Acropyga nipponensis

LaPolla (2004) - A. nipponensis can survive in a wide range of habitats, occurring in both rainforests and temperate forests. It has been collected along creek beds and under stones. This species has been found in trophobiotic association with the mealybug Eumyrmococcus nipponensis in Japan.

Identification
From Lapolla (2004) - Worker: 11 segmented antennae; mandible broad, with 5 teeth, basal tooth enlarged and rectangular, apically truncated; HW: < 0.5 mm. Queen: As in worker with modifications expected for caste. Male: 12 segmented antennae; parameres extremely thin and long; mandible with 4 teeth; basal tooth as in worker though less pronounced. Compare with Acropyga butteli and Acropyga inezae.

The primary means of separating workers of A. nipponensis from Acropyga butteli is by differences in head width < 0.5 mm in the former, > 0.5 mm in the latter). Examination reveals distinct morphometric differences between the two species. Queen morphology also suggests that the two species are not conspecific. An A. nipponensis queen measured had a total length of 2.85 mm versus an A. butteli queen with a total length of 4.02 mm.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Borneo, Indonesia, Philippines. Oriental Region: Taiwan. Palaearctic Region: China, Japan.

From LaPolla (2004): This species has been recorded as far north as temperate regions of Japan, south and west to China and Indonesia.

Nomenclature

 *  nipponensis. Acropyga (Atopodon) nipponensis Terayama, 1985b: 287, figs. 14-18 (w.) JAPAN. LaPolla, 2004a: (q.). Senior synonym of jiangxiensis: LaPolla, 2004a: 39. See also: Terayama, Fellowes & Zhou, 2002: 30.
 * jiangxiensis. Acropyga (Atopodon) jiangxiensis Wang, C. & Wu, 1992a: 226, figs. 1-4 (w.m.) CHINA. Junior synonym of nipponensis: LaPolla, 2004a: 39.

LaPolla (2004) - The male described in this study as A. nipponensis is associated with workers of the species originally described as A. jiangxiensis, a species now treated as a junior synonym. This male is clearly different from A. butteli and Acropyga inezae males. The paratype worker of A. jiangxiensis examined cannot be separated from workers of A. nipponensis and they are therefore considered to be conspecific. The two characters cited by Terayama et al. (2002) as separating A. nipponensis and A. jiangxiensis are suspect, for both are difficult to interpret with such a small sample size. Slight shape changes in the posterior margin and the dorsum of the propodeum were used to warrant recognition of two species, but here I treat those morphological differences as simply intraspecific variation. As male specimens are collected from across the range of A. nipponensis the status of this species should be reexamined.

Worker
From LaPolla (2004) - Head: light brownish-yellow; covered in a dense layer of short, appressed hairs; head longer than broad; posterior margin entire to slightly concave medially; 11 segmented, incrassate antennae; scape fails to reach posterior margin by about half the length of pedicel; clypeus broad, with appressed to erect hairs on surface; anterior clypeal margin uneven coming to three points, a medial and 2 lateral points; mandible broad, with 5 teeth; basal tooth enlarged and rectangular, apically truncated; anterior clypeal margin and inner mandibular margin nearly parallel. Mesosoma: light brownish-yellow; in lateral view, with short shelf before rising sharply toward mesonotum; pronotum with appressed hairs, long erect hairs posteriorly; mesonotum slightly higher than propodeum, covered in a layer of appressed to erect hairs; metanotal area distinct; propodeum gently rounded, with appressed hairs dorsally; declivity steep. Gaster: petiole thick and erect, reaching height of anterior portion of propodeal spiracle; gaster light brownish-yellow with dense layer of appressed hairs, with scattered erect hairs throughout.

Measurements (n=5): TL: 1.97-2.05; HW: 0.457-0.487; HL: 0.576-0.597; SL: 0.391-0.417; ML: 0.436-0.532; GL: 0.878-0.944; CI: 76.55-83.97; SI: 80.29-89.72.

Queen
From LaPolla (2004) - As in worker with modifications expected for caste.

Meausurements (n=1): TL: 2.85; HW: 0.604; HL: 0.688; SL: 0.528; ML: 0.882; GL: 1.3; CI: 90.42; SI: 87.42.

Male
From LaPolla (2004) - Head: brownish-yellow, darker toward apex around 3 prominent ocelli; head longer than broad; covered in a thick layer of appressed hairs; eyes large, breaking outline of head in full frontal view; 12 segmented, incrassate antennae; scape surpasses posterior margin by about length of the pedicel; clypeus broad, slightly convex medially, with scattered erect hairs; mandible with 4 teeth, the basal as in worker, though less distinct; inner mandibular margin and anterior clypeal margin nearly parallel. Mesosoma: unfortunately the mesosoma of the single examined male specimen was too badly distorted to be described properly. Gaster: brownish-yellow; covered in a thick layer of appressed hairs with scattered erect hairs throughout. Genitalia: in lateral view, parameres long and very thin, each tapering to a pointed apex; cuspi bent slightly toward digiti; cuspi apices with short, peg-like teeth; digiti straight and long, about 2 times as long as cuspi; digiti with apices rounded, each with short peg-like teeth midlength where cuspi bends toward them.

Measurements: not completed as specimen was too badly distorted to be measured properly.

Type Material
Acropyga nipponensis Terayama, 1985: 287 (w.). 1 holotype worker, JAPAN: Noboritachi, Mikura-jima Is., Tokyo (K. Masuko) (NIAS) [not examined]. Terayama et al., 2002: 30, description and key.

Acropyga jiangxiensis Wang and Wu, 1992: 226 (w.m.). 1 holotype worker, CHINA: Jiangxi Provin., Fenyi Co., Dagang Mt. (c. Wang) (CFRB) [not examined]; 1 worker paratype, 1 male paratype, same locality as holotype (CFRB) [examined]. NEW SYNONYM. Terayama et al., 2002: 29, description and key.

Additional References

 * Terayama, M. 1985e. Two new species of the genus Acropyga (Hymenoptera, Formicidae) from Taiwan and Japan. Kontyû 53: 284-289
 * LaPolla, J.S. 2004a. Acropyga of the world. Contributions of the American Entomological Institute 33 (3): 1-130.