Strumigenys medusa

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

Pyramica medusa casent0102603 dorsal 1.jpg

Specimen labels

Nothing is known about the biology of Strumigenys medusa.

Identification

Bolton (2000) - A member of the Strumigenys leptothrix-group. S. medusa is a very distinctive species that is closest related to Strumigenys scylla but has longer scapes, smaller eyes, more abundant long pilosity and longer, narrower propodeal lobes. Separation of the two is tabulated under scylla. Both species belong in the rudinodis-complex of this group, characters of which are noted under rudinodis. The dentition of medusa and its allies is outlined in the introducion to the leptothrix-group.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: Borneo, Indonesia, Malaysia (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.

  • medusa. Pyramica medusa Bolton, 2000: 436, figs. 273, 296 (w.) BORNEO. Combination in Strumigenys: Baroni Urbani & De Andrade, 2007: 123

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 3.2, HL 0.79, HW 0.54, CI 68, ML 0.13, MI 16, SL 0.50, SI 93, PW 0.36, AL 0.90. With head in full-face view the dorsolateral margin with numerous very long fine acutely pointed hairs that project laterally or dorsolaterally. These hairs commence in front of the level of the eye and continue to the apex of the occipital lobe. In profile the cephalic dorsum, from the occipital margin to a point about midway between the highest point of the vertex and the posterior clypeal margin, with abundant very long fine hairs that are curved or flexuous and directed more or less vertically. Eye with 4 ommatidia in the longest row. Scape relatively long (see measurements), the leading edge with decumbent to appressed short hairs that are directed toward the apex of the scape; without freely projecting hairs of any form. Vertex weakly reticulate-punctate and with fine longitudinal rugulae that extend back to the occipital margin. Dentition discussed in introduction to group. Pronotum marginate dorsolaterally, the dorsum approximately flat and with spaced fine longitudinal costulae; gaps between costulae with superficial, almost vestigial, reticulate-punctation. Dorsal surfaces of alitrunk, waist and first gastral tergite with numerous erect to suberect long fine hairs that are acute apically. Dorsal (outer) surfaces of middle and hind tibiae with numerous long freely projecting erect to suberect hairs that are more or less straight; all are distinctly longer than the maximum width of the segment from which they arise. Similar projecting hairs occur on all other leg segments, including the tarsi. Propodeum with a pair of stout acute triangular spines, base of declivity with a pair of narrowly triangular acute propodeal lobes that are longer than half the length of the spines; the two linked on each side by a fine carina that runs down the lateral margin of the declivity. Spongiform appendages of waist segments well developed in profile. Maximum depth of ventral petiolar appendage greater than maximum depth of petiole at the node. Lateral lobe of petiole small, not extending anteriorly along the side of the node. Disc of postpetiole in dorsal view margined with spongiform tissue on all sides, the disc finely longitudinally costulate.

Paratypes. TL 3.0-3.2, HL 0.75-0.82, HW 0.52-0.56, CI 68-69, ML 0.12-0.14, MI 16-18, SL 0.45-0.52, SI 87-94, PW 0.33-0.36, AL 0.84-0.90 (10 measured).

Type Material

Holotype worker, Malaysia: Sabah, Kinabalu, 25.iv.1987, 1500 m., no. 3a (Burckhardt & Lobl) (Musee d'Histoire Naturelle Genève).

Paratypes. 17 workers with same data as holotype; 3 workers, Kinabalu, 30.iv.1987, 1500 m., no. 9b (Burckhardt & Lobl); 5 workers, Sabah, Crocker Range, K.K.-Tambunan, 18.v.1987, 1600 m., no. 30 (Lobl & Burckhardt); 4 workers, Crocker Range, l8.v.1987, 1600 m., no. 30a (Lobl & Burckhardt); 9 workers, Crocker Range, 19.v.1987, 1200 m., no. 31a (Burckhardt & Lobl) (MHNG, The Natural History Museum, Museum of Comparative Zoology, Australian National Insect Collection).

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 436, figs. 273, 296 worker described)