|Strumigenys (Epopostruma) quadrispinosa, now Epopostruma quadrispinosa|
(Species Checklist, Species by Country)
|Based on Ward et al. (2014), Blaimer et al. (2018) and Li et al. (2018).|
An Australian genus, Epopostruma workers can be fairly common but are often overlooked. Workers are slow-moving and most lie motionless when disturbed. Their nests are small, with up to about 100 workers, and are found in open soil or in soil under rocks, logs or small sticks. They also nest in cracks in large rocks. When nesting in open soil they are often found near the bases of trees.
|At a Glance||• Trap-Jaw|
- 1 Identification
- 2 Distribution
- 3 Biology
- 4 Castes
- 5 Morphology
- 6 Nomenclature
- 7 References
The antennae are 6 segmented (including the scape) and the scapes pass below the eyes when laid back against the head in their normal resting position. The mandibles are thin and elongate and when fully closed they are separated by a broad gap for most of their length, touching only at the tips. These characters will separate Epopostruma from all other Australian ants, including the superficially similar Colobostruma, Eurhopalothrix, Mesostruma and Rhopalothrix.
|See images of species within this genus|
Keys including this Genus
Keys to Species in this Genus
Distribution and Richness based on AntMaps
Almost all species forage at night although one species is known to occasionally forage on mallee stems during the day. They are also regularly found in leaf litter. Workers have been attracted to honey baits on trees in the late evening and at night. Their elongate and specialised mandibles form a type of snap-trap which is used to captured soft-bodied prey such as Collembola.
Life History Traits
- Mean colony size: Up to 100 (Greer et al., 2021)
- Compound colony type: not parasitic (Greer et al., 2021)
- Nest site: hypogaeic (Greer et al., 2021)
- Diet class: omnivore; predator (Greer et al., 2021)
- Foraging stratum: subterranean/leaf litter (Greer et al., 2021)
• Eyes: >100 ommatidia • Pronotal Spines: absent • Mesonotal Spines: absent • Propodeal Spines: present • Petiolar Spines: absent • Caste: none or weak • Sting: present • Metaplural Gland: present • Cocoon: absent
- n = 10, 2n = 20, karyotype = 20M (Australia) (Crozier, 1968d).
All Karyotype Records for Genus
The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.
- EPOPOSTRUMA [Myrmicinae: Dacetini]
- Epopostruma Forel, 1895f: 422 [as subgenus of Strumigenys]. Type-species: Strumigenys (Epopostruma) quadrispinosa, by subsequent designation of Wheeler, W.M. 1911f: 163.
- Epopostruma raised to genus: Emery, 1897c: 573.
- Epopostruma senior synonym of Hexadaceton: Taylor & Brown, D.R. 1985: 63; Bolton, 1999: 1681; Shattuck, 2000: 53.
- Epopostruma senior synonym of Colobostruma, Mesostruma: Baroni Urbani & De Andrade, 2007: 94.
- HEXADACETON [junior synonym of Epopostruma]
- Hexadaceton Brown, 1948e: 120. Type-species: Hexadaceton frosti, by original designation.
- Hexadaceton junior synonym of Epopostruma: Taylor & Brown, D.R. 1985: 63; Bolton, 1999: 1681; Shattuck, 2000: 53.
Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.
With characters of the epopostrumiform genus group......
Palp formula 5 , 3.
Labrum large or very large, forming a massive shield in Colobostruma and Mesostruma that can reflex tightly over the labio-maxillary complex and completely cover the buccal cavity; somewhat smaller in Epopostruma where it covers approximately the apical half of the labio-maxillary complex.
Basimandibular gland bulla absent.
Antenna usually with 4 - 6 segments, rarely more.
Scape, when laid back in its normal resting position , passes below the eye or across the ventral margin of the eye; basal part of scape strongly downcurved.
Scrobe usually present, extending below the eye, the latter not located ventrolaterally on side of head.
Femora and tibiae lack gland bullae on their dorsal surfaces.
Pronotal humeri usually armed.
Metapleural gland with apex of bulla close to or abutting the annulus of the propodeal spiracle.
Propodeal spiracle at about the m idheight of the sclerite, separated from margin of declivity.
Tergite of petiole or postpetiole with lateral cuticular laminar outgrowths; extremely rarely (1 species) with traces of spongiform tissue.
Postpetiolar spiracles ventral.
Limbus absent from first gastral tergite.
Suture separating first gastral tergite and stemite angulate laterobasally; horizontal basal margin of stemite with a raised rim or crest adjacent to the tergite margin , this crest usually continues round the laterobasal angle.
Bizarre pilosity never developed.
......and the following.....
Mandibles linear, with kinetic mode of action, edentate except for two enlarged teeth apically that overlap at full closure; in ventral view without an inflected basalexternal angle.
Mandibles at full gape open to 170° or more.
Basal process of mandible a curved truncated bar.
Labrum covers approximately the apical half of the labio-maxillary complex, its anterior margin not evenly convex; side of labrum with a small rectangular process.
Labrum mediodorsally with a very broadly and deeply concave depression in its proximal half.
Trigger hairs two in number, long and stout, arising from labrum and widely separated.
Side of head with a vertical preocular groove that may extend onto the ventral surface.
Scrobe strongly present, extending below eye.
- Ashmead, W. H. 1905c. A skeleton of a new arrangement of the families, subfamilies, tribes and genera of the ants, or the superfamily Formicoidea. Can. Entomol. 37: 381-384 (page 384, Epopostruma in Cryptoceridae, Dacetonini)
- Bolton, B. (1999). Ant genera of the tribe Dacetonini (Hymenoptera: Formicidae). Journal of Natural History 33: 1639–1689 [generic status]
- Bolton, B. 2003. Synopsis and Classification of Formicidae. Mem. Am. Entomol. Inst. 71: 370pp (page 187, Epopostruma as genus)
- Brown, W. L., Jr. (1954). A preliminary report on dacetine ant studies in Australia. Annals of the Entomological Society of America. 46 : 465–471 [tribal placement]
- Brown, W. L., Jr. (1988). Data on Malpighian tubule numbers in ants (Hymenoptera: Formicidae). pp. 17–27 in Trager, J. C. Advances in Myrmecology. Leiden : E. J. Brill. xxvii + 551 pp.
- Brown, W. L., Jr. 1948e. A preliminary generic revision of the higher Dacetini (Hymenoptera: Formicidae). Trans. Am. Entomol. Soc. 74: 101-129 (page 119, Epopostruma in Myrmicinae, Dacetini)
- Brown, W. L., Jr. 1973b. A comparison of the Hylean and Congo-West African rain forest ant faunas. Pp. 161-185 in: Meggers, B. J., Ayensu, E. S., Duckworth, W. D. (eds.) Tropical forest ecosystems in Africa and South America: a comparative review. Wash (page 181, Epopostruma provisional senior synonym of Hexadaceton)
- Brown, W. L., Jr., Wilson, E. O. (1959). The evolution of the dacetine ants. Quarterly Review of Biology 34: 278–294 [overview]
- Crozier, R. H. (1968). The chromosomes of three Australian dacetine ant species (Hymenoptera: Formicidae). Psyche (Cambridge). 75: 87–90
- Donisthorpe, H. 1943g. A list of the type-species of the genera and subgenera of the Formicidae. [part]. Ann. Mag. Nat. Hist. 11(10): 617-688 (page 644, Epopostruma in Myrmicinae, Dacetini)
- Emery, C. 1897c. Formicidarum species novae vel minus cognitae in collectione Musaei Nationalis Hungarici quas in Nova-Guinea, colonia germanica, collegit L. Biró. Természetr. Füz. 20: 571-599 (page 573, Epopostruma raised to genus)
- Emery, C. 1914e. Intorno alla classificazione dei Myrmicinae. Rend. Sess. R. Accad. Sci. Ist. Bologna Cl. Sci. Fis. (n.s.) 18: 29-42 (page 42, Epopostruma in Myrmicinae, Dacetini)
- Emery, C. 1924f . Hymenoptera. Fam. Formicidae. Subfam. Myrmicinae. [concl.]. Genera Insectorum 174C: 207-397 (page 329, Epopostruma in Myrmicinae, Dacetini)
- Forel, A. 1895g. Nouvelles fourmis d'Australie, récoltées à The Ridge, Mackay, Queensland, par M. Gilbert Turner. Ann. Soc. Entomol. Belg. 39: 417-428 (page 422, Epopostruma as subgenus of Strumigenys)
- Forel, A. 1917. Cadre synoptique actuel de la faune universelle des fourmis. Bull. Soc. Vaudoise Sci. Nat. 51: 229-253 (page 246, Epopostruma in Myrmicinae, Dacetini)
- Larabee, F.J., Suarez, A.V. 2014. The evolution and functional morphology of trap-jaw ants (Hymenoptera: Formicidae). Myrmecological News 20: 25-36.
- Shattuck, S. O. 2000. Genus Colobostruma. Genus Mesostruma. Genus Epopostruma. Pp. 31-67 in: Bolton, B. The ant tribe Dacetini. Mem. Am. Entomol. Inst. 65: 1-1028 (page 53, Epopostruma as genus)
- Taylor, R. W. (1991). Nomenclature and distribution of some Australasian ants of the Myrmicinae (Hymenoptera: Formicidae). Memoirs of the Queensland Museum 30: 599–614
- Taylor, R. W.; Brown, D. R. 1985. Formicoidea. Zool. Cat. Aust. 2:1- 149: 1-149, 30 (page 63, Epopostruma senior synonym of Hexadaceton (accepted as confirmation))
- Wheeler, W. M. 1911g. A list of the type species of the genera and subgenera of Formicidae. Ann. N. Y. Acad. Sci. 21: 157-175 (page 163, Type-species: Strumigenys (Epopostruma) quadrispinosa)
- Wheeler, W. M. 1922i. Ants of the American Museum Congo expedition. A contribution to the myrmecology of Africa. VII. Keys to the genera and subgenera of ants. Bull. Am. Mus. Nat. Hist. 45: 631-710 (page 667, Epopostruma in Myrmicinae, Dacetini)