Strumigenys exilirhina

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

Common Name

Kibabuto-uroko-ari
Language:	Japanese

Known from disturbed habitats, e.g., rubber plantations, and natural habitats, e.g., rainforest. Samples have been collected under moss and in litter samples. This is one of the most common species of Strumigenys in Hong Kong. It has been collected in a variety of habitats including disturbed urban forests, tree plantations (Lophostemon confertus Wilson & Waterh.), shrubland, secondary forest, and Feng Shui woods. The known elevation range in Hong Kong for this species is from 1 to 407 m (Tang et al., 2019; Tang & Guenard, 2023).

Identification

Bolton (2000) - A member of the feae complex in the Strumigenys mayri-group. Series from Thailand tend to have the preapical tooth slightly smaller and somewhat closer to the apicodorsal tooth that does material from elsewhere. At present I am not able to decide if this is significant at species rank or is geographical variation within a single species; suffice to say that apart from this small difference all samples are remarkably similar.

S. exilirhina is closest related to Strumigenys stenorhina of China and Japan but tends to be smaller and have slightly shorter mandibles and scapes (compare measurements). Apart from the key characters the upper scrobe margins of exilirhina are distinctly convex from just in front of the level of the eyes to the scrobe apex; in stenorhina the upper scrobe margins are almost straight in this area and distinctly more straight-divergent posteriorly. Both of these species separate from Strumigenys rallarhina as the latter has a long spiniform preapical tooth on the mandible, whereas in both exilirhina and stenorhina the preapical tooth is short and triangular. S. exilirhina and stenorhina together are closely related to Strumigenys kraepelini and Strumigenys barylonga but the last two tend to be larger and are decidedly more slender, attenuated species with long scapes and very narrow heads.

Tang & Guenard (2023) - Most specimens collected from southern Thailand and Vietnam, after a careful examination of the morphology of their mandibles, in particular the preapical tooth, were identified as closer to Strumigenys feae than S. exilirhina (Fig. 18F). Together with the remarks made by Bolton (2000) on the preapical tooth morphology of specimens from Thailand, it is possible that at least some of the S. exilirhina previously recorded in Thailand should be reconsidered, thus a re-examination of specimens is recommended. It is also possible that these Indochinese specimens constitute a separate species, though at the moment they cannot be delimited as a new species without ambiguity. Refer to S. feae for a detailed discussion.

Tang & Guenard (2023), Fig. 17. New species records of Strumigenys in full-face, profile and dorsal views. A–C. Worker of S. emmae from Thailand (ANTWEB1011939). D–F. Worker of S. exilirhina from Hainan, mainland China (HNA-00471). G–I. Worker of S. feae from Hainan, mainland China (HNA-01127).
Tang & Guenard (2023), Fig. 18. Mandible close-ups of sibling species of Strumigenys from the feae-complex of the S. mayri-group. A. Syntype worker of S. formosensis before synonymization. B–C, F. Workers of S. feae from Hainan, mainland China. D. Syntype worker of S. feae. E. Worker of S. feae from Hong Kong. G–H. S. cf. feae from Vietnam. I. S. exilirhina from Hainan, mainland China. A. CASENT0909309, from AntWeb, taken by Zach Lieberman. B. HNA-01503. C. HNA-01127. D. CASENT0904951, from AntWeb, taken by Will Ericson. E. RHL01266. F. HNA-01520. G. CTS13-4m2-sp15. H. NN-S69-sp18-W1. I. HNA-00471.

Keys including this Species

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: 30.3416° to 21.85766667°.


North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

Source: AntMaps

Distribution based on Regional Taxon Lists

Oriental Region: Bhutan, India, Nepal (type locality), Thailand.
Palaearctic Region: China, Japan.

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

Using Malaise traps at various locations in Hong Kong, Tang et al. (2019) collected female alates in sampling conducted from mid-May to mid-June.

Castes

Nomenclature

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

exilirhina. Strumigenys exilirhina Bolton, 2000: 881 (w.q.) NEPAL.

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 2.4, HL 0.66, HW 0.44, CI 67, ML 0.29, MI 44, SL 0.41, SI 93, PW 0.26, AL 0.64. Characters of the feae-complex. Preapical tooth elongate-triangular and slightly recurved, slightly shorter than width of mandible at point where tooth arises. Outer margin of mandible in full-face view shallowly convex from close to base to level of preapical tooth; inner margin between same points shallowly concave to almost straight. Upper scrobe margin with two freely laterally projecting long flagellate hairs, the posterior one in apicoscrobal position. Cephalic dorsum with 4-6 erect subflagellate or looped hairs along the occipital margin, a similar but shorter pair at level of highest point of vertex. Preocular notch absent but ventrolateral margin of head narrowed immediately in front of eye. Maximum diameter of eye varying from slightly greater to slightly less than the maximum width of the scape; 3-4 ommatidia across the greatest diameter. Pronotal humeral hair flagellate; pronotal dorsum finely reticulate-punctate and without erect hairs; mesonotum with 2 pairs of erect flagellate hairs. Dorsal surfaces of waist segments and first gastral tergite with flagellate hairs. Pleurae and side of propodeum smooth. A long fine erect flagellate hair present on the dorsal (outer) surface of the hind basitarsus and another on the hind tibia; similar pilosity present on the other legs. Petiole in profile with anterior face of node slightly shorter than length of dorsum, or the two subequal. Disc of postpetiole smooth. Basigastral costulae shorter than disc of postpetiole.

Paratypes. TL 2.2-2.4, HL 0.62-0.67, HW 0.42-0.45, CI 64-68, ML 0.27-0.29, MI 42-45, SL 0.40-0.43, SI 93-96, PW 0.25-0.26, AL 0.60-0.64 (8 measured).

Dimensions of non-paratypic workers. TL 2.3-2.7, HL 0.63-0.78, HW 0.42-0.51, CI 65-68, ML 0.27-0.33, MI 42-46, SL 0.38-0.48, SI 88-96 (12 measured).

Type Material

Holotype worker, Nepal: Sanghu, 3.x.1961, in moss on rock (K. H. Hyatt) (The Natural History Museum). Paratypes. 19 workers and 2 queens with same data as holotype (BMNH, Museum of Comparative Zoology, Musee d'Histoire Naturelle Genève, Oklahoma Museum of Natural History, University of Oklahoma).

References

References based on Global Ant Biodiversity Informatics

Bharti H. 2011. List of Indian ants (Hymenoptera: Formicidae). Halteres 3: 79-87.
Bolton, B. 2000. The Ant Tribe Dacetini. Memoirs of the American Entomological Institute 65
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Leong C. M., S. F. Shiao, and B. Guenard. 2017. Ants in the city, a preliminary checklist of Formicidae (Hymenoptera) in Macau, one of the most heavily urbanized regions of the world. Asian Myrmecology 9: e009014.
Liu X. 2012. Taxonomy, diversity and spatial distribution characters of the ant family Formicidae (Insecta: Hymenoptera) in southeastern Tibet. PhD Thesis 139 pages
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Tang K.L., Pierce M.P., and B. Guénard. 2019. Review of the genus Strumigenys (Hymenoptera, Formicidae, Myrmicinae) in Hong Kong with the description of three new species and the addition of five native and four introduced species records. ZooKeys 831: 1-48.
Terayama M., S. Kubota, and K. Eguchi. 2014. Encyclopedia of Japanese ants. Asakura Shoten: Tokyo, 278 pp.
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Wang W. R., S. Q. Zhang, and Z. H. Xu. 2012. A faunistic and taxonomic study of ants (Hymenoptera: Formicidae) in Shenzhen Municipality. Journal of Southwest Forestry University 32(1): 64-73.
Wang W., S. Zhang, and Z Xu. 2012. Distribution patters of ant species in Shenzhen City. Journal of Southwest Forestry University 32(3): 70-74.
Wang W., S. Zhang, and Z. Xu. 2012. Distribution Patterns of Ant Species in Shenzhen City. Journal of Southwest Forestry University 32(3): 69-74.
Zhou S.-Y. and Xu Z. 2003. Taxonomic study on Chinese members of the ant genus Strumigenys F. Smith (Hymenoptera, Formicidae) from the mainland of China. Acta Zootaxonomica Sinica28(4): 737-740.