Description of the male and female adults of Sparsorythus srokai Srinivasan et al. (Ephemeroptera: Tricorythidae) from India Author Muthukatturaja, Marimuthu 0000-0001-5796-0211 Department of Zoology, Thiagarajar College, Madurai- 625009, Tamil Nadu, India. & drmkraja 83 @ gmail. com; https: // orcid. org / 0000 - 0001 - 5796 - 0211 drmkraja83@gmail.com Author Balasubramanian, Chellaiah 0000-0001-8563-1677 Department of Zoology, Thiagarajar College, Madurai- 625009, Tamil Nadu, India. & ulab 62 @ yahoo. com; https: // orcid. org / 0000 - 0001 - 8563 - 1677 ulab62@yahoo.com text Zootaxa 2022 2022-12-16 5222 1 77 82 journal article 53818 10.11646/zootaxa.5222.1.6 3b3a3191-ac3b-47b8-a2da-a2d8a4c58039 1175-5326 7456483 9A4F4E4C-F760-4ED4-B90C-E17789DADC94 Sparsorythus srokai Srinivasan et al . ( Figs. 1–7 ) Sparsorythus srokai Srinivasan, Sivaruban, Barathy & Isack, 2022: 186 (larva). Material examined : 5 male (ZSI-SRC, Reg. No.: I/E-733), 5 female imagoes (ZSI-SRC, Reg. No.: I/E- 734) and 5 male , 5 female subimagoes with final instar larval exuvia, INDIA , Tamil Nadu , Dindigul district , Pullaveli falls , 10.303570° N , 77.752182 °E ; 1650 m . a.s.l., 09.III.2022 , Colls. Balasubramanian & Muthukatturaja . Descriptions Male imago ( Fig. 1 ): body length, 3.2–3.4 mm ; cerci length, 16.2–17.5 mm ; terminal filament, 18.0– 19.5 mm ; length of head, 0.2 mm ; width of head, 0.8 mm ; length of antenna, 0.5 mm ; length of forewing, 4.8–5.0 mm; width of forewing 2.3–2.5 mm ; dorsal diameter of eye 0.2 mm ; distance between compound eyes 0.4 mm ; length of fore femur: tibia: tarsus (mm): 0.6: 0.7: 0.5. General body coloration greyish brown to pale yellow. Head: grey to pale brown, anterior margin and area around antennal base pale grey; scape and pedicel grey, flagellum translucent; compound eyes black. Thorax: pronotum grey to pale yellow, meso and metanotum yellowish brown to pale yellow, margins darker. Legs: femur grey, tibia and tarsi translucent; fore tibia slightly longer than femur; middle and hind tibia equal in length to corresponding femur; foreleg with two paddle-like claws, middle and hind legs with one claw paddle-like and the other apically hooked. Wings: hyaline with grey shading in basal area of C and Sc ( Fig. 3 ); pterostigmatic region faint grey, usually no discernible cross veins in costal space; venation mostly grey; C and Sc grey; two cross veins between MA 2 and MP 1 ; cross veins of CuP and AA frequently not visible along their entire length.Abdomen: terga pale grey to yellowish brown; sterna paler; terga with grey smudges on lateral margin; dorsomedial line paler. Genitalia ( Fig. 5 ): styliger plate slightly protruded; forceps two segmented; distal segment slightly longer than basal segment, length (mm) = 0.15: 0.20; forceps base broad, without tiny bristles; inner margin of segment two of forceps covered with numerous short, leaf-shaped attachment structures; penis lobes simple, straight and tubular, swelled near base, slightly bent in dorsal direction (live specimen); penis apex reaching approximately 2/3 of second segment of forceps; apex of penis rounded, with distinct medial emargination ( Fig. 6 ). Caudal filaments: translucent, basal 1/2 of each segment with grey smudge; approximately five times longer than body length, cerci glabrous, terminal filament slightly longer than cerci. FIGURES 1–2. Sparsorythus srokai Srinivasan et al . , 1, male imago; 2, female imago. Male subimago : similar to imago, general body coloration yellowish grey to pale yellow; head grey to pale yellow, scape and pedicel grey, flagellum translucent; compound eyes black; pronotum grey to pale yellow, meso- and metanotum yellowish brown to paler, margins darker; femur grey, tibia and tarsi translucent; femur subequal in length to tibia; foreleg with two paddle-like claws, middle and hind legs with one claw paddle-like and the other apically hooked; forewings with grey shading and sparse microtrichia on margins; pterostigmatic region paler; venation mostly grey; tergum pale gray, sternum paler; tergum with grey smudges on lateral margin; genitalia almost as in imago; cerci and terminal filament longer than body, but distinctly shorter than in imago. Female imago ( Fig. 2 ): body length, 3.8–4.0mm; cerci length, 5.5–6.0 mm; terminal filament, 7.5–8.0 mm; length of head, 0.4 mm ; width of head, 1.2 mm ; length of antenna, 0.6 mm ; length of forewing, 6.0– 6.3 mm ; width of forewing, 2.3–2.6 mm ; dorsal diameter of eye 0.25 mm ; distance between compound eyes 0.7 mm ; length of fore femur: tibia: tarsus (mm): 0.7: 0.75: 0.4. General coloration similar to male. Head: dark grey to pale grey, anterior margin and area around antennal base grey to pale grey; scape and pedicel grey, flagellum pale grey to translucent; compound eyes black. Thorax: pronotum grey to pale yellow, meso and metanotum brownish yellow to pale yellow, margins darker. Legs: foreleg femur and tibia grey, and tarsi pale grey to translucent; coloration of middle and hind legs similar to male. Wings ( Fig. 4 ): coloration similar to male imago; four cross veins between MA 2 and MP 1 ; cross veins between CuP and AA frequently not visible along their entire length (some specimens with these cross veins and other without). Abdomen: terga grey; sterna pale yellow; terga with grey smudges on lateral margin; dorsomedial line paler. Caudal filaments: translucent, basal 1/2 of each segment with grey smudge; approximately two times longer than body length, cerci glabrous, terminal filament slightly longer than cerci. Female subimago : body length, 3.0– 3.5 mm ; length of fore wing, 5.4–5.8 mm ; width of forwing, 2.2–2.4 mm ; cerci and terminal filament length 2.5–3.0 mm. General body coloration dark grey to pale yellowish grey; head coloration darker; composed eyes, black, distanced approximately half of mesonotum width; basal half of ocelli darker and apical portion paler or white; antennal pedicle approximately 2 times longer than scape; pronotum coloration darker with a small blank area on either side of the ecdysial suture at posterior margin; dorsum of meso and metanotal regions with pale yellowish grey makings; femora of legs pale grey, basal end of fore femur, tibia and tarsus transparent; tarsal claws double on all legs, posterior margin of both claws paddle-like on forlegs, and one paddle-like and the other apically hooked on middle and hind legs; forewing coloration pale grey, with numerous microtrichia on dorsal surface and margins; abdominal terga I–VII dark, remainders with pale yellowish grey markings; median od thoracic sternum with a grey longitudinal markings; abdominal sterna paler; posterior margin of subanal (sternum IX) plate triangular in shape, posterior margin smoothly rounded; cercus and terminal filament little smaller than the body length, coloration as in male imago. FIGURES 3–6. Sparsorythus srokai Srinivasan et al . , imago. 3, forewing (male); 4, forewing (female); 5, male genitalia; 6, penis. Diagnosis . Imago : (i) forewings of male shaded with grey color in basal area of C and Sc regions; (ii) penis apex reaching approximately 2/3 of second segment of forceps; posterior margin of subanal plate (sternum IX) in female imago triangular, smoothly rounded at apex. Ecology of Sparsorythus srokai . Pullaveli stream is a tributary of Kamarajar Sagar dam (also known as Athoor Dam) and runs through conserved forest and cultivated areas of the Western Ghats, Dindigul district, Tamil Nadu ( Fig. 7 ). In the collection site, the maximum width of the river is around ~ 15 meters, and wet width 5 meters; water depth ~ 30–45 cm . The current velocity of the water was 1.0 m/sec at the time of collection, sandy substratum mainly with boulders, cobbles, pebbles, sand and silt, canopy cover about 80%. Water pH is about 7.2–7.4; water temperature is 24±2°C and air temperature about 27°C ±2°C. The larvae are mainly associated with the submerged roots of the riverside vegetation. Larvae of Sparsorythus srokai were associated with other mayfly genera such as Thalerosphyrus Eaton, 1881 (Heptageniidae) , Teloganodes Eaton, 1882 (Teloganodidae) , Choroterpes Eaton, 1881 (Leptophlebiidae) , Ephemera Linnaeus, 1758 (Ephemeridae) , Procloeon Bengtsson 1915 , Baetis Leach, 1815 and Nigrobaetis Novikova & Kluge, 1987 (Baetidae) . Adults of the species generally emerged in the dusk (about 6.00 pm to 8.00 pm).