Strumigenys mailei

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Strumigenys mailei
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Strumigenys
Species: S. mailei
Binomial name
Strumigenys mailei
Wilson & Taylor, 1967

Strumigenys mailei casent0186741 p 1 high.jpg

Strumigenys mailei casent0186741 d 1 high.jpg

Specimen Labels

A Fiji endemic known from wet forest habitats. All of the collections have been from litter samples and nothing is known about its biology.

Identification

Bolton (2000) - A member of the signeae complex in the Strumigenys godeffroyi-group. The Fijian endemic species with characters of the signeae-complex appear to represent a single adaptive radiation on the islands. The variation of pilosity and sculpture characters that they show overlaps other aggregations of species in the complex. However, their combination of scrobe, propodeal and petiolar features, noted in the introduction to this complex, is not duplicated by other members. In addition the four Fijian species have relatively long scapes, with a combined range of SI 87-103. The remainder of the signeae-complex has a range of SI 54-93.

Of the four species included here two are instantly recognisable. Strumigenys sulcata has the head coarsely longitudinally rugose, the dorsal alitrunk completely covered with broad longitudinal sulcate sculpture; the postpetiole disc is also sulcate but more finely so. Strumigenys tumida has a very short preapical tooth on the mandible, the postpetiole disc is strongly swollen and densely reticulate-punctate, and the metapleuron and side of the propodeum are uniformly reticulate-punctate.

The other two, mailei and Strumigenys praefecta, lack these striking features and are closely related. They differ as the former has a humeral hair present, has traces of oblique costulate sculpture posteriorly on the side of the pronotum and has a shorter, broader petiole node. These are lacking in the latter, and in addition the apical antennomere of praejecta is more narrowed and slender basally than in mailei.

Sarnat and Economo (2012) - Strumigenys mailei is a light yellow brown to reddish brown species with a narrow head that is shallowly impressed posteriorly, long mandibles, and no hairs on the pronotal humeri. The signeae complex has four Fijian species (S. mailei, Strumigenys praefecta, Strumigenys sulcata and Strumigenys tumida). All of these species lack flagellate hairs, and can thus be separated from nearly all the other species within the godeffroyi group. The Fijian species of the signeae group are characterized by having the antennal scrobe absent behind the eye, the propodeal declivity with a narrow carina (no lamella), and the petiole with a long and low node that in profile shows the anterior face to be much shorter than the dorsum.

Of the Fijian signeae complex species, S. sulcata is easy to separate by the coarse sulcate sculpture of its head and mesosoma. Strumigenys tumida is easy to separate by its short preapical tooth on the mandible, the densely punctate-reticulate and swollen postpetiolar disc, and the uniformly punctate-reticulate metapleuron on sides of the propodeum. Strumigenys mailei and S. praefecta lack the striking features of the two aforementioned species. Strumigenys mailei can be separated from S. praefecta by the presence of humeral hair, traces of oblique costulae posteriorly on the side of the pronotum, a shorter, broader petiolar node, and a more slender apical antennomeres.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: Fiji, Samoa (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.

  • mailei. Strumigenys mailei Wilson & Taylor, 1967: 38, fig. 28 (w.) SAMOA. Dlussky, 1993: 59 (q.). See also: Bolton, 2000: 823.

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 2.4-2.9, HL 0.62-0.74, HW 0.43-0.50, CI 66-70, ML 0.29-0.34, MI 46-50, SL 0.38-0.45, SI 88-92, PW 0.28-0.31, AL 0.66-0.81 (9 measured).

Characters of signeae-complex. With head in profile scrobe absent behind level of eye. Dorsolateral margin of head with a short simple fine hair in apicoscrobal position and margin posterior to this with 1-2 projecting short hairs; these hairs directed more dorsally than laterally. Cephalic dorsum with a transverse row of 4-6 erect hairs at occipital margin and with a single pair of standing hairs at or just in front of highest point of vertex. Pronotal humeral hair short and stiff, straight and simple. Pronotal dorsum with 1-2 pairs of short erect hairs, mesonotum also with 1-2 pairs. Dorsal alitrunk entirely reticulate-punctate. Side of alitrunk with katepisternum smooth; metapleuron and side of propodeum partially to mostly smooth and shining. Propodeal teeth acute, free; propodeal declivity carinate, the carina concave and closely paralleling the curve of the declivity. Petiole node reticulate-punctate dorsally; in profile lateral spongiform lobe small, confined to posterolateral portion of node; anterior face of node shorter than length of dorsum. Disc of postpetiole glassy smooth. First gastral tergite with short stiff simple standing hairs.

Type Material

Bolton (2000) - Holotype worker, SAMOA: Upolu, Afiamalu, 700 m., 15.iii.1962, rain forest, berlesate of moss on tree, 10-12 m. from ground, no. 581 (R. W. Taylor); paratype worker, FIJI IS: Viti Levu, Navai Mill, nr Nandarivatu, 800 m., 17.ix.1938 (E. C. Zimmerman) (Museum of Comparative Zoology) [examined].

References