Strumigenys leptorhina

Strumigenys leptorhina
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmicinae
Tribe:	Attini
Genus:	Strumigenys
Species:	S. leptorhina
Binomial name
	Strumigenys leptorhina; Bolton, 2000 Specimen Labels

Known from a lowland rainforest litter-sample.

Identification

Bolton (2000) - A member of the feae complex in the Strumigenys mayri-group. Only two species of the feae-complex lack erect long fine hairs on the dorsal (outer) surface of the hind basitarsus, leptorhina and Strumigenys ecliptacoca. These two species are also the only ones of the complex that lack erect fine hairs on the dorsal surface of the hind femur; in all others at least one such hair is present, and usually more. The two separate easily as leptorhina has elongate-triangular propodeal teeth and conspicuous propodeal lamellae, does not have a freely laterally projecting hair on the upper scrobe margin anterior to the apicoscrobal, and has a narrower head (CI 58-59). In ecliptacoca the propodeum has a pair of minute triangular tubercles and lacks lamellae, the upper scrobe margin has a freely laterally projecting hair anterior to the apicoscrobal (located at about the level of the posterior margin of the eye), and has a broader head (CI 64-65). Finally, in ecliptacoca the there is a small intercalary tooth between the apical fork teeth and the spiniform preapical tooth is nearly twice as long as the maximum width of the mandible. In leptorhina intercalary teeth are absent and the preapical tooth is only approximately equal to the maximum width of the mandible.

Keys including this Species

Key to Strumigenys of East Asia

Distribution

Distribution based on Regional Taxon Lists

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

leptorhina. Strumigenys leptorhina Bolton, 2000: 886, figs. 470, 512 (w.) BORNEO.

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 2.9, HL 0.83, HW 0.48, CI 58, ML 0.38, MI 46, SL 0.54, SI 113, PW 0.28, AL 0.80. Characters of the feae-complex. Preapical tooth spiniform, its length about equal to the maximum width of the mandible. Outer margin of mandible in full-face view straight from close to base to level of preapical tooth. Apical fork of mandible without intercalary teeth. Dorsolateral margin of head with two freely laterally projecting simple, non-flagellate hairs, one apicoscrobal and the other posterior to this; upper scrobe margin anterior to apicoscrobal hair does not have freely laterally projecting long hairs. Cephalic dorsum with 4 erect stiff simple hairs along the occipital margin, a similar pair present at highest point of vertex. Preocular notch absent, ventrolateral margin of head minutely shallowly concave immediately in front of eye and straight anteriorly. Pronotal humeral hair flagellate; pronotal dorsum with a pair of inclined curved simple standing hairs, mesonotum with one pair of erect flagellate hairs. Dorsal surfaces of waist segments and first gastral tergite with long flagellate hairs. Pleurae and side of propodeum smooth; dorsal alitrunk reticulate-punctate, tending to be weak or faded anteriorly on pronotum. Dorsal (outer) surfaces of hind basitarsus and hind tibia without erect fine long hairs of any form; dorsum of hind femur without erect long fine hairs. Petiole in profile with a differentiated anterior face that is shorter than the dorsum. Disc of postpetiole narrow, smooth and shining. Basigastral costulae shorter than disc of postpetiole.

Paratype. TL 2.8, HL 0.79, HW 0.47, CI 59, ML 0.36, MI 46, SL 0.51, SI 109, PW 0.28, AL 0.78.

Type Material

Holotype worker, Malaysia: Sarawak, 4th Div., G. Mulu Nat. Pk, RGS Expd., Long Pala, 30.ix.1977, lowland rainforest, leaf litter (B. Bolton) (The Natural History Museum). Paratype. 1 worker, Malaysia: Sarawak, Gn. Mulu NP, 200 m., 2.iii.1978, limestone forest, pitfall trap (H. Vallack) (BMNH).

References

Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028. (page 886, figs. 470, 512 worker described)
Tang, K. L., Guénard, B. 2023. Further additions to the knowledge of Strumigenys (Formicidae: Myrmicinae) within South East Asia, with the descriptions of 20 new species. European Journal of Taxonomy 907, 1–144 (doi:10.5852/ejt.2023.907.2327).

References based on Global Ant Biodiversity Informatics

Pfeiffer M.; Mezger, D.; Hosoishi, S.; Bakhtiar, E. Y.; Kohout, R. J. 2011. The Formicidae of Borneo (Insecta: Hymenoptera): a preliminary species list. Asian Myrmecology 4:9-58
Zhou S.-Y. 2001. Ants of Guangxi. Guangxi Normal University Press, Guilin, China, Guilin, China. 255 pp.