Neoperla planidorsum, 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 : 52

19. Neoperla planidorsum n. sp.

( Figs. 91–95 )

Type material studied: Republic of Guinea, holotype ♁, riv. Léleko affluent Milo près de Kousankoro 11.3.88 ( SMNS, gift Élouard) (slide Z16/55, NEOP054 ) .

Paratypes: Republic of Liberia, Suakoko, light trap C.C.Blickenstaff: 1♁, 3–9 May 1952 ( USNM 31 ) ; 1♁, 10–20 March 1952 ( USNM 30 ) ; 1♀, 31 Jan 52 ( USNM 04 ; pinned egg slide Z16/19) . Republic of Sierra Leone: 1♀: Sierra Leone, Rokel à Katik, 7.2.1989 ( SMNS, gift Élouard , slide Z16/97, NEOP055 ) .

Habitus. WL 10.8–12mm in males, 15.0– 15.2 mm in females. Ochre, only the interocellar space dark, ocellar rings separate. Ventral side yellowish. Flagellum, legs and wings slightly infuscate.

Male ( Figs. 91–93 ). The caudal membranous area of T7 contains a triangular sclerite ending in a low pyramidal process, with some SB along the edge and on the underside. T8 is caudally raised as a flat plate without hump, the Y-shaped sclerite with a central group of SB, some isolated ones in the lateral membranous areas. Antecosta 9 not seen, T9 is a narrow sclerotised arch with numerous SB and long setae, the middle only shallowly depressed, the depression leads to a flat caudal plate with SB. Mediobasal callus of HT10 broad, rounded, anterior process slender, sinuous, the blunt tip rests on T9.

Penis ( Fig. 93 ) straight, tube sclerotised, the endophallus is as long as the tube but wider. Endophallus base with a ventral belt of slender spines. Armature dispersed, entire surface roughened by minute slender spinules, larger spinules concentrate distally on the convex dorsal side but single large spines occur also ventrally.

Female ( Fig. 94 ). Caudal edge of S7 with strong setae, caudal edge of S8 medially almost hairless. Vagina about as long as S8, without sclerites, front end rounded, unmodified, a few ring-shaped folds behind the attachment of the SSt which resembles a curved funnel and is short, the wide base resting on top of the vagina narrows rapidly, the end is only little wider than the spermathecal duct, the spermatheca is coiled. SSt densely coated by brown scales resembling fish scales (similar to Fig. 108 ).

Egg ( Fig. 95 ). 390*230 µm, plump, about a dozen ridges on the chorion, the fine punctures between them without order. Sides of egg curved, collar narrow and short, without cells, its rim flanged. Small serrations along the ridges grow successively smaller towards the operculum which is a low conical top with dense unordered punctures. Anchor cavity a bowl with thick bottom. Anchor mushroom-shaped, stem long, cap bell-shaped, rim resting on collar. Micropyles are exposed.

DNA ( Figs. 492–493 ). The male holotype from Guinea and a female paratype from Sierra Leone were sequenced for the COX1 DNA barcode fragment, which groups the two very strongly together (99.9/100/100). The species is moderately well supported (49.1/99/91) as sister to N. decorata n. sp., and both species together with similar support (73.9/98/0) as sister to N. cataractae n. sp..

Notes. The slender sinuous HT10 and the dense cover of slender spines on the endophallus resemble N. ivanloebli n. sp. which otherwise differs strongly, in particular T7. No other species is similar.

Etymology. The name is a noun in apposition, a combination of Latin planus, flat and dorsum, back, describing the flat male T8.

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.

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.

FIGURES 91–95. Neoperla planidorsum, n. sp., holotype male: 91, abdominal tip, dorsal and partial lateral view, tergites numbered; 92, everted penis. 93, everted penis of ♁ from Suakoko. Female paratype: 94, caudal edge of S7 and genital situs in S8, diagrammatic, scaly area of SSt shaded, asterisk marks location of enlarged inset, the scale is 5µm; 95, egg. mi, micropyle; mic, micropylar canal; sa, spermatheca; sd, spermathecal duct; SSt, spermathecal stalk; v, vagina.

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.