Perissomyrmex bidentatus

Xu and Zhang (2012) - In a large sample, 30 individuals were collected from a nest constructed inside top soil. Among the 30 individuals, one queen (3.2%), two soldiers (6.7%), and 27 workers (90%) were involved. In addition, four workers and one queen were collected from ground and soil samples, and two winged females were collected from ground and tree crown samples respectively. The winged females were collected from October 10 to 19. The collection data show that the species is monogynous and nests in soil; workers are weakly dimorphic and forage on the ground; the soldier caste only occupies a small percentage; nuptial flight occurs on the plants and ground; and the nuptial flight time is mid-October in Hengduan Mountains of southwestern China. Collected from forest habitats.

Identification
Zhou & Huang (2006) - Differs from all known species by anterior clypeal border with 2 teeth. It differs from Perissomyrmex guizhouensis by occipital border slightly concave, central clypeal lobes without external teeth, antennal scape shorter, SI 78, promesonotal suture poorly distinguishable.

Distribution based on Regional Taxon Lists
Palaearctic Region: China.

Nomenclature

 *  bidentatus. Perissomyrmex bidentatus Zhou & Huang, 2006: 192, figs. 4  6 (w.) CHINA. Xu & Zhang, 2012: 151 (s.q.). Senior synonym of emarginatus: Xu & Zhang, 2012: 150.
 * emarginatus. Perissomyrmex emarginatus Ogata & Okido, 2007: 359, figs. 14, 16a-c, 17a (w.q.) CHINA. Junior synonym of bidentatus: Xu & Zhang, 2012: 150.

Worker
Holotype minor worker. TL 3.8, HL 0.93, HW 0.93, SL 0.73, EL 0.10, AL 1.03, PW 0.56, PL 0.31, PNW 0.17, PH 0.28, PPL 0.24, PPW 0.22, PPH 0.28, CI 100, SI 78, PI 54, PPI 91. Head as broad as long, widened forward. In full face view, occipital margin slightly concave, occipital corners rounded, sides slightly convex. Mandible rectangular, inner margin with one tooth in the middle, masticatory margin with 3 teeth and a diastema, arranged as apical tooth, preapical tooth, diastema and basal tooth. Median region of clypeus flattened, anterior clypeal border with 4 teeth: the central pair slightly larger than the two external teeth. Frontal carinae absent leaving antennal sockets completely exposed. Antenna 9-segmented, apical three enlarged to formed antennal club. Antennal scape surpassing occipital corner by 1/6 of its length. Eyes protuberant but small, placed at the middle length of the sides of the head. In profile view, pronotum slightly convex, promesonotal suture poorly distinguishable. Propodeal impression well developed. Propodeal spines divergent, directed backwards, dorsum of propodeum slightly convex. Petiole 2 times longer than broad, without subpetiolar process. Petiolar node relatively high and thin, weakly narrowed upwards, dorsum moderately convex, anterodorsal corner higher than posterodorsal corner. Anteroventral corner of postpetiole right-angled, postpetiolar node inclined posteriorly, as high as petiolar node.

Mandible coarsely longitudinally striate. Clypeus smooth and shining. Head and alitrunk sparsely longitudinally striate. Lateral sides of mesothorax, metathorax smooth and shining, propodeum sparsely longitudinally striate, and the striations on pronotum concentrate on humeri. Petiole and postpetiole smooth and shining. Gaster smooth and shining. Dorsal surfaces of head and body with abundant erect or suberect long hairs hairs. Antennal scapes and tibiae with abundant subdecumbent long hairs and decumbent short hairs. Color reddish brown, antennal scapes and legs lighter, gaster darker.

Paratype minor worker: TL 3.9, HL 0.93, HW 0.93, CI 100, SL 0.73, SI 78, EL 0.10, AL 1.03, PW 0.56, PL 0.31, PNW 0.17, PH 0.27, PI 54, PPL 0.24, PPW 0.22, PPH 0.29, PPI 91.

Xu and Zhang (2012) - TL 3.7-4.1, HL 1.00-1.20, HW 1.00-1.20, CI 95-100, SL 0.83-0.93, SI 75-88, ED 0.13-0.15, PW 0.58-0.68, AL 1.08-1.25 (11 individuals measured). Well conform to the measurements, description, and images of the species, but median teeth of anterior clypeal margin are variable, which show a normal apically obliquely truncated state or weakly apically bifid state.

Soldiers. TL 4.3-4.4, HL 1.25-1.33, HW 1.28-1.38, CI 102-104, SL 0.90-0.95, SI 67-71, ED 0.16-0.20, PW 0.70-0.73, AL 1.23-1.25 (two individuals measured). Similar to worker caste, but body relatively larger, head proportionally larger. Occipital margin more deeply concaved. Teeth on masticatory margin of mandibles moderately reduced and blunt. Median teeth of anterior clypeal margin broad and truncated at apices, with shallow notch between teeth. Antennae relatively short, apices of scapes just reaching occipital corners.

Morphological variations. The morphology of the clypeus shows rich variations in worker, soldier, and queen castes. In the worker caste, the median teeth of anterior clypeal margin may be either apically obliquely truncated (60% individuals) or weakly apically bifid (40% individuals). In the two soldiers obtained, the median teeth are apically truncated and short, which is different from the worker caste. In the queen caste and winged females, the median teeth are apically truncated in three individuals (75%), or apically obliquely truncated in one winged female (25%).

Queen
Xu and Zhang (2012) - TL 4.6-5.0, HL 1.18-1.25, HW 1.23-1.33, CI 100-106, SL 0.90-0.96, SI 68-76, ED 0.18-0.23, PW 0.83-0.95, AL 1.35-1.45 (four individuals measured). Similar to worker caste, but body relatively larger, head proportionally larger. Median teeth of anterior clypeal margin variable, showing a normal apically truncated state (as in soldier caste) or apically inward curved state (as the normal state in worker caste). Antennae relatively short, apices of scapes just reaching to occipital corners. Vertex with three ocelli. Mesosoma winged or dealate, massive in volume. In profile view, mesonotum high, weakly convex and sloped down backward. Mesopleuron with oblique furrow. Metanotum very short, overhung by scutellum. Dorsum of propodeum weakly concave, steeply sloped backward. Propodeal spines straight, slightly longer than dorsum. Declivity weakly concave, about as long as spines. In dorsal view, scutum of mesonotum without longitudinal furrows, posterior margin weakly convex. Anterior margin of scutellum very bluntly angled, posterior margin rounded. Propodeal spines strong and very obviously curved inward. Ocellus area, anterior and lateral areas of mesonotal scutum black.

Type Material
Holotype worker, Baiyun Mountain, Song County, Henan Province, 33°38'N, 111°48'W. 25 July 2002, Jianhua Huang leg. Paratype 1 worker, Qinling Natural Reserve, Shaanxi Province, 32 40'N, 105 30'W, 9 July 2004, Ru Tie leg. The holotype is deposited in the Insect Collection, Guangxi Normal University, Guilin, P. R. China.