Choroterpes (Euthraulus) nandini Selvakumar & Sivaramakrishnan 2015

Kluge, Nikita, Srinivasan, Pandiarajan & Isack, Rajasekaran, 2022, Review of the subgenus Euthraulus (Ephemeroptera, Leptophlebiidae, genus Choroterpes) from the Western Ghats (India), Zootaxa 5181 (1), pp. 1-85 : 21-22

9. Choroterpes (Euthraulus) nandini Selvakumar & Sivaramakrishnan 2015

( Figs 9 , 15 , 392–425 )

Choroterpes (Monophyllus) nandini Selvakumar & Sivaramakrishnan (in Selvakumar, Janarthanan & Sivaramakrishnan) 2015: 285 (larva).

Material examined. INDIA, Karnataka state, border of Shivamogga and Udupi districts near Agumbe and Nadpal , 11–31.I.2013, coll. N. Kluge & L. Sheyko: 3 L-S-I ♂, 1 L-S/I ♂, 2 L-S ♂, 1 L-S-I ♀, 1 L-S ♀, 24 larvae (ZIN) . Kerala state, Poothumoola stream, Wayanad district , 20.III.2021, coll. M. Vasanth: 12 I ♂, 6 S ♂, 6 I ♀ 12 larvae (ZSI) .

Descriptions

Larva. CUTICULAR COLORATION: Head, pronotum and mesonotum with diffusive brown and ochre areas ( Figs 392–293 ). Femora of all legs light brown-ochre, with diffusive lighter and darker areas; tibiae and tarsi brown-ochre ( Figs 394–396 ).Abdominal terga and sterna light ochre, some terga diffusively darkened laterally ( Fig. 397 ).

HYPODERMAL COLORATION: Femur of each leg with contrasting brown maculae at middle and near apex (as in imago—as in Figs 418–420 ). In immature larvae, posterior part of each abdominal tergum more or less extensively colored with brown; each abdominal sternum with pair of more or less extensive brown spots laterally. In last larval instar, abdominal terga get coloration as in imago (as in Figs 412–415 ).

SHAPE AND SETATION: Labrum with median emargination deep and sharp, with 5 denticles smoothed out or absent ( Fig. 399 ); distal transverse setal row arched, as long as about 1/2 of labrum width; proximal transverse setal row arched, slightly shorter than distal transverse setal row ( Fig. 398 ) Mandibles with outer margin moderately convex ( Fig. 392 ). Maxillae: Medio-apical projection of maxilla well-expressed, overlaps base of comb-like dentiseta, directed medially; subapical ventral row of comb-like setae reduced to 6–9 setae, far not reaches apex of medio-apical projection and divided by curvation into median portion with larger sockets and lateral portion with smaller sockets ( Figs 401–402 ). Inner margin of maxillary palp with 1–2 setae on apex of 2nd segment, 2–3 setae on 3rd segment ( Fig. 400 ).

Fore femur: widest proximally; margins and anterior side with stout non-pectinate setae, partly blunt, partly pointed ( Fig. 405 ). Middle femur: widest at middle; margins and anterior side with stout, non-pectinate, blunt and pointed setae ( Fig. 406 ); Hind femur: widest at middle; outer margin with stout, non-pectinate, blunt and pointed setae; anterior side with row of shortly truncated setae parallel to inner margin and few such setae proximally ( Fig. 407 ); pointed, curved, pectinate setae forming irregular row on posterior side of hind femur, located mostly in proximal part of femur; in distal part sparse and small (as in Fig. 354 ).

Fore tibia: stout, pointed, pectinate setae on inner side form irregular stripe with 1–3 setae in cross section, occupy most part of tibia length and form separate group on tibia apex ( Fig. 408 ). Middle tibia: stout setae on inner side pointed, non-pectinate, form very sparse row of 3–6 longer setae and several shorter setae ( Fig. 409 ). Hind tibia: stout setae forming longitudinal row on outer side, mostly longer than tibia width; stout setae on inner and inner-anterior sides shorter than tibia width, blunt or pointed, non-pectinate ( Fig. 410 ); pointed, bipectinate setae on posterior side absent on proximal 1/3 of tibia, sparse on distal 2/3 of tibia ( Fig. 411 ).

Tarsi: inner side of hind tarsus with one preapical and one apical stout setae; smaller stout setae proximad of them and on inner sides of fore and middle tarsi ( Figs 408–410 ).

Abdomen: Terga of anterior part of abdomen only slightly wider and shorter than terga of posterior part of abdomen ( Fig. 397 ). Posterior margins of abdominal terga: terga I– VIII with minute denticles ( Fig. 403 ); terga IX –X with larger pointed denticles ( Fig. 404 ); sterna without denticles. Posterolateral spines of terga VIII incised, of tergum IX non-incised ( Fig. 9 ).

Tergalii ( Fig. 392 ): Tergalius I unilamellate and thread-like. Tergalius II consists of one narrow lamella terminated with 2 processes; tergalii III–VII each consist of one narrow lamella terminated with 3 processes. Each lamella gray, tracheae pigmented by blackish.

Subimago. CUTICULAR COLORATION: Pronotum light brownish. Mesonotum with chromozones light brown ( Fig. 423 ). Thoracic pleura and sterna with light brown and colorless areas. Wings with microtrichial circles very light brownish. Legs light brownish; tibiae not darkened at base ( Figs 416–417 ). Abdominal terga, sterna, and caudalii light brownish; gonostyli darker brown.

HYPODERMAL COLORATION: As in imago.

TEXTURE: On all legs of both sexes, 1st tarsomere covered with microtrichia (as tibia), at least 5th tarsomere covered with sharply narrowed, pointed microlepides; on fore legs of male all 2nd–5th tarsomeres covered with such microlepides (as in Figs 239–240 ); on middle and hind legs of male and on all legs of female 2nd–4th tarsomeres with mixture of such microlepides and microtrichia.

Imago, male ( Figs 412–413 ). Head ochre with brown. Scape and pedicel either brown, or ochre proximally and brown distally, flagellum ochre or brown. Dorsal eyes not elevated, brownish-orange. Thorax brown. On fore wing base including costal brace brown, other membrane colorless; pterostigma with simple, perpendicular crossveins. On hind wing base brown, other membrane colorless; costal projection blunt (as in Fig. 108 ). Legs light ochre; on each leg cuticle of knee area (apex of femur and base of tibia) colored with brown; fore femur with two black hypodermal maculae—apical macula and middle with proximal maculae fused together; middle and hind femora with 2 black hypodermal maculae—apical and middle ones, with or without smaller proximal macula ( Figs 418–420 ). Each abdominal tergum III–VII in median part mostly ochre, laterally and posteriorly mostly brown; more anterior and more posterior terga mostly brown ( Figs 413, 415 ); sterna ochre. Caudalii ochre with black dots in joinings ( Fig. 413 ).

Male genitalia. Both in subimago and imago, 1st segment of gonostylus with inner-apical angle right, with length equal to width ( Figs 421–422 ). Penes widest in proximal part; portion distad of gonopores less than half of length from proximal constriction to apex; apices smooth ( Fig. 15 ).

Imago, female. Leg coloration as in male. Abdominal terga nearly uniformly dark brown with small blanks; sterna ochre with brown maculae laterally ( Fig. 414 ).

Egg ( Figs 424–425 ). Irregularly oval. Chorion partly covered with relief formed by papillae and ridges (see Notes about Euthraulus ) ( Fig. 424 ); most part of egg surface lacks regular relief, so that egg viewed from certain side looks as lacking this relief ( Fig. 425 ). Some papillae enlarged.

Dimension. Fore wing length (and approximated body length) 4–5 mm.

Distribution. Mountains of the Western Ghats in southern India (Karnataka state).

Comments. This species was originally placed in the subgenus Monophyllus Kluge 2012 , which is recently renamed to Monochoroterpes Kluge & Jacobus 2015 , because of homonymy. However, this species is closely related to Ch. (E.) angustifolius sp. n., which is why we move it to the subgenus Euthraulus , and regard Monochoroterpes (the objective synonym of Monophyllus) to be subjective synonym of Euthraulus (see above).

Figures

FIGURES 1–9. Posterolateral spines of larval abdominal segments VIII and IX, dorsal view. 1, Choroterpes (Euthraulus) alagarensis; 2, Ch. (E.) armillatus sp. n. (holotype); 3, Ch. (E.) latus sp. n. (holotype); 4, Ch. (E.) atelobranchis sp. n. (holotype); 5, Ch. (E.) unicolor sp. n. (holotype); 6, Ch. (E.) sp. «Mumbai»; 7, Ch. (E.) nambiyarensis; 8, Ch. (E.) angustifolius sp. n. (holotype); 9, Ch. (E.) nandini.

FIGURES 10–15. Penis of male imago, ventral view. 10, Choroterpes (Euthraulus) armillatus sp. n. (holotype); 11, Ch. (E.) latus sp. n. (holotype); 12, Ch. (E.) unicolor sp. n. (holotype); 13, Ch. (E.) nambiyarensis; 14, Ch. (E.) angustifolius sp. n.; 15, Ch. (E.) nandini.

FIGURES 392–397. Choroterpes (Euthraulus) nandini, exuviae of male larva with the same magnification: 392, head; 393, pronotum and mesonotum; 394–396, fore, middle and hind legs; 397, abdominal tergum with tergalii.

FIGURES 398–404. Choroterpes (Euthraulus) nandini, larvae. 398–399, labrum; 400–402, maxillae; 403–404, posterior margins of abdominal terga VIII and IX.

FIGURES 405–407. Choroterpes (Euthraulus) nandini, larval exuviae of fore, middle and hind femora, with focus on anterior side.

FIGURES 408–411. Choroterpes (Euthraulus) nandini, larval exuviae of tibiae, tarsi and claws. 408–410, fore, middle and hind legs, with focus on anterior side; 411, hind tibia with focus on posterior side.

FIGURES 412–423. Choroterpes (Euthraulus) nandini. 412–413, male imagines; 414, abdominal segments IV–VI of female imago; 415, abdomen of male imago; 416–417, subimaginal exuviae of male fore and middle legs; 418–420, fore, middle and hind legs of male imago; 421, genitalia of male imago; 422, their subimaginal exuviae; 423, subimaginal exuviae of half of mesonotum.

FIGURES 424–425. Choroterpes (Euthraulus) nandini, eggs.

FIGURES 346–356. Choroterpes (Euthraulus) angustifolius sp. n., larvae. 346–347, labrum; 348–350, apex of labrum with focus on proximal transverse setal row (348), distal transverse setal tow (349) and median emargination (350); 351–352, maxilla; 353–354, middle portion of inner margin of hind femur with focus on anterior side (353) and posterior side (354); 355–356, posterior margins of abdominal terga VIII and IX (353–356, holotype).

FIGURES 234–242. Choroterpes (Euthraulus) unicolor sp. n. 234–235, labrum; 236–238, posterior margins of larval abdominal terga V, VIII and IX; 239–240, subimaginal tarsus; 241–242, maxilla.

FIGURES 95–108. Choroterpes (Euthraulus) armillatus sp.n. 95, head and thorax of male imago; 96, abdomen of male imago; 97, subimaginal exuviae of half of mesonotum; 98–99, exuviae of male subimaginal fore and hind legs; 100–102, fore, middle and hind legs of male imago; 103–104, female imago, ventral and dorsal view; 105, proximal part of caudalius of male imago; 106, subimaginal exuviae of gonostylus; 107, imaginal genitalia; 108, hind wing (95–102, 105–108, holotype).