Baetis (Tenuibaetis) jhargramensis Vasanth, Kubendran, Subramanian & Gattolliat 2025, sp. nov.

Baetis (Tenuibaetis) jhargramensis Vasanth, Kubendran, Subramanian & Gattolliat sp. nov. (Figs 5–8, 13) Material examined: Holotype (ZSI). ♀ mature larva, INDIA, West Bengal, Jhargram district, Belpahari range, grassland nearby Khandarani lake, 22.66543° N 86.70812° E, Alt. 173 m. 17.X.2022, Coll. T. Kubendran (Reg. No. I/E/877). Paratypes. 30 larvae, same data as holotype (Reg. No. I/E/878). Mature larva (Figs 5A–C). Body length: 3.7–3.8 mm; cerci length 1.8–2.0 mm; paracercus length 1.4–1.5 mm; antenna 0.7–0.9 mm. Coloration (Figs 5A–C): Head brown, medially with pale yellow pattern; clypeus pale yellow; pronotum brown; anterior margin of mesonotum dark brown, posterior half of mesonotum yellowish. Abdominal terga I– III brown with reduced pale yellow pattern; terga IV– V pale yellow with brown pattern medially, terga VI –VIII brown and IX–X pale yellow with brown pattern. Cerci pale brown; thorax ventrally pale yellow, legs pale yellow with brown marks; femur pale yellow with brown marks, distally brown; claws distally brown; abdominal sternum pale yellow. Head. Antenna (Fig. 7C): Scape and pedicel sub-cylindrical, flagellum with thin small stout setae on apex of each segment. Labrum (Fig. 6A): Rounded with length 0.5× maximum width. Medial emargination of distal margin deeply cleft, with apically blunt process. Dorsally with numerous fine, simple setae; submarginal arc of setae of 1+6 simple setae. Distal margin with row of long, bifid, pectinate setae. Ventral surface with four short, spine-like setae near lateral and anterolateral margin. Hypopharynx (Fig. 6B): Lingua slightly rounded, as long as superlingua. Superlingua rectangular, with numerous thin small setae along distal margin. Right mandible (Fig. 6C): Incisors fused. Outer and inner incisors with 3+4 denticles respectively. Prostheca slender, with numerous setae distolaterally, and without minute intermediate denticles, mola with small bunch of setae. Margin between prostheca and mola without setae or crenelation. Tuft of two setae at apex of mola present. Left mandible (Figs 6D–E): Incisors fused. Outer and inner incisors with 4+4 denticles. Prostheca robust, apically with small stout denticles and comb-shape structure. Margin between prostheca and mola almost straight, without setae. Denticles of mola apically constricted. Tuft of setae at apex of mola. Both mandibles with lateral margins almost straight; basal half with fine, simple setae scattered over dorsal surface. Maxilla (Figs 6F–G): Galea-lacinia with two simple setae under crown. Inner dorsal row of setae with three denti-setae, distal denti-seta tooth-like, middle denti-seta slender, and pectinate, proximal denti-seta slender, and pectinate, furcation well developed and abducted. Medially with two feathered, spine-like seta and 5–6 long, simple setae. Maxillary palp 1.5× as long as length of galea-lacinia. Palp segment II 0.9× length of segment I; segment II enlarged. Fine simple setae scattered over surface of segments I and II. Apex of segment II rounded without nipple. Labium (Fig. 7A–B): Glossae shorter than paraglossae; inner margin of glossae with 8 long, spine-like setae; apex with 5 long, robust setae and a medium robust seta; outer margin with 4 spine-like setae, base with simple setae. Paraglossae subrectangular slightly curved inward; apex slightly rounded with three rows of long robust distally pectinate setae in apical area and few simple setae in antero-medial area. Dorsally with a row of long spine-like setae near inner margin. Labial palp 3-segmented; segment I slightly longer than segments II and III combined. Segment II slightly produced inward to form a moderately expanded lobe at distal corner; dorsally with a row of 5 fine, simple setae; segment III conical with small tip at apex, slightly asymmetrical with a small concavity at inner apex; covered with short stout spine-like setae. Segments II and III with fine simple setae scattered over dorsal surface. Thorax. Hind wing pads (Fig. 8D): Present. Foreleg (Figs 7D–G): Ratio of foreleg segments (femur: tibia: tarsi: claw) 1.1:0.9:0.7:0.2. Femur length 2.9× maximum width. Dorsal margin with a row of 20–21 long, stout, apically rounded 2-channel setae; length of setae 0.21× maximum width of femur. Lateral surface with 4 stout setae. Apex rounded with a row of short, stout, pointed setae. Villopore well developed. Dorsal margin of tibia with a row of 8–12 short spine-like setae and tuft of long, fine, simple setae; lateral surface with scattered short, stout setae along patella-tibial suture. Dorsal margin of tarsus with hair-like setae; ventral margin with stout, spine-like setae increasing in length towards apex. Claw with a row of 10–11 denticles (Fig. 8C). Middle leg (Fig. 8A): Dorsal margin of femora with a row of 18–19 long, stout, apically rounded setae; length of setae 0.18× maximum width of femur. Dorsal surface of femur with stout, spatulate setae and distally with more than 7 stout setae. Dorsal margin of tibia with stout, spatulate short setae and inner margin with spine-like stout setae and lateral surface spatulate stout setae along patella-tibial suture. Dorsal margin of tarsi bare; ventral margin with 6–7 stout setae increasing in length towards apex, apex with one short, stout, spine-like setae. Hind leg (Fig. 8B): Dorsal margin of femora with a row of 19–20 long, stout, apically rounded setae; length of setae 0.19× maximum width of femur. Dorsal surface of femur with few, clavate setae and distally without setae. Dorsal margin of tibia with numerous stout, spatulate short setae and inner margin with spine-like stout setae. Lateral surface of tibia with stout, spatulate setae along patella-tibial suture. Dorsal margin of tarsi with 6 stout short setae. Abdomen. Terga (Fig 8E). Posterior margin of terga with regular row of broad short blunt U-shaped denticles, surface with scale bases and scattered fine, simple setae. Gills (Figs 8F–I): Single lamellate gills present on segments I–VII. Margin serrated with fine, simple setae. Tracheation transparent, dorsal surface with small micropores. Paraproct (Fig. 8J): Distally not expanded, with 9–10 marginal stout spines. Surface scattered with micropores and fine simple setae, with notched scales. Cercotractor with apically minute marginal spines. Imago: Unknown. Etymology: The specific epithet jhargramensis is a Latinized adjective formed from the type locality. Distribution: West Bengal, India (Fig. 13). Diagnosis: Baetis (T.) jhargramensis Vasanth, Kubendran, Subramanian & Gattolliat sp. nov. can be distinguished from all known species of the subgenus Tenuibaetis by the following combination of characters: (i) submarginal arc of labrum with 1+6 simple setae (Fig. 6A); (ii) maxillary palp segment II enlarged (Figs 6F–G); (iii) lateral surface of forefemur with 4 stout setae (Figs 7D–G); (iv) dorsal margin of forefemur with 20–21 long, stout, apically rounded 2-channel setae (Fig. 7D); (v) claw with a row of 10–11 denticles (Fig. 8C); (vi) tergum IV–V pale yellow with brown medially, tergum IX pale yellow (Fig. 5A); (vii) posterior margin of tergum I–X with broad ‘U’ shaped denticles (Fig. 8E); (viii) gills I–VII with serrated margins, tracheation not visible and with small pores (Figs 8F–I). Ecology: The type locality of the new species is a small stream near Khandarani Lake, located near the Belpahari forest range office in Jhargram district, West Bengal. The stream bed is predominantly composed of silt particles, fine sand, and some pebbles. The environmental parameters are temperature (atmosphere) 25°C, temperature (water) 21.1°C, humidity 45% and pH 6.2. Larvae of the new species were collected from leaf litter and small pebbles on the bottom of stream.