Neoperla pallidogigas, 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 : 41-42

12. Neoperla pallidogigas n. sp.

( Figs. 59–62 )

Material studied: Holotype ♀: 4°58’32.77’’N, 9°42’43.40’’E, Republic of Cameroon, SW-Reg., Bangem , Bakossi Mts, Musback, vegetable garden, 1150m asl, A. Zwick, 24 Oct 2011, MV-lamp ( NEOP008 , SMNS).

Habitus. Female WL (wing tips damaged) approximately 24 mm. Front wings with four or five free branches of Rs. Membrane nearly clear. Body whitish, a dark interocellar spot and faint greyish tinge on anterior portion of head and on pronotum. Scape pale, pedicellus and available fragments of flagellum dark. Legs pale, tibiae long and thin, greyish. Cercus pale, tip slightly infuscate.

Male. Unknown.

Female ( Fig. 59 ). Sternites unmodified, caudal edge of S8 soft. Genitalia ( Fig. 59 ) unpigmented and transparent, not easily recognised in the microscope slide. Vagina with straight sides and anterolateral corners, in it occur a few convergent bands of needle-fine spinules. SSt slender, little longer than the vagina. Curved base of SSt with colourless triangular scales. Finger-shaped distal part directed obliquely backward, distally restricted and not distinctly separate from curled spermatheca.

Egg ( Figs. 60–62 ): Length 465–485µm, inversely drop-shaped. Sessile collar 109–114 µm wide, thick, with occasional deep depressions. Greatest egg width near midlength is 267–277µm. The convex operculum is shallow, diameter 230µm, covered by polygones with a complex internal pattern ( Fig. 62 ). Approximately 16–18 oblique slightly dextrogyrous striae. Costae wide and bare, each with a faint median longitudinal line ( Fig. 61 , black arrow). Sulci are only narrowly open to outside but deep, floor subdivided by transverse lamellae ( Fig. 61 ) which extend a little under the costae and pairs there form well-defined U-shapes. Lamellae of a pair are a little closer together than the distance from neighbouring pairs, micropyles are simple holes between two lamellae ( Fig. 61 , white arrow). A ring of narrow transverse cells along the eclosion line between striae and operculum. The mushroom-shaped anchor is inserted in a funnel-shaped cavity.

DNA ( Figs. 491–493 ). Only the female holotype from Cameroon was sequenced for the COX1 DNA barcode fragment, yet its placement as sister to N. costata n. sp. + N. rostrata n. sp. lacks significant statistical support (16.9/45/83).

Notes. The presumedly related N. rostrata is known only in the male gender. The female genitalia of the probably also related N. costata are similar to the transvaalensis group while those of N. pallidogigas are very different and resemble N. duodeviginti .

Etymology. A contraction of Latin pallidus, pale, and gigas, the name of a giant. A noun in apposition.

III. The N. duodeviginti- assemblage (= clade B)

Molecular data provide moderate support (96.6/69/5) for a heterogeneous group (= clade B) comprising N. juxtadidita with spiral SSt full of slender microtrichia and an egg with less than 20 ridges, and three other species which differ between each other in SSt and in eggs which are either not striate or have proper striae (instead of ridges). Morphologically, none of the species fit elsewhere. A clearer situation is hoped for when presently unknown males will be discovered in future.

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.

FIGURES 59–62. Neoperla pallidogigas n. sp., female holotype: 59, genital situs, diagrammatic; 60, egg; 61, detail of striae, the white arrow points at a micropyle, the black arrow indicates the faint longitudinal line on the costa; 62, detached operculum. Scales are 100µm. sa, spermatheca; SSt, spermathecal stalk; tc, transverse cells between operculum and striae; V, vagina.