Nonnullidens silvaepumilorum, Sartori & Salles, 2025

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

Nonnullidens silvaepumilorum sp. nov.

Figs 54 , 55

Material examined.

Holotype. • Papua New Guinea, one nymph on slide, Madang Province, Aiome area 130 m, 11.III.2007, 05°10.593'S, 144°42.800'E, Kinibel col [PNG 156], GBIFCH 01223146 ( ZSM) . Paratype. • Papua New Guinea, one nymph in ethanol, GBIFCH 01523470 , same data as holotype ( MZL) .

Nymph.

Body length, female: 5 mm.

Diagnosis.

Median emargination of labrum shallow with flat denticles; ventral surface of labrum with stout setae in row; femora pale brown with two transverse dark brown bands in middle and at apex; posterolateral expansions present on segments VII – IX.

Colouration.

Head. Medium brown, washed with greyish brown between ocelli, pale brown between lateral ocelli and compound eyes, occiput with pale brown vermiform maculae around the sagittal line, clypeus dark brown. Antenna broken. Mouth parts pale brown. Thorax. Pronotum pale brown, dark brown anteriorly and laterally, as well as along the sagittal line. Mesonotum pale brown, washed with dark brown laterally and along the distal half of the sagittal line, fore wing pads medium brown, with a dark brown spot at the base. Femur pale brown, with a large medium brown band in the middle and at apex. Tibia yellowish, with a dark brown ring at apex. Tarsi yellowish to pale brown. Abdomen. Terga segments I and II entirely dark brown, segments III and IV medium brown with a dark brown macula in anteromedian position, this macula with a light brown longitudinal line on segments V – VII, segments VII – X dark brown. Sterna yellowish grey, segments III – VI with a dark brown macula in anteromedian position. Gills pale grey, tinted with purple. Terminal filaments broken.

Description.

Head. Labrum cordiform (Fig. 54 A ). Ratio labrum width / clypeus width 0.95. Medial emargination shallow with flat denticles. Proximal row of setae present, simple. Number of setae on proximal row ~ 22. Distal row of setae present, simple. Median part of labrum in ventral view with stout setae in row (Fig. 54 B ). Mandibles. Outer margin with row of setae on distal 1 / 2. Ending of the row near incisor. Right mandible with eight setae below the mola (Fig. 54 C ). Maxillae. Posterior margin of cardo broken. Proximo-lateral margin of stipes with one long and stout seta. Apical-ventral row with 16 pectinate setae. Maxillary palp segment II 0.84 as long as segment I. Maxillary palp segment III 0.67 as long as segment I (Fig. 54 D ). Stout setae on outer margin of segment I absent. Segment II inner margin with four stout setae, outer margin with four stout setae. Segment III inner margin with four stout setae, dorsal surface with few setae at apex. Segment III 1.64 × as long as base width. Labium. Labial palp segment II 0.94 as long as segment I. Labial palp segment III 0.82 as long as segment I (Fig. 54 E ). Segment I inner margin with 14 stout setae, outer margin with 13 stout setae. Segment II outer margin with seven stout setae. Segment III dorsal face with six stout setae. Segment III 3.11 × as long as base width. Hypopharynx. Apex of superlingua truncate (Fig. 54 F ).

Thorax. Dorsal margin of fore femur with long, stout, pointed setae, and a submarginal row of long, stout, pointed setae; dorsal margin of mid- and hind femur with a row of long, stout, pointed setae; a submarginal row of pointed setae as long as or a little bit shorter than those on the dorsal margin; ventral margin with short, stout setae and an irregular submarginal row of long, pointed stout setae, except on hind leg where those on ventral margin are shorter; central area of upper surface with few short or long stout and pointed setae (Fig. 55 A – B ). Fore tibia with two or three rows of long simple or feathered setae on ventral margin, dorsal margin with numerous hair-like setae; middle tibia with two rows of long, simple, pointed setae on ventral margin, outer margin with numerous hair-like setae; hind tibia with two rows of simple and feathered long, stout setae on ventral margin, outer margin with a row of long and short simple stout setae, with numerous hair-like setae. Tarsal claw hooked with 4–6 denticles progressively larger apically (Fig. 55 C ).

Abdomen. Gill I with both lamellae. Gills II – VII with dorsal and ventral lamellae of the same size. Gills very small, gill I with five or six filaments on each lamella, gills II – VI with 7–10 filaments on each lamella (Fig. 55 D ). Posterior margin of terga IX with denticles. Posterior margin of terga VIII without or with minute denticles. Posterior margin of terga V – VII without denticles. Posterolateral projections present on segments VII – IX.

Derivatio nominis.

The species name is a Latin word composed of silva (forest) and pumilo (dwarf) to recognise the Melanesian Dwarf tribe of Aiome, and the land where the specimens of this new species come from.

Figures

Figure 54. Nonnullidens silvaepumilorum 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, F); 50 µm (B); 200 µm (C – E).

Figure 55. Nonnullidens silvaepumilorum 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).