Leptanilla ujjalai

This new species is collected from the Neora valley National Park (189.89 km2 ), located in the Eastern Himalaya in the State of West Bengal, India, nesting inside a fallen tree trunk, above ground; the nest occupying an area of about three inches in diameter. Its distribution seems to be restricted, as a single colony only was located within a radius of 25 km. Air temperature during collection time was 7° C at night to maximum 16° C at day time. The park is among the oldest reserve forests of India, known for its endemic entomofaunal diversity and being located at trijunction of Indo-Malayan, Palaearctic and Sino-Japanese realms considered of ecological significance. Its pristine forests with high altitudinal variations and complex topography might help in diversification and evolution of endemic species.

Identification
Saroj et al. (2022): Workers of the new species have unique combination of characters from other species of the genera in having the mandible subtriangular (linear in most of the species) with four teeth. First three teeth on masticatory margin and the largest truncate tooth on basal margin; anterior clypeal margin with a truncate apical lobe, subpetiolar process lamellate and denticulate; petiolar spiracle larger than post petiolar spiracle; 3rd abdominal tergum weakly narrow in its anterior part and post petiole with equal width at anterior and posterior margin. It differs from other two Indian species, in having four distinct teeth on masticatory margins (Figs 1C, 3B) against three teeth in L. escheri and L. lamellata; anterior clypeal margin transverse (anterior clypeal margin concave and bilobed in L. escheri and L. lamellata), subpetiolar process lamellate and denticulate (subpetiolar process not denticulate in L. escheri and L. lamellata). L. ujjalai comes close to L. tanakai Urbani from Japan in that abdominal tergite anteriorly constricted, mandibles with four teeth and the basal mandibular teeth distinct; but it differs from L. tanakai in postpetiole width equal in anterior and posterior margin, (post petiole trapezium shaped in L. tanakai) post petiole not truncated posteriorly, dorsal face of post petiole smoothly passing to posterior face without any edge in ujjalai (post petiole posteriorly truncated, posterior margin of post petiole delimited by an edge between dorsal and posterior face in tanakai). Leptanilla ujjalai resembles L. japonica Urbani described from Japan, in the number of mandibular teeth; rectilinear dorsal profile, dorsum of propodeum descending to apex with a smooth curve without a defined declivity, hair and colour pattern, but differs in the subtriangular mandibles (Figs. 1D, 1E), F3 to F9 transverse, anteriorly straight petiole and post petiole, the post petiole width equal on anterior and posterior sides (Fig. 1A) and anterior margin of first gastral tergite narrowly attached to post petiole (in japonica, mandibles nearly linear, F3 transverse, F4 to club, gradually increasing length, anterior margins of petiole and post petiole concave, the post petiole broader posteriorly than anteriorly and first gastral tergite broadly attached to post petiole). L. ujjalai shows affinities to L. hypodracos Wong and Guénard from Singapore in presence of basal tooth on mandibles and anterior margin of clypeus straight (concave to straight in hypodracos). But it differs from hypodracos in presence of four teeth on mandible (only three teeth in hypodracos), basal tooth truncate (basal tooth sharp in hypodracos); petiole as long as wide and post petiole wider than long (petiole twice its width and post petiole longer than wide in hypodracos).

Distribution based on Regional Taxon Lists
Oriental Region: India.

Nomenclature

 * . Leptanilla ujjalai Saroj, Mandi & Dubey, 2022: 3, figs. 1-3 (w.) INDIA (West Bengal).

Type Material

 * HOLOTYPE: Worker,  INDIA:  West  Bengal, Kalimpong district, Neora valley National Park, 27°03ʹ572ʺN, 088°46ʹ100ʺE, 2014m alt., 22.x.2019, S. Bhattacharya (NZC, ZSI, Kolkata; Reg. no.24034/H3).
 * PARATYPES: Eight workers. with same data as that of the holotype (Deposited in NZC, ZSI, Kolkata; Reg. nos. 24035/ H3-24042/H3).

Description
Worker

Head: Longer than wide, posterior margin widely concave in full face view, slightly broader than anterior margin, lateral margins weakly convex; postero-lateral angles smoothly curved; clypeus anteriorly produced as a distinct lobe with straight anterior margin (Fig. 3B); posterior margin of clypeus not separated by suture; mandibles with four teeth (Fig. 1C), outer margin curved ; masticatory margin long, with three unequal teeth placed at more or less equal distance; apical tooth long, curved, acute, sub-apical tooth minute but distinct, sub-basal tooth acute and larger than sub-apical one; two small denticles between sub-apical and sub-basal teeth; basal tooth large, broad and truncate apically, placed on basal margin (Figs. 1D & 1E); a small ridge from the base of sub-basal tooth diagonally run towards exterior mandibular articulation, which separates the apex of mandible from the base (Fig. 3B); palp formula 2,1; antennal furrows oval shaped with base narrow; scape reaching a little above midline of head, running short of posterior margin of head by 3/4th its length; pedicel comparatively narrow, pedicel and F2 subequal, F1 longer than F2, F3 to F9 broader, club longer than preceding two segments combined; eyes absent.

Thorax: Mesosoma (Figs 1A, 3A) narrower and subequal to gaster; pronotum convex, wider than rest of mesosoma in dorsal view, sides weakly convex, posteriorly constricted; pro-meso-notum weakly convex above; pro-meso-notal suture distinct; meso-meta-notal suture absent; dorsum of propodeum descending to apex with a smooth curve, without distinct separation of declivity from dorsal face; meso-metanotum more or less flat and capsule like in dorsal view; coxae, femora and tibiae swollen; fore-basi-tarsus sickle shaped (Fig. 2B); hind tibial spur thick.

Gaster: Petiole as long as braod and distinctly longer than postpetiole, sides nearly parallel; anterior margin straight; petiole with a very thin, narrow subpetiolar lamella at anterior half, subpetiolar process lamellate and denticulate (Fig. 2A), four setae arranged in a row on it; postpetiole distinctly broader than long, sides curved; sternal portion of postpetiole separated from tergal part by a distinct groove and anterior margin making a deep concavity at this groove; tergal height of postpetiole less than that of sternum; spiracles of petiole and postpetiole situated on anterior margin, petolar spiracle wider than post petiolar spiracle (Fig. 3C). Metasoma flat, oval, antero-lateral margins smoothly round and narrowly attached to post petiole; first tergite covers more than half of dorsum; sting exserted.

Sculpture and colour: Whole body smooth and shining with dense, long and short, suberect and decumbent pilosity all over. Fine punctation visible on antennae, anterior neck of pronotum, legs and ventral part of petiole and post petiole. Uniform yellowish with head, gaster and joints slightly darker.

Remarks: Paratypes share the characters same as that of holotypes with some variations: denticles between teeth on mandible vary from one to two and sometimes not visible in some specimens. In some specimens sub petiolar lamella clearly visible with sharp spiniform teeth (Fig. 2B) with ventral setae; postpetiolar sternal height also varies in that some times tergum higher than sternum, equal to sternum or lower than sternum.

Measurements:

Holotype: TL 1.71 mm; HL 0.4 mm; HW 0.31 mm; MaL 0.18 mm; SL 0.24 mm; WL 0.52 mm; PW 0.22 mm; PTL 0.12 mm; PTW 0.12 mm; PTH 0.14 mm (excluding sting); PTNL 0.14mm; PPTL 0.09 mm; PPTW 0.12 mm; PPTH 0.18 mm; PPTNL 0.12 mm; CI 79, SI 76, MaI 58, PI 93, PPI 123, PPHI 66.

Paratypes (n = 8): TL 1.58-1.71mm; HL 0.38-0.40 mm; HW 0.30-0.32 mm; MaL 0.16- 0.18 mm; SL 0.24-0.25 mm; WL 0.51-0.54 mm; PW 0.21-0.22 mm; PTL 0.11-0.12 mm; PTH 0.13- 0.14 mm; PTNL 0.13-0.15 mm; PTW 0.10-0.12 mm; PPTH 0.17-0.19 mm; PPTL 0.08-0.09 mm; PPTNL 0.11-0.12 mm; PPTW 0.10-0.12 mm; CI 78-80; SI 76-80; MaI 53-60; PI 91-93; PPI 125- 133; PPHI 59-66.

Etymology

The species is named after Sri. Ujjal Ghosh, Chief Coservator of Forests, Wildlife North, West Bengal, recognising his conservation efforts in the type locality.