Recurvidris lekakuli

The type series was collected from leaf litter on the forest floor in a dry evergreen forest near a stream. Heterick & Kitching (2022) collected this species in a pitfall trap within a lowland dipterocarp forest in Brunei.

Identification
Jaitrong et al. (2019) - Head in full-face view round, almost as long as broad; masticatory margin of mandible with four sharp teeth, fourth (basal) tooth almost as large as third tooth; basal margin with a small tooth; propodeal declivity lacking infradental lamella or ridge linking propodeal spine to metapleural lobe; head, promesonotum, propodeum, petiolar node, postpetiole and gaster entirely smooth and shiny; mesopleuron and peduncle of petiole superficially reticulate with slightly smooth and shiny interspaces; propodeal dorsum with a pair of very short appressed hairs in front of spiracles.

Recurvidris lekakuli is closely related to Recurvidris chanapaithooni, Recurvidris kemneri and Recurvidris proles in having the following characteristics: masticatory margin of mandible with a series of four sharp teeth (acute basal tooth), basal margin of mandible with a small tooth; propodeum without infradental lamella or ridge linking the propodeal spine to metapleural lobe; head smooth and shining. Among them Recurvidris lekakuli is more similar in general appearance to Recurvidris chanapaithooni and Recurvidris kemneri than to Recurvidris nigrans and Recurvidris proles, the former two sharing the clear yellow body that is unicolorous (black to dark brown in Recurvidris nigrans and Recurvidris proles). Recurvidris lekakuli is easily separated from Recurvidris chanapaithooni by the following characteristics: clearly larger body (TL 2.28– 2.34 mm, HW 0.50–0.56 mm in Recurvidris lekakuli; TL 2.00–2.10 mm, HW 0.38–0.41 mm in Recurvidris chanapaithooni); mesopleuron largely smooth and shiny, only partly superficially reticulate (strongly reticulate in Recurvidris chanapaithooni); petiole relatively longer (DPI 30–35 in Recurvidris lekakuli; 42–43 in Recurvidris chanapaithooni); petiolar node clearly smooth and shiny (petiole entirely reticulate in Recurvidris chanapaithooni); propodeal dorsum with a pair of very short appressed hairs (with 2 pairs of standing hairs in Recurvidris chanapaithooni). Recurvidris lekakuli differs from Recurvidris kemneri by the clypeus clearly smooth and shiny (median portion of clypeus weakly bicarinate in Recurvidris kemneri) and having a pair of very short appressed hairs on propodeal dorsum (without hairs in Recurvidris kemneri). The new species is also similar to Recurvidris glabriceps from China, but the latter lacks a small tooth on basal margin of mandible.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Brunei Darussalam. Oriental Region: Thailand.

Nomenclature

 * . Recurvidris lekakuli Jaitrong, Tokeeree, et al. 2019: 55, figs. 1-5 (w.) THAILAND.
 * Type-material: holotype worker, 10 paratype workers.
 * Type-locality: holotype Thailand: Kanchanaburi Prov., Thong Phaphum Dist., Ban Sahakhon Nikhom, 14.76255°N, 98.80966°E, 13.vii.2018, WJT130718-07, dry evergreen forest (W. Jaitrong); paratypes: 3 workers with same data, 1 worker with same data but 26.vii.2018 (C. Sathiandee), 5 workers with same data but 6.xi.2018 (W. Jaitrong), 1 worker with same data but 6.xi.2018 (C. Sathiandee).
 * Type-depositories: TNHM (holotype); MHNG, SKYC, TNHM (paratypes).
 * Distribution: Thailand.

Worker
Holotype and four paratype workers (n = 5): DPW 0.10–0.12, ED 0.12–0.13, HL 0.50–0.56, HW 0.50–0.56, PW 0.23–0.26, ML 0.69– 0.73, SL 0.53–0.56, TL 2.28–2.34, CI 97–100, DPI 30–35, OI 22–27, SI 100–107. (Holotype and paratypes). Head in full-face view round and almost as long as broad, with posterior margin convex. Eye with seven ommatidia along longest axis. Antennal scape extending posteriorly slightly beyond posterolateral corner of head. Masticatory margin of mandible with four sharp teeth, fourth (basal) tooth as large as third tooth; basal margin with a small tooth. Clypeus without paired carinae, its anterior margin almost straight. Promesonotum in profile strongly convex dorsally and sloping gradually to metanotal groove. Propodeum in profile with almost straight dorsal outline; propodeal spines very slender, divergent, and in posterior view very narrow. Propodeal declivity lacking infradental lamella or ridge linking propodeal spine to metapleural lobe. Peduncle of petiole in profile relatively long, with its dorsal outline concave and ending posteriorly in right angle; its ventral outline convex with long acute subpetiolar process. Head entirely smooth and shiny, lacking sculpture except some short longitudinal rugulae near mandiblular base. Antennal scape smooth and shiny. Promesonotum smooth and shiny; mesopleuron superficially reticulate with smooth and shiny interspaces; entire propodeum including propodeal spine smooth and shiny. Peduncle of petiole superficially reticulate with smooth and shiny interspaces; petiolar node entirely smooth and shiny; postpetiole entirely smooth and shiny; legs smooth and shiny. Gaster smooth and shiny. Head with relatively dense short hairs; promesonotum with sparse longer hairs (8–10 hairs); longest pronotal hairs 0.13–0.15 mm long; propodeum dorsally with a pair of very short decumbent or appressed hairs (these hairs missing in two paratypes). Petiole with two dorsal pairs of long hairs. Postpetiole with two dorsal pairs of long hairs. Body colour yellow.

Type Material
Holotype: worker (THNHM-I-01219, ), West Thailand, Kanchanaburi Province, Thong Phaphum District, Ban Sahakhon Nikhom, dry evergreen forest (DEF), 14.76255N, 98.80966E, 13.VII.2018, W. Jaitrong leg., WJT130718-07. Paratypes: three workers (THNHM-I-01220 to THNHM-I-01222, THNHM), same data as holotype; one worker (THNHM-I-01249, THNHM), West Thailand, Kanchanaburi Province, Thong Phaphum District, Ban Sahakhon Nikhom, dry evergreen forest (DEF), 14.76255N, 98.80966E, 26.VIII.2018, C. Sathiandee leg.; five workers (THNHM-I-02617,, , THNHM), West Thailand, Kanchanaburi Province, Thong Phaphum District, Ban Sahakhon Nikhom, dry evergreen forest (DEF), 14.76255N, 98.80966E, 6.XI.2018, W. Jaitrong leg., WJT061118-12; one worker (THNHM-I-02618, THNHM), West Thailand, Kanchanaburi Province, Thong Phaphum District, Ban Sahakhon Nikhom, dry evergreen forest (DEF), 14.76255N, 98.80966E, 6.XI.2018, C. Sathiandee leg., WJT1/5.

Etymology
The specific name is dedicated to the late Dr. Boonsong Lekakul, who was the most excellent specialist in zoological sciences in Thailand and helped and inspired many young biologists.

References based on Global Ant Biodiversity Informatics

 * Jaitrong W., Y. Tokeeree, and P. Pitaktunsakul. 2019. A new species of the ant genus Recurvidris Bolton, 1992 (Hymenoptera, Formicidae, Myrmicinae) from Thailand. ZooKeys 830: 53–61.