Neoperla gibbosa, 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 : 149-150

71. Neoperla gibbosa n. sp.

( Figs. 402–406 )

Type material studied. Republic of Angola, ♀ Holotype ( NEOP297 , slideZ17.53) 1 ♀ paratype ( NEOP298 , slide Z17.54), prov. Uíge, Finca 7°38’08.6’’S, 14°56’25.8’’E 645m, 24.x.2013, at light, leg. M.Nuss ( SMTD). Democratic Republic of the Congo, 2♀ paratypes: B.Congo, 50km S of Tshela [5.01S, 12.96E], 26.7.57, Ross & Leech ( CASENT 8413102 , slide Z.18.61; and SMNS, slide Z18.62).

Habitus. WL 12.2–13.8 ( HT) mm. General appearance dark greyish-ochre. Head yellowish near inner edge of eyes, there is a small brown spot between the ocelli. Thoracic nota and wings are darker than head, wings turbid. Scape light, flagellum brownish to almost black ( PT). Cercus and legs greyish-ochre, without pattern.

Male. Unknown.

Female ( Fig. 402 ). Central part of S8 brown, caudal edge sclerotised, gonopore in a rounded notch between short blunt lobes. Straight setae inserted in front of the notch reach across it. A triangular sclerite inside the vagina extends forward to about the middle of S8. The sclerite has no sharp borders and no transverse keels. Vagina long, reaching far into S7, dense patches of spinules on both sides of insertion of SSt. The coiled SSt forms about 1.5 rings of uniform width and is densely paved with pointed scales, except on a narrow strip along the convex edge in the basal third ( Fig. 402 ).

Egg ( Figs. 403–406 ). Plump ( Fig. 403 ) to ovoid ( Fig. 406 ), hard-shelled, 303*163µm. Collar about half as wide as maximum egg width. The mushroom-shaped anchor ( Fig. 403 ) is inserted in a funnel-shaped cavity. Operculum blunt, rounded and wider than the collar. About 25 levogyrous spiral striae start from a single ring of cells on the collar, the costae bear two rows of rounded humps. Slightly smaller pale humps ( Fig. 405 ) suggest an eclosion line. The operculum is covered by large punctures forming hexagonal groups ( Fig. 404 ). No micropyle observed.

DNA ( Figs. 491–492 , 498). The female holotype and a female paratype from Angola were sequenced with the genome-skimming approach, resulting in 10,854bp of mitochondrial, protein-coding genes from the holotype. The monophyly of the species is near maximally supported (99.3/100/100), and its sister relationship to N. dolium n. sp. is also very strongly supported (97.5/100/100) .

Variation. The eggs of the smaller specimens from Tshela are plump, on average 302*196µm. Collar not very apparent, a wide short ring without cells ( Fig. 406 ). Structure of striae, operculum, and female genitalia agree with the other specimens.

Notes. The large notches in the caudal margin of S 8 in N. arambourgana and N. excavata n. sp. are hairless and have different shapes, eggs of these two species differ strongly from N. gibbosa n. sp.. Neoperla crenulata n. sp. also has humps on egg costae but female S8 bears a nail.

Etymology. The name is an adjective refering to the surface of egg costae: Latin gibbosus, with humps.

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.

FIGURES 402–406. Neoperla gibbosa n. sp., female holotype: 402, genital situs; 403, egg; 404, oblique view of opercular pole; 405, detail of striae; 406, egg of paratype from Tshela. Scales are 100µm. 403, 406 to the same, 405 not to scale. co, costa; SSt, spermathecal stalk; su, sulcus; V, vagina.