Neoperla dolium, Zwick & Zwick, 2023

Zwick, Peter & Zwick, Andreas, 2023, Revision of the African Neoperla Needham, 1905 (Plecoptera: Perlidae: Perlinae) based on morphological and molecular data, Zootaxa 5316 (1), pp. 1-194 : 150-153

72. Neoperla dolium n. sp.

( Figs. 407–417 )

Type material. Holotype ♀, 4°51'42.89''N, 9°38'21.17'' E, Republic of Cameroon, SW Region, Tumbel , Ngusi, Etambo River, 490m asl, 23.Oct.2011, MV-lamp ( NEOP296 , body + slide), 1 paratype ♀ (slide and fragments of abdomen), 1 presumed ♁ (tip of abdomen in microvial, penis on slide, all A.Zwick & D.Bartsch, SMNS)).

Additional paratypes: 1 ♀, mis-associated paralectotype of N. camerunensis (End.) : Ochthopetina camerunensis Enderl. Type ♀ [in Enderlein’s hand] det. Dr. Enderlein [print] \ Kamerun Barombi Conradt \ Co-Typus [print, yellow paper] \ Mus. Zool. Polonicum Warszawa 12/45 \ Mus. Zool. Polonicum Warszawa Typus n. 1297 Ochthopetina camerunensis Enderlein 1909 Paralectotypus [red label]; ( MIZ; pinned genitalia and egg slide on Zelluloid on the specimen pin; slide with eggs from same individual, made by P. Zwick in 1973, also in SMNS). 2♀ paratypes, Muyuka [4°43'18''N, 9°38'27''E; 305m], Victoria Div., Brit Cameroons,VI-25-49 B.Malkin at Light (in alcohol; MfNB).

Habitus. WL 9–13mm. General colour light ochre, wings slightly infuscate and turbid. Frontoclypeus in front of occipital suture with vague brownish tinge, occiput and a strip along inner edge of eye paler than rest. Ocellar spot sometimes with an anterior point. Thoracic nota with grey tinge. Antenna light, cercus dark, legs light ochre.

Male (presumed). T7 with a long and narrow pyramidal process. The median sclerite on T8 is wide in front and bears a narrow but strongly raised process near midlength. In dorsal view it is hidden under the process of T7, in side view the two processes almost meet, there is only a narrow gap between them ( Figs. 413, 414 ). T9 with the usual lateral humps and median furrow, otherwise unmodified. Base of HT10 curved and with long pilosity, basomedial callus parabolic, the forward-directed tip of HT10 slender, concave in dorsal, straight in lateral view. Epiproct with sharp tip ( Figs. 413–417 ).

The straight penis ( Figs. 415–417 ) is slender, the apical dorsal swelling is large, beset with sharp spines pointing towards the base. A bare section ( Fig. 416 , bs) separates the spines from numerous transverse scales on the wide endophallus base. The endophallus is about twice as long as the tube, its basal third with slender teeth. The non-everted distal part of the endophallus is well visible by transparency and the narrow recurrent inner tube which contains sharply pointed conical teeth, distally over a long stretch in two regular rows, can be followed to near the basal penis opening.

Female ( Fig. 407 ). S8 pale, median area slightly sclerotised, antecosta concave in middle, caudal edge with a wide shallow notch. Vagina distinctly longer than S8, slender, waisted, supported by a vaginal sclerite. The SSt is a coil of about 1.5 rings, the base with only a few scales along the convex face is long, distally the entire diameter with dense cover of triangular scales.

Egg ( Figs. 408–412 ). A stout drum, 330–340µm long, EL/EW 1.45 ( Fig. 408 ). Collar sessile, wide, short, no cells. Some knobs and pearls along the inward-bent edge constrain the opening of the funnel-shaped anchor cavity ( Fig. 410 ). Anchor mushroom-shaped, with a solid stem and a thin cap just covering the wide anchor pole. The operculum is a blunt cap with deep punctures ( Fig. 409 ). The approximately 27 levogyrous striae have wide costae with a longitudinal fissure (black arrows in Fig. 411 ), the narrow sulci with two regular rows of micropunctures are lower than the costae. The micropyles are roughly 1.7µm wide and stand between the two rows of micropunctures ( Fig. 412 , white arrow) in a ring near the operculum. At the base of the operculum the egg contour is slightly angular, at this site wide low scales or knobs on the costae (black arrow in Fig. 412 ) suggest an eclosion line.

DNA ( Figs. 492 , 498). Only the female holotype from Cameroon was sequenced for the COX1 DNA barcode fragment. Its sister relationship to N. gibbosa n. sp. is very strongly supported (97.5/100/100) .

Notes. Association of genders is supported by common occurrence in the light trap sample at the Etambo River. Other species in the same sample were known in both genders ( N. nigricauda Klap. , N. africana Klap. , N. duodeviginti n. sp., and N. lujana Navás ) or belonged to a different taxonomic group (1♁ N. erinaceus n. sp.). At Muyuka, female N. dolium n. sp. co-occurred with ♀♀ of N. spironema n. sp., with the ♀ type of N. muyukae n. sp., and the ♁ N. sp. Afr_A.

Etymology. The name is a noun in apposition describing the egg: Lat. dolium , a drum or barrel.

Figures

FIGURE 492. Simplified overview of codon-model maximum likelihood phylogram based on 356 mitochondrial genome and COX1 DNA barcode sequences (all-NT). Terminal labels include information on the species only. Clades of particular interest highlighted with colours that correspond to the clades in other trees. The full tree is shown in Figs 493-498.

FIGURES 407–412. Neoperla dolium n. sp., holotype from Cameroon, Etambo R.: 407, genital situs; 408, full view of an egg; 409, oblique view of operculum; 410, oblique view of collar and opening of anchor cavity; 411, egg fragment showing the very wide costae, each with a median furrow (black arrows) and as dark shades the double rows of micropunctures in the deep-lying sulci between them; 412, opercular end of striae, with a micropyle (white arrow) and cell-like modification of a costa (black arrow). Scales are 100µm, unless differently indicated; 411, 412 not to scale. ac, anchor cavity; c, costa; SSt, spermathecal stalk; su, sulcus; V, vagina; vag. scler., vaginal sclerite.

FIGURES 413–417. Presumed ♁ of Neoperla dolium n. sp.: 413, dorsal view of abdominal tip; 414, dorsal portion of terminal abdominal segments, oblique side view (after a photograph); 415, penis, endophallus everted; 416, 417, base and tip, respectively, of endophallus. Only 416 to scale; bs, bare section between penis tube and endophallus; ss, sharp spines on dorso-apical swelling of penis; ts, transverse scales on base of endophallus.