Platybaetis uenoi Muller-Liebenau 1980
Creators: name: Vasanth, M.
name: Kubendran, T.
name: Subramanian, K. A.
name: J. - L
name: Suttinun, C.
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Ephemeroptera
Baetidae
Platybaetis
Platybaetis uenoi

description: Platybaetis uenoi Müller-Liebenau, 1980
(Figs 8–14, 15B, 16)
Material examined: (1 larva on slide); 12 larvae, India, Nagaland, Peren district, Teipuki River near Poilwa village, 25.54165°N, 93.80529°E, 770 m, 19.VIII.2022, coll. T. Kubendran, Reg. no. I/E/840; 5 larvae (1 larva on slide), India, Longleng district, Dikhu tributary River, 26.78654°N, 94.78654°E, 223 m, 23.VIII.2022, coll. T. Kubendran, Reg. no. I/E/841.
Description. larva (Figs 8A, D; 9A–B): male: body length 7.4–7.5 mm; female: body length 8.4–8.5 mm. Cerci 6.0– 6.2 mm, median caudal filament five segments (Figs 8E, 9C, 14E–F); antennae 1.2–1.4 mm (Fig. 8F).
Head: Flattened, slightly wider than long; brownish yellow with diffusing irregular black and pale markings, well visible; frons and vertex with dark brown pattern; male turbinate eye reddish (Fig. 9B). Antennae brown with ecru, scape thick with small setae on anterior margin, base broader, pedicel cylindrical, and flagellum brown with ecru markings, slightly shorter than head width, small hair-like setae on each segment (Figs 8A, F). Posterior margin of head with incision (Figs 8A–B, D). Labrum (Figs 10A–C) rounded, 2.0× wider than long; distal margin with row of apically hair-like setae and feathered setae, dorsal surface with hair-like setae; arc of 1+4 stout medium setae (Fig. 10B). Distal margin with medial emargination with blunt crenation (Fig. 10C). Hypopharynx (Fig. 10D) with long, thin setae and well-developed lingua and superlingua. Right mandible (Fig. 11A) incisors with 6–7 denticles, prostheca slender, apex of mola with reduced tuft of setae. Left mandible (Figs 11B–C) incisors with 6–7 denticles; prostheca comb-shaped; mola with thumb-like long apical extension. Basal half with 6–7 short simple setae scattered over dorsal surface. Maxillae (Figs 11D–F) with 3 dentisetae and 3 canines; setae of inner dorsal row 1.3x longer than setae of inner ventral row; palps 2-segmented; segment II longer than segment I, inner margin slightly curved and outer margin almost straight, with small rounded well-visible projection at apex surrounding with simple setae. Labium (Figs 10E–G) with glossae longer than paraglossae; glossae with long triangular setae at apex; a few small stout setae on dorsal margin; 7–8 long, stout setae on inner margin and a long, stout seta in middle; paraglossae broad with 3 rows of long, stout setae apically; dorsal surface with long, stout setae; palps 3-segmented, segment I broad with several micropores on dorsal surface (Fig. 10G); segment II square, outer margin with short, fine, simple setae; dorsally with several micropores; ventrally with two medium, simple stout setae. Segment III slightly rounded with several short, stout acute setae (Fig. 10E).
Thorax: Yellowish brown (Figs 8A–B). Pronotum almost as broad as head capsule (Figs 8A–B); pronotum posterolateral margin slightly rounded. Ventral side of the pronotum and mesonotum with small medial suture (Fig. 8C). Hindwing pads absent. Legs generally yellow with a brown pattern (Figs 12A–C; 13A–D). Foreleg (Figs 12A, 13A): femur apex slightly rounded, dorsal surface with small, stout scattered setae, outer margin with a row of long feathered and ciliate setae (Fig. 12F), inner margin with small, stout scattered setae (Fig. 12D); tibia 0.7x femur length, dorsal margin with row of long, hair like setae and few short stout setae (Fig. 13A), patella tibial suture present along with long hair-like setae; tarsus 2.2x shorter than tibia, with dorsal row of simple setae, inner margin with a row of short, stout setae ending with fine, long seta near apex, claw with a single row of 8–9 denticles increasing in size towards apex, with few apical stripes, subapical setae absent (Fig. 13E). Middle and hind legs as forelegs (Figs 12B–C, 13B–C).
Abdomen: Coloration of terga generally brown with yellowish pattern (Figs 8A, D, 9A–B); terga I–IV brown with yellow pattern, medially with four black spots; tergum V pale yellow with brown marks laterally; VI–VII dark brown with “T”-shaped pale yellowish marking; VIII pale yellow with medially black spots; IX–X brown; posterior margin of terga I–X with both blunt and sharp spines (Figs 14A–C). Sterna I–X ecru mixed with yellow. Gills present on segments I–VII, simple, leaf-like, and rather broad; tracheae brown on gills II–VI, tracheae on gills I and VII not clearly marked, margin with minute setae (Figs 14G–N). Paraproct distally slightly expanded, without marginal spines, surface covered with small rounded scale bases, fine simple setae, and small micropores (Fig. 14D). Posterolateral extension (cercotractor) with small spines. Cerci shorter than body length; paracercus composed of only 5 segments (Figs 8E, 9C, 14E–F).
Imago: Unknown.
Distribution: Nagaland (India) (Figs 15B).
Diagnosis: Platybaetis uenoi is distinguished by the following characters: (i) posterior margin of abdominal segments I–X with both acute and blunt denticles (Figs 14A–C); (ii) gills on segments I–VII; tracheae well marked on II–VI; indistinct on I and VII (Figs 14G–N); (iii) claw with 8–9 denticles; apical denticle larger than others and presence of strips (Fig. 13E); (iv) paracercus composed of five segments, each with large hair-like setae alongside (Figs 14E–F); (v) hindwing pads absent; (vi) labrum rounded with arc of 1+4 small blunt setae and medial emargination with blunt crenation (Figs 10A–C); (vii) glossae with long triangular setae at apex (Figs 9D, 10F).
Ecology: Larvae of P. uenoi occur in the river Tepuiki (Fig. 15B), which are the only tributaries of the Barak River in the state of Nagaland. The nearest human habitations are the Poilwa village, 4–5 km from the type locality. Poilwa is situated in the hilly tract of the Peren district in Nagaland and is inhabited by the Zeliang-Naga Tribe. The Tepuiki River has diverse aquatic resources. The villagers of Poilwa are conserving the river by prohibiting fishing gear and other destructive elements. In the river, remarkable numbers of aquatic insects were collected, especially Ephemeroptera (Vietnamellidae, Heptageniidae, Ephemerellidae, and Baetidae), Plecoptera (Perlidae and Peltoperlidae), fishes, Mollusca, etc. The environmental parameters are as follows: air temperature: 26.6°C, water temperature: 21.8°C, humidity: 69%, pH: 6.68, canopy: open, substrate index of the river: gravel: 10%; cobbles: 10%; boulders: 40%; bedrock: 30%; fine sand: 5%; and silt: 5%.
description: Published as part of Vasanth, M., Kubendran, T., Subramanian, K. A., J. - L & Suttinun, C., 2025, Contribution to the genus Platybaetis Müller-Liebenau, 1980 (Ephemeroptera: Baetidae) in India, pp. 511-532 in Zootaxa 5570 (3) on pages 520-528, DOI: 10.11646/zootaxa.5570.3.4, http://zenodo.org/record/14745384