Thalerosphyrus meghalayensis Selvakumar & Chandra, 2017

Selvakumar, C., Chandra, Kailash, Sivaramakrishnan, K. G. & Jehamalar, E. Eyarin, 2017, A new species of Thalerosphyrus Eaton 1881 (Ephemeroptera: Heptageniidae: Ecdyonurinae) from India, Zootaxa 4350 (1), pp. 84-90 : 85-89

Thalerosphyrus meghalayensis Selvakumar & Chandra n. sp.

( Figs 1–21 )

Material examined. Holotype: 1 larva, INDIA, Meghalaya, East Khasi Hills district, Lawsohtun, Umjasai Nala , 25°30'56.16" N, 91°51'20.16" E, 1707 m, 27.ii.2016, coll. E.E. Jehamalar (Reg. No. 5485/H13) . Paratypes: 4 larvae, same data as holotype (Reg. No. 5486/H13) ; 3 larvae, East Khasi Hills district, Sangmain, Umpaimmaw Nala , 25°32'31.49" N, 91°51'3.6" E, 1767 m, 08.iii.2016, coll. E.E. Jehamalar (Reg. No. 5487/H13) ; 4 larvae, East Khasi Hills district, Lumparing, Umrisa Nala, 25°33'11.48" N, 91°53'3.59" E, 1707 m, 27.ii.2016, coll. E. E. Jehamalar (Reg. No. 5488/H13); 1 larva, East Jaintia Hills district, Narpuh Wildlife Sanctuary, Jamchera village stream, 25°05'31.99" N, 92°21'39.1" E, 234 m, 11.iii.2016, coll. E.E. Jehamalar (Reg. No. 5489/H13).

Description. Larva. Body length 7 mm and cerci length 10 mm (full grown female larva). Dorsal and ventral side colour pattern as in Figs 1–3 .

Head. Labrum greatly expended laterally, 3x as broad as long, with narrow and somewhat acute apexes ( Fig. 4 ); dorsal surface and anterior margin covered with long and thin setae; ventral surface with a long median arch of 20 strong and pointed setae ending close to anterior margin. Hypopharynx with robust lingua bearing a tuft of small setae, superlinguae densely covered with long and thin setae replaced before apex by very small setae up to lower part of superlinguae ( Fig. 5 ). Left mandible ( Fig. 6 ) with 11–12 fimbriate setae below inner incisor and 6 long simple and thin setae below mola. Right mandible ( Fig. 7 ) with 10–11 fimbriate setae below inner incisor and 9 long simple and thin setae below mola. Crown of galea-lacinia of maxillae composed of 19–20 comb-shape setae, median ones bearing 10–12 teeth ( Fig. 8 ). Labium with glossae rhomboid, clearly concave on their inner and outer margins near apex, dorsal surface with numerous stout setae and numerous thin and simple setae ( Figs 9–10 ).

Thorax. Pronotum moderately expanded laterally and posteriorly ( Fig. 1 ). Femora with a row of setae on outer margin; outer margin of fore tibia with few thin setae on proximal fourth, mid tibia with a row of thin setae on outer margin almost to tarsi ( Figs 11–13 ). Bristles on upper face of hind femora with subparallel or slightly convergent margins, apex truncate or rounded ( Fig. 14 ). Outer margin of hind tibia with a row of 12–13 pointed bristles in marginal or submarginal position and one row of thin setae in marginal or submarginal position ( Fig. 15 ). Tarsal claw with 3–4 teeth ( Fig. 16 ).

Abdomen. Posterolateral expansions not developed on segment I, weakly developed on segment II, strongly developed on segment III and increasing in size up to VII where they may be as long as segment VIII, shorter on segment VIII and smaller proportionally to those of segments III ( Fig. 3 ). Gill I elongated with concave outer margin, more than 2 times longer than wide ( Fig. 17 ); gill III–VI strongly asymmetrical, wider than long ( Figs 18– 19 ), gill VII oval and asymmetrical with rounded apex ( Fig. 20 ). Posterior margin of tergites with regular pointed teeth, and numerous microdenticles ( Fig. 21 ). Terminal filament well developed, cerci yellowish with 4–5 white bands increasing in size towards apex; segments with whorls of stout and pointed setae.

Adult. Unknown.

Etymology. This species is named after the place of collection, Meghalaya state, India.

Diagnosis. Thalerosphyrus meghalayensis Selvakumar & Chandra n. sp. can be distinguished from Th. vietnamensis ( Dang 1967) by posterolateral expansions of the abdomen more or less developed, those of segment VIII always shorter than those of segment VII ( Fig. 3 ) and from Th. bishopi Braasch & Soldan 1986 by gill VII oval and asymmetrical with rounded apex ( Fig. 20 ) and superlinguae of hypopharynx densely covered with long and thin setae replaced before apex by very small setae up to lower part of superlinguae ( Fig. 5 ). Moreover, Thalerosphyrus meghalayensis n. sp.

can be distinguished from other species by the following combination of characters: (i) pronotum moderately enlarged laterally ( Fig. 1 ); (ii) bristles on the dorsal face of hind femora truncate or rounded at apex ( Fig. 14 ); (iii) hind tibia with a row of thin setae ( Fig. 15 ) and (v) posterior margin of tergites with regularly pointed teeth, and numerous microdenticles ( Fig. 21 ).

Figures

FIGURES 1 – 3. Larva of ThaleroSphyruS meghalayenSiS Selvakumar & Chandra n. sp. 1. Habitus in dorsal view; 2. Habitus in ventral view; 3. Detail of abdominal segments VI – IX in ventral view.

FIGURES 4 – 10. Larva of ThaleroSphyruS meghalayenSiS Selvakumar & Chandra n. sp. 4. Labrum; 5. Hypopharynx; 6. Left mandible; 7. Right mandible; 8. Maxilla; 9. Labium; 10. Labial glossae.

FIGURES 11 – 16. Larva of ThaleroSphyruS meghalayenSiS Selvakumar & Chandra n. sp. 11. Foreleg; 12. Midleg; 13. Hindleg; 14. Bristles on the dorsal face of hind femur; 15. Outer margin of hind tibia; 16, Claw.

FIGURES 17 – 21. Larva of ThaleroSphyruS meghalayenSiS Selvakumar & Chandra n. sp. 17. Gill I; 18. Gill IV; 19. Gill VI; 20. Gill VII; 21. Posterior margin of abdominal tergite IV.