Carebara bokorensis Matsuura & Hosoishi, 2024

Wimolsuthikul, Chaipat, Yamane, Seiki, Samung, Yudthana & Jaitrong, Weeyawat, 2024, A revision of the Carebara pygmaea (Emery, 1887) species group (Hymenoptera: Formicidae) in Thailand, Zootaxa 5481 (1), pp. 79-100 : 85-88

Carebara bokorensis Matsuura & Hosoishi, 2024

( Figs. 3–5 )

Carebara bokorensis Matsuura & Hosoishi , in Matsuura et al. 2024: 3 , figs. 1–2.

Type materials: Holotype major worker ( KUEC, collection code KUECCRB001, images in Matsuura et al. 2024 were examined), 2 paratype major workers ( KUEC, collection code KUECCRB002, KUECCRB003), and 7 paratype minor workers ( KUEC, collection code KUECCRB004, KUECCRB005, KUECCRB006, KUECCRB007, KUECCRB008, KUECCRB009, KUECCRB010), Cambodia, Bokor National Park , 663m alt., Kampot Province, 10°36N, 104°06E, 19.XII.2011, S. Hosoishi leg. SH11-Cam-55, decayed wood.

Non-type material examined. Western Thailand: 4 major worker ( THNHM-I-00028081 , THNHM-I-00028201 to THNHM-I-00028202 , THNHM; THNHM-I-00028203 , SKYC), 6 ergatoid queens ( THNHM-I-00028216 to THNHM-I-00028220 , THNHM; THNHM-I-00028215 , SKYC), and 12 minor workers (THNHM-I-00028082, THNHM-I-00028204 to THNHM-I-00028213 , THNHM; THNHM-I-00028214 , SKYC), Ratchaburi Province, Suan Phueng District, Khao Lam, Hill Evergreen Forest , 13.538840ºN, 99.209962ºE, 1005 m a.s.l., Rotting log, 28.VII.2020, W. Jaitrong leg., TH20-WJT-082. Eastern Thailand: Chanthaburi Province, Soi Dao District, Sai Khao Subdistrict, near Khao Soi Dao , 13.106065ºN, 102.196120ºE, 285 m a.s.l., 19.I.2008, W. Jaitrong leg., TH08-WJT-91 ( THNHM) ; Chachoengsao Province, Thatakeab District , 13.371229ºN, 101.817599ºE, 153 m a.s.l., 27.VIII.2005, W. Jaitrong leg., WJT270805-01 ( THNHM) ; Chachoengsao Province, Khao Ang Reu Nai WS, Lumchangwat stn., 21.VIII.2003, Sk. Yamane leg., TH03-SKY-27 & -44 ( SKYC) .

Measurements (in mm). Major worker (n = 4): TL 3.7–3.99, HL 0.92–0.97, HW 0.84–0.96, SL 0.4–0.46, ED 0.06–0.07, ML 0.83–0.86, MW 0.5–0.53, DPW 0.23–0.26, PL 0.36–0.4, PH 0.26–0.3, CI 91–93, SI 47–52, PI1 133–138, PI2 64–67. Minor worker (n = 5): TL 1.52–1.62, HL 0.33–0.36, HW 0.3–0.33, SL 0.23–0.26, ED 0.01–0.02, ML 0.33–0.36, MW 0.20–0.21, DPW 0.07–0.1, PL 0.17–0.2, PH 0.1–0.13, CI 90–91, SI 89–90, PI1 150–167, PI2 40–60. Ergatoid queen (n = 5): TL 3.76–4.03, HL 0.99–1.02, HW 0.89–0.92, SL 0.43–0.46, ED 0.07, ML 0.86–0.89, MW 0.53–0.56, DPW 0.26–0.3, PL 0.4–0.43, PH 0.3–0.33, CI 90–91, SI 46–52, PI1 130–133, PI2 61–69.

Diagnosis. Major ( Fig. 3 ): head, promesonotum, and gastral tergite I with dense and long erect hairs mixed with decumbent hairs; with head in full-face view, posterior one-third with dense fovea, lacking transverse striation, while anterior two-thirds with longitudinal striation; eye small, with ca. 13–15 ommatidia; gastral tergite I punctate. Minor ( Fig. 5 ): propodeal dorsum entirely punctate; petiole and postpetiole with decumbent hairs; propodeal junction roundly convex; body reddish brown.

Ergatoid queen ( Fig. 4 ). Similar to the major worker in structure, sculpture, coloration and pilosity, with the following conditions that should be noted: body slightly larger in average (HW 0.89–0.92 in ergatoid queen; 0.84– 0.96 mm in major worker); ocelli present (absent in major worker), located on vertex; distance between anterior ocellus and lateral ocelli slightly shorter than distance between lateral ocelli; eye larger than in the major.

Habitat. This species nests in rotting wood in lowland dry evergreen forests (200–500 m a.s.l.).

Distribution. Thailand (Chanthaburi, Chachoengsao, and Ratchaburi Provinces, Fig. 13 ).

Remarks. The major worker of this species can be easily distinguished from other species of the group in having dense erect and decumbent hairs on the head, promesonotum and gaster; posterior one third of head with dense punctures (with transverse striation in other species); and dense punctures on gastral tergite I (more or less smooth and shiny in other species). This species is similar to C. parva and C. panhai . See “Remarks” under C. parva and C. panhai for comparison.

Carebara bokorensis is also similar to Carebara altinoda (Xu, 2003) . However, C. bokorensis can be easily separated from C. altinoda by 1) in major worker, Dorsa of head, mesosoma, and gaster with dense erect hairs mixed with dense decumbent hairs (with dense decumbent on head and with sparse erect hairs on mesosoma and gaster in C. altinoda ); 2) in major worker, without a pair of minute horns on vertex (with a pair of minute horns in C. altinoda ); 3) in minor worker, propodeum in profile roundly convex (bluntly angulates in C. altinoda ); in minor worker, distance between propodeal spiracle and metanotal groove ca. 4 times as long as distance between propodeal spiracle and propodeal junction (ca. 8.5 times in C. altinoda ).

Figures

FIGURE 3. Carebara bokorensis, non-type major worker (THNHM-I-00028081).A, Body in profile view; B, head in full-face view; C, body in dorsal view.

FIGURE 4. Carebara bokorensis, ergatoid queen (THNHM-I-00028220). A, Body in profile view; B, head in full-face view; 2C, body in dorsal view.

FIGURE 5. Carebara bokorensis, non-type minor worker (THNHM-I-00028204).A, Body in profile view; B, head in full-face view; 2C, body in dorsal view.

FIGURE 13. Distribution of Carebara pygmea species group in Thailand.