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 : 131-133

19. Thraulodes sp. «Palo Seco»

( Figs 613–636 )

Material examined. PANAMA, Provincia de Bocas del Toro, bosque protector Palo Seco: Altos del Valle , Rio Buris (8°47’37’’N, 82°11’35’’W), 24–28.I.2018, coll. N. Kluge, L. Sheyko: 5 larvae.

Descriptions.

Larva. CUTICULAR COLORATION. Dorsal side of head, thorax and abdomen mostly brown with few blanks: pronotum bordered by light laterally; fore protoptera with longitudinal veins slightly darker than background ( Fig. 617 ); abdominal terga with blanks on lateral parts, area mediad of tergalii attachments on most terga nearly unicolorous brown; terga IV–V (or at least tergum V) with blank medially, terga VIII–X vary from mostly brown with median or submedian blanks ( Fig. 617 ) to nearly entirely light ( Fig. 616 ). Femora brown, with longitudinal blanks; tibiae and tarsi uniformly light brownish.

HYPODERMAL COLORATION. Abdominal terga with posterior margins narrowly bordered by blackish, without other hypodermal markings. Tergalii gray, tracheae black ( Figs 627–633 ).

SHAPE AND SETATION. Clypeus slightly widened distally; labrum 1.15–1.25 times wider than clypeus ( Fig. 613 ). Labrum sharply widened, widest at 1/3 length from base, with lateral sides angulate; fore margin (often turned ventrally), without median emargination, with all 5 denticles wide; anterior transverse setal row regular (as in Fig. 88 ), as wide as all 5 denticles; fine, irregularly situated setae on ventral side of labrum near anterior margin longer and denser than in other species. Mandibles with outer margin angulate ( Figs 614–615 ). Maxilla with 18 pectinate setae in apical-ventral row.

Femora: Stout setae on anterior surface narrowed distally, apically truncated or pointed ( Figs 625 ). Irregular row of hairs near inner margin present on all femora.

Fore tibia ( Figs 621–622 ): outer hairs form two dense stripes of irregularly situated hairs; inner-anterior row of recurved hairs present on proximal 1/4 of tibia; inner-anterior row of stout setae represented by few (4–5) stout blunt setae in proximal 1/3 of tibia; inner field of stout pointed setae reduced: its setae as parse and small as on middle and hind legs, only near apex of tibia longer and dense setae of this row present, including subapical inner-posterior row of arched pointed setae.

Hind tibia ( Figs 623–624 ): each of three rows of stout setae—outer-anterior, outer-posterior and inner-anterior ones—consists of stout setae of various lengths, all narrowed distally, apically pointed or truncated; hairs located between outer-anterior and outer-posterior rows, dense and form more than one row; hairs posteriad of outer-posterior row of stout setae dense and partly form irregular row.

Claws with 6–7 denticles on rigid portion, with several minute denticles on articulatory portion.

Tergalii ( Figs 627–633 ): wide; on both lamellae main trachea with many branches directed toward costal and anal margins; dorsal lamella with anal margin most convex in distal part, sharply narrowed toward apex, with short slender apical filament; ventral lamella widest near base, gradually narrowed toward apex, with short slender apical filament.

Male genitalia in last larval instar ( Figs 634–636 ): protogonostyli separated one from another by moderately deep emargination. Each protopenes lobe with gonopore-bearing process short and located near median margin; gonopore opened caudally-laterally.

Subimago and imago. Unknown. Judging by hypodermal coloration of legs of mature larvae, in winged stages fore leg has blackish hypodermal pigmentation on inner-distal part of femur and on apex of tibia ( Fig. 621 ), while middle and hind legs either have no such pigmentation, or have such pigmentation worse developed. Judging by venation and hypodermal pigmentation of last instar larval protoptera, in winged stages fore wing with well-developed cross veins in all fields, including costal field proximad of bulla; pterostigmatic cross veins dense, perpendicular to longitudinal veins and partly anastomozed ( Fig. 618 ); fore wing with brown macula on base of Sc near costal brace ( Fig. 620 ); hind wing with larger brown macula on area of costal brace ( Figs 619 , 626 ). Judging by hypodermal coloration of larval abdomen, winged stages have no pronounced midway spots on abdominal terga.

Eggs. Unknown.

Dimension. Length of mature larva 9 mm.

Comments. Larva described here, differs from other species by greater widened labrum and angulate mandibles ( Figs 613–615 ). Among larvae described here from Panama, only this species has wide tergalii with well developed tracheal branches (the same in some South American species). This larva cannot belong to the sympatric species Th. viviparus sp. n. (whose imagines were not reared from larvae), because Th. viviparus sp. n. has very thin costal cross veins on fore wing, while larval protoptera of Th. sp. «Palo Seco» has these veins as wide as the others. Among species, reported from mountains of western Panama, whose larvae remain to be non-associated with imagines, these larvae could belong to Thraulodes valens ( Eaton 1892) : this species has well developed costal cross veins proximad of bulla, pterostigmatic cross veins transverse and anastomosed ( Ulmer 1943: fig. 48a) and black hypodermal markings of femora, apices of tibiae and bases of fore and hind wings. The same transverse and anastomosed pterostigmatic cross veins are present in Th. irretitus Navás 1924 described as imago from neighboring Costa Rica; description of Th. irretitus is incomplete and does not allow us to recognize this species.

Figures

FIGURES 613–625. Thraulodes sp. «Palo Seco», larva. 613, clypeus and labrum; 614–615, left and right mandibles; 616–617, larvae with brown cuticular coloration and blackish hypodermal markings; 618, fragment of fore protopteron with venation of pterostigma; 619, hind protopteron; 620, fore protopteron; 621, fore tibia with dark brown hypodermal marking; 622, anterior side of fore tibia; 623, hind tibia with focus on outer-posterior row of stout setae; 624, the same with focus on outer-anterior and inner-anterior rows of stout setae; 625, anterior side of hind femur.

FIGURES 626–636. Thraulodes sp. «Palo Seco», larva. 626, hind protopteron; 627–633, tergalii I–VII; 634–635, protogono- styli and protopenis at the same magnification; 636, protopenis enlarged.

FIGURES 86–93. Thraulodes telegraphicus. 86, median longitudinal section of labrum in usual condition; 87, the same, in spread condition; 88, labrum in spread condition in dorsal view (setal rows shown as dotted lines); 89, transverse section of hind tibia; 90–93, tergalii I, III, VI and VII. Abbreviations: anter.r, anterior transverse row of setae; dent., five denticles separated by six sensilla; poster.r, posterior transverse row of setae; i.f, inner field of stout pointed setae; i-a.h, inner-anterior recurved hairs; i-a.r, inner-anterior row of stout setae; o-a.r, outer-anterior row of stout setae; o.h, outer hairs; o-p.r, outer-posterior row of stout setae; p.r, row of posterior pointed pectinate setae.