Neoperla nigricauda Klapálek, 1909

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 : 101-103

44. Neoperla nigricauda Klapálek, 1909

( Figs. 231–237 )

Neoperla nigricauda Klapálek, 1909: 228 .

Type material. Republic of Cameroon, Lectotype ♁ (here designated): N. Kamerun, Johann-Albrechtshöhe L.Conradt S. ii/5.96 \ nigricauda Klapálek \ Typus ( NMCZ, Abdomen and penis in microvial on pin). For a misassociated paralectotype see under N. conradti .

Additional material. Republic of Cameroon : 8♁, 4♀ ( NEOP182 , NEOP183 , NEOP184 , NEOP185 , NEOP186 , NEOP187 , NEOP188 ) : 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, A. Zwick; 2♀ ( NEOP181 , NEOP189 ) : 6°8’26.25’’N, 10°6’3- 68’’E, Cameroon , NW Reg., Bamenda, Mentchum River contributor 15 km NNW Bafut, 630m asl, 9 Nov.2011, MV-lamp, A. Zwick (coll. SMNS) . 1♁, Kumba , Cameroon, light trap, early Dec.1952, lg. Nicholas (Z16/170; gift H.B.N.Hynes). 1♁: Kamerun Ekona 17.4.-20.5.38 Buhr S. G. ( MfNB) . 1♀, CAMEROUN: 28 mi. S. Ngaoundéré, 1250m, 1-X-1966, E.S.Ross & K. Lorenzen. ( NEOP180 ) , CASENT 8413107, slide CAS.001; some eggs on slide Z17.55, in SMNS). Republic of Kenya : 1♁, Lake Turkana , Sibiloi National Park [3.92N, 36.18], Koobi Fora Base Camp 14.3.1988 (Slide Z 19/77; HNHM) .

Habitus ( Fig. 231 ): WL 10.3–11.5mm (male), 10.5–14.9mm (female). Specimens from Etambo and Mentchum rivers with dark grey to black wings, pronotum dark greyish brown; a dark arch along occipital suture and across ocelli. Antenna and maxillary palpus brown. Cercus black. Tip of femur and base of tibia black, in sharp contrast with the yellow distal parts. The length of dark sections decreases from front to hind leg. Some other individuals are pale, perhaps faded.

Male ( Figs. 232–235 ). Hind tibiae widened. A bilobed sclerite in the intersegmental fold T7/T8 forms a hinge similar to Fig. 113. T 7 process long, conical, opposite a hump on T8 ( Fig. 233 ). Caudally from the hump the T8- sclerite is band-shaped and flat. T9 unmodified. Basomedial callus of HT10 parabolic. The HT10 process curves outward, the wide spatulate tips rest between the pilose lateral humps of T9 ( Fig. 232 ).

Penis ( Figs. 234–235 ) 1.50–1.60 mm long, diameter 0.12–0.16 mm. Straight, penis tip dorsally membranous, ventrally with a low terminal swelling. Endophallus about as long as the penis, carrot-shaped, with 2 dorsolateral rows of 8–10 slender spines on the base which tapers rapidly to a narrow tube with 2 regular rows of small teeth ( Fig. 235 ).

Female ( Fig. 236 ). S8 with a large anteriorly rounded and medially incised brown macula which is caudally divided by a transverse pale angle. Vagina unmodified except anterolateral cornes rough, with spinules (arrow in Fig. 236 ). SSt coiled and narrow, 3–4 times as long as S8, forming ca 3 rings, completely coated with scales, except the short base.

Egg ( Fig. 237 ). Ovoid, size 340–375 * 195–220µm. More than 20 straight striae are present. Costae wide, flat, impunctate, sulci very narrow, slightly expanded around micropyles, the fine punctures are in no order. Striae become narrow before reaching the parabolic punctate operculum which has no cells. Anchor pole flat to gently convex, 75–90µm wide, with fine marginal rim instead of a collar. Anchor large, mushroom-shaped, often forming a cupule over the anchor pole to which it is attached on a low button. Details vary, see below.

DNA ( Figs. 491–492 , 496 ). A total of 10 specimens from Cameroon were sequenced for the COX1 DNA barcode fragment and with the genome-skimming approach, representing the core geographic distribution of this species and providing maximum support (100/100/100) for the monophyly of the species. The species is very strongly supported (89/97/96) as sister to a group that comprises N. bella n. sp., N. bipolaris n. sp., and N. schuelei n. sp.. Both sexes are well represented.

Notes and variation. Black cerci and other details of pigmentation were the presumed specific characters in Klapálek’s key (1909) to African Neoperla species. However, very dark to black cerci occur also in other species (e.g., N. schuelei n. sp. and N. conradti (Enderlein) : see the latter species for a misassociated paralectotype of N. nigricauda ). On the other hand, several pale (variation or faded?) males from localities far from each other are in fact N. nigricauda according to their genitalia.

The female from Ngaoundéré and those from the Etambo and Mentchum rivers are N. nigricauda by DNA but egg sulci have two lines of micropunctures and the anchor pole has no button; instead the large anchor is inserted in a navel-like impression.

Figures

FIGURE 491. Codon-model maximum likelihood phylogram based on 83 largely complete mitochondrial genome sequences only (mt-NT). Statistical support values (SH-aLRT, UFBoot) from this and other analyses summarised by squares as explained in the figure. Terminal labels include information on the species, type status, gender, originating country, unique sequence identifier (NEOP###), sequencing approach and total basepairs of 13 mitochondrial, protein-coding genes. Clades of particular interest highlighted with colours that correspond to the clades in other trees. HT = holotype; PT = paratype; PCR = Polymerase Chaine Reaction; WGS = Whole Genome Shotgun.

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.

FIGURE 496. Partial (clades G, H) codon-model maximum likelihood phylogram based on 356 mitochondrial genome and COX1 DNA barcode sequences (all-NT). See Fig. 493 for common details.

FIGURES 231–237. Neoperla nigricauda Navás: 231–234, male fore body, abdominal tip and penis (length 1.18mm), specimens from Cameroon, Etambo r.; 235, everted endophallus of pale ♁ from Kumba. 236, ♀ genital situs, arrow indicates the large spine patch in the vagina); 237, egg (Etambo r.).

FIGURES 108–113. Neoperla spp., structural details.108, N. africana Klap., 109, N. kalengonis n. sp., 110, N. sjostedti needhami Lestage, all from the stream Kalengo: 108, 109 scales in the SSt. Close-ups of egg chorion: 110, three egg striae, the 2 rows of micropunctures in the sulci diverge around an island with a micropyle; 111, N. africana, 112 N. camerunensis (End.), chorion with 2 micropyle orifices; 113, processes of tergites 7 and 8, and modifications of antecosta 8 (AC8), a combination of inner structures (light grey), and of fine pilosity and sclerites (dark grey) on the surface of tergites; diagrammatical. The SEM microgaphs are courtesy of MPI of Limnology, PL̂n.

FIGURES 6–10. Neoperla transvaalensis (Enderlein) (6, 7) and N. laticollis Klapálek (8–10): 6, female situs, specimen from Rwanda; 7, egg, semi-diagrammatic, not to scale; 8, female situs; 9, egg, lateral view; 10, enlarged detail of a costa. The scales are 100µm; a, anchor; c, collar; fo, stack of membranous folds; gp, gonopore; hk, hard knob, retractor apodeme; ls, lateral vaginal sclerite; mc, mediobasal callus of HT10, the hemitergite 10. mi, micropyle; op, operculum; sa, spermatheca; sd, spermathecal duct; S9, protruding tip of S9; sa, coiled spermatheca; V, vagina.