Neoperla benti, 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 : 98-99

41. Neoperla benti n. sp.

( Fig. 222 )

Holotype ♀: Republic of Guinea, riv. Léleko affluent Milo près de Kousankoro [Conakry-Kousankoro, 9.538N, -13.677], 11.3.88 (Z16.50; NEOP159 ; SMNS, gift J. M. Élouard).

Habitus. WL 13.0mm.

Male. Unknown.

Female. S8 with minimal transverse projection in middle of caudal margin. Sternite with a triangle of three light brown marks, the anterior marks large, the distal one elongate. Vagina with patches of small spines laterally from SSt attachment. SSt about 11* as long as S8, narrow over entire length, densely coated with scales, except in a short basal section.

Egg ( Fig. 222 ). Oval, 377*212µm (n=3). Anchor pole a little narrower than operculum which is broadly rounded, blunt, covered by shallow cells. The bare costae and the irregularly punctate sulci of the ≥ 25 straight striae are of similar width, the micropyles are freely visible. The collar is sessile and not set off against the egg contour, with a bare edge distally from the ring of low cells. The mushroom-shaped anchor with entire stem rises from a deep cavity.

DNA ( Figs. 491–492 , 496 ). Only the female holotype from Guinea was sequenced with the genome-skimming approach, obtaining 10,965bp of mitochondrial, protein-coding genes. The species is very strongly supported (92.3/100/100) as sister to a maximally supported (100/100/100) group that comprises N. spironema n. sp., N. filamentosa n. sp., and N. orthonema n. sp..

Notes. The holotype has no outstanding or unique morphological traits and was regarded as an unusual specimen of N. burgeoni or N. beta until molecular evidence suggested the present status.

Many Plecoptera nymphs contain worm cysts, mainly in the abdominal fat body, the present specimen had many of them. They probably are Nematomorpha whose minute egg larvae bore into water insects and form cysts that infect terrestrial consumers in which the adult worm develops ( Schmidt-Rhaesa 1997, Westheide & Rieger 1996). Occurrence in Plecoptera hosts was documented by Winterbourn (2005), during dissections we noticed them in several Neoperla specimens.

Etymology. Named for Stephen Bent (CSIRO), in recognition of his support with data assemblies and annotations.

Figures

FIGURE 222. Neoperla benti n. sp., holotype (NEOP159), genital situs and the only egg, not to scale od, oviduct; SSt, spermathecal stalk; V, vagina.

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.