Brachyponera Emery, 1900

Duanchay, T., Buttachon, S., Pinkaew, N. & Jaitrong, W., 2024, Two new cave dwelling species of the ant genus Brachyponera Emery, 1900 (Hymenoptera: Formicidae, Ponerinae) from Thailand, Far Eastern Entomologist 511, pp. 1-12 : 3-7

Genus Brachyponera Emery, 1900

Brachyponera (as subgenus Euponera ) Emery, 1900: 315. Type species: Euponera (Brachyponera) croceicornis , by monotypy.

Brachyponera (as subgenus Euponera ): Emery, 1911: 83; Wheeler, 1922: 649.

Brachyponera : Bingham, 1903: 101; Wilson, 1958: 346; Schmidt & Shattuck, 2014: 77 .

Pachycondyla (part.): Snelling, 1981: 389; Brown, in Bolton, 1994: 164.

DIAGNOSIS. Workers of Brachyponera can be distinguished from other ponerine genera by the following combination of characters: 1) mandible usually with basal pit (obsolete or vestigial in some species); 2) eye small and placed near mandibular insertions; 3) antenna 12-segmented; 4) metanotal groove deep; 5) propodeum located lower elevation than promesonotum and usually strongly narrowed dorsally; 6) propodeal spiracle small and round; 7) petiole squamiform; 8) prora absent from anterior margin of first gastral sternite; 9) gaster with only a slight girdling constriction; 10) metatibiae with two spurs ( Schmidt & Shattuck, 2014).

In Southeast Asia, Brachyponera is most similar to the large size species of Hypoponera , but the latter lacks the mandibular pit, has a metatibial spur, and tend to be slightly smaller. Brachyponera is also similar to small size species of Ectomomyrmex , but Brachyponera can be separated from Ectomomyrmex by 1) body size tends to be smaller; 2) mesopleuron lacks a transverse groove (divided mesopleuron in Ectomomyrmex ); 3) propodeum located lower in elevation than promesonotum and usually strongly narrowed dorsally (same level in Ectomomyrmex ).

Brachyponera kumtongi Duanchay et Jaitrong , sp. n. https://zoobank.org/NomenclaturalActs/ EBE88190-5DBC-427E-98AC-3404E20CF5A7

Fig. 1

TYPE MATERIAL. Holotype – worker (THNHM-I-00029078, THNHM), Thailand: Chiang Mai Province, Chiang Dao District, Chiang Dao Cave , 9.I 2023, W. Jaitrong leg., WJT090123-01 . Paratypes: 14 workers (THNHM-I-00029079 to THNHM-I-00029092, THNHM), same data as holotype .

NON-TYPE MATERIAL EXAMINED. Sixteen workers (THNHM-I-00029093 to THNHM-I-00029104, THNHM-I-00029106 to THNHM-I-00029109), Thailand: Chiang Mai Province, Chiang Dao District, Chiang Dao Cave , 9.I 2023, W. Jaitrong leg. , WJT090123-05; 19 workers (THNHM-I-00029110 to THNHM-I-00029128), same locality, date and collector, WJT090123-03; 4 workers (THNHM-I-00029135 to THNHM-I-00029138), same locality and collector, 3.I 2023 , TH23-WJT-04; 5 workers (THNHM-I-00029143 to THNHM-I-00029145, THNHM-I-00029150 to THNHM-I-00029151), same locality, date and collector, WJT090123-04; 5 workers (THNHM-I-00029105, THNHM-I-00029139 to THNHM-I-00029142), same locality and collector, 10.I 2023 , TH23-WJT-951; 4 workers (THNHM-I-00029129, THNHM-I-00029146 to THNHM-I-00029148), same locality and collector, 10.I 2023 , TH23-WJT-954; 2 workers (THNHM-I-00029130 to THNHM-I-00029131), same locality and collector, 11.I 2023 , TH23-WJT-959; 3 workers (THNHM-I-00029132 to THNHM-I-00029134), same locality and collector, 3.I 2023 , TH23- WJT-05, 16 workers (THNHM-I-00029154, THNHM-I-00029157 to THNHM-I-00029169, THNHM-I-0002188 to THNHM-I-00029189), same locality, 3.X 2019, S. Jantarit leg. , 9 workers (THNHM-I-00029174 to THNHM-I-00029182), Thailand: Nan Province, Chiang Dao District, Chiang Dao Cave , 19. V 2018, S. Jantarit leg.; 5 workers (THNHM-I-00029183 to THNHM-I-00029187); Thailand: Lamphun Province, La District, Luang Weang Keaw Cave , 13. V 2018, S. Jantarit leg.; 4 workers (THNHM-I-00029170 to THNHM-I-00029173), Thailand: Lamphun Province, La District, Luang Weang Keaw Cave , 12. V 2018, S. Jantarit leg.; 2 workers (THNHM-I-00029155 to THNHM-I-00029156), Thailand: Tak Province, Umphang District, Husi Lapoo Cave , 6.III 2019, S. Jantarit leg.

DESCRIPTION. Worker. Medium size (head width 0.78–0.90 mm); body reddish brown; eye very small, with 6–7 ommatidia (with 2–3 ommatidia along longest axis); mandible with basal pit; antennal scape relatively short compared with head width (SI 106–126); promesonotum distinctly convex to form a dome; propodeum in profile extremely located lower than promesonotum, long, its dorsal outline weakly convex; in profile propodeal dorsum longer than length of propodeal declivity; body finely micropunctate and covered densely with gray pubescence mixed with sparse short brown erect hairs.

Head: in full-face view, distinctly longer than broad, broadened medially; lateral margin weakly convex; posterior margin almost straight; posterolateral corner of head roundly convex. Mandible subtriangular and with basal pit; masticatory margin with six teeth, including largest apical tooth, followed by five large teeth; basal margin sinuate. Clypeus in full-face view broad and convex medially, shorter than broad, its anterior margin entirely convex but feebly concave medially. Antennal scape long, when folded back in full-face view extending beyond posterolateral corner of head; antennal segment II almost as long as broad; segments III–VI each shorter than II but almost as long as broad; segment XII as long as segments X+XI. Frontal carina in full-face view distinct, reaching anterior to mid-length of head. Frontal lobe broad, outer margin roundly convex, coving antennal socket. Eye in profile located close to mandibular base, round, relatively small compared with maximum width of antennal scape, with 6–7 ommatidia (2–3 ommatidia along longest axis).

Mesosoma: in profile promesonotum distinctly convex to form a dome; in dorsal view, pronotum almost as long as broad and clearly broader than mesonotum and propodeum; mesopleuron in profile clearly shorter than high, clearly demarcated from metapleuron by deep suture; metapleuron not clearly demarcated from lateral face of propodeum. Propodeum in profile located extremely lower than promesonotum, long, its dorsal outline weakly convex; propodeal dorsum in profile round into propodeal declivity; in profile propodeal dorsum longer than length of propodeal declivity; propodeal declivity shallowly concave.

Petiole sessile; in profile petiolar node subtriangular, shorter than high, its anterior face weakly convex, while posterior somewhat flat; petiolar height distinctly twice as long as length of propodeal dorsum.

Body entirely finely micropunctate, except for mesopleuron smooth and shiny; procoxa smooth and shiny; other parts of legs and antenna finely micropunctate; mandible somewhat smooth except for hair pits. Body entirely covered with short gray pubescence. Dorsal side of head, mesosoma, petiole and gaster with sparse short erect hairs; propodeal dorsum usually without erect hairs (present in some paratypes but if present then shorter than those on head and pronotum). Antenna and legs with dense short suberect hairs. Body reddish brown to dark brown. Antennal scape reddish brown, flagellum of antenna yellowish brown. Mandible reddish. Legs yellowish brown.

MEASUREMENTS AND INDICES. Holotype: TL 3.51, ED 0.07, HL 0.97, HW 0.80, SL 0.85, ML 1.30 , MW 0.60, PL 0.31, PH 0.70, CI 82, OI 9, SI 106 , PI 44 . Paratypes (n = 10). TL 3.51–4.69, ED 0.07–0.10, HL 0.69–1.10, HW 0.78–0.90, SL 0.85–1.00, ML 1.29 – 1.45 , MW 0.55–0.65, PL 0.31–0.41, PH 0.62–0.70, CI 75– 92, OI 9–13, SI 106–126 , PI 44–63 .

DIAGNOSIS. New species is most similar to Brachyponera arcuata (Karavaiev, 1925) from Indonesia in having a reddish-brown body. However, new species can be easily separated from B. arcuata by 1) head slightly longer than broad (almost as long as broad in B. arcuata ); 2) eye small, with 2–3 ommatidia along longest axis (eye relatively larger, with 6–7 ommatidia along longest axis in B. arcuata ); 3) with sparse erect hairs on dorsa of head, mesosoma, and gastral tergite I (without erect hairs in B. arcuata ); 4) in profile propodeal dorsum weakly convex (distinctly convex in B. arcuate , see figs. 1A and 3A for comparison). B. kumtongi sp. n. is similar to B. jerdonii (Forel, 1900) in general appearance. However, it can be distinguished from the latter by 1) eye small, with 2–3 ommatidia along longest axis (eye relatively larger, with about 10 ommatidia along longest axis in B. jerdonii ); 2) antennal scape relatively longer (SI 106–126 in new species vs. SI 88 in B. jerdonii ). Brachyponera kumtongi sp. n. is also similar to B. troglomorpha sp. n. in having a reddish-brown body but former can be easily separated from latter species by 1) eye with 2–3 ommatidia along longest axis (7–8 ommatidia in B. troglomorpha ); 2) body color slightly darker (see figs 1 and 2 for comparison); 3) antennal scape with dense short suberect hairs (without erect hairs in B. troglomorpha ); 4) propodeal dorsum longer than length of propodeal declivity (shorter in B. troglomorpha ); 5) metapleuron micropunctate (smooth and shiny in B. troglomorpha ).

HABITAT. This species is known only in caves in northern Thailand. We found workers in both twilight and dark zones. Nests were found in soil or under stones on the cave floor. Ant crickets ( Myrmecophilus Berthold, 1827 ) were found together with foraging workers of the new species.

DISTRIBUTION. Chiang Mai, Lamphun, Nan, and Tak Provinces ( Fig. 4 ).

ETYMOLOGY. The specific name is dedicated to Mr. Pornarin Kumtong (Head of Doi Chiang Dao Wildlife Sanctuary, Thailand), who supported W. Jaitrong for his field survey in northern Thailand.

Figures

Fig 1. Brachyponera kumthongi Duanchay et Jaitrong, sp. n., holotype worker (THNHM-I- 00029078, THNHM). A – body in profile view; B – head in full-face view; C – body in dorsal view.

Fig 4. Distributions of Bracyrponera spp. in Thailand.