Platythyrea homasawini, Jaitrong & Xu & Khachonpisitsak, 2022

Jaitrong, Weeyawat, Xu, Zhenghui & Khachonpisitsak, Salinee, 2022, A new species of the ant Platythyrea clypeata species group (Hymenoptera, Formicidae, Ponerinae) from continental Asia, ZooKeys 1115, pp. 151-168 : 151

Platythyrea homasawini sp. nov.

Figs 3 , 5B1-B3

Platythyrea clypeata : Xu and Zeng 2000: 214, figs 1-3.

Type.

Holotype worker (THNHM-I-26225), northern Thailand, Chiang Mai Prov., Doi Saket Dist., Ban Mae Pong , 24.XI.2021, K. Homasawin leg., Colony No. WJT241121-01. Paratypes: 29 workers (THNHM-I-26226 to THNHM-I-26250, THNHM-I-24977 to THNHM-I-24979, and THNHM-I-26445), same data as holotype .

Non-type material examined.

China • 1 worker, Yunnan Prov., Menghai County, Meng’a Town, Papo Village, 1280 m, No. A97-2318, collected from secondary monsoon evergreen broadleaf forest, 10.IX.1997, Zhenghui Xu leg. - Thailand • 1 worker (THNHM-I-02463), northern Thailand, Chiang Mai Prov., Muang Dist., restored forest, 8.V.2002, S. Sonthichai leg. • 1 worker (THNHM-I-02454), western Thailand, Kanchanaburi Prov., Thong Pha Phum N.P., Natural Forest, 8.III.2005, W. Sakchooeong leg.

Measurements and indices.

Holotype. TL 7.72, HL 1.60, HW 1.08, SL 1.72, EL 0.20, PW 0.96, ML 2.84, PL 1.08, PH 0.68, DPW 0.44, CI 68, EI 19, SI 159. Paratypes (n = 10). TL 7.72-7.80, HL 1.56-1.64, HW 1.08-1.12, SL 1.64-1.68, EL 0.16-0.20, PW 0.96-0.99, ML 2.80-2.84, PL 1.08-1.12, PH 0.60-0.64, DPW 0.40-0.44, CI 68-69, EI 15-19, SI 150-159.

Description of workers

(holotype and paratypes). Head in full-face view subrectangular, clearly longer than broad, weakly widening anteriorly, sides weakly convex, posterior margin almost straight, posterior corners narrowly rounded. Antennae relatively long, scapes extending beyond posterior corners of head by about 1/4 of their length. Clypeus roughly triangular, roundly convex medially, anterior margin bluntly angled. Mandibles triangular, masticatory margin with a large apical tooth, followed by eight smaller teeth, large and small teeth alternating, basal margin without denticle. Eyes flat, located at anterior 1/3 of head length, moderately large, each with 7 or 8 ommatidia along its longest axis. Frontal lobes close to each other and rounded. Space between frontal carinae distinctly narrowed posteriad.

Mesosoma elongate, in profile view pronotum weakly convex, promesonotal suture distinct, dorsal outline of mesonotum and propodeum straight, metanotal groove absent, propodeal junction broadly rounded, declivity of propodeum obviously concave; propodeal spiracle opening elliptical. Legs very long.

Petiole cylindrical and sessile, in profile view clearly longer than high, dorsal outline weakly convex, anterodorsal corner broadly rounded, posterodorsal corner extending into an acute angle, posterior margin oblique and straight, ventral margin almost straight with narrowly prominent anteroventral corner; in dorsal view the node of petiole rectangular, longer than broad, sides straight and parallel, posterior margin weakly convex.

Sculpture. Head entirely finely micropunctate. Dorsum of mesosoma finely micropunctate, mesopleuron, metapleuron and sides of propodeum punctate. Petiole finely micropunctate. Gaster superficially shagreened.

Pilosity. Whole body surface and appendages covered with very short thin pubescence. Standing hairs absent.

Coloration. Body color reddish brown; antennae, legs, and tip of gaster yellowish brown. Eyes grey. Pubescence white.

Distribution.

China (Yunnan Province) and Thailand (Chiang Mai and Kanchanaburi provinces) (Fig. 6).

Etymology.

The specific name is dedicated to Mr Kaisihanat Homasawin, who donated the type series.

Comparative notes.

The new species is similar to P. janyai but it can be separated from P. janyai by the following characteristics (characters of P. janyai in parentheses unless otherwise stated): 1) head weakly widening anteriorly (head not widening anteriorly); 2) dorsal outline of petiole weakly convex (dorsal outline of petiole almost straight); 3) posterior margin of petiolar node without a concavity in the middle (posterior margin of petiolar node with a concavity in the middle): 4) body surface with thin pubescence (body surface with thick pubescence); 5) head longer (CI = 66 in P. homasawini , CI = 72 in P. janyai ); 6) antennal scape relatively long, 1/3 of its length extending beyond posterolateral corner of head (clearly extending beyond posterolateral corner of head); 7) eye smaller and flat (EL = 0.17 mm in P. homasawini ; EL = 0.20 mm and slightly convex in P. janyai ); 8) seen from back propodeal declivity rounded above (propodeal declivity tapering above); 9) dorsal outline of petiole weakly convex (almost straight).

Platythyrea homasawini can be easily separated from P. clypeata by the following characteristics (characters of P. clypeata in parentheses unless otherwise stated): 1) head in full-face view, posterior margin weakly concave (posterior margin almost straight); 2) antennal scape relatively long, 1/3 of its length extending beyond posterolateral corner of head (antennal scape short, 1/4 of its length extending beyond posterolateral corner of head); 3) clypeus broad (clypeus narrow); 4) eye larger (EI = 15, with 7 ommatidia in P. homasawini ; EI = 11, with 5 ommatidia in P. clypeata ); 5) mesosoma relative longer (WL = 2.64 in P. homasawini ; WL=1.85-2.05 in P. clypeata ); 6) mesopleuron not demarcated from mesonotum (mesopleuron clearly demarcated from mesonotum by shallow furrow); 7) in profile view, propodeal junction roundly convex (propodeal junction obtusely angulate); 8) in dorsal view, posterior margin of petiole clearly convex (posterior margin of petiole convex with shallow median concavity); 9) lateral face of head entirely micropunctate (lateral face of head areas behind, above and below eye punctate, with dense foveae); 10) gaster superficially shagreened (finely reticulate).

Platythyrea homasawini can be distinguished from P. gracillima by the following characteristics (characters of P. gracillima in parentheses unless otherwise stated): 1) clypeus roundly convex (rather flat in P. gracillima ); 2) petiole laterally convex; 3) seen from above longer than high (petiole laterally compressed); 4) seen from above a little more than twice as long as broad); 5) mandible finely micropunctate (mandible finely and densely punctate); 6) head entirely finely micropunctate (rather smooth in P. gracillima ).

Figures

Figure 3. Platythyrea homasawini sp. nov. (holotype worker, THNHM-I- 02463). A body in profile view B head in full-face view C body in dorsal view.

Figure 5. SEM images of Platythyrea clypeata (A 1 - A 3) P. homasawini sp. nov. (B 1 - B 3) and P. janyai (C 1 - C 3). A 1, B 1, C 1 sculpture on lateral face of head A 2, B 2, C 2 ommatidia of eye A 3, B 3, C 3 petiole in profile view.