Baetis (Tenuibaetis) dzulekensis Vasanth, Kubendran, Subramanian & Gattolliat, 2025

Vasanth, M., Kubendran, T., Subramanian, K. A., Gattolliat, J-L. & Banerjee, Dhriti, 2025, Three new species of the subgenus Tenuibaetis Kang & Yang, 1994 (Ephemeroptera: Baetidae) from India, Zootaxa 5665 (3), pp. 374-396 : 375-380

publication ID	https://doi.org/10.11646/zootaxa.5665.3.4
publication LSID	lsid:zoobank.org:pub:1729896A-7BEB-4084-B455-9FC970B54A97
DOI	https://doi.org/10.5281/zenodo.16609395
persistent identifier	https://treatment.plazi.org/id/F77E8793-8806-FF92-FF2C-FB7AF485FAB9
treatment provided by	Plazi
scientific name	Baetis (Tenuibaetis) dzulekensis Vasanth, Kubendran, Subramanian & Gattolliat
status	sp. nov.

Treatment

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

( Figs 1–4 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 , 13 View FIGURE 13 )

Material examined: Holotype (ZSI) ♀ mature larva, INDIA, Nagaland, Kohima district, Dzuleke village, Dzulerudi River , 25.61643° N, 93.93918° E, Alt. 1680 m. 20.VIII.2022, Coll. T. Kubendran (Reg. No. I /E/875) GoogleMaps . Paratypes. 15 larvae, same data as holotype (Reg. No. I /E/876) GoogleMaps .

Mature larva ( Fig. 1A–C View FIGURE 1 ). Body length: 3.5–3.7 mm; cerci length 1.4–1.8 mm; paracercus length 0.9–1.2 mm; antenna 0.6–0.8 mm. Coloration ( Figs 1A–C View FIGURE 1 ): Head brown, medially with yellow pattern; clypeus yellow; pronontum pale yellow with brown pattern; anterior margin of mesonotum with dark brown streak, posterior half of mesonotum yellow.Abdominal terga I– II brown; terga III – VI pale yellow with brown pattern; terga VII–VIII brown with pale yellow mark medially; terga IX–X pale yellow. Thorax ventrally pale yellow, legs pale yellow with brown marks; femur pale yellow, brown medially and apically; claws distally brown.Abdominal sterna pale yellow, laterally and medially pale brown. Cerci pale yellow. Head. Antenna ( Fig. 1B View FIGURE 1 ): Scape and pedicel sub-cylindrical, flagellum with thin, small stout setae at apex of each segment. Labrum ( Fig. 2A View FIGURE 2 ): Rounded with length 0.7× maximum width. Medial emargination of distal margin deeply cleft, with apically blunt process. Dorsally with numerous fine, simple setae; submarginal arc of 1+5 simple setae; anterolateral margin slightly rounded. Distal margin with row of long, feathered setae. Ventral surface with four short, spine-like setae laterally. Hypopharynx ( Fig. 2B View FIGURE 2 ): Lingua slightly rounded laterally and as long as superlingua. Superlingua rectangular, with numerous thin small setae along distal margin. Right mandible ( Fig. 2C View FIGURE 2 ): 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 ( Fig. 2D View FIGURE 2 ): Outer and inner incisors with 3+4 denticles respectively. 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 present at apex of mola. Both mandibles with lateral margins almost straight; basal half with fine, simple setae scattered over dorsal surface. Maxilla ( Figs 2E, F View FIGURE 2 ): 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, trifid and pectinate furcation. Medially with a feathered, spine-like setae and 3–5 long, simple setae. Maxillary palp 1.7× as long as length of galea-lacinia. Fine simple setae scattered over surface of segments I and II. Apex of segment II rounded without nipple. Labium ( Fig. 3A View FIGURE 3 ): 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. Paraglossae slightly curved inward; apex slightly rounded with three rows of long robust apically pectinate setae 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 4 fine, simple setae; segment III conical and small tip at apex, slightly asymmetrical with a small concavity at inner apex; covered with short, spine-like setae. Segments II and III with fine simple setae scattered over dorsal surface. Thorax. Hind wing pads ( Fig. 4F View FIGURE 4 ): Present. Foreleg ( Figs 3B–E View FIGURE 3 ): Ratio of foreleg segments (femur: tibia: tarsi: claw) 1:0.9:0.6:0.2. Femur length 2.7× maximum width. Dorsal margin with a row of 24–25 long, stout, spatulate 2-channel setae; length of setae 0.18× maximum width of femur. Lateral surface with 5–6 stout 2-channel setae. Apex of femur rounded with a row of short, stout, pointed setae, 5 stout lanceolate 2-channel setae on lateral surface. Villopore well developed. Dorsal margin of tibia with stout, clavate setae; ventral margin with a row of 8–10 spine-like setae; lateral surface with stout, short, spatulate setae along patello-tibial suture. Dorsal margin of tarsus with hair–like setae; ventral margin with stout setae increasing in length towards apex. Claw with a row of 12–13 denticles ( Fig. 3E View FIGURE 3 ). Middle leg ( Figs 3F–J View FIGURE 3 ): Dorsal margin with a row of 18–20 long, stout, apically rounded 2-channel setae; length of setae 0.18× maximum width of femur. Lateral surface of femur with numerous stout, clavate 2-channel setae. Dorsal margin of tibia with stout, clavate setae and inner margin with spine-like stout setae. Lateral surface of tibia with stout, short, spatulate 2-channel setae along patello-tibial suture. Tarsi and claw similar to foreleg. Hind leg similar to middle leg (4A–C). Abdomen ( Fig. 4G View FIGURE 4 ): Posterior margin of terga with a row of U-shaped long blunt spines, surface with scale bases and scattered fine, simple setae. Gills ( Figs 4D–E View FIGURE 4 ): Single lamellate gills present on segments I–VII. Margin serrated with fine, simple setae; transparent poorly visible tracheation, dorsal surface with micropores. Paraproct ( Fig. 4H View FIGURE 4 ): Distally not expanded, with 15–16 marginal stout spines. Surface with scattered micropores and fine simple setae, and with small notched scales. Cercotractor with medium, marginal spines.

Imago: Unknown.

Etymology: The specific epithet dzulekensis is a Latinized adjective formed from the toponym Dzuleke. In the local Angami language, a major tribal language in Nagaland, “Dzu” means water and “leke” means underground. Thus, the name Dzuleke reflects the unique hydrological feature of the stream in this region as it flows underground at one point in its course.

Distribution: Nagaland, India ( Fig. 13 View FIGURE 13 ).

Diagnosis: Baetis (T.) dzulekensis Vasanth, Kubendran, Subramanian & Gattolliat sp. nov. can be distinguished from all known species of the subgenus Tenuibaetis by the following combination of characters: (i) labrum rounded, dorsal submarginal arc of setae composed with 1+5 simple setae ( Fig. 2A View FIGURE 2 ); (ii) right mandible: canine with 3+4 denticles ( Fig. 2C View FIGURE 2 ); (iii) maxillary palp much longer than galea-lacinia; ( Figs 2E–F View FIGURE 2 ); (iv) paraglossae with 3–4 long setae on dorsal surface, labial palp segment II slightly produced apicolaterally ( Fig. 3A View FIGURE 3 ); (v) dorsal margin of forefemora with 24–25 long, stout, spatulate 2-channel setae ( Fig. 3B View FIGURE 3 ); (vi) dorsal surface of all tibia with stout, apically rounded setae ( Figs 3J View FIGURE 3 , 4B View FIGURE 4 ); (vii) claw with a row of 12–13 denticles ( Figs 3E View FIGURE 3 , 4C View FIGURE 4 ); (viii) posterior half of mesonotum without any distinct marking ( Figs 1A–C View FIGURE 1 ); (ix) tracheation of gills transparent ( Figs 4D–E View FIGURE 4 ).

Ecology: The riverbed composition is as follows: Gravel 5%, Cobbles 30%, Boulders 35%, Bed rock 5%, Fine sand 15% and Slit 5%. In summer, the Dzulerudi River is 3–3.5 m wide and 22–25 cm depth and medium water current (0.6 m /sec.), temperature (atmosphere) 21°C, temperature (water) 18.1°C, humidity 40% and pH 6.6. This stream is located in the eastern part of the Himalayas at an altitude of around 1700m. Larvae of the Baetis (T.) dzulekensis were collected from the stony bottom along the edges of the Dzulerudi River.