Thraulus (Thraulus) nabire, Sartori & Salles, 2025

Sartori, Michel & Salles, Frederico F., 2025, The Leptophlebiidae of New Guinea (Ephemeroptera, Choroterpinae, Thraulini), ZooKeys 1245, pp. 41-175 : 41-175

Thraulus (Thraulus) nabire sp. nov.

Figs 9 , 10

Material examined.

Holotype. • Indonesia, Papua, nymph on slide, Road Nabire-Enarotali KM 62 , 340 m, 22.X.2011, 03°31.684'S, 135°42.802'E, M. Balke col [PAP 11], GBIFCH 01223096 ( MZB) . Paratypes. • Indonesia, Papua, 1 nymph in ethanol, GBIFCH 01523574 , 1 nymph mounted on slide, GBIFCH 01223097 , same data as holotype ( MZL) .

Nymph.

Body length, male: 4.5 mm.

Diagnosis.

Labrum cordiform, medial emargination shallow with flat denticles; median part of labrum in ventral view with stout setae in a row; proximal row of setae on dorsal face of labrum with 19–23 setae; apical ventral row of maxilla composed of 15–17 pectinate setae; tarsal claw with eight or nine teeth, distal one much larger; gill lamellae on segments II – VI fringed only on distal half, with <20 filaments on each.

Colouration.

Head. Greyish brown, clypeus medium brown. Antenna yellowish. Compound eye lower portion black, upper portion brownish red. Mouth parts pale brown, labrum and mandibles medium brown. Thorax. Pronotum yellowish brown, greyish brown on edges and in the middle. Mesonotum pale brown, washed with greyish maculae. Femur whitish with distal 1 / 3 greyish. Tibia yellowish. Tarsi yellowish. Abdomen. Terga: segments II – VIII medium brown, posterior 1 / 3 dark brown, segment IX – X medium brown. Sterna greyish brown, posterior 1 / 3 medium brown. Gills greyish brown to greyish purple. Terminal filaments broken.

Description.

Head. Labrum cordiform (Fig. 9 A ). Ratio labrum width / clypeus width 0.81–0.90. Ratio labrum width / insertion width 1.15–1.26. Medial emargination shallow with flat denticles. Proximal row of setae present simple. Number of setae on proximal row ~ 19–23. Distal row of setae present, simple. Median part of labrum in ventral view with stout setae in row (Fig. 9 B ). Mandibles. Outer margin with middle and distal tuft of setae. Right mandible with eight to nine setae below the mola (Fig. 9 C ). Maxillae. Posterior margin of cardo with few hair-like setae and one or two stout and long setae in submarginal position. Proximo-lateral margin of stipes with a single long and stout seta. Apical-ventral row with 15–17 pectinate setae. Maxillary palp segment II 0.88–0.90 as long as segment I. Maxillary palp segment III 0.76–0.85 as long as segment I (Fig. 9 D ). Stout setae on outer margin of segment I absent. Segment II inner margin with three or four stout setae. Segment II outer margin with 3–5 stout setae. Segment III inner margin with 2–4 stout setae. Segment III 1.86–2.00 × as long as base width. Labium. Labial palp segment II 0.78–0.81 as long as segment I. Labial palp segment III 0.69–0.74 as long as segment I (Fig. 9 E ). Segment I inner margin with 8–13 stout setae, outer margin with nine stout setae. Segment II outer margin with three or four stout setae. Segment III dorsal face with four or five stout setae. Segment III 2.86–3.29 × as long as base width. Hypopharynx. Apex of superlingua somewhat pointed (Fig. 9 F ).

Thorax. Dorsal margin of femur with a row of long, stout, pointed setae; submarginal row with long setae decreasing in size towards apex (Fig. 10 A ); ventral margin with short and stout setae and a submarginal row of long and pointed stout setae, except on hind leg where those on ventral margin are short and blunt (Fig. 10 B ); central area of upper surface with few long and pointed setae. Fore tibia with several rows of numerous mostly feathered setae on ventral margin; outer margin of fore tibia with few hair-like setae; middle tibia with two rows of long and simple or feathered, pointed setae on ventral margin, outer margin with numerous hair-like setae; hind tibia with a row of simple short thin setae on ventral margin, upper and lower surfaces covered with simple and feathered setae, outer margin with short and long, pointed, stout setae. Tarsal claw hooked with eight or nine denticles progressively larger, except distal one much larger (Fig. 10 C ).

Abdomen. Gill I with single bifid lamella. Gills II – VII with dorsal and ventral lamellae, dorsal lamella smaller. Gill II – VI with upper lamella lacking filaments on basal half of outer margin, with <20 short filaments, lower lamella with <20 short filaments (Fig. 10 D ). Posterior margin of terga IX with denticles. Posterior margin of terga VIII without denticles, or with minute denticles. Posterior margin of terga V – VII without denticles. Posterolateral projections present on segments VI – IX.

Derivatio nominis.

This species is named after the district of Nabire where it can be found and is a noun in apposition.

Figures

Figure 9. Thraulus (Thraulus) nabire sp. nov. nymphal mouthparts. A. Labrum, dorsal view; B. Emargination of the labrum; C. Right mandible; D. Maxilla; E. Labium; F. Superlingua of hypopharynx. Scale bars: 100 µm (A, C, E, F); 50 µm (B); 200 µm (D).

Figure 10. Thraulus (Thraulus) nabire sp. nov. thorax and abdomen. A. Fore femur; B. Hind femur; C. Claw; D. Gill IV. Scale bars: 200 µm (A, B); 100 µm (C).