Strumigenys natynion

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

A specimen of this species was collected in a montane rainforest litter-sample. Tang & Guenard (2023) report it in secondary forest, with elevation from 140 to 501 m.

Identification

Bolton (2000) - A member of the caniophanes complex in the Strumigenys caniophanes-group. See notes under Strumigenys mododonta. Representation of this species is a small number of isolated and varying individuals, no two of which are identical. All appear to belong to a single plastic species but it is distinctly possible that more than one real species is concealed here. Resolution of the problem must await the discovery of more, and larger, samples. Because of this I have restricted the type-series to a single nest sample.

Variation in the material available includes density and length of erect pilosity on head, alitrunk and gaster; presence or absence of small erect hairs on ventral surface of head; length and thickness of propodeal teeth.

Tang & Guenard (2023) - Specimens from Thailand and Vietnam all show a smaller preapical tooth, a slightly broader propodeal spine, a larger lateral lobe of the petiole (in both profile and dorsal views), relatively denser erect filiform to flagellate setae on the gaster than specimens from Borneo. They are also smaller (TL 2.5–2.7, HL 0.62–0.71, ML 0.63–0.66) than specimens from Borneo (TL 3.2–3.5, 0.88–0.94, ML 0.98) but retain similar body ratios (CI 72–74, Si 67–74 vs CI 68–74, SI 71–77). Bolton (2000) mentioned that the species appears plastic, with variations in pilosity and propodeal teeth. Hence, it is uncertain if the aforementioned morphological differences between specimens from Thailand and Vietnam on the one hand and those from Borneo on the other hand are geographical differences or an indication of a separate species. Based on the current species diagnosis, we consider material from Thailand and Vietnam as S. natynion.

Tang & Guenard (2023), Fig. 34. New species records of Strumigenys in full-face, profile and dorsal views. A–C. Worker of S. natynion from Thailand (ANTWEB1011940). D–F. Worker of S. nepalensis from Hainan, mainland China (HNA-00614). G–I. Worker of S. rallarhina from Hainan, mainland China (HNA-01469W).

Keys including this Species

Key to Strumigenys of East Asia

Distribution

Tang & Guenard (2023) - The records in northern Thailand and southern Vietnam imply that the species is not endemic to Borneo, but instead may be more widespread in the Indochinese Peninsula. Its presence is likely in the other parts of the region, e.g., Peninsular Malaysia, Cambodia, Laos and Myanmar.

Distribution based on Regional Taxon Lists

Indo-Australian Region: Borneo (type locality), Indonesia, Malaysia.
Oriental Region: Thailand, Vietnam.

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.

‎

Castes

Nomenclature

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

natynion. Strumigenys natynion Bolton, 2000: 762 (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 3.5, HL 0.94, HW 0.70, CI 74, ML 0.44, MI 47, SL 0.50, SI 71, PW 0.41, AL 0.98. Mandible with a small preapical tooth. Dorsolateral margin of head in full-face view with 5 or more freely laterally projecting filiform hairs; occipital lobe margin also with a number of shorter hairs that are directed dorsally. Cephalic dorsum with erect fine hairs in a transverse row across occipital margin and usually with a single more anterior pair, close to highest point of vertex. Dorsum of head finely and densely punctate-rugulose. Apical funicular segment moderately tapered basally. Promesonotal dorsum, side of pronotum, pleurae and side of propodeum everywhere densely punctate to reticulate-punctate. Pronotal humeral hair long and fine. Dorsal alitrunk with numerous erect fine simple hairs; waist segments and first gastral tergite with numerous similar hairs. Dorsal and ventral surfaces of hind femur with suberectlerect hairs; dorsal (outer) surfaces of hind tibia and basitarsus each with long erect freely projecting hairs. Petiole in profile claviform, in dorsal view much longer than broad.

Dimensions of non-paratypic workers. TL 3.2-3.5, HL 0.88-0.90, HW 0.60-0.62, CI 68-70, ML 0.40-0.44, MI 45-50, SL 0.46-0.48, SI 76-77 (6 measured).

Type Material

Holotype worker, Malaysia: Sabah, Kinabalu, 29.iv.1987, 1540 m., no. 8a (Burckhardt & Lobl) (Musee d'Histoire Naturelle Genève).

Paratypes. 4 workers with same data as holotype (MHNG, The Natural History Museum).

References

Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028. (page 762, 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