A revision of the Carebara pygmaea (Emery, 1887) species group (Hymenoptera: Formicidae) in Thailand Author Wimolsuthikul, Chaipat 0009-0001-7229-4752 Office of Natural Science Research, National Science Museum, 39, Moo zygosoma@gmail.com Author Yamane, Seiki 0000-0002-6865-0865 Haruyama-chô 1054 - 1, Kagoshima-shi, 899 - 2704 Japan. mayiopa0@gmail.com Author Samung, Yudthana 0000-0003-4069-4257 Khlong & Department of Medical Entomology, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand. yudthana.sam@mahidol.ac.th Author Jaitrong, Weeyawat 0000-0003-1362-0754 Office of Natural Science Research, National Science Museum, 39, Moo & Office of Natural Science Research, National Science Museum, 39, Moo & Khlong Luang, Pathum Thani, 12120 Thailand. polyrhachis@yahoo.com text Zootaxa 2024 2024-07-15 5481 1 79 100 http://dx.doi.org/10.11646/zootaxa.5481.1.5 journal article 299942 10.11646/zootaxa.5481.1.5 0423a610-a41f-4de4-9d39-289e7ec7168f 1175-5326 12742641 987E3EFF-7867-4186-A26A-79359DF762C8 Carebara panhai Jaitrong, Pitaktunsakul & Jantarit, 2021 ( Figs. 6–7 ) Carebara panhai Jaitrong, Pitaktunsakul & Jantarit, 2021: 9 , Figs. 1–2 . Type materials: Holotype major worker ( THNHM-I-14191 , THNHM , examined), 4 paratype major workers ( THNHM-I-14192 , THNHM-I19032 to THNHM-I-19034 ; SKYC , THNHM , examined), and 60 paratype minor workers ( THNHM-I-14193 , THNHM-I-19035 to THNHM-I-19093 ; SKYC , THNHM , examined), western Thailand , Kanchanaburi Province , Thong Pha Phum District , Sahakhon Nikhom Community Forest , 14.76255556ºN , 98.80966667ºE , 679 m s.a.l., 3 m from a cave entrance, 27.XI.2019 , W. Jaitrong leg., TH19-WJT-156. Non-type material examined. Western Thailand : Kanchanaburi Province , Sai Yok District , Lum Sum Subdistrict , Cha Loei Cave , 31.V.2024 , T. Jeenthong leg. , TJ310524-01 ( THNHM ). Measurements (in mm). Major worker ( paratypes , n = 4): TL 3.6–3.8, HL 1.09–1.1, HW 0.89–0.96, SL 0.53– 0.56, ML 0.79–0.86, MW 0.46–0.5, DPW 0.2–0.23, PL 0.33–0.36, PH 0.3–0.33, CI 82–83, SI 59–61, PI1 110–122, PI2 55–60. Minor worker ( paratypes , n = 10): TL 2.15–2.18, HL 0.53–0.56, HW 0.46, SL 0.46, ML 0.53–0.56, MW 0.25–0.26, DPW 0.1, PL 0.26–0.3, PH 0.17, CI 82–88, SI 100, PI1 150–180, PI2 33–38. FIGURE 7. Carebara panhai , paratype minor worker (THNHM-I-14193). A, Body in profile view; B, head in full-face view; C, body in dorsal view. Diagnosis. Major ( Fig. 6 ): head and gastral tergite I with dense erect hairs mixed with decumbent hairs; promesonotum with sparse short erect hairs; with head in full-face view, posterior one-third with transverse striation, while anterior two-thirds with longitudinal striation; eye small, with ca. 12–13 ommatidia; gastral tergite I somewhat smooth and shiny. Minor ( Fig. 7 ): propodeal dorsum smooth and shiny; petiole and postpetiole with 2–4 erect hairs; propodeal junction roundly convex; body yellowish. Full descriptions of major and minor workers see Jaitrong et al . (2021) . Habitat. The type series was collected from a cave at the twilight zone, about 3 m from the entrance in limestone dry evergreen forest ( Jaitrong et al . 2021 ). Distribution. Thailand ( Kanchanaburi Province , Fig. 13 ). Remarks. Carebara panhai is most closely related to C. bokorensis and C. parva , but can be separated from C. bokorensis by the following characteristics in the major worker: 1) posterior one-third of head with transverse striation (punctate, without striation in C. bokorensis ); 2) gastral tergite I smooth and shiny (with dense foveae in C. bokorensis , see Fig. 3C and Fig. 6C for comparison); 3) head and promesonotum with sparse erect and decumbent hairs (dense hairs in C. bokorensis , see Fig. 3 and Fig. 6 for comparison). For the difference between C. panhai and C. parva , see “Remarks” under C. parva . Minor workers of C. panhai can be separated from other members of the species group by 1) dorsa of petiole and postpetiole each with 2–4 erect hairs (without erect hairs in other species); 2) propodeal junction roundly convex (blunt angle in C. parva and C. adisaki ).