Strumigenys pedunculata

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Strumigenys pedunculata
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Strumigenys
Species: S. pedunculata
Binomial name
Strumigenys pedunculata
(Brown, 1953)

Strumigenys pedunculata casent0217925 p 1 high.jpg

Strumigenys pedunculata casent0217925 d 1 high.jpg

Specimen Labels

Known from mesic forest habitats, with specimens collected from litter and rotting logs.

Identification

Bolton (2000) - A member of the Strumigenys capitata-group. Together with Strumigenys capitata and Strumigenys theia, pedunculata forms a complex of closely related species within the group. The complex is characterised by a lack of flagellate hairs both apicoscrobally and at the pronotal humeri (stout non-flagellate hairs are present instead), the presence of costulate sculpture- on the postpetiole disc, and their relatively large size (HW 0.50-0.62). A closely related complex of species includes Strumigenys charybdis, Strumigenys tethys and Strumigenys themis, but these are usually distinctly smaller (HW 0.39-0.50) with the postpetiole mostly or entirely un sculptured and smooth.

In theia the lateral alitrunk is completely covered with s harp reticulate-punctate sculpture and the mesonotum has 3 (or rarely 4) pairs of stout standing hairs. In both capitata and pedunculata the mesopleuron is mostly or entirely smooth and shining, and the mesonotum has only 2 pairs of standing hairs. Differentiation of capitata from pedunculata depends upon the characters noted in the key, concerning the shape of the petiole node and size of the postpetiolar spongiform appendages.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: Malaysia, Philippines (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

Worker

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • pedunculata. Smithistruma (Smithistruma) pedunculata Brown, 1953g: 118, pl. 1, fig. 14 (w.q.) PHILIPPINES. Combination in Pyramica: Bolton, 1999: 1673; in Strumigenys: Baroni Urbani & De Andrade, 2007: 125. See also: Bolton, 2000: 402.

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

Description

Worker

TL 2.4-3.1, HL 0.60-0.70, HW 0.50-0.58, CI 80-84, ML 0.16-0.20, MI 25-29, SL 0.32-0.39, SI 64-69, PW 0.36-0.44, AL 0.68-0.88 (10 measured).

Apicoscrobal hair stout, usually somewhat flattened or weakly remiform apically but never flagellate. Dorsum of the densely reticulate-punctate head with a transverse row of 4 standing hairs close to the occipital margin and with a single pair of similar hairs just in front of the highest point of the vertex. Eye with 4-5 ommatidia in the longest row. Pronotal humeral hair long and stout, usually slightly flattened or weakly remiform. Mesonotum with two pairs of standing hairs, the posterior pair the longest; these hairs weakly remiform to feebly clavate apically. Similar hairs occur on the petiole node (2 pairs), the postpetiole disc (3 pairs) and the first gastral tergite (3-4 transverse rows). Side of alitrunk reticulate-punctate except for the mesopleuron which is mostly or entirely smooth and shining. Petiole in profile with the curved dorsal surface of the node distinctly longer than its anterior face. In dorsal view the petiole node reticulate-punctate and longer than broad, even if only slightly so. Disc of postpetiole finely and densely longitudinally costulate. In profile the ventral spongiform lobe of the postpetiole is at least equal in size to, and frequently larger than, the area of exposed disc.

Type Material

Holotype worker, paratype workers and queen, PHILIPPINES: Negros Oriental, nr Dumaguete, Camp 4-18-27, iv.1927, from log in wet draw, no. 1378 (J. W. Chapman) (Museum of Comparative Zoology, The Natural History Museum, Naturhistorisches Museum Wien, Vienna) [examined].

References

  • Baltazar, C. R. 1966. A catalogue of Philippine Hymenoptera (with a bibliography, 1758-1963). Pac. Insects Monogr. 8: 1-488 (page 253, listed)
  • 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 402, redescription of worker)
  • Brown, W. L., Jr. 1953g. Revisionary studies in the ant tribe Dacetini. Am. Midl. Nat. 50: 1-137 PDF (page 118, pl. 1, fig. 14 worker, queen described)