Neoperla orthonema, 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 : 116

IV.4 The Neoperla orthonema -complex (= clade H)

The N. orthonema -complex is proposed for three West African species whose ovoid eggs at first glance seem to have a mushroom-shaped anchor. However, the delicate cap rests on several filaments which rise directly from the anchor cavity and form a curled bundle under the cap. When the anchor attaches to some substrate the filaments stretch out and turn into long threads, the cap is then no longer visible ( Fig. 302 ).

Egg striae differ between the species, those of N. filamentosa n. sp. are levogyrous and resemble the N. sjostedti - and N. arambourgana complex with extremely narrow sulci with a row of micropunctures on each side ( Fig. 307 ). In N. orthonema n. sp. and N. spironema n. sp. eggs have no typical sulci but two kinds of raised ridges, with the micropyles on top of the lower ridges ( Fig. 312 ). Both of these characters are unique in Neoperla .

Female S8 have a large brown spot enclosing a pale anchor pattern (e.g., Fig. 301 ). The slightly sclerotised caudal segment edge has a shallow bare notch ( Fig. 305 ). The vagina has spines next to the attachment of the SSt which forms 2–3 rings with a dense coat of triangular scales, and the floor of the vagina is roughened by microscopic spinules. We cannot distinguish females without eggs, the eggs differ between species. The>20 to approximately 30 striae are straight in N. orthonema n. sp. but are levogyrous spirals in N. filamentosa n. sp. and N. spironema n. sp..

DNA ( Figs 491–492 , 496 ). The N. orthonema -complex (= clade H) is maximally supported and genetically very distinct as indicated by the length of its branch. It is very strongly supported (92.3/100/100) as sister to N. benti n. sp., and together they are strongly supported (65.7/100/90) as sister to the extensive N. spio -complex (~ clade G). The morphology-based concept of the N. orthonema -complex (= clade H) renders the extensive N. burgeoni - complex (~ clade G) paraphyletic but including N. benti sp. n. in the N. orthonema -complex would result in two reciprocally monophyletic complexes.

Notes. The only known male in the N. orthonema -complex fits perfectly in the N. spio -group and is easily identified. In contrast, females had to be included in several keys and can only be identified by details of egg structure which are difficult to see.

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 294–304. Neoperla orthonema n. sp.: Male paratype from Lakota, Ivory Coast: 294, 295, abdominal tip; 296, everted penis, with detail from middle of endophallus; 297–299, apex of contracted penis, in dorsal, ventral and lateral views (from left); 300, lateral view of penis apex, beginning eversion (♂ from Kousankoro); 301, female genital situs (vagina flipped back to show the anchor pattern on S8) and 302, egg, Ankasa game prod. res., Ghana; 303, view onto edge of chorion fragment showing variable size of costae (Ivory Coast, Lakota); 304, detail of collar with end of striae (Wli Falls, Ghana). Scales are 100µm. Tergites, sternites and hemitergite 10 are labeled. d, dorsal spines; eb, spines at base of endophallus; sa, spermatheca; SSt, spermathecal stalk; V, vagina; vs, ventral spines.

FIGURES 305–308. Neoperla filamentosa, n. sp., holotype. 305, genital situs; 306, egg of HT; 307, detail of striae, arrows indicate micropyles. 308, egg of doubtful ♀ from Touba, Senegal. Scales are 100µm, eggs to same, details not to scale. Sa, spermatheca; SSt, spermathecal stalk; V, vagina.

FIGURES 309–312. Neoperla spironema n. sp.: 309, 310, holotype; 311, a paratype; both from Ankasa Game. Res; 312, SEMdetail of chorion with the 2 kinds of costae and a micropyle (Ivory Coast, USNM; from Moore, 1991). Scales are 100µm, or as indicated. mi, micropyle; sa, spermatheca; SSt, spermathecal stalk; V, vagina.