Ponera sinensis

Known from only two collections.

Identification
Taylor (1967) - The nominate species of the sinensis group, which also includes the similar and closely related Ponera oreas. P. sinensis may be distinguished from oreas by the following characters:

1. Larger size (head width 0.54 mm, opposed to 0.47-0. 5 1 mm in areas)

2. Narrower head (cephalic index 89 against 92-95).

3. Slightly higher scape index (83; 78-81 in areas)

4. Antennal club indistinctly 5-segmented, where it is 4-s.egmented in areas.

5. The 3 apical mandibular teeth occupy only the anterior 2/5 of masticatory border; no posterior denticles delimitated (this is possibly an artifact due to wear since the apical teeth look well worn on the holotype!).

6. Cephalic sculpturation consisting of a close cover of punctures about 0.006 mm in diameter, separated by distances of about 1/2 their average diameter. In areas the head is distinctly more dull, with sculpturation best described as ‘shagreening.’ It consists of similarly sized punctures, but they are almost contiguous, with very little exposed interpunctural surface. Remaining sculpturation similar in 2 species, except that most areas workers have a shining, almost apunctate, median posterior strip on the propodeal dorsum; this area is evenly punctate in sinensis.

Distribution based on Regional Taxon Lists
Oriental Region: Taiwan. Palaearctic Region: China.

Biology
Pierce et al. (2019): To the best of our knowledge, the only confirmed specimen of P. sinensis from Hong Kong is the holotype, collected by Professor F. Silvestri from an unknown location, and described by Wheeler (1928). Despite numerous faunal studies in Hong Kong over recent years, no further specimens of P. sinensis have been identified. On the contrary, the vast majority of Ponera specimens collected from Hong Kong represent the newly recorded Ponera guangxiensis. Whether this represents an underlying ecological change or simply an artifact of sampling remains unclear, and future sampling in Hong Kong may yield new specimens of P. sinensis.

Nomenclature

 *  sinensis. Ponera sinensis Wheeler, W.M. 1928c: 6 (w.) CHINA (Hong Kong). See also: Taylor, 1967a: 53.

Worker
Taylor (1967) - My measurements of the holotype differ slightly from Wilson's: HL 0.61 mm; HW 0.54 mm; SL 0.45 mm; CI 89; SI 83; PW 0.41 mm; PNL 0.20 mm; PH 0.39 mm; DPW 0.35 mm; PNI 85. Note that certain characters given (see the identification section above) contradict those of Wheeler's description, which is inaccurate in places. The eyes of the holotype are not one-faceted as he claimed, but the visible left one, at least, has 4 fairly distinct facets. The oral palpi have not been dissected.

Leong et al. (2019) - Holotype: HL 0.61; HW 0.55; SL 0.43; A06L 0.02; A07L 0.03; A08L 0.05; A09L 0.07; A10L 0.08; PrW 0.38; WL 0.82; PeH 0.39; PeNL 0.19; PeW 0.34; ATL N.A.; ATW N.A.; CI 90, SI 78, PeI 90, LPeI 50, DPeI 178, ATI N.A. [measured from images] (n=16): HL 0.57–0.61; HW 0.49–0.56; SL 0.40–0.44; PrW 0.36–0.43; A06L 0.03; A07L 0.03; A08L 0.05; A09L 0.06; A10L 0.08; WL 0.73–0.88; PeH 0.38–0.45; PeNL 0.18–0.22; PeW 0.31–0.38; ATL 0.41–0.48; ATW 0.46–0.53; CI 86–94, SI 77–85, PeI 81–94, LPeI 46–54, DPeI 159–181, ATI 80–92.

Head. In full-face view, head subrectangular and longer than broad (CI: 86–94), with slightly concave posterior margin, moderately convex lateral margins, and broadly rounded posterolateral corners. Eye small; composed of a total of 4 to 7 indistinct facets. Anterior clypeal margin with distinct and blunt medial tooth. Masticatory margin of mandible edentate, but with three large teeth on the apical part. Antennal scape, when laid backward, with a remaining distance of about 5% of the scape length to the posterolateral corner; average ratio of the length of antennomeres 7/6:8/6:9/6:10/6 = 1.16: 1.81: 2.55: 3.14 (n=17).

Mesosoma. Mesosomal dorsum in lateral view slightly convex. Pronotum in dorsal view with well convex anterior margin and moderately convex lateral margins. Metanotal groove in dorsal view distinctly incised. Propodeal dorsum in dorsal view moderately broad, with straight lateral margins. Posterodorsal corner of propodeum in lateral view angular, propodeal dorsum and declivity forming approximatively a 120 degree angle.

Metasoma. Petiolar node in dorsal view remarkably thin and arched, with broadly convex anterior margin, and moderately concave posterior margin. Petiolar node in lateral view, moderately thick and triangular, with straight anterior margin, broadly convex posterior margin, and dorsum forming an acute corner. Subpetiolar process with small and suboval/circular fenestra, anteroventral corner blunt, slightly concave ventral margin, and posteroventral corner concave with a pair of developed teeth. Third abdominal tergum distinctly broader than long (ATI: 80–92), with almost straight anterior and posterior margins.

Sculpture. Head densely punctate. Mandible sparsely punctate. Pronotum and mesonotum evenly punctate. Mesopleuron with weakly striate lower portion and sparsely punctate upper portion. The portion contained between metapleuron and propodeum very smooth. Propodeal declivity smooth. Lateral face of petiole sparsely punctate, with smooth posterior face, dorsum with few punctures. The third and fourth abdominal segments evenly punctate, other segments smooth and shining with few punctures.

Pubescence. Head with dense and short hairs. Mesosoma with evenly distributed short hairs; mesopleuron, metapleuron and propodeum with scattered short hairs. Petiolar node with scattered short hairs in lateral and anterior faces, posterior and dorsal faces with few short hairs. Dorsal and ventral faces of head, anterior margin of clypeus, sides of mandibles, dorsum of petiolar node, gastral sterna and posterior half of gastral terga with many long erect hairs. Subpetiolar process with a few long erect hairs.

Color. Body color dark to dark brown. Mandible, clypeus, antennae, legs, and apex of gaster orange brown.