Strumigenys orchidensis

The type material was collected from a nest found on Orchid Island, Taiwan. Nothing is known about the biology of .

Identification
Lin & Wu (2001) - Closely related to Strumigenys formosensis by the (1) sickle-like mandibles with an extreme apex; and (2) anterior median margin border of the clypeus being deeply concave. However it is easily distinguished from the latter by the following characters: (1) smaller body size (TL < 2.6 mm in orchidensis, TL > 2.8 mm in formosensis); (2) different pilosity on the cranium (with numerous short, narrowly spatulate hairs in orchidensis, with sparse hairs in formosensis); (3) the preapical teeth of mandible spiniform in orchidensis and reduced in formosensis; and (4) the different sculpturing on the pronotum.

This species has not been assigned to a species group (Strumigenys species groups).

Distribution
Known only from Orchid Island, Taiwan.

Distribution based on Regional Taxon Lists
Oriental Region: Taiwan.

Nomenclature

 *  orchidensis. Strumigenys orchidensis Lin & Wu, 2001: 162, figs. 11-18 (w.q.) TAIWAN.

Worker
Holotype. TL, 2.89 mm; HL, 0.83 mm; HW, 0.59 mm; SL, 0.54 mm; ML, 0.39 mm; FCD, 0.20 mm; PW, 0.37 mm; WL, 0.84 mm; CI, 71; MI, 47; SI, 91; FCI, 34; MSI, 44.

Paratypes. TL, 2.78-2.93 mm; HL, 0.80-0.85 mm; HW, 0.58-0.60 mm; SL, 0.53-0.55 mm; ML, 0.39-0.42 mm; FCD, 0.20-0.21 mm; PW, 0.35-0.38 mm; WL, 0.82-0.86 mm; CI, 71-73; MI, 46-49; SI, 88-91; FCI, 33-34; MSI, 43-47.

Head as in Fig., with microreticulate sculpturing, with abundant, short, narrowly spatulate hairs on cranium; in full face view, posterolateral corners of head with 3 pairs of long flagellate hairs. Mandibles sickle-like, slender in full face view; external and internal margins almost straight; preapical teeth of mandibles prominently spiniform; apical fork with 2 spiniform teeth and an intercalary denticle. Anterior clypeal margin deeply concave medially. Antennae 6-segmented, in a ratio of 14.5:2.5: 1: 1: 4.5: 9.5 in length from base; scape microreticulate, with a row of narrowly spatulate hairs; 2nd segment 2 X as long as wide; 3rd and 4th segments each shorter than wide; 5th segment 3 X as long as wide; apical segment 6 X as long as wide. Eyes relatively large, 0.07 mm in maximum diameter, with about 15 ommatidia.

Dorsum of promesonotum with microreticulate sculpturing; pairs of long flagellate hairs and erect hairs present. Mesopleuron and metapleuron smooth and shiny on most parts. Metanotum with microreticulate sculpturing. Propodeal teeth acute and well developed; propodeal lamellae weakly developed.

Petiole with microreticulate sculpturing, with long flagellate hairs; peduncle long; dorsal margin of node convex in profile. Spongiform appendages of pedicelled segments well developed.

First gastral tergite smooth and shiny, with numerous, long flagellate hairs.

Body brownish yellow.

Queen
Paratype. TL, 2.80 mm; HL, 0.72 mm; HW, 0.56 mm; SL, 0.44 mm; ML, 0.34 mm; FCD, 0.19 mm; PW, 0.36 mm; WL, 0.74 mm; CI, 78; MI, 47; SI, 79; FCI, 34; MSI, 47.

General shape of head and alitrunk as shown in Figs. Head and antennal scape with microreticulate sculpturing. Head with narrowly spatulate hairs on cranium; in full face view, posterolateral corners of head with 3 pairs of long flagellate hairs. Compound eyes large. Ocelli relatively large, each with blackened callus.

Alitrunk in profile more even dorsally, arching from anteriormost of mesonotum to posteriormost of metanotum. Propodeal teeth acute and well developed; propodeal lamellae weakly developed. Dorsum of alitrunk with numerous short erect hairs. Long flagellate hairs present on dorsal of alitrunk, petiole, postpetiole, and 1st gastral tergite.

Body brownish yellow.

Type Material
Holotype, worker, Taiwan: Orchid Island, Taitung County, 10-ix-1997 (C. C. Lin) (Type depository: National Taiwan University).

Paratypes. One queen, 16 workers, Taiwan: Orchid Island, Taitung County, 10-ix-1997 (C. C. Lin), from the same nest as the holotype; 49 workers, Orchid island, Taitung County, 10-ix-1997 (C. C. Lin) (Type depository: National Taiwan University; National Museum of Natural Science, Taiwan; Taiwan Agricultural Research Institute).

Etymology
Named after Orchid Island, the type locality of this new species.

References based on Global Ant Biodiversity Informatics

 * Guénard B., and R. R. Dunn. 2012. A checklist of the ants of China. Zootaxa 3558: 1-77.
 * Hu C.-H. 2006. Indigenized conservation and biodiversity maintenance on Orchid Island. PhD Thesis, graduate school of the University of Minnesota. 150 pages.
 * Lin C.-C., and W. J. Wu. 2001. Three new species of Strumigenys Fr. Smith (Hymenoptera: Formicidae) with a key to Taiwanese species. Formosan Entomologist 21: 159-170.
 * Terayama M. 2009. A synopsis of the family Formicidae of Taiwan (Insecta: Hymenoptera). Research Bulletin of Kanto Gakuen University. Liberal Arts 17:81-266.
 * Terayama Mamoru. 2009. A synopsis of the family Formicidae of Taiwan (Insecta, Hymenoptera). The Research Bulletin of Kanto Gakuen University 17: 81-266.
 * Terayama, M. 2009. A synopsis of the family Formicidae of Taiwan (Insecta; Hymenoptera). The Research Bulletin of Kanto Gakuen University 17: 81-266.