Thraulus plumeus Selvakumar, Vasanth and Subramanian, 2022

Vasanth, M., Subramanian, K. A., Selvakumar, C. & Sivaramakrishnan, K. G., 2022, Contribution to the knowledge of Thraulus Eaton, 1881 (Insecta: Ephemeroptera: Leptophlebiidae: Atalophlebiinae) from India with the description of five new species, Records of the Zoological Survey of India 122 (2), pp. 125-151 : 143-144

publication ID

https://doi.org/ 10.26515/rzsi/v122/i2/2022/168290

persistent identifier

https://treatment.plazi.org/id/2B7587A7-FFBF-9C2B-FE8B-FADCFB077C74

treatment provided by

Felipe

scientific name

Thraulus plumeus Selvakumar, Vasanth and Subramanian
status

sp. nov.

Thraulus plumeus Selvakumar, Vasanth and Subramanian sp. nov.

( Figures 57–73 View Figures 57–63 View Figures 64–70 View Figures 71–73 )

Material examined: Holotype: Larva, India, Meghalaya, East Jaintia Hills, Daidung Village Pool , 25.33547 N,

92.61981 E, 1079 m, 12.iii.2016, coll. E. Eyarin Jehamalar (Reg. No. 5145/H13). Paratypes: 3 larvae, same data as holotype (Reg. No. 5146/H13); 1 larva, Meghalaya, East Jaintia hills, Daidung village stream , 25.33389°N,

92.62089°E, 1112 m, 12.iii.2016, coll. E. Eyarin Jehamalar (Reg. No. 5151/H13); 1 larva, Meghalaya, East Khasi hills, Parsmile, Santmain Nala , 25.53903°N, 91.84417°E, 1790 m, 27.ii.2016, coll. E. Eyarin Jehamalar (Reg. No. 5152/ H13); 1 larva, Nagaland, Peren district, Intanki National Park, Dhansri river , 25.55940°N, 93.52678°E, 185 m,

22.iii.2017, coll. C. Selvakumar (Reg. No. 5674/H13). Types are deposited in CEL, Kolkata.

Description (holotype): Mature larva. Body length 4.5–5.0,

cerci 5, median filament 6 ( Figure 57 View Figures 57–63 ).

Head: Head capsule and area between ocelli washed with dark brown; median line of vertex pale; margins of clypeus parallel. Labrum with posterior margin slightly convex, irregular sparse setae on both dorsal and ventral surfaces, additionally median and an apical row of setae dorsally along the anterior margin; width slightly greater than clypeus; labrum anteromedian emargination broad with undulate medially ( Figures 59 and 60 View Figures 57–63 ). Lingua of hypopharynx with well-developed lateral processes, anterior margin shallowly cleft ( Figure 61 View Figures 57–63 ). Mandibles with sparse lateral setae, prostheca of the left mandible with a stout spine ( Figures 62 and 63 View Figures 57–63 ). Maxilla with dense stout spines and fine setae on anterior margin, a large stout pectinate projection on the inner corner; outer margin of maxilla and cardo with setae; palp III segmented, length of segment I 1.2–1.4 times length of segment II, outer margin with few setae on segment II; length of segment III 0.8–0.9 times length of segment II, outer and inner margins of both with setae, the third segment with a small tuft of apical setae ( Figure 64 View Figures 64–70 ). Labium: glossa with thick plate-like setae on the ventral surface, fewer setae on dorsal surface; paraglossa with denser but fewer setae on dorsal surface; I segment of labial palp with thick setae on margins, II segment with setae on outer margin, an apical segment with thick and fine setae on margin and surface, those near apex of apical segment gathered into small tufts; segment I length ca. 1.2 times segment II length, segment III length 0.9 times segment II length ( Figure 65 View Figures 64–70 ).

Thorax: Pronotum brown with pale irregular markings on the dorsal surface. Mesonotum brown, median area pale. Foreleg of trochanter with anterior surfaces lite black, and lateral surface yellowish; basal femora yellowish, apically yellowish mixed with black, tibiae blackish with very sparse and thin setae on the inner margin, densely covered with a row of feathered setae and with a row of stout and transverse setae ( Figure 66 View Figures 64–70 ). Hind tibiae dense with feathered and hair-like setae on the dorsal surface; tarsi of all legs with several stout setae on the inner margin and sparse setae on the outer margins ( Figures 66, 67 and 68 View Figures 64–70 ). Claws with a row of 13–14 denticles, progressively larger towards the apex ( Figure 70 View Figures 64–70 ).

Abdomen: Abdomen brown, with indistinct paired submedian pale spots along the body axis. Terga III–IX with posterolateral projections, terga VIII–IX larger ( Figure 57 View Figures 57–63 ). Sterna with blackish brown, segment I–VII medially dark brown and segment VIII–X yellowish brown ( Figure 58 View Figures 57–63 ). Segments I–VII with gills; gills I slender, lanceolate, ventral lamellae wider than dorsal ( Figure 71 View Figures 71–73 ); gills II–VII similar in shape, with dorsal and ventral lamellae; each lamella elongated-ovate, with entire margins fimbriate; tracheae visible ( Figures 72 and 73 View Figures 71–73 ). Caudal filaments with a whorl of setae on alternate segments; setae shorter than the length of the corresponding segment.

Adult: Unknown.

Etymology: The species epithet is a Latin adjective and means feathery. It refers to the feather-like setae on the hind tibia.

Distribution: Meghalaya and Nagaland (Intanki NP, Peren dist.).

Diagnosis: Thraulus plumeus sp. nov. can be distinguished from other known species of the genus by the following combination of characters: • Labrum anteromedian emargination of broad with undulate medially ( Figures 59 and 60 View Figures 57–63 ).

• Dorsal surface of the hind tibia, there are dense feathered and hair-like setae ( Figures 68 and 69 View Figures 64–70 ).

• Claws with a row of 13–14 denticles, progressively larger towards the apex ( Figure 68 View Figures 64–70 ).

• Gills I slender, lanceolate, ventral lamellae wider than dorsal ( Figure 71 View Figures 71–73 ).

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