Myopias sonthichaiae, Jaitrong & Tasen & Guénard, 2018

Jaitrong, Weeyawat, Tasen, Wattanachai & Guénard, Benoit, 2018, The ant genus Myopias Roger, 1861 (Hymenoptera: Formicidae: Ponerinae) in Thailand, with descriptions of three new species, Zootaxa 4526 (2), pp. 151-174 : 168-172

Myopias sonthichaiae sp. nov.

( Figs. 37–43 )

Etymology. The specific name is dedicated to Assoc. Prof. Sauwapa Sonthichai of Chiang Mai University, who has been a leading myrmecologist in Thailand.

Type. Holotype worker (THNHM-I-00946, THNHM), N Thailand, Chiang Mai Prov., Doi Ang Khang , 19.87111111°N, 99.05250000°E, 1780 m a.s.l., 24.VIII.2002, S. Hasin leg., Colony no. TH-02 SH-052 . Paratypes: one worker (THNHM-I00947) and 1 queen (THNHM-I-00948) are deposited in THNHM, same colony as holotype; one worker, same data as holotype, is deposited in SBSHKU .

Non-type material examined. One worker, N Thailand, Chiang Mai Prov., Muang Dist., Hill Evergreen Forest (HEF), 18.VII.2016, W. Jaitrong leg. ( THNHM); 1 worker , Chiang Mai Prov., Muang Dist., Hill Evergreen Forest , 8.VI.2001, S. Hasin leg. ( AMK); 1 worker , same locality, Secondary Forest , 15.V.2008, S. Sonthichai leg., Colony no. SS 150808 -1 ( THNHM); 1 worker, same locality and collector, VII, 2008 ( THNHM) ; 1 dealate queen, Tak Prov., Um Phang Dist., Thung Yai Naresuan East W.S., 21.I.2014, W. Jaitrong leg. ( THNHM); 1 worker , same locality, Dry Evergreen Forest , V.1999, W. Jaitrong leg. ( AMK); 1 worker, same locality, 18.X.2000, S. Hasin leg. ( THNHM) . See also discussion below .

Diagnosis of worker. Body 6.50–7.00 mm in total length (large size, but presenting important variation). Masticatory margin of mandibles with five teeth, including large basal tooth, large prebasal tooth, minute preapical tooth (denticle), and medium-sized apical tooth; basal margin with an ill-defined protuberance; median clypeal lobes slightly broader than long, subtriangular, widened forward, its anterior margin weakly concave, lateral margin and anterior margin meet so as to form blunt angle; eyes relatively large with 13–15 ommatidia along the longest axis; frontal lobes high, not passing over anterior clypeal margin; with head in full-face, antennal scapes slightly extending beyond posterior margin of head; in profile, anteroventral corner of head with bluntly angled process; petiole subrectangular, shorter than high; subpetiolar process well developed, with strongly concave ventral outline, with a posteroventrally pointed triangular denticle at anteroventral corner, and with a pair of small posteriorly pointed denticles at posteroventral corners. Mandibles sparsely punctate, interspaces smooth and shiny. Head with moderate-sized macropunctures, distance between punctures about equal to diameter of punctures, interspaces smooth and shiny; dorsum of head in central portion with sparse punctures. Dorsa of mesosoma, petiole and first gastral segment with sparse, large, elliptic macropunctures; lateral faces of metapleuron and propodeum finely longitudinally rugulose, opaque; declivity of propodeum superficially transversely rugulose; declivity of petiolar node superficially shagreenate, less shining. Metasomal segments IV–IX largely smooth and shiny, but anterior half of segment IV sparsely punctate. Head and body with dense erect and suberect hairs mixed with dense decumbent pubescence. Antennal scapes with sparse suberect hairs and dense decumbent pubescence. Body colour black; mandible, antenna, legs, and apex of metasoma reddish brown; hairs and pubescence light yellow.

Worker description (figs 37–39)

Measurements. Holotype: TL 9.57, HL 1.62, HW 1.58, ED 0.26, SL 1.42, ML 1.49, PW 1.25, MSL 2.31, PL 0.89, PH 1.06, DPW 0.83; CI 98, OI 17, SI 90, MI 92, LPI 119, DPI 93.

Paratype worker (n=2): TL 9.05–9.30, HL 1.61–1.62, HW 1.49–1.57, ED 0.23, SL 1.25–1.39, ML 1.32–1.48 mm, PW 1.16–1.18, MSL 1.96–2.55, PL 0.83–0.86, PH 0.99–1.05, DPW 0.73–0.75, CI 93–97, OI 15, SI 84–89, MI 82–91, LPI 119122, DPI 87–88.

Head: In full-face view head slightly longer than broad, subrectangular with side convex and posterior margin feebly concave; posterolateral corners of head roundly convex. Mandibles long and slender, inner margin of

mandibles with 5 teeth, apical tooth acute while basal tooth triangular. Median clypeal lobe trapezoidal, widened anteriorly, with lateral margins clearly diverging from one another in particular on their anterior half; anterior margin of clypeal lobe weakly concave; lateral margin and anterior margin meet so as to form blunt angle. Eyes relatively large, composed of 13–15 ommatidia along longest axis, located close to base of mandibles. Antennal scapes relatively long extending slightly beyond posterior margin of head; flagella incrassate towards apex, with apical segment slightly longer than segments X and XI combined. Frontal lobes high, not passing over anterior clypeal margin. Median longitudinal frontal sulcus deep, reaching level of posterior margin of eyes. Ventral face of head with bluntly angled process in the middle and close to the anterior margin.

Mesosoma: Stout, in profile with weakly convex dorsal outline; promesonotal suture and metanotal groove distinct and depressed; in dorsal view pronotum slightly narrower than head and slightly broader than propodeum; mesonotum short, crescent, about ¼ length of pronotum in dorsal view.

Metasoma: Dorsum of propodeum slightly convex, rounded into declivity of propodeum; the latter shallowly concave. Petiole in profile subrectangular, shorter than high, its anterior face vertical with weakly concave, dorsal outline roundly convex, posterior face flat vertical with narrow depression in each side close to lateral margin; in dorsal view petiolar node longer than broad (DPI 88–93), anterior margin convex, but posterior margin almost straight; subpetiolar process well developed, with strongly concave ventral outline, with a posteroventrally pointed triangular denticle at anteroventral corner, and with a pair of small posteriorly pointed denticles at posteroventral corners. Metasomal segments III to IX elongate. In dorsal view, metasomal segment III narrower and shorter than gastral segment IV. Sting long, sharp and upcurved.

Mandibles sparsely punctate, interspaces smooth and shiny. Head with moderate-sized macropunctures, distance between punctures about equal to diameter of punctures, interspaces smooth and shiny; dorsum of head in central portion with sparse punctures. Dorsa of mesosoma, petiole and first gastral segment with sparse, large, elliptic macropunctures; lateral faces of metapleuron and propodeum finely longitudinally rugulose, opaque; declivity of propodeum superficially transversely rugulose; declivity of petiolar node superficially shagreenate, less shining. Metasomal segments IV–IX largely smooth and shiny, but anterior half of segment IV sparsely punctate. Head and body with dense erect and suberect hairs mixed with dense decumbent pubescence. Antennal scapes with sparse suberect hairs and dense decumbent pubescence. Body colour black; mandible, antenna, legs, and apex of metasoma reddish brown; hairs and pubescence light yellow.

Dealate queen description (figs. 40–43)

Measurements. Paratype queen: TL 11.12, HL 1.84, HW 1.76, ED 0.37, SL 1.54, ML 1.50, PW 1.49, MSL 3.15, PL 1.02, PH 1.23, DPW 0.93, CI 96, OI 21, SI 87, MI 81, LPI 121, DPI 92.

Similar to the worker in structure, sculpture and pilosity, with the following conditions that should be noted: body slightly larger; head in full-face view almost as long as broad, rectangular with side weakly convex and posterior margin almost straight; head with three ocelli; eyes large, located close to mandibular base; distance between eye and mandibular base much shorter than eye length; median ocellus as large as lateral ocelli; mesoscutum trapezoidal with slightly protruding borders, anterior edge convex in dorsal view; in profile, its anterior portion slightly bulged and flattened caudad; parapsidal lines indistinct; scutellum oblong, clearly broader than long; metanotum very short; metanotal-propodeal sulcus deeply impressed; anepisternum clearly demarcated from katepisternum by a distinct groove; dorsum of propodeum slightly convex and shorter than declivity; propodeal junction rounded; petiole shorter than high; gaster relatively larger than in the worker.

Habitat. The type series of M. sonthichaiae was collected in highland forest plantation, hill evergreen and dry evergreen forests (1,000–1,300 m a.s.l.) in northern and western Thailand. The colonies were found in rotten wood at an advanced stage of decomposition.

Distribution. Thailand (Chiang Mai and Tak Provinces, fig. 52).

Comparative notes. Myopias sonthichaiae is most similar to M. conicara (figs. 44–47) and M. hania Xu & Liu, 2012 (figs. 48–51) in general appearance. However, M. sonthichaiae can be distinguished from M. conicara by the following characteristics: frontal lobes high, not passing over anterior clypeal margin (low, passing over anterior clypeal margin in M. conicara ); lateral margins and apical margin of median clypeal lobe meet so as to form blunt angle (sharp angle in M. conicara ); petiole subglobular (subrectangular in M. conicara ); in profile view subpetiolar process strongly concave ventral outline (weakly concave in M. conicara ); in dorsal view, petiolar node clearly longer than wide (as wide as long in M. conicara ). Myopias sonthichaiae differs from M. hania by the following characteristics: antennal scapes relatively long, extending beyond posterolateral corners of head (short, not reaching posterolateral corners of head in M. hania ); frontal lobes high, not passing over anterior clypeal margin (low, passing over anterior clypeal margin in M. hania ); posterolateral margin of petiolar node with an oblique furrow (lacking in M. hania ); in profile view petiolar node subglobular (rectangular in M. hania ); in profile view subpetiolar process strongly concave ventral outline (ventral margin distinctly convex behind anteroventral tooth in M. hania ).

A Thai specimen at BMNH bears a paratype label of an unpublished manuscript name by W. L. Brown. Images are available on Antweb (https://www.antweb.org/specimenImages.do?code=casent0902521). The images were compared with M. sakaeratensis and M. sonthichaiae and with holotype images of M. conicara and M. hania . The images agree well with specimens of M. sonthichaiae . Moreover, the location and elevation of this specimen (Doi Inthanon [misspelled Doi Indhanont], Chiang Mai Prov.) match the holotype of M. sonthichaiae . They were collected about 150km from each other, at similar elevation (1750 and 1780 m). Thus, this unpublished species is identified as M. sonthichaiae .

Figures

FIGURES 37–39. Myopias sonthichaiae sp. nov. (paratype worker, TH02 SH-052); 37, Body in profile view; 38, body in dorsal view; 39, head in full-face view.

FIGURES 40–43. Myopias sonthichaiae sp. nov. (paratype queen, THNHM-I-00291); 40, Body in profile view; 41, metasoma in profile view; 42, body in dorsal view; 43, head in full-face view.