Thraulus (Masharikella) sp. B

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

Thraulus (Masharikella) sp. B

Fig. 33

Material examined.

• Indonesia, Papua, one nymph on slide, Road Nabire – Enarotali KM 52 , 555 m, 23.X.2011, 03°30.107'S, 135°42.971'E, M. Balke col [PAP 17], GBIFCH 01223123 ( MZL) .

Diagnosis.

Nymph. Labrum width smaller than clypeus width; proximal row of setae on dorsal face of labrum with <30 setae; ventral side of labrum with scattered stout setae; maxillary palp segment III ~ 1.7 × as long as base width; posterior margin of abdominal segment VIII with minute denticles; posterolateral projections on the abdomen present on segments VII – IX.

Description.

Head. Labrum cordiform (Fig. 33 A ). Ratio labrum width / clypeus width 0.95. Ratio labrum width / insertion width 1.33. Medial emargination shallow with flat denticles. Proximal row of setae present simple. Number of setae on proximal row 23. Distal row of setae present, simple. Median part of labrum in ventral view with only scattered stout setae (Fig. 33 B ). Mandibles. Outer margin with middle and distal tuft of setae. Right mandible with 11 setae below the mola (Fig. 33 C ). Maxillae. Posterior margin of cardo with few hair-like setae. Proximo-lateral margin of stipes with two long and two short stout setae. Apical-ventral row with 24 pectinate setae. Maxillary palp segment II 0.78 as long as segment I. Maxillary palp segment III 0.74 as long as segment I (Fig. 33 D ). Stout setae on outer margin of segment I absent. Segment II inner margin with three stout setae. Segment II outer margin with four stout setae. Segment III inner margin with three stout setae, dorsal surface with few setae at apex. Segment III 1.70 × as long as base width. Labium. Labial palp segment II 0.71 as long as segment I. Labial palp segment III 0.90 as long as segment I (Fig. 33 E ). Segment I inner margin with seven stout setae, outer margin with ten stout setae. Segment II outer margin with one stout seta. Segment III dorsal face with five stout setae. Segment III 3.00 × as long as base width. Hypopharynx. Apex of superlingua emarginated (Fig. 33 F ).

Abdomen. Gill I dorsal lamella narrow and lanceolate, ventral lamella shaped as other gills. Gill I with ~ 18 filaments. Posterior margin of terga IX with denticles. Posterior margin of terga VII – VIII with minute denticles. Posterior margin of terga V – VI without denticles. Posterolateral projections present on segments VII – IX.

Figures

Figure 33. Thraulus (Masharikella) sp. B. 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).