Thraulodes, Ulmer, 1920

Kluge, Nikita J., 2020, Systematic position of Thraulodes Ulmer 1920 (Ephemeroptera: Leptophlebiidae) and descriptions of new and little-known species, Zootaxa 4756 (1), pp. 1-142 : 134-136

20. Thraulodes sp. «Itaya»

( Figs 637–653 )

Material examined. PERU, Rio Itaya, upstream Puente Itaya (57 km by road from Iquitos ), near Omaguas , 1– 15.11.2006 (N. Kluge): 3 incomplete larval exuviae (last instar male, last instar female and young female).

Descriptions.

Larva. CUTICULAR COLORATION ( Figs 638–645 ). Dorsal side of head brown. Pronotum and mesonotum brown with diffusive blanks; fore protopteron with veins darker than background. Femur light brown with diffusive blanks; tibia with 2 wide brown bands (proximal and middle); tarsus colorless.Abdominal terga without contrasting markings, posterior terga gradually darker than anterior ones. Abdominal sterna lighter, posterior sterna with brown arched macula.

HYPODERMAL COLORATION. Coloration of body unknown. Tergalii dark gray ( Fig. 637 ).

SHAPE AND SETATION. Clypeus slightly widened anteriorly; labrum 1.2 times wider than clypeus ( Fig. 650 ). Labrum widest at midlength, with narrow median emargination exposed ventrally; anterior transverse setal row wider than all 5 denticles, in its median part represents field of irregularly situated setae ( Figs 651–653 ). Maxilla with 12–14 pectinate setae in apical-ventral row.

Femora: Stout setae on anterior surface narrowed apically and truncate ( Fig. 646 ). Row of hairs near inner margin absent on fore and middle femora, sparse on hind femur.

Fore tibia ( Fig. 647 ): outer hairs form two irregular rows; inner-anterior row of recurved hairs absent; inneranterior row of stout setae represented by few (2–3) stout blunt setae in proximal part of tibia; inner field of stout pointed setae consists of pointed smooth setae, situated irregularly, 1–2 setae in cross section.

Hind tibia ( Figs 648–649 ): outer-anterior and outer-posterior rows of stout setae consist of blunt stout setae of various lengths and long spoon-like stout setae; posterior hairs located between these rows form more than one row (besides row of hairs posteriad of outer-posterior row of stout setae); stout setae of inner-anterior row elongate, arched, narrowed distally and blunt.

Claws with 4–5 denticles on rigid portion, often without denticles on articulatory portion.

Tergalii ( Fig. 637 ): wide, but with few side trachea; dorsal lamella oval, widest in distal part, apically abruptly turned to slender apical filament; ventral lamella widest near base, gradually narrowed toward apex, with slender apical filament, with main trachea arched repeating outline of anal margin.

Subimago, imago, eggs. Unknown.

Discussion. By cuticular coloration of larval femora and structure of tergalii this species resembles Th. alboniger sp. n., but clearly differs from Th. alboniger by structure of labrum and absence of contrasting blanks on abdominal terga.

Figures

FIGURES 637–649. Thraulodes sp. «Itaya», larva. 637, tergalius III; 638–645, larval exuviae at the same magnification: 638, part of head with labrum; 639–640, left and right mandibles; 641, right half of pronotum and mesonotum; 642–644, fore, middle and hind legs; 645, abdominal terga and sterna; 646, anterior side of hind femur; 647, anterior side of fore tibia; 648, hind tibia with focus on outer-posterior row of stout setae; 649, the same with focus on outer-anterior and inner-anterior rows of stout setae.

FIGURES 650–653. Thraulodes sp. «Itaya», labrum. 650, general view; 651, focus on ventral side and six sensilla (shown by arrows); 652, with focus on anterior transverse setal row (transformed to field of irregularly situated setae); 653, with focus on posterior transverse setal row.