Discothyrea periyarensis

The type material was collected from a litter sample. The site had minimal sunlight exposure and very damp soil.

Identification
Bharti et al. (2015) - Among the known Oriental species Discothyrea periyarensis is close to Discothyrea bryanti but can be easily differentiated from it with following combination of characters: the frontal carinae extending posteriorly up to 1/2 length of head, anterior margin of clypeus not crenulate, cheeks without a prominent blunt tooth in front of the eyes, while in D. bryanti frontal carinae extending posteriorly to 2/3 length of head, anterior margin of clypeus crenulate, cheeks with a prominent blunt tooth in front of the eyes. The new species can also be easily separated from the Indian species (Discothyrea sringerensis and Discothyrea stumperi) on the basis of propodeal declivity more gradual, in lateral view, posterodorsal corner of propodeum rounded or very bluntly angled, forming an angle much greater than 90°, while in the latter species propodeal declivity abrupt, in lateral view, posterodorsal corner of propodeum narrowly to acutely toothed, forming an angle equal to or smaller than 90°. Some of the other additional characters by which the new species differs from Discothyrea sringerensis include: smaller size (TL 1.67, HL 0.73, HW 0.63) with smaller eyes consisting of 3–4 ommatidia, anterior margin of clypeus not crenulate, frontal carinae extending back about 1/2 the length of head and propodeum without distinct propodeal teeth, while the latter is larger in size (TL 3.05, HL 0.8, HW 0.54) with larger eyes consisting of 11–12 ommatidia, anterior margin of the clypeus crenulated, frontal carinae extending back about 2/3 the length of head and propodeum with distinct propodeal teeth. And Discothyrea periyarensis differs from D. stumperi Baroni Urbani, 1977 in having larger size (TL 1.67, HL 0.73, HW 0.63) and smaller eyes consisting of 3–4 ommatidia, posterodorsal corner of propodeum rounded to bluntly angled, forming an angle much greater than 90°, petiole scale like, much thicker with prominent subpetiolar process and mesosoma having humeral corners nearly rounded with lateral margins nearly straight, while the latter is smaller in size (TL 1.5, HL 0.53, HW 0.47) with larger eyes consisting of 10–12 ommatidia, posterodorsal corner of propodeum acutely toothed, forming an angle equal to or smaller than 90°, petiole compressed very thin, without any distinct subpetiolar process and mesosoma having distinct humeral angles with lateral margins strongly concave.

Distribution based on Regional Taxon Lists
Oriental Region: India.

Nomenclature

 *  periyarensis. Discothyrea periyarensis Bharti, Akbar & Singh, 2015: 122, figs. 1-6 (w.q.) INDIA.

Worker
TL 1.67, HL 0.73, HW 0.63, CI 86.3, SL 0.44, SI 69.84, ED 0.04, PW 0.44, MSL 0. 81, PL 0.13, PH 0.31, DPW 0.29, LPI 238, DPI 223 (n = 1).

In full-face view, head longer than broad, roughly trapezoidal and narrowed anteriorly. Posterior margin nearly straight, posterolateral corners rounded. Sides evenly convex, notched in front of mandibular insertions. Mandibles triangular, masticatory margin edentate, apical tooth acute, small. Anterior margin of clypeus straight. Frontal lobes confused each other and formed a large roughly rhombic frontal area, distinctly longer than broad, anterolateral and posterolateral margins straight. Frontal carinae small and well separated, extending posteriorly to 1/2 of head-length. Antennae 10-segmented, apices of scapes reaching to 2/3 of distance from antennal sockets to posterolateral corners. Eyes small and convex, with 3–4 ommatidia on maximum diameter, located below the mid-length of sides. In posterior view, frontal area weakly elevated and roughly rhombic, with a broad base, anterior margin weakly convex, lateral corners acutely angled.

In lateral view, dorsum of mesosoma convex and sloping down posteriorly, promesonotal suture and metanotal groove absent. Posterodorsal corner of propodeum rounded or almost bluntly angled, forming an angle much greater than 90°, declivity weakly concave. Propodeal lobes large and rounded. Petiolar node short and low, scale like, dorsal face sloping down anteriorly and weakly concave, anterodorsal corner indistinct. Subpetiolar process prominent, bluntly angled ventrally. 1st gastral segment large, about 2/3 of the total length of gaster. Constriction between the two basal gastral segments broad and deep.

In dorsal view, mesosoma trapezoidal and narrowed posteriorly, humeral corners nearly rounded, lateral margins nearly straight, posterior margin concave medially. Petiolar node transverse and rectangular, anterior and posterior margins nearly straight, lateral and posterior margins also straight.

Mandibles finely punctured. Head, mesosoma, petiole, and 1st gastral segment densely and coarsely punctured, interface much smaller than puncture diameter.

Whole body covered with dense, suberect to subdecumbent short pubescence, without standing hairs; mandibles with few large hairs. Scapes and tibiae with dense decumbent short pubescence, without standing hairs.

Colour reddish brown. Apical antennal segments, legs, and gastral apex yellowish brown. Eyes black.

Queen
TL 2.01, HL 0.75, HW 0.67, CI 89.33, SL 0.5, SI 66.66, ED 0.13, PW 0.59, MSL 0.79, PL 0.16, PH 0.29, DPW 0.21, LPI 181, DPI 131 (n = 1).

Like workers with differences accepted for the caste including larger size; presence of 3 prominent ocelli; larger compound eye; large mesosoma and gaster.

Type Material
Holotype, worker: India, Kerala, Periyar Tiger Reserve, 9°46′N / 77°14′E, 1005 m a.s.l., 10.10.2011. Paratype: 1 gyne, same data as holotype, Winkler method (Coll. Shahid A. Akbar; det. H. Bharti and Shahid A. Akbar). Holotype and paratype in.

Etymology
The new species is named after its type locality.