Choroterpes (Choroterpes) kaegies Selvakumar, Subramanian & Chandra, 2017

Selvakumar, C., Subramanian, K. A., Chandra, Kailash & Jehamalar, E. Eyarin, 2017, A new species of Choroterpes Eaton, 1881 (Ephemeroptera: Leptophlebiidae) from India, Zootaxa 4338 (1), pp. 189-194 : 190-193

Choroterpes (Choroterpes) kaegies Selvakumar, Subramanian & Chandra sp. n. ( Figs 1–16 )

Material examined. Holotype: 1 larva, INDIA, Meghalaya, East Khasi Hills, Khrang village, Wankwar River , 25.32481 N, 91.77519 E, 1658 m, 02.iii.2016 , coll. E. Eyarin Jehamalar (Reg. No. 5144). Paratypes: 5 larvae, same data as holotype ; 2 larvae, Meghalaya, East Khasi Hills, Thangasalai village, Umkhen River , 25.59186 N, 92.05494 E, 937 m, 05.iii.2016 , coll. E. Eyarin Jehamalar (Reg. No. 5147/H13); 1 larva, Meghalaya, East Garo Hills, Upper Rongbu village , 25.91615 N, 90.83157 E, 101 m, 26.vi.2016 , coll. E. Eyarin Jehamalar (Reg. No. 5149/H13); 1 larva, Himachal Pradesh, Bilaspur district, Mandodari, River stream, 31.783 N, 76.332 E, 18.xi.2012 , coll. K.A. Subramanian.

Description. Body length 4.6–5.0 mm ( Fig. 1 ). Antennae approximately 3.0 mm. Head prognathous, light yellowbrown with diffuse black markings. Labrum with 3 transverse, near parallel, rows of setae on dorsal surface, both distal and proximal transverse setal rows regular; anteromedian emargination broad ( Fig. 2 ). Lingua of hypopharynx with well developed lateral process, anterior margin cleft ( Fig. 3 ). Lateral margins of mandibles with scattered setae, inner mandibular incisor slightly longer than outer one ( Figs 4–5 ). Maxillary palp 3 segmented; segment 2 subequal in length to segment 1, segment 3 approximately ¾ length of segment 2 ( Fig. 6 ). Labium: glossa with thick plate-like setae on ventral surface, fewer setae on dorsal surface; paraglossa with denser but fewer setae on dorsal surface; first segment of palp with thick setae on margins, second segment with setae on outer margin, apical segment with thick and fine setae on margin and surface, those near apex of apical segment gathered into small tufts; segment 1 length subequal to segment 2 length, segment 3 length 0.7 times segment 2 length ( Fig. 7 ).

Pronotum light yellow-brown with diffuse black markings medially. Meso- and metanota yellow-brown tinged with dark brown or black laterally. Legs pale; each femur with a dark brown spot at middle and near apex; femora with thick and thin setae on outer margin; tibiae with fine and thick setae on inner margin, and very sparse and thin setae on inner margin, and very sparse and thin setae on outer margin, but hind tibiae mixed with more denser thick and few feathered setae on surface; tarsi of all legs with several thin setae on inner margin and sparse setae on outer margins ( Figs 8–10 ). Claw apically hooked with a row of 4–5 denticles, progressively larger apically ( Fig. 11 ).

Abdominal terga 1–10 light yellow-brown with diffuse black markings; terga 1–10 with posterior marginal spines; posterolateral margins of abdominal terga with pointed denticles, size of denticles increases from tergum 6 to tergum 9. Gills on segments 1–7; gill 1 single, slender, lanceolate ( Fig. 12 ); gills 2–7 alike, well-tracheated, upper and lower lamellae of gills 2–7 with 3 apical processes, median process relatively long and other relatively short ( Figs 13–16 ). Sternum 9 of male with deep apical cleft, sternum 9 of female with apex entire and without emargination. Caudal filaments pale yellow-brown; with a whorl of setae on alternate segments; setae shorter than length of corresponding segment.

Adult. Unknown.

Etymology. The species name “ kaegies ” (pronounced as KGS) is abbreviated patronym of Prof. K.G. Sivaramakrishnan who has significantly contributed to Ephemeroptera taxonomy in India. He is popularly known among his peers, friends and students as “KGS” and hence the species name.

Distribution. India (Meghalaya and Himachal Pradesh).

Diagnosis. Choroterpes (C.) kaegies Selvakumar, Subramanian & Chandra sp. n. can be distinguished from all known species of Choroterpes (C.) by the following characters: (i) anteromedian emargination of labrum broad ( Fig. 2 ); (ii) each femur with a dark brown spot at middle and near apex ( Figs 8–10 ); (iii) gill 1 single and slender ( Fig. 12 ) and (iv) upper and lower lamellae of gills 2–7 with 3 apical processes, median process relatively slender and longer than laterals ( Figs 13–16 ).

Discussion. In India, only two species are recorded from the subgenus Choroterpes s. str. viz., Choroterpes (C.) petersi Tong and Dudgeon, 2003 from southern Western Ghats by Selvakumar et al. (2015) which was originally described from Hong Kong and the present new species, Choroterpes (C.) kaegies Selvakumar, Subramanian & Chandra sp. n. from Himachal Pradesh and Meghalaya. The distribution of Choroterpes (C.) petersi Tong and Dudgeon, 2003 appears to be disjunct in its geographical range. However, Choroterpes (C.) kaegies Selvakumar, Subramanian & Chandra sp. n. is probably widely distributed in Himalaya as the collection localities from two states are geographically widely separated. However, detailed surveys are required. In future detailed morphosystematics and molecular phylogenetic studies are required to fine-tune the subgeneric relationships within the genus Choroterpes Eaton, 1881 .

Figures

FIGURES 1 – 7. Larva of Choroterpes (Choroterpes) kaegies sp. n. 1. Dorsal view; 2. Labrum; 3. Hypopharynx; 4. Left mandible; 5. Right mandible; 6. Maxilla; 7. Labium.

FIGURES 8 – 16. Larva of Choroterpes (Choroterpes) kaegies sp. n. 8. Foreleg; 9. Midleg; 10. Hindleg; 11. Hind claw; 12. Gill I; 13. Gill II; 14. Gill III; 15. Gill IV; 16. Gill VII.