Ponera japonica

Ponera japonica is found in forested habitats, as are most Ponera, but is unusual in also nesting in open sites.

Identification
Taylor (1967) - The relatively large size, the tendency to develop a median clypeal denticle, the large eyes, the relatively long scapes, and the broad petiolar node, mark japonica as the most primitive species of its group. Total length of workers around 2.5 mm. Body color brown  to  blackish  brown. Scapes not  reaching median posterior border of head, failing to do so by at least 1/5 maximum scape thickness.

Distribution
Widespread in the Orient and Indonesia.

Distribution based on Regional Taxon Lists
Palaearctic Region: China, Democratic People's Republic of Korea, Japan, Republic of Korea, Russian Federation.

Biology
Taylor (1967) - Detailed information is given by Hayashida (1957, 1960), concerning the ecology of japonica (erroneously identified as Ponera scabra). It is not uncommon, though sparsely distributed, in the vicinity of Sapporo, on the Ishikari Plain of Hokkaido, an area once extensively forested but now largely urban or cultivated. Of 28 ant species collected there it was 18th in abundance (18 or 1.3% of 1491 colonies taken in a total of 43 hours collecting, divided equally between 8 habitat types). P. japonica apparently has fairly broad habitat preferences and was taken in the following situations: (1) arid sparsely vegetated sand dunes or river sides (50% of the 18 colonies); (2) dry sparsely vegetated, disturbed cropfields or roadsides (6% of colonies); (3) rather humid pastures and meadows with dense grass and herb cover and loamy clay soil (22 % of colonies); (4) humid woods or forests with low insolation, loamy soils and abundant decaying matter lying on the ground (22% of colonies). It was not taken at the sea shore, in peat bogs, or on the margins of wood lots. The general parameters of habitat preference were given as low light intensity, and moderate moisture conditions (Hayashida 1957). Foraging is restricted to the ground layer, as usual in Ponera.

In woods and grasslands nests were in or under humus and other debris, but in more open habitats japonica was found nesting among the roots of grasses or in exposed soil, even where it was sandy. If debris or stones were available in open habitats nests were usually constructed beneath them. In the arid sand dunes or dry river beds about 75% of colonies were under stones.

P. japonica nests under stones and in the soil, especially in the humus layer. Okamoto (1972) reported that larvae do not spin cocoons and the pupae are thus naked. It is found from low-lying to mountainous sites.

Nomenclature

 *  japonica. Ponera japonica Wheeler, W.M. 1906c: 306 (w.q.) JAPAN. Imai, Brown, et al. 1984: 67 (k.). Senior synonym of crocea: Taylor, 1967a: 76. See also: Kupyanskaya, 1990: 86.
 * crocea. Ponera japonica var. crocea Santschi, 1941: 273 (w.) JAPAN. [Unresolved junior primary homonym of crocea Roger, 1860: 288, above.] Junior synonym of japonica: Taylor, 1967a: 76.

Queen
Taylor (1967) - Two Japanese syntypes have the following dimensions: HL 0.65 mm; HW 0.53 mm; SL 0.45 mm; CI 81; SI 85; PW 0.46 mm; PNL 0.22 mm; PH 0.43 mm; DPW 0.33-0.34 mm; PNI 72-74; maximum diameter of compound eye 0.15 mm; ocular index 28; palpal formula: Maxillary 2: Labial 2 (1 inspected).

Type Material
Wheeler, as usual, designated no holotype from his original series of P. japonica. A worker ( collection) with the measurements given below is here designated lectotype and is so labeled. Four additional syntype workers in the MCZ collection and 8 in the, along with 2 queens (one in each of these collections) have been designated and labeled as paralectotypes. Yamanaka, Suruga (West slope, Hakone Mts), Japan (Syntypes examined- MCZ, AMNH).

Ponera japonica var. crocea Type locality: Namase, Honshu (Syntypes examined-Santschi coll.).