Strumigenys nathistorisoc

Strumigenys nathistorisoc was only recorded in secondary forests and Feng Shui woods, along a relatively large gradient of elevation ranging from 29 to 572 m.

Identification
Dorsum of head, scape, and mandibles covered with appressed spatulate hairs, but no standing hairs. Side of mesosoma generally smooth and shining. Elongated propodeal spines subtended by narrow concave lamellae. Masticatory margin of mandibles engaging only at the apical half (or slightly less than half) of their lengths, with a prominent diastema proximal to this and first 3 preapical teeth not reaching their counterpart from the opposing mandible. Dentition consisting of a small conical tooth, a series of alternating long conical teeth and low round teeth, a crowded series of minute denticles at the down curvature of the apex of mandible, and a small conical apical tooth.

Strumigenys nathistorisoc is well distinguished from other Strumigenys species by a combination of the characteristics listed in the diagnosis. It does not fit the description of any existing Strumigenys species group, in particular due to its highly distinctive mandibles and dentition.

Comparing S. nathistorisoc with the most similar appearing Strumigenys species, such as Strumigenys kichijo and species from the S. leptothrix-group, these species, in contrast, are often either hairless or have simple or flagellate hairs on the cephalic and pronotal dorsum, or have sculpture on the sides of the mesosoma, or have propodeal spines subtended by medium to broad lamellae. S. nathistorisoc also lacks the laterally projecting hairs in full-face view or the distinct transverse striations on the pronotal dorsum and dorsum of the petiolar node that characterise Strumigenys nankunshana.

Focusing on the mandibles and dentition, in contrast to the description of S. nathistorisoc, S. kichijo has only conical teeth. S. nankunshana and species from the S. leptothrix-group have masticatory margins that engage throughout the entire length. Strumigenys wilsoniana has a much wider gap between the mandibles, the masticatory margins engage at the apical third (instead of around half as in S. nathistorisoc) of their length, with the basal 2 teeth (instead of 3) situated at around the mid-length of the mandible (instead of sparsely across the basal half of the mandible) and not reaching their counterparts from the opposing mandible when the mandibles are fully closed.

Distribution based on Regional Taxon Lists
Palaearctic Region: China.

Nomenclature

 *  nathistorisoc. Strumigenys nathistorisoc Tang, Pierce & Guénard, 2019: 31, figs. 12A-D (w.) CHINA.

Type Material

 * Holotype worker: HONG KONG: Islands District, Lantau Island, Sunset Peak, 22.263923N, 113.953762E, 467 m, 3 June 2015 (R.H. Lee) (collection code RHL-HK-LSP-T3WM) [IBBL, ANTWEB1016948].
 * Paratype workers (n = 26): same data as holotype.