Adult in a shade of dark brown to black with blue lustre on carapace and abdomen (Fig. 1 & 4). Thoraxic fovea smaller than ocular width (Fig. 1d). Maxillary stridulatory setae scattered on the prolateral face and not present in a defined “C” shaped band (Fig. 3c). Spermathecae in shape of two small mounds.

Comparison:Thrigmopoeus psychedelicus sp. nov. differs from putative species of the genus in bearing maxillary stridulatory setae being scattered on the prolateral face (Fig. 3c) as opposed to being aligned in a “C” shaped manner as seen in T. insignis Pocock 1899 and T. truculentus Pocock 1899 (Fig. 3d). Furthermore the new species differs from T. insignis and T. truculentus in the adult colouration being dark black to brown with a blue metallic sheen on its carapace and abdomen (Fig. 1 & 4) vs. overall dark or light brown colouration in T. insignis and T. truculentus (Fig. 7a & b).

carapace 18.26 long, 14.18 wide, chelicerae 9.79 long. Sternum 7.22 long, 6.63 wide. Abdomen 19.38 long, 14.15 wide. Spinnerets: PMS, 1.64 long, 0.99 wide, 0.65 apart; PLS, 1.96 basal, 1.56 middle, 2.19 distal; midwidths 1.59, 1.42, 1.14 respectively. Leg and palp morphometry given in Table 1.

Colouration (Fig. 1): overall in a shade of black to dark brown, with extremities of leg with a tinge of light brown. Carapace greyish, abdomen dark brownish to black, each with blue lustre overall. Colouration in preservative is more faded and is in a shade of brown to reddish brown. The metallic blue lustre is reduced.

Carapace (Fig. 2a, d): covered with short silvery grey hair, dense on caput and carapace edges. Fovea procurved, slightly shorter than ocular width. Vestigial thick black bands radiating from the fovea running along the interstitial ridges. A few long bristles present on the ocular tubercle. A band of spinules present posterior to the fovea scattered in a fairly longitudinal manner.

Eyes (Fig. 2c): ratio of group width to length 1.4. PLE smaller than ALE but perceptibly bigger than PME, ALE clearly larger than the rest. Eye diameter: ALE, 0.58; AME, 0.38; PLE, 0.24; PME, 0.22. Distance between the eyes: AME-AME, 0.26; PME-PLE, 0.08; AME-ALE, 0.29; PME-PME, 1.09. Ocular quadrate, 1.26 long, 2.91 wide. MOQ: length, 0.73; front width, 1.10; back width, 2.91.

Maxilla: posterior ventral edge gently rounded and long; retrolateral face yellowish-red, smooth, glabrous. Cuspules: over 130 in anterior corner in roughly triangular region. Posterior edge almost straight, concave near heel.

Maxillary lyra (Fig. 3c): thick spike setae in 2–3 rows present above the maxillary suture aligned along the suture; bellow the suture with thick long spike setae scattered in distal half of the prolateral face, not in a defined ‘C’ pattern.

Labium: nearly 120 cuspules in band for one-fourths of anterior length; cuspules ca. similar in size to maxillary. Basal groove shallow, distinct with two distinct mounds.

Chelicera: inter-cheliceral peg setae absent. Basal oral fringe of chelicerae with a clustre of thick long curved setae in 4–5 curved (parallel) lines (Fig. 3a & b). Promarginal teeth 15, many small granules at basal cheliceral groove (Fig. 3a).

Sternum (Fig. 2b): longer than wide, high in centre, slopping gradually, covered with a mat of short brown and long, black setae. Posterior edge pointed but not separating coxae IV. Pedicel not clearly seen.

Sigilla: 3 pairs, posterior 1.30 diameter, ca. 1.70 lengths apart; ca.1.40 dist. from margin; middle 0.80 diameter, ca. 4.34 lengths apart; ca.0.50dist.from the margin; anterior very small, marginal.

Leg: formula 1423. Coxae-Prolateral face of coxa with thin, long horizontally aligned setae above the coxal suture, bellow suture with numerous short, thick spike setae scattered in the distal half of the coxa. Retrolateral face with thick, long bristles in anterior distal region. Spines-spines present on metatarsi of leg III & IV. Leg III mt, p 1, r 1, v 3, d 1; leg IV mt, p 1, r 1, v 3, d 1.

Scopulae: entire, dense on tarsi I-III; tarsi II entire, long hair in the centre but not divided; on tarsi II entire divided at base with few long hairs; tarsi IV divided by a band of 3–4 spike setae for its entire length. Scopula well developed on ventrolateral tarsus I-II. Absent on prolateral tibia. Metatarsi I-II entire; metatarsi III for ⅔ length, not divided; on metatarsi IV for ¼ of length, divided by 3–4 rows of setae

Tricobothria: tarsi I, 35 clavate and 15–16 long and short filiform in basal half in two rows; tarsi II, 30 clavate and 17–18 long and short filiform in distal half in two rows; tarsi III, 25 clavate and 12–13 long and short filiform in distal half in two rows; tarsi IV, 16 clavate and 7–8 long and short filiform in distal half in two rows; palp tarsi with 5–6 clavate and 10–11 long and short filiform.

Claws: inferior tarsal claw present only on tarsi IV. Superior tarsal claws on all legs without dentition; single bare claw on palp.

Abdomen pilosity (Fig. 2a, b): cuticle not exposed dorsally and ventrally; dorsally covered with fine layer of brown long hair and bristles, many pallid; ventrally black with fine layer of many long black hair bristles.

Spinnerets: 2 pairs, blackish brown, covered with black hair.

Spermethecae (Fig. 3f): Hillock shaped pair of lobes, broader at base and gradually narrowing towards apex.

Carapace 11.57 long, 9.30 wide, chelicerae 6.39 long after dissection. Abdomen 16.40 long, 11.39 wide. Spinnerets: PMS, 1.10 long, 0.70 wide, 0.51 apart; PLS, 2.00 basal, 1.22 middle, 1.66 distal; midwidths 1.05, 0.94, 0.74 respectively; apart 0.99. Eyes: Ratio of group width to length 1.4. PLE smaller than ALE but perceptibly larger than PME, ALE clearly larger than the rest. Eye diameter: ALE, 0.45; AME, 0.42; PLE, 0.25; PME, 0.15. Distance between the eyes: AME-AME, 0.17; PME-PLE, 0.07; AME-ALE, 0.15; PME-PME, 0.90. Ocular quadrate, 0.98 long, 2.14 wide. Maxilla: front length 4.09, back length 1.97, mid-width 2.89; Labium: Long 1.21, width 1.37; Chelicera: 12 promarginal teeth and 32–33 basomesal teeth; Sternum: long 5.28, wide 5.19; Sigilla: 3 pairs, posterior 0.73 diameter, ca. 1.07 lengths apart; ca.0.97 dist. from margin; middle 0.20 diameter, ca. 3.24 lengths apart; ca. 0.10 dist. from the margin; anterior very small, marginal.

Colouration in life (Fig. 4): Carapace and femur of all legs in a shade of black with a deep blue metallic sheen. Abdomen in a shade of pale metallic pink with a silvery lustre to it throughout. Anterior legs with dense mat of light brown to pale setae on their metatarsi and tarsi; patella and tibia of leg I whitish and that of leg II-III browner. Leg IV tibia and patella with a light mat of brown setae on its dorsum, lateral portion blackish with blue sheen throughout.

Distribution and natural history: the new species lives in burrows ca. 0.609 meters deep with a tubular extension made up of soil and leaves. Horizontal burrows of juveniles were mostly seen along roadside mud embankments (Fig. 5), whereas adults were found mostly in deep and vertical burrows. The female holotype was found in a burrow along a road. The female occupied a cavity in a rock crevice. The female paratype BNHS SP116 was dug out from its burrows along a road. Based on reports from locals residents, researchers and our own observation, T. psychedelicus sp. nov. appears to be distributed in West Coast Tropical Evergreen Forest in the vicinity of the type locality (Fig. 8) [7]. Dominant floral elements in the immediate vicinity include Dipterocarpus bourdillonii, Kingiodendron pinnatum, Polyalthhia sp. and Vitex altissima among tea and rubber plantations (Fig. 6). The habitat at the type locality is contiguous with Shendurney Wildlife Sanctuary and the new species likely occurs throughout this landscape. The specimen CES 10/1028 was collected from Sabarimala which lies ca. 40 km north of the type locality (Fig. 7) and is situated in Periyar Tiger Reserve. Based on the present available data, the new species likely inhibits low elevation evergreen forest, rubber as well as Tea plantations.