Neoperla serrula Zwick & Zwick 2023, n. sp.

5. Neoperla serrula n. sp.

(Figs. 15, 25)

Type material: Republic of Ghana, Holotype ♀ (NEOP010), paratype ♁ (NEOP009):, Volta region, Agumatsa waterfalls, Wli, [0.56°N, 12.86°E, 484m], St. 10, 19.11.1993, Kjaerendsen, light trap (ZMBN). 4♀ paratypes with the same data (ZMBN, PZ). 1♀ paratype, Republic of Ghana, Western Region, Ankasa Game Prod. Reserve 16.12.83 J.Kjaerandsen & T. Andersen [Ankasa Game Reserve, 5.25N, - 2.57W] (ZMBN).

Additional material studied. 1♀, Republic of Cameroon, Makak [3.55, 11.02], 11.–16.XI.72, blacklight, Gruwell (USNM, Washington).

Habitus. Indistinguishable from N. costata.

Male (Fig. 15). Externally as for the transvaalensis -group. Penis (Fig. 15) slender, tube relatively strongly sclerotised, also ventrally. Everted endophallus curving ventrad, widening distally until it is about twice as wide as the penis tube, the narrower distal fourth of endophallus points caudad. The armature is composed of slender triangular teeth which form a continuous dorsal band from base to tip. On the widest section of endophallus the spine band is expanded while the ventral side is bare. Terminal section of endophallus narrow surrounded by long spines.

Female. S8 with a very short truncate subgenital plate. Vagina unmodified, no supporting sclerites, dorsally without large folds. SSt strongly curved, pale minute denticles form a narrow band near the thick cuticle of the convex side, from the base to near midlength.

Egg (Fig. 25). 455*215µm, widest near middle, sides converging little towards the conical operculum but much towards the long, distally widening collar (Fig. 25). At the base of the conical operculum the profile has a distinct shoulder. The approximately 12 straight ridges are very high where the egg is widest, lowering towards the collar where they are connected to the high walls of large cells. Operculum and floor of sulci with irregular large rough punctures extending far up on the sides of ridges, their edge appears in side view like a regular saw (detail in Fig. 25). Anchor mushroom-shaped.

DNA (Figs. 491–493). Only the female holotype and a male paratype from Ghana were sequenced for the COX1 DNA barcode fragment, which does not differ between the two specimens. The species is placed as sister to N. spectabilis n. sp., N. kalengonis n. sp., N. lujan a Navás, and N. transvaalensis (Enderlein), but while a close relationship is moderately supported (88.9/76/93), the placement as sister taxon lacks significant statistical support (33.6/56/4).

Etymology. The name is a noun in apposition alluding to the egg ridges which resemble a small fine saw, Latin serrula.