Strumigenys ebbae

Strumigenys ebbae
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmicinae
Tribe:	Attini
Genus:	Strumigenys
Species:	S. ebbae
Binomial name
	Strumigenys ebbae; Forel, 1905 Specimen Labels

Nothing is known about the biology of this species, which has only been collected twice.

Identification

Bolton (2000) - A member of the ebbae complex in the Strumigenys koningsbergeri-group. The variation noted (see below) reflects the suspicion that more than one real species is currently concealed within the concept of ebbae. I have tentatively separated two closely related species from the mass, Strumigenys conturba and Strumigenys disturba, for the reasons given under those names, but can find no obviously stable characters to subdivide the mass further. Failure to resolve the variation is in large part due to shortage of material; a definitive analysis of this part of the ebbae-complex must await the amassing of more samples.

Within the ebbae-complex this small agglomeration of species (conturba, disturba, ebbae) is characterised by reduced concavity of the apical section of the inner mandibular margin, lack of a mandibular lamella, lack of a preocular impression and relative abundance of erect short hairs on the cephalic dorsum.

Keys including this Species

Key to Strumigenys of East Asia

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: Indonesia (type locality), Malaysia.

Distribution based on AntMaps

Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.

Biology

Explore Overview of Strumigenys 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.

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Castes

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

ebbae. Strumigenys ebbae Forel, 1905c: 11 (w.) INDONESIA (Java). See also: Bolton, 2000: 842.

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

Description

Worker

TL 2.1-2.5, HL 0.57-0.69, HW 0.45-0.55, CI 76-80, ML 0.24-0.30, MI 40-46, SL 0.30-0.37, SI 66-72, PW 0.27-0.33, AL 0.58-0.72 (15 measured).

With characters of ebbae-complex. Preapical tooth short-conical and close to the apicodorsal tooth; length of preapical tooth half or less than half the width of the mandible at point where it arises. Inner margin of mandible proximal of preapical tooth straight to very shallowly convex, sharp-edged but without a lamella. Inner margin of mandible distal of preapical tooth only very shallowly concave, almost straight but weakly diverging from previous line of margin in some samples. Outer margin of mandible straight to very shallowly convex from base to level of preapical tooth. Upper scrobe margins evenly divergent, more or less straight from frontal lobes posteriorly; outer arc of eye visible in full-face view. Ventrolateral margin of head without a preocular impression although the margin may narrow fractionally immediately in front of the eye. Dorsum of head in profile with short erect hairs along occipital margin and numerous erect hairs anterior to this; with 1-3 pairs in front of pair at highest point of vertex, the anteriormost pair at about level of eye. Pronotum with two or more pairs of short standing hairs (as well as the humeral pair). Mesonotum with 1-3 pairs of short erect hairs. Propodeal dorsum often with a pair of erect hairs close to metanotal groove. Katepisternum partially to mostly smooth, metapleuron and side of propodeum superficially reticulate to densely reticulate-punctate, sometimes a small smooth patch on metapleuron. Bullae of femoral glands minute and inconspicuous on middle and hind legs, or invisible. Lamella on propodeal declivity narrow, its posterior (free) margin concave. Dorsum of petiole node reticulate-punctate. Disc of postpetiole with sculpture variable. In least sculptured samples disc smooth medially, finely punctulate posteriorly. In most strongly sculptured samples disc as strongly reticulate-punctate as petiole node and sometimes also with weak longitudinal rugulae on anterior portion of disc. Standing hairs on first gastral tergite simple or blunt apically.

Type Material

Holotype worker, INDONESIA: Java, Tjompea, leg. 11.iii.1904, ded. 6.vi.1904 (K. Kraepelin) (Musee d'Histoire Naturelle Genève) [examined].

References

Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028. (page 842, fig. 448 redescription of worker)
Emery, C. 1924f [1922]. Hymenoptera. Fam. Formicidae. Subfam. Myrmicinae. [concl.]. Genera Insectorum 174C: 207-397 (page 321, catalogue)
Forel, A. 1905f. Ameisen aus Java. Gesammelt von Prof. Karl Kraepelin 1904. Mitteilungen aus dem Naturhistorischen Museum in Hamburg 22: 1-26. (page 11, worker described)

References based on Global Ant Biodiversity Informatics

Bolton, B. 2000. The Ant Tribe Dacetini. Memoirs of the American Entomological Institute 65
Chapman, J. W., and Capco, S. R. 1951. Check list of the ants (Hymenoptera: Formicidae) of Asia. Monogr. Inst. Sci. Technol. Manila 1: 1-327
Forel A. 1905. Ameisen aus Java. Gesammelt von Prof. Karl Kraepelin 1904. Mitt. Naturhist. Mus. Hambg. 22: 1-26.