Neoperla juxtadidita, 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 : 50-51

18. Neoperla juxtadidita n. sp.

( Figs. 87–90 )

Type material studied: Gabonese Republic, ♀ holotype, Belinga 155 L Coiffait leg. ( NEOP042 ; SMNS, slide Z16.162) .

Habitus. Large size, WL 15.8mm. Faded, even the ocellar spot indistinct, uniformly light ochre, wings slightly tinged and turbid.

Male. Unknown.

Female ( Figs. 87–88 ). S8 unmodified. Vagina elongate, some wide transverse folds at base, many fine folds along sides. SSt originates in front of some folds on top of vagina ( Fig. 87 ). SSt long, slender, forming a single oval loop. Basal third internally with longitudinal undulating folds, more distally an internal cover of brown elongate closely packed scales ( Fig. 88 ), a wide band along concave side is bare. Longitudinal folds occur also in the spinose part of coil. End of SSt blunt, the narrow spermathecal duct is attached to the convex side.

Egg ( Figs. 89–90 ). Slender, 368*215µm, poles relatively wide, deep cells on operculum ( Fig. 89 ). The flat anchor pole has a rim-like very wide collar around a minute sclerotised projection in the centre of the pole, the mushroom-like anchor is attached to it ( Fig. 90 ). About 20 straight fine and low smooth ridges. Micropyles are in the wide areas between ridges, there are no visible punctures, even at magnification 630*.

DNA ( Figs. 491–493 ). The female holotype from Gabon was sequenced with the genome-skimming approach, obtaining 10,959bp of mitochondrial, protein-coding genes. Its placement as sister to the well-supported (85.7/92/86) remainder of the N. duodeviginti -assemblage is only moderately well supported (96.6/69/5).

Etymology. The name is an adjective describing the close relation with N. didita, Latin juxta meaning close by or next to.

Notes. Neoperla juxtadidita and N. didita may be relictual early members of the N. africana- group (below). They have been rarely collected. The SSt is spiral but has an armature of slender spicules which resembles N. kalengonis in the transvaalensis -group and N. pickeri . Other members of the large africana -group have wide flat scales in the SSt.

IV. The N. africana-group

The N. africana- group includes many African species but also a few Asian ones. The N. africana -group is distinguished by three apomorphies but contradicted by the very strongly supported node C:

1. Caudal process of male T7 three-dimensional (e.g., Figs. 102–103 , 169–170 ). The anterior half of T7 forms a continuous sclerotised ring in front of a pale transverse pale line or a short weakly sclerotised zone. The soft caudal half of T7 accomodates an approximately triangular sclerite ending in a pyramidal process with SB near its tip and along a ridge on the underside. T8 is flat to slightly convex, no raised hump or process. Penis tube sclerotised, dorsal and ventral faces of endophallus differ and are (except in N. planidorsum ) separated by bare lateral strips. Most spines stand on the convex side, details vary (e.g., Figs. 164 , 203 , 317 , 376 , 440 ).

2. Females with a flat, band-shaped SSt which is strongly curved or coiled, details vary. If short, the SSt resembles a section cut out of a circle (e.g., Figs. 124 , 167 , 224 ) but in most species it forms a full circle or several superimposed rings which may be drawn out into a long spiral (e.g., Figs. 123, 126 ). The winding or spiral spermatheca lies in the center of the coil and is not always visible. Female S8 without structural modifications but often with three brown maculae in triangular arrangement. The pattern is variable, the maculae may be large and merge more or less around a pale center which is often anchor-shaped.

3. Pigmented scales form an almost gap-less coat on the wall of the SSt, only the concave edge is free of them. Scales are obliquely rooted in the cuticle, with tips directed towards the vagina (e.g., Fig. 108 ). The basal region near the attachment of the SSt to the vagina seems to be extensible and contains many longitudinal folds. In this basal section scales are restricted to near the convex edge, distally scales occupy the entire width of the coil.

External genitalia alone rarely permit species identifications, usually inner genital structures and eggs must also be examined. The penis is a sclerotised tube, only a small ventrobasal region is soft (e.g., Figs. 117 , 145 ). The endophallus tends to be longer than the penis tube and is folded up inside. The endophallic armature is not dispersed over the surface, instead bare sides separate a long dorsal area with various kinds of spines from a similar but shorter ventral area. Eggs vary between species complexes.

Keys to species in the N. africana -group

Males (several unknown)

1 T8 flat, sometimes generally slightly convex but no hump or process............................................ 2

1' T8 with a distinct hump or a process.................................................... N. spio -complex, p. 87

2 Region between penis tip and the endophallus base armed with spines........................................... 2

2' A long bare zone between penis tip and spines on endophallus (e.g., Fig. 164 )............... N. pilulifera -complex, p. 70

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 493. Partial (outgroup, clades A, B, D) codon-model maximum likelihood phylogram based on 356 mitochondrial genome and COX1 DNA barcode sequences (all-NT). Statistical support values above branches or near nodes are SH-aLRT and UFBoot for the codon-model analyses, followed by NT123 UFBoot. 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. See Fig. 492 for an overview. HT = holotype; PT = paratype; PCR = Polymerase Chaine Reaction; WGS = Whole Genome Shotgun.

FIGURES83–90.Neoperladidita(Enderlein)andN.juxtadiditan.sp.:N.didita:83,spermathecalstalkofthefemalefromMamfe; 84,fragment ofan eggfromthe lectotype;85,eggof thespecimenfrom Mamfe;86,anchor poleofsame,opticalsectionandsurface view combined (diagrammatic, from a photograph). N.juxtadidita: 87, genital situs of holotype female from Belinga; 88, spinules from inside the spermathecal stalk; 89, egg; 90, anchor pole with anchor.Scales are 100µm, 84, 85 to the same, others not to scale. a, anchor; c, collar; r, ridges on egg; sa, spermatheca; SSt, spermathecal stalk; V, vagina.

FIGURES 102–107. Neoperla erinaceus n. sp., ♁ holotype: 102, 103, tergites 7–10, not to scale; 104, penis with everted endophallus, a white arrow indicates the location of the detail in Fig. 105; 106, 107, endophalli of the paratypes. Scale lines are 100µm, penes to same scale. cb, convergent bands of teeth; dat, dorso-apical teeth; ep, epiproct; is, isolated sclerite. Lines connect corresponding areas on the endophalli.

FIGURES 169–176. ♁♁ in the Neoperla pilulifera-complex. N. pilulifera n. sp.: 169, 170, abdominal tip, dorsal and lateral, semi-diagrammatic, tergites and hemitergite 10 labelled; 171, contracted, 172, everted penis; 173, distal half of penis tube and base of endophallus (holotype ♁): all from Bayanga. N. crustata n. sp.: 174, 175, ♁ from Mali, Niger at Bamako; by transparency of the slide mount the basal end of the distodorsal spine group seems to overlap with the far distally displaced basolateral spine group (encircled); 176, holotype from Guinea (NEOP073). 174 and 178 to the same, other figures not to scale. bbs, bare basal stretch; bl, basolateral, dd, distodorsal, dl, distolateral spines.

FIGURES 161–168. Neoperla amoena n. sp.. ♁ holotype: 161–163, habitus and abdominal tip (not to scale; NEOP070); 164–166, penis, only 164 to scale; ♀ paratype from Bamako: 167, 168, genital situs and egg. Scales are 100µm. bbs, bare basal stretch; tf, transverse folds; sa, spermatheca; SSt, spermathecal stalk; V, vagina.

FIGURES 201–204. Neoperla brachyphallus n. sp., ♁ holotype: 201, 202, terminal tergites in dorsal and lateral views, semidiagrammatic, tergites and hemitergite 10 are labelled; 203, penis with everted endophallus; 204, distal part of endophallus, enlarged. Only 203 to scale.

FIGURES 313–322. Males in the Neoperla dubia-complex: N. dubia Klapálek (from Makak, Cameroon): 313, terminal segments, dorsal view; 314, 315, enlarged centre of tergites 7 and 8, dorsal and lateral; 316, contracted, 317, everted penis with detail of distal armature (not to scale, from Ikom, Nigeria). Neoperla proxima n. sp.: 318, abdominal tip in dorsal view; 317, tip of penis with everted endophallus (D. R. Congo, Odzala N. P.). Neoperla vicina n. sp.: 320, 321, abdominal tip, dorsal and lateral views; 322, penis tip with everted endophallus in lateral view, and a detail of external spines in oblique lateral view (D. R. Congo, Bukavu). Scales in 317 and 322 are 100µm, scale in 320 is 0.5mm. The tergites, hemitergite 10 and the cercus are labeled.

FIGURES 373–385. Neoperla heideae n. sp. and N. larvata n. sp. N. heideae: 373, 374, abdominal tip and contracted penis of a misassociated paralectotype of N. excisa Klap. from Lolodorf (to the same scale), with the label in Sütterlin script; 375, contracted penis, dorsal view, 376, everted endophallus (from Libamba); 377, ♀ situs from near Kama (D. R. Congo); 378, ♀ situs (D. R. Congo, Odzala N.P., NEOP242); 379, egg (Sangmelina,Cameroon). N. larvata: 380, everted endophallus (CAR, Bayanga, NEOP240); 381, ♀ situs, sternites 8 and 9 labeled (Ghana, Ankasa Res.); 382, ♀ situs (Togo, Kati); 383, ♀ situs (Ghana, Volta R., Z21.41); 384, egg with detail, Guinea, Simbareya (NEOP237); 385, aberrant contracted penis, ♁ from Ivory Coast, Boa. The scales are 100µm; tergites, HT10 and cercus labeled. a, anchor; mi, micropyle; n, nail; sa, spermatheca; SSt, spemathecal stalk; V, vagina.

FIGURES 439–442. Neoperla socia n. sp., from Mutwanga. ♁ paratype (NEOP307): 439, abdominal tip, dorsal view, tergites and hemitergite 10 labeled; 440, penis with everted endophallus and detail of armature at site indicated by white arrow; the yellow arrow points at the annulated penis tip. ♀ paratype (NEOP306): 441, genital situs, sternites 7 and 8 labeled, the spermatheca happens to lie on top of the nail; 442, fragment of an egg with flanged costae; arrow indicates a micropyle in a sulcus. Scales are 100µm, unless differently indicated. n, nail; sa, spermatheca; SSt, spermathecal stalk; V, vagina.

FIGURES 123–126. Neoperla africana-group, female genital situs and spermathecal stalk: N. africana Klapálek: 123, Ghana, Subri R., vagina and spermathecal coil folded back from S8, for better visibility of anchor spot on S8. N. panafricana n. sp.: 124, Waterberge, Mapote Farm. N. camerunensis (Enderlein): 125, Ethiopia, Ghibe R.; 126, Cameroon, Bamenda, NEOP128. Scales are 100µm. am, anchor mark; ap, angular projection; lf, longitudinal folds; lscl, lateral vaginal sclerite; tf, transverse folds; SSt, spermathecal stalk; V, vagina.

FIGURES 223–226. Neoperla bipolaris n. sp.: 223, 224, egg, SEM micrograph (from Moore, 1991); 225–226, egg and genital situs of holotype. FIGURES 227–230. Neoperla schuelei n. sp.: 227, female genital situs, paratype; 228–230, egg from holotype; 229, enlarged detail of chorion; 230, oblique view of anchor pole showing the relation between striae and cells on collar. Scale lines are 100µm, unless differently indicated. Arrows indicate micropyles.

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 114–122. Neoperla africana Klapálek: ♁ from Makokou, Gaboon: 114, 115, abdominal tip, dorsal and lateral view; 116, 117 contracted penis, dorsal and lateral; 118, partly everted endophallus, lateral. 119–121, the lectotype ♁: 119, Klapálek’s labels; 120, penis, endophallus artificially everted; 121, base of same, white arrow points at the transverse short spine group. 122, male from Ghana, Volta region, Wli Falls, black arrow points at the recurrent tube inside the penis. Scales are 100µm, others not to scale. ll, lateral line; n, membranous notch; rt, recurrent tube; sl, sleeve of dense scale-like spinules; so, soft ventrobasal region of penis tube; sr, short spine row.

FIGURES 143–149. Neoperla camerunensis (Enderlein), penes and everted endophalli: 143, from Makak, endophallus not completely everted (USNM_086); 144, 145, holotype of the synonymous N. haugi from Lambaréné, before and after artificial eversion of endophallus; 146, penis tip with protruding base of endophallus, specimen from Ghana,Ankasa Reserve (NEOP125). 147, Congo, Boma (Z19.035); 148, Ivory Coast, Cavally R.; 149, Ethiopia, Cojeb R. (NEOP123). Figs. 146–147 to the same scale, the others to a scale similar to Fig. 143. so, soft ventrobasal region of penis tube.