Platythyrea clypeata Forel, 1911

Phengsi, Natthaporn, Jaitrong, Weeyawat, Ruangsittichai, Jiraporn & Salinee Khachonpisitsak,, 2018, A sibling species of Platythyreaclypeata Forel, 1911 in southeast Asia (Hymenoptera, Formicidae, Ponerinae), ZooKeys 729, pp. 87-102 : 89-95

Platythyrea clypeata Forel, 1911 Figs 2, 3, 5A1-A3

Platythyrea clypeata Forel, 1911: 378; Brown 1975: 50; Bolton 1995: 336; Xu and Zeng 2000: 214; Schmidt and Shattuck 2014: 51. Senior synonym of P. thwaitesi : Brown, 1975: 8.

Platythyrea thwaitesi Donisthorpe, 1931: 496. Junior synonym of P. clypeata : Brown 1975: 8.

Type.

The syntype alate queen from "Pays de Moïs”, Cochinchina française (S.E. Asia), deposited in MHNG (not examined).

Non-type material examined.

Nine workers, eastern Thailand, Chachoengsao Province, Tha Takiab District, Khao Ang Reu Nai Wildlife Sanctuary, 27.IX.2002, W. Jaitrong leg., Colony no. WJT270902-1 (THNHM-I-02423 to THNHM-I-02431); three workers, same locality, date and collector, Colony no. WJT270902-1 (THNHM-I-02432 to THNHM-I-02434); six workers, eastern Thailand, Sa Kaeo Province, Khao Ang Reu Nei Wildlife Sanctuary, 26.VI.2003, W. Jaitrong leg., Colony no. WJT03-TH-228 (THNHM-I-02435 to THNHM-I-02440); 23 workers and one male, eastern Thailand, Chanthaburi Province, Soi Dao District, 14.V.2008, W. Jaitrong leg., Colony no. WJT08-E065 (THNHM-I-02441 to THNHM-I-02453). Ten workers and one dealate queen, Laos, Vientiane, Pak Ngum District, Ban Phang Dang, ca. 300 m alt, 14.VI.2010, W. Jaitrong leg., Colony no. WJT-LAO-143 (THNHM); one dealate queen from same locality and collector, 12.VI.2010 (THNHM).

Measurements and indices.

TL 5.74-6.20 mm; HL 1.29-1.39 mm; HW 0.86-0.89 mm; SL 1.12-1.18 mm; EL 0.10 mm; WL 1.85-2.05 mm; PL 0.66-0.73 mm; PH 0.46-0.53 mm; PW 0.40-0.43 mm; CI 61-69, EI 11, SI 125-138.

Worker redescription.

Head. Head in full-face view rectangular, clearly longer than broad, with sides weakly convex or almost parallel, occipital corner roundly convex, and posterior margin feebly concave; antennal scape slender, relatively short, slightly extending beyond posterolateral corner of head (by 1/4 of its length); clypeus narrow, in profile with median portion distinctly convex, in full-face view lateral portion relatively broad and anterior margin clearly convex; mandible triangular, its masticatory margin with a large apical tooth, followed by ten smaller teeth (including basal tooth), large and smaller teeth alternating, but the series as a whole decreasing in size; basal margin of mandible without denticle; eye flat, located laterally at anterior to mid-length of head, very small, 0.10 mm in maximum diameter, with five omma tidia along longest axis; distance between mandibular base and anterior margin of eye approximately three times as long as maximum eye length; with head in lateral view, distance between posterior margin of eye and occipital corner of head 2.7 times as long as distance between mandibular base and anterior margin of eye; frontal lobes close to each other and rounded; frontal carinae strongly narrowed posteriorly.

Mesosoma elongate, in profile with almost straight dorsal outline; promesonotal suture distinct; mesopleuron demarcated from mesonotum and metapleuron by shallow furrows; propodeum in profile with almost straight dorsal outline; propodeal junction obtusely angulated; declivity of propodeum shallowly concave; seen from back propodeal declivity rounded above; propodeal spiracle opening elliptical; legs relatively long.

Petiole cylindrical and sessile, slightly longer than high and clearly longer than broad, its dorsal outline almost straight; in profile posterodorsal corner forming an acute angle; declivity deeply concave; in dorsal view node rectangular, slightly narrower posteriorly, its posterior margin convex and with shallow median concavity; subpetiolar process developed, located anteroventrally, subtriangular, its apex truncate and pointed forward; ventral outline of petiole feebly concave.

Sculpture. Dorsum of head finely punctate; lateral face of head behind, above and below eye punctate with dense foveae; dorsum of mesosoma with fine micropunctures similar to those on dorsum of head; lateral faces of pronotum, metapleuron and propodeum punctate with sparse shallow foveae; petiole finely micropunctate; gastral tergites I and II finely reticulate; antennal scape finely micropunctate; coxae microreticulate with smooth and shiny interspaces.

Pubescence white, very short and fine; setae present on tip of gaster.

Colouration. Head, mesosoma, petiole, and gaster reddish brown to dark brown (tip of gaster yellowish); antenna and legs yellowish brown to reddish brown (flagellum paler than scape).

Measurements and indices

(n = 2). TL 7.49 mm; HL 1.52 mm; HW 1.06 mm; SL 1.32 mm; EL 0.20 mm; WL 2.31 mm; PL 0.79 mm; PH 0.73 mm; PW 0.46 mm; CI 69, EI 18, SI 125.

Dealate queen description.

Body size slightly larger than worker. Head. Head in full-face view rectangular, clearly longer than broad with convex sides and almost straight posterior margin, occipital corner roundly convex; antennal scape extending beyond posterolateral corner of head by approximately 1/4 of its length; eye relatively large and convex, located anterior to mid-length of head, 0.20 mm in maximum diameter with ca. 17 ommatidia on the longest axis; frontal lobe and frontal carina similar to those in worker caste; distance between anterior margin of eye and mandibular base almost as long as eye length; ocelli clearly absent.

Mesosoma in profile with slightly convex dorsal outline; pronotum long and broad; mesoscutum trapezoidal, anterior edge clearly convex in dorsal view, separated from mesoscutellum by a shallow but wide suture and from pronotum by narrow suture; parapsidal lines indistinct, relatively long, straight and running anteriorly to mid-length of mesoscutum; mesoscutellum almost as long as broad; metanotum very short, separated from mesoscutellum and propodeum by deep grooves; propodeum relatively long; mesopleuron broad, anepisternum not demarcated from katepisternum; propodeal junction obtusely angulated; declivity of propodeum shallowly concave; seen from back propodeal declivity rounded above.

Petiole in profile view relatively short, rhombus, almost as long as high, its anterior margin weakly convex while posterior margin concave; declivity of petiole shallowly concave; subpetiolar process low and subtriangular, located anteroventrally, its apex pointed forward; ventral outline of petiole feebly concave. Gaster larger than in worker.

Sculpture, colouration, and setae similar to those of worker caste.

Distribution.

Sri Lanka, Vietnam, China (?) and Thailand (new record).

Ecology.

Platythyrea clypeata occurs in lowland (200-300 m alt) and inhabits primary and disturbed forests. All colonies of this species were collected from dead wood on the forest floor in an advanced stage of decomposition.