: 384; in Pyramica: Bolton, 1999: 1673; in Strumigenys: Baroni Urbani & De Andrade, 2007: 121. See also: Bolton, 2000: 233.

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

Description

Worker

Bolton (2000) - TL 2.2, HL 0.68-0.69, HW 0.48-0.53, CI 71-77, ML 0.02-0.04, MI 3-5, SL 0.25-0.27, SI 50-52, PW 0.22-0.25, AL 0.58-0.63 (2 measured). Clypeus in profile with dorsal outline forming a massively arched-convex crest from anterior to posterior border; maximum height of clypeal crest ca 0.10 (maximum depth of head behind level of eye ca 0.20). In full-face view apex of clypeal crest with a narrow longitudinal incision that is broadest and deepest anteriorly and peters out toward the posterior border. Clypeus almost entirely conceals mandibles so that only their extreme apices are visible. Frontal lobes and frontal carinae fused, massively expanded laterally, semi translucent and entirely concealing preocular carinae. Cephalic dorsum close to occipital margin with a transverse blunt raised ridge, behind which the dorsum is shallowly concave to the occipital margin. Apex of transverse ridge with a spaced row of stiff spindle-shaped hairs that are the only hairs arising from the dorsum proper; all other cephalic pilosity is marginal. Stout hairs project dorsally from dorsolateral margin of the head, from apicoscrobal position to occipital corner; longer hairs project more laterally from side of occipital lobe below dorsolateral margin; a row of erect hairs present across width of occipital margin. Eye with about 9 ommatidia in total. Leading edge of scape with 1-2 simple short hairs that are strongly directed toward the apex of the scape. Stout stiff suberect to erect hairs are present on dorsal surfaces of alitrunk, waist segments and gaster, and are also numerous on femora and tibiae. Head unsculptured except for faint patchy reticulation within scrobe. Alitrunk and disc of postpetiole smooth. Middle and hind femora distinctly bilaterally compressed, the ventral surface of each femur bounded on each side by a narrow longitudinal carina of clear cuticle. Femoral gland bullae small but quite easily visible. Petiole without trace of lateral spongiform lobes on node but with a long and extremely deep ventral curtain. Peduncle of petiole dorsally with a subspongiform crest that extends its length and ascends the anterior face of the node. Lateral spongiform lobes of postpetiole extensive, projecting far out laterally and in profile seen to extend posteriorly beneath the basigastral limbus. Postpetiole without trace of ventral spongiform lobes and base of first gastral sternite entirely lacking spongiform tissue. Basigastral costulae extending about two-thirds the length of the first gastral tergite, the surface of the latter depressed basally.

Type Material

Bolton (2000) - Holotype worker, VENEZUELA : Territorio Federal Amazonas, Alto Rio Siapa, 1°40'N, 64°35'W, 540 m., 2.ii.1989, sifted leaf litter (J. Lattke) (Instituto de Zoologia Agricola) [not seen].

References

  • Baroni Urbani, C.; De Andrade, M. L. 1994. First description of fossil Dacetini ants with a critical analysis of the current classification of the tribe (Amber Collection Stuttgart: Hymenoptera, Formicidae. VI: Dacetini). Stuttg. Beitr. Naturkd. Ser. B ( (page 17, combination in Strumigenys)
  • Baroni Urbani, C. & De Andrade, M.L. 2007. The ant tribe Dacetini: limits and constituent genera, with descriptions of new species. Annali del Museo Civico di Storia Naturale “G. Doria”. 99:1-191.
  • Bolton, B. 1999. Ant genera of the tribe Dacetonini (Hymenoptera: Formicidae). J. Nat. Hist. 3 33: 1639-1689 (page 1673, combination in Pyramica)
  • Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028. (page 233, redescription of worker)
  • Lattke, J. E. 1992b. Trichoscapa inusitata n. sp., a remarkable dacetine ant from the Orinoco watershed (Hymenoptera Formicidae). Trop. Zool. 5: 141-144 (page 142, fig. 1 worker described)