Strumigenys dentiscapa

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Strumigenys dentiscapa
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Strumigenys
Species: S. dentiscapa
Binomial name
Strumigenys dentiscapa
(Bolton, 2000)

Strumigenys dentiscapa casent0900109 p 1 high.jpg

Strumigenys dentiscapa casent0900109 d 1 high.jpg

Specimen Labels

The type material was collected from a rotten log in montane rainforest.

Identification

Bolton (2000) - A member of the Strumigenys capitata-group. This large, stockily-built species falls into the size range of Strumigenys rhea, Strumigenys serradens and Strumigenys serraformis but is not closely related to them as it lacks their specialisations of mandibular and petiolar structure (see there). In reality dentiscapa appears to be an overgrown relative of Strumigenys capitata, Strumigenys pedunculata and Strumigenys theia, but is easily distinguished from them by its size, broad head (CI 97-101, as opposed to a combined CI 80-89 in the other three species), unique scape structure, reduced lateral postpetiolar spongiform lobe, apically upcurved propodeal spines, more numerous cephalic hairs, and a reticulate-punctate rather than costulate postpetiole disc.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: New Guinea.

Check distribution from AntMaps.

Distribution based on specimens

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The above specimen data are provided by AntWeb. Please see Strumigenys dentiscapa for further details

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.

  • dentiscapa. Pyramica dentiscapa Bolton, 2000: 396, fig. 249 (w.q.m.) NEW GUINEA. Combination in Strumigenys: Baroni Urbani & De Andrade, 2007: 118

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 4.4, HL 0.94, HW 0.95, CI 101, ML 0.24, MI 26, SL 0.46, SI 48, PW 0.66, AL 1.26. Basal lamella of mandible low, triangular, smaller than basal tooth and not visible in full-face view when mandibles closed. Basal lamella followed by 7 stout triangular teeth, outer margin of fully closed mandibles shallowly convex. Leading edge of scape, distal of the narrow basal section, expanded into a flattened triangular lobe or tooth that projects anteriorly and bears the longest hair of the leading edge at its apex; distal to this lobe the relatively short scape narrows to its apex. Dorsum of head finely and densely reticulate-punctate everywhere, the vertex also with some fine disorganised rugular sculpture. Apicoscrobal hair short and stout, weakly curved. Cephalic dorsum with two arched transverse rows of short stout standing hairs; a posterior row of 6 close to the occipital margin and an anterior row of 4 just in front of the highest point of the vertex. Ground-pilosity of head of short appressed spatulate hairs. Eye with 7 ommatidia in the longest row. Pronotal humeral hair short and stout. Mesonotum with 2 pairs of stout standing hairs (anterior pair abraded in holotype). Petiole with one pair of hairs, postpetiole with 2 pairs; first gastral tergite with several hairs, the basal ones tending to be weakly clavate apically. Posterior half of mesonotum sloping very steeply to the metanotal groove. Propodeum with a pair of stout triangular teeth, the apices of which are slightly upcurved. Lamella on propodeal declivity vestigial, base of declivity with low but distinct lobes. Petiole node in profile with a distinctly differentiated anterior face that is shorter than the dorsal length of the node. Subpetiolar spongiform strip narrowest anteriorly, terminating in the anterior third of the peduncle length. Postpetiole in profile massively subglobose; exposed area of disc much larger than ventral spongiform lobe. Lateral spongiform lobe of postpetiole very small, little more than a slight expansion of the end of the posterior collar. Petiole node in dorsal view slightly longer than broad, with a shallow median longitudinal impression. Postpetiole in dorsal view massive, broadly anteroposteriorly convex and with spongiform tissue restricted to the posterior margin and posterolateral angles. Alitrunk, petiole and postpetiole predominantly with weakly defined shallow reticulate-punctate sculpture; mesopleuron smooth, promesonotal dorsum with faint disorganised fine rugular traces. Gaster unsculptured, smooth and shining (when clean) except for the short but sharply defined basigastral costulae.

Paratypes. TL 4.3-4.5, HL 0.94-0.98, HW 0.93-0.95, CI 97-101, ML 0.24-0.26, MI 25-27, SL 0.44-0.48, SI 46-51, PW 0.64-0.66, AL 1.18-1.26 (5 measured).

Type Material

Holotype worker, Papua New Guinea: 12 km. SW Telefomin, 5°13'S, 141°35'E, 7.vii.1980, 1600 m., rotten log, montane rainforest, #4718 (P.S. Ward) (Australian National Insect Collection).

Paratypes. 16 workers, 4 queens (3 alate) and 3 males with same data as holotype (ANIC, The Natural History Museum, University of California, Davis, Museum of Comparative Zoology). (A number of unmounted specimens, including several queens and males, remain in alcohol in ANIC).

References

  • 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. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028. (page 396, fig. 249 worker described)