Kosminympha Sartori & Salles, 2025

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

Kosminympha Sartori & Salles gen. nov.

Diagnosis.

Gill I similar in shape to the following ones. Ventral lamella of gills smaller but not highly reduced, with ≥ 9 processes; claws with 6–10 teeth; posterior margin of abdominal segment VIII with small denticles; posterolateral expansions on abdominal segments VII – IX, VI – IX or even V – IX. Eggs fusiform with hook-like attachment structures at each pole.

Derivatio nominis.

From the greek κόσμημα meaning jewel and νύμφη meaning nymph, to recognise the peculiar beauty of the species in this genus. The gender is feminine.

Type species.

Kosminympha sabrinae sp. nov. by present designation.

Species included.

Kosminympha asarorum sp. nov., K. balkei sp. nov., K. baruya sp. nov., K. kalamorum sp. nov., K. paulinae sp. nov., K. sabrinae sp. nov.

Description.

Size: 10.0–11.0 mm for male mature nymphs; 10.5–12.5 mm for mature female nymphs.

Head. Prognathous; labrum cordiform or trapezoid, anterior emargination either shallow with flat denticles or narrow with pointed denticles; proximal row of setae long, with 80–140 setae; distal row of setae multiple; median part of labrum in ventral view with scattered thin and long setae or with stout and short setae in a row. Outer margin of mandibles with a row of setae. Proximo-lateral margin of stipes with a bunch of setae, either long and thin or short and stout. Apex of superlingua of hypopharynx either truncate or emarginate. Thorax. Central area of upper face of femora with numerous short or long, pointed, or blunt setae; tarsal claw hooked, with 6–10 teeth. Abdomen. Gill I similar in shape to the following ones; gill I composed of dorsal and ventral lamellae, each with 9–15 filaments; gills II – VI composed of dorsal and ventral lamellae, each with 15–25 filaments; gill VII composed of dorsal and ventral lamellae, each with 5–15 filaments, depending on species. Posterior margin of abdominal terga II – VIII without or with minute denticles; posterolateral expansions of the abdomen present on segments V – IX, VI – IX or VII – IX. Egg. Elongated, with attachments structures fixed at each pole, composed of a long branch ending by a double fishhook.

Affinities.

Among mayfly nymphs of the subfamily Choroterpinae and of the tribe Thraulini , the genus Kosminympha is most similar to Nonnullidens by its gill composition. It differs anyway by the less reduced gill ventral lamella, bearing ≥ nine filaments whereas in Nonnullidens , ventral lamella bears at most eight filaments (in N. mariae , it can also reach ten filaments). Posterolateral projections of the abdomen are present on segments V – IX, VI – IX or VII – IX, whereas they are present on segments VIII – IX in Nonnullidens (VII – IX in some species). Posterior margin of tergite VIII always bears small denticles, whereas they are absent in Nonnullidens (present and well-developed in N. mariae ). Finally, the eggs of Kosminympha are similar in shape to those of the genus Thraulus , being elongated and bearing attachment structures at each pole, whereas they are rounded and without attachment structure in Nonnullidens .

Distribution.

The genus Kosminympha is only known from Papua New Guinea and has been found on the eastern part of the island; the genus has yet not been recorded from Indonesia Papua.