Nonnullidens anga, 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 anga sp. nov.

Figs 35 A , 39 , 40

Material examined.

Holotype. • Papua New Guinea, one nymph on slide, Morobe Province, Menyamya, Mt Inji , 1700 m, 14.XI.2006, approx. 07°14.813'S, 146°01.330'E, M. Balke & Kinibel col [PNG 96], GBIFCH 01223129 ( ZSM) . Paratype. • Papua New Guinea, one nymph in ethanol, GBIFCH 01523458 , same data as holotype ( MZL) .

Nymph.

Body length, female: 4.8 mm.

Diagnosis.

Labrum cordiform; dorsal face of labrum with proximal and distal rows multiple; femora pale brown with two transverse dark brown bands in middle and at apex; gill I with ventral lamella composed of a single filament; gill II – VI with six or seven filaments on dorsal lamella and two or three on ventral lamella; gill VII with four or five filaments on dorsal lamella and a single one on ventral lamella.

Colouration.

Head. Vertex greyish brown, with characteristic yellowish maculae posteriorly, frons greyish brown with a middle pale brown oval macula. Antenna: scape greyish, pedicel and flagellum broken. Mouth parts pale brown. Thorax. Pronotum pale brown, washed with medium brown laterally and medio-anteriorly. Mesonotum pale brown, washed with medium brown as in Fig. 35 A . Femur yellowish brown, with a large median greyish brown stripe and another one at apex. Tibia yellowish. Tarsi pale brown. Abdomen. Terga dark brown, segments VII – X somewhat lighter, pale brown along the sagittal line. Sterna yellowish grey, yellowish on lateral margins. Gills greyish brown. Terminal filaments yellowish, basally yellowish brown.

Description.

Head. Labrum cordiform (Fig. 39 A ). Ratio labrum width / clypeus width 1.05. Ratio labrum width / insertion width 1.36. Medial emargination narrow with flat denticles. Proximal row of setae present, multiple. Number of setae on proximal row ~ 104. Distal row of setae multiple. Median part of labrum in ventral view with scattered thin setae (Fig. 39 B ). Mandibles. Outer margin with row of setae on distal 1 / 2. Ending of the row near incisor. Right mandible with seven setae below the mola (Fig. 39 C ). Maxillae. Posterior margin of cardo with many long hair-like setae. Proximo-lateral margin of stipes twisted. Apical-ventral row with 23 pectinate setae. Maxillary palp segment II 0.88 as long as segment I. Maxillary palp segment III 0.68 as long as segment I (Fig. 39 D ). Stout setae on outer margin of segment I absent. Segment III dorsal surface half covered with setae. Segment III 1.55 × as long as base width. Labium. Labial palp segment II 0.82 as long as segment I. Labial palp segment III 0.71 as long as segment I (Fig. 39 E ). Segment I inner margin with nine stout setae, outer margin with 14 stout setae. Segment II outer margin with four stout setae. Segment III dorsal face with four stout setae. Segment III 2.67 × as long as base width. Hypopharynx. Apex of superlingua truncate.

Thorax. Dorsal margin of femur with a row of very long, thin, pointed setae; regular submarginal row of pointed setae as long as those on the dorsal margin; ventral margin with relatively long, pointed setae and an irregular submarginal row of long, pointed thin setae (Fig. 40 A – B ); central area of upper surface with very long pointed setae, as long as those on the dorsal margin. Fore tibia with two or three rows of long simple or feathered setae on ventral margin, dorsal margin with few hair-like setae; middle tibia with a row of short, simple, pointed setae on ventral margin and a submarginal row of long, simple setae, outer margin with numerous hair-like setae; hind tibia with a marginal row of simple short, thin setae and a submarginal row of long to very long setae on ventral margin, outer margin with long to very long pointed setae and hair-like setae (Fig. 40 C ). Tarsal claw hooked with three or four denticles progressively larger, except distal much larger.

Abdomen. Gill I with both lamellae. Gills II – VII with dorsal and ventral lamellae, ventral lamella smaller. Gill I with three filaments on dorsal lamella, ventral lamella with a single filament (Fig. 40 E ); gill II – VI with six or seven filaments on dorsal lamella and two or three on ventral lamella (Fig. 40 F ); gill VII with four or five filaments on dorsal lamella and a single one on ventral lamella (Fig. 40 G ). Posterior margin of terga IX with minute denticles (Fig. 40 D ). Posterior margin of terga V – VIII without denticles. Posterolateral projections present on segments VIII – IX.

Derivatio nominis.

The specific name is to recognize the Anga people who live in the area where the new species has been found and is a noun in apposition.

Figures

Figure 35. Habitus of Nonnullidens anga sp. nov. (A), Nonnullidens fuyugensis sp. nov. (B) and Nonnullidens cozzarolae sp. nov. (C). Scale bars: 1 mm.

Figure 39. Nonnullidens anga sp. nov. nymphal mouthparts. A. Labrum, dorsal view; B. Emargination of the labrum; C. Right mandible; D. Maxilla; E. Labium. Scale bars: 100 µm (A, C, E); 50 µm (B); 200 µm (D).

Figure 40. Nonnullidens anga sp. nov. thorax and abdomen. A. Fore femur; B. Hind femur; C. Detail of hind tibia; D. Posterior margin of tergite IX; E. Gill I; F. Gill IV; G. Gill VII. Scale bars: 100 µm (A – C); 50 µm (D).