Derlethina Sartori, 2008

Sartori, Michel, Peters, Janice G. & Hubbard, Michael D., 2008, A revision of Oriental Teloganodidae (Insecta, Ephemeroptera, Ephemerelloidea), Zootaxa 1957 (1), pp. 1-51 : 44

Derlethina Sartori gen. nov.

Type species: Derlethina eloisae Sartori sp. nov. by present designation

Teloganodes sp. sensu McCafferty & Wang (1997)

Teloganodes sp. T3 sensu Kluge (2004)

eloisae

Description. Adult: Forewing ( Fig. 14 ) long and slender, posterior margin regularly convex. Pterostigmatic area without crossveins; vein MP 2 very short, and free; cubital field with 2 intercalary veins. Hind wing ( Fig. 15 ) minute with costal process acute and located almost at apex of wing; a single simple longitudinal vein. Claws of all legs dissimilar. Dorsal margin of hind femora concave. Subanal plate of female almost straight. Gill socket vestiges visible on segments II–IV. Terminal filament absent.

Nymph ( Fig. 147 ): Body flattened, eyes in dorsal position blackish in male nymphs; outer margin of head fringed with a row of forked setae from behind eyes to labrum insertion. Labrum with a single row of simple setae ( Fig. 24 ). Galea-lacinia with 2 setae on ventral side ( Fig. 46 ). Forefemora broad and dilated with a transverse row of setae on dorsal face (Fig. 75). Hind femora with a distinct concave outer margin ( Fig. 147 ). Gills on abdominal segments II–IV (Figs. 95–97); gills II–III with ventral lobes, gill IV without ventral lobe and entire (not incised), gill III incised. Abdominal carina (median tubercles on terga), poorly developed. Posterolateral expansions very well developed on segments VI–IX. Lateral margins of terga with very long and thin setae. Terminal filament absent.

Egg: rounded, chorion without attachment structures, one polar cap, no triangular or polygonal structures at the base of the cap ( Figs. 115–119 ).

Diagnosis. Derlethina winged stages can easily be told from Teloganodes and Dudgeodes by the shape of the hindwing, the absence of crossvein in the pterostigmatic area of the forewing, and the shape of the hind femur; the nymphal stage is distinguished by the absence of gill V and the shape of the posterior femora.

Etymology. This new genus is named after Dr Pascale Derleth (Lausanne), wife of the first author, who collected most of the material during her work in East Kalimantan, and was the first to recognize it as a separate genus. The gender is feminine.

Distribution. Known only from Borneo (East Malaysia – Sabah - and Indonesia – East Kalimantan)

Figures

FIGURES 14–15. Derlethina eloisae. Fig. 14: Forewing; Fig. 15: Hindwing.

FIGURES 144–149. Holotypes of Dudgeodes and Derlethina in dorsal view (144, 147), abdomen in ventral view (145, 148) and in lateral view (146, 149). Figs. 144–146: Dudgeodes celebensis; Figs. 147–149: Derlethina eloisae

FIGURES 16–25. Labrum (16, 18, 20, 22, 24), with details of the dorsal setae (17, 19, 21, 23, 25), of Oriental Teloganodidae. Insertion of the setae indicated by dots on the labrum. Figs. 16–17: Teloganodes tuberculatus; Figs. 18–19: T. hubbardi; Figs. 20–21: T. jacobusi; Figs. 22–23: Dudgeodes hutanis; Figs. 24–25: Derlethina eloisae. All labra at same scale and all setae at same scale, two times enlarged compared to the labra.

FIGURES 40–46. Maxillae (40, 41) and detail of the setae on the apico-ventral part (42–46) of Oriental Teloganodidae. Fig. 40: Teloganodes tuberculatus; Fig. 41: Dudgeodes hutanis; Fig. 42: T. jacobusi; Fig. 43: T. kodai; Fig. 44: D. pescadori; Fig. 45: D. ulmeri; Fig. 46: Derlethina eloisae.

FIGURES 115–119. Egg structure of Derlethina eloisae (SEM pictures). Fig. 115: Shape of the egg; Fig. 116: Detail of the polar cap; Fig. 117: Detail of the coiled threads of the epithema; Fig. 118: Detail of the different chorionic structures; Fig. 119: Micropyle area.