Neoperla bella, 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 : 106-108

46. Neoperla bella n. sp.

( Figs. 250–257 )

N. spio — Zwick 1976a: 686, figs 1, 5, 387; misidentification.

Type material: Democratic Republic of the Congo, emergence trap on the stream Kalengo [~ 2.2°S, 28.7°E], near Institut pour la Recherche Scientifique en Afrique Centrale at Lwiro, 10km W of Lake Kivu, 1750–1800m, K. Boettger (Viets & B̂ttger 1974, B̂ttger 1975) .

Holotype J ( NEOP172 , slide Z17/48), paratypes: 1 J, abdominal tip & penis, Z16/29; 2♀ ( NEOP173 , Z19/24 & NEOP174 , Z17.49) ( SMNS).

Additional material. Democratic Republic of the Congo, numerous ♁ and ♀ taken together with the types; 1♀ slide Z73/1; 1♁ slide Z21/16) ( SMNS). 1♁, Hung. Sci. Africa Exp. “ Teleki ” 16 May 1988 leg. A. Vojnits \ light trap no.330 MVlamp \ Zaire 180 km W of Bukavu, rain foirest, light trap 160W MV lamp No. 330 ( HNHM) . Federal Democratic Republic of Ethiopia, 1♁ (pinned, genitalia on plastik slide): Tissisat falls [Blue Nile Falls, 11.49N, 37.59E] VII-5-1965 A. B. Gurney [ USNM 09 ] .

Habitus. WL 8.7–13.2mm, mean 9.3mm in males, 12.2mm in females. Dorsal side ochre coloured, wings distinctly infuscate. An arched dark band along occipital suture extends to near the eye, the spot across the ocelli projects a little. Ocelli are approximately 1.5 diameters apart. Antenna and cercus dark brown, all femora bright yellow, all tibiae and tarsi dark brown.

Male ( Figs. 250–254 ). Hind tibiae slightly widened and flattened. Anterior tergites are medially pale, T5 and T6 are brown. A large square sclerite with blunt corners in the caudal 2/3 of T7 ends in a raised short nipple. T8 with large pale areas, medially with a short triangular sclerite with rounded hump, caudally with a band-shaped sclerite. Small groups of SB occur in the intersegmental fold 7/8. T9 is unmodified, lateral pilose humps are low, the median furrow is shallow. The basomedial callus of HT10 is short and rounded, the process is plump, straight, and has a spatulate apex ( Fig. 250 ). The V-shaped epiproct is exposed.

Penis ( Figs. 251–254 ) tubular, about 5 times longer than wide, distally narrower. Fine sharp external teeth roughen the dorsal side of the caudal third (es in Fig. 252 ). Endophallic armature generally delicate, spines are small. The soft penis apex and the base of the endophallus with sparse needle-like spines, more distally the endophallus is a narrow tube with sharp triangular spines ( Fig. 254 ).

Female ( Fig. 255 ). A wide brown macula covers the anterior 2/3 of S8. A pale transverse strip with forward directed point separates it from a narrow brown macula in front of the caudal edge of S8. Vagina with numerous spinules on either side of attachment SSt. SSt only twice as long as segment 8, forming 1.5 rings of uniform width with dense scale coat, except in a short basal section.

Egg ( Figs. 256–257 ). 320–340µm long, average size 331* 208µm. It is a plump ovoid widest near midlength, the anchor pole is wider than the blunt operculum ( Fig. 256 ). Approximately 27 straight striae, sulci and costae are of similar width, the sulci are irregularly punctate, the micropyles exposed ( Fig. 257 ). The bare costae are rounded. There are shallow cells on top of the operculum and in one ring of cells on the short sessile collar. The anchor cavity is deep, funnel-shaped, the anchor is mushroom-shaped.

DNA ( Figs 491–492 , 496 ). The male holotype and two female paratypes from D. R. Congo were sequenced for the COX1 DNA barcode fragment (holotype) and with the genome-skimming approach, representing part of the geographic distribution of this species and providing maximum support (100/100/100) for the monophyly of the species. The species is very strongly supported (94.1/95/100) as sister to N. bipolaris n. sp. + N. schuelei n. sp..

Notes. In the emergence trap collections on the stream Kalengo, N. bella was by far the most abundant species. Emergence of both sexes was non-seasonal ( Zwick 1976a), despite seasonal rain fall. One male has the endophallus fully everted ( Fig. 251 ). The ectodermal pouch in which the penis normally rests is extruded and reversed, the finger-like penis projects between the HT10, their mediobasal callus rests on it. The penis passes laterally from the T7 process, the apex has a knee-like bulge, the narrow endophallus extends forward to near the front edge of T6 where it turns back in a narrow U-shaped curve. The lance-like terminal section is directed back so that the gonopore lies at the level of the abdominal tip.

Neoperla bella was confused with the superficially similar West African N. spio . Both have fine external teeth on the penis outside. Neoperla spio is yellowish without pattern (faded?). The two species differ in shape of the sclerite on male T7 and of HT10, and by larger endophallus spines in N. spio . Female N. bella have a much shorter SSt and about twice as many egg striae as N. spio . Neoperla amoena and N. nigricauda resemble N. bella in colour but differ much in structures. Females have a much longer SSt than N. bella .

Etymology. The name is the female gender of the Latin adjective bellus, beautiful, an allusion to the appearance of fresh specimens. Colouration, however, faded quickly.

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 250–257. Neoperla bella n. sp., 250, ♁ abdominal tip, dorsal view; 251, abdominal tip of ♁ holotype with naturally fully everted penis; 252, contracted penis; 253, penis tip and everted endophallus, 254, distal end of endophallus; 255, ♀ situs, vagina flipped back to expose pattern on S8; 256, slide mounted egg; 257, detail of chorion structure, arrow indicates a micropyle.All from Kalengo stream, D.R.Congo. Not all figures to scale, scales are 100µm, except as indicated in 257. Tergites, HT10, cercus and S8 are labeled. ea, external asperities on penis tube; es, endophallic spines; SSt, spermathecal stalk; V, vagina; vd, vas deferens, visible through the delicate integument.