Edmundsula meghamalaiensis Vasanth, Subramanian & Selvakumar, 2021

Vasanth, M., Subramanian, K. A., Selvakumar, C., Kubendran, T. & Sivaramakrishnan, K. G., 2021, Three new species of Atalophlebiinae (Ephemeroptera: Leptophlebiidae) of India with a new record of the genus Megaglena Peters and Edmunds, 1970, Zootaxa 5076 (1), pp. 56-70 : 61

Edmundsula meghamalaiensis Vasanth, Subramanian & Selvakumar n. sp.

( Figs 17–37 )

Material examined: Holotype: ♀ immature larva, INDIA, Tamil Nadu, Theni district, Suruli colony, Upper Manalar stream; 09.59167 N, 077.34261 E; Alt. 1530 m; 03.iii.2019, coll. M. Vasanth (Reg. No. I /E/433) . Paratypes: 10 larvae (Reg. No. I /E/434), same data as holotype ; 14 larvae, Kerala, Trivandrum district, Peppara Wildlife Sanctuary, Pandipath stream; 08.67741 N, 077.19390 E, Alt. 1326 m; 19.i.2019, coll. M. Vasanth (Reg. No. I /E/435) .

Mature larva. Length: body 8.5–9.0 mm; antennae 3.2–3.5 mm; cerci 6.5–7.0 mm; paracercus 7.2–7.5 mm. General coloration dark brownish yellow ( Fig. 17 ).

Head. Dark brown, washed with pale yellow. Upper portion of male compound eye reddish, lower portion black. Antennae white. Labrum ( Figs 18–19 ): dorsum with two rows of thin, long setae; anterior region with a row of feather like setae ventrally; anteromedian emargination with moderate ‘V’ shaped cleft and without denticles. Hypopharynx ( Fig. 20 ): lingua with well developed lateral process; anterior margin deeply cleft; superlingua with a row of setae on anterior margin. Mandibles: ( Figs 21–22 ) translucent, with dark brown incisors and molars; lateral margins with scattered setae, inner incisor slightly longer than outer one. Maxilla ( Fig. 23 ): segments I– III of palp equal in length, apical segment not tapering at apex. Labium ( Figs 24–25 ): palps 3-segmented, segments II – III narrower, with row of thick setae on dorsal margin of third segment; outer and inner margins of palp with row of long and pointed setae; segment I slightly longer than segment II, segment III shorter than segment II, tapering at apex.

Thorax. Pale yellowish brown, irregularly washed with dark brown; pronotum with lateral margins white; dark brownish with diffuse hypodermal markings. Legs: brownish yellow; coxae brown; outer surface of all femora with long, thick and thin setae; dorsal surface of foreleg with short stout setae as a group in the distal region; pale macula on distal end ( Fig. 26 ); femur of midleg moderately developed with numerous short stout setae on dorsal surface ( Fig. 27 ); dorsal surface of hindfemora with numerous short stout setae ( Figs 28–29 ). Fore and mid tibia with thick feathered setae and long stout setae; hind tibia with thick feathered setae ( Fig. 30 ). Claws with denticles, progressively larger from the middle, apical denticle much larger ( Fig. 31 ).

Abdomen. Terga I–X dark yellowish brown with diffuse hypodermal markings; terga I– VI with yellowish streaks laterally; terga IV–IX with posteriolateral spines, progressively larger posteriorly, spines on terga VII–IX pointed ( Fig. 36 ). Gills on segments I–VII; gill I slender and lanceolate with branched tracheae; dorsal and ventral portions of lamellae of gills II –VII wider, long and smoothly tapered at apex ( Figs 32–35 ). Subanal plate deeply cleft in male and female larva ( Figs 36–37 ). Paracercus longer than cerci; caudal filaments with whorl of setae on alternate segments, setae shorter than length of corresponding segment.

Adult. Unknown.

Etymology. This species is named after the type locality, Meghamalai WLS, Theni District, Tamil Nadu, India.

Distribution. Southern Western Ghats, India (Tamil Nadu and Kerala).

Diagnosis. Edmundsula meghamalaiensis n. sp. can be distinguished from the previously described species, E. lotica Sivaramakrishnan 1985 by the following combination of larval characters: (i) anteromedian emargination of labrum with moderate ‘V’ shaped cleft and without denticles ( Figs 18–19 ); (ii) segment I–III of maxillary palps shorter and apical segment not tapering at apex ( Fig. 23 ); (iii) segment II–III of labial palp narrower and with a row of thick setae on the dorsal margin of third segment ( Figs 24–25 ); (iv) distal region of dorsal surface of the foreleg with a group of short spines ( Fig. 26 ).

Habitat: Larvae of Edmundsula meghamalaiensis n. sp. inhabit first order (from 2–3 m wide) mountain stream (Manalar stream, 1530 m a.s.l.) of the Meghamalai Wildlife Sanctuary, Theni District, Tamil Nadu ( Figs 58–59 ). The stream is characterized by medium water temperature (18–22°С at the time of sampling) and average current velocity. Larvae were collected from cobbles and pebbles where the new species was found with the larvae of the Baetis sp. , Afronurus sp. , Choroterpes sp. and Dudgeodes sp.

Discussion: With an array of several plesiomorphic character states, Edmundsula is a genus of Gondwanian origin, presently the genus is endemic to southern peninsular India, which may have phylogenetic links with genera disjunctly distributed in Sri Lanka, Madagascar, South Africa and Australia. However, this requires in depth study through further exploration in respective areas. Furthermore, Sivaramakrishnan (1985) suggested a tenuous link of Edmundsula Sivaramakrishnan 1985 with Neozephlebia Penniket 1961 from New Zealand due to the dorsolateral expansion of the glossae in both the genera. Dense rows of setae on the outer margins of fore and middle legs in Edmundsula Sivaramakrishnan 1985 and in Indialis Peters & Edmunds 1970 , another genus endemic to southern India apparently show relationship established the genus Sangpradubina from Thailand as pointed out by Boonsoong & Sartori (2016); Kluge (2020) recognized to given the morphological notes of femoral and tibial setation of genus Thraulodes Ulmer 1920 from Panama and Peru. These phylogenetic riddles can only be solved when combined morphological and molecular studies of both larval and respective alate stages of all these Gondwanan genera with intensified international collaboration.

Figures

FIGURES 17–22. Larva of Edmundsula meghamalaiensis n. sp. 17. Dorsal view; 18. Labrum; 19. Labrum dorsal view; 20. Hypopharynx; 21. Left mandible; 22. Right mandible.

FIGURES 23–31. Larva of Edmundsula meghamalaiensis n. sp. 23. Maxilla; 24. Labium; 25. Glossae dorsal view; 26. Foreleg; 27. Midleg; 28. Hindleg; 29. Hind femur anterior margin; 30. Hind tibia; 31. Claw.

FIGURES 32–37. Larva of Edmundsula meghamalaiensis n. sp. 32. Gill I; 33. Gill III; 34. Gill V; 35. Gill VII; 36. Subanal plate ♂ (Arrow indicate genital parts); 37. Subanal palte ♀.

FIGURES 57–60. Type locality of new species. 57. Choroterpes (C.) andamanensis n. sp.; 58–59. Edmundsula meghamalaiensis n. sp.; 60. Megaglena agasthiya n. sp.