Neoperla gordius, 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 : 127-128

58. Neoperla gordius n. sp.

( Figs. 332–333 )

Holotype ♀, Democratic Republic of the Congo, Coll. Mus.Tervuren Mayumbe: Kilengi [-5.14989, 13.22159] (à la lampe) 27.V.1970 P.M.Elsen ( MRAC; pinned; slide Z19.46; NEOP248 ).

Habitus. WL 12.5mm. Yellowish ochre except dark ocellar spot. No pattern on legs. Antenna and cercus not available. Wings slightly turbid, with yellowish-grey tinge.

Male. Unknown

Female ( Fig. 332 ). S8 with a pair of elongate brown sclerites extending from antecosta to just beyond midlength. A narrow pale furrow separates the plates which are in front coriaceous and bear finer setae than the rest of sternite which is caudally unmodified. Vagina elongate and soft, no identifiable structures. Spermathecal stalk unusually long, irregularly coiled. Scales in the wide basal portion resemble roof tiles, distal scales are successively more slender. Basal portion of SSt exceptionally wide, forming about 1.5 rings, the distal part is very narrow and much longer ( Fig. 332 ). Spermatheca not clearly visible.

Egg ( Fig. 333 ). Natural shape unknown, the only available exemplar is spherical and empty by decay. No collar, many straight striae with two lines of micro-punctures which do not diverge around micropyles. A small area with fine cells on top of operculum.

DNA ( Figs. 491–492 , 497). The female holotype from the D. R. Congo, the only known specimen, was sequenced with the genome-skimming approach, obtaining 10,971bp of the mitochondrial, protein-coding genes. The species is maximally supported (100/100/100) as sister to N. vicina n. sp., N. dubia Klapálek , and N. proxima n. sp..

Notes. Placement of N. gordius n. sp. in the manuscript follows DNA-evidence while punctation of egg sulci had suggested affinity with the N. needhami -subgroup. Two narrowly separated plates on S8 occur also in N. spaghetti n. sp. whose spermathecal coil is even longer but uniformly narrow over its entire length. Eggs of N. spaghetti n. sp. have irregularly punctate sulci.

Etymology The generic name of the worm Gordius (Nematomorpha; a noun in apposition) was chosen because the long spermathecal stalk, same as the worm, resembles a Gordian knot.

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 332–333. Neoperla gordius n. sp., ♀ holotype; female genital situs and a macerated egg. The vagina was flipped back to expose the sclerites in the anterior part of S8, the arrow points at the pale furrow (pf) between the sclerites. SST, spermathecal stalk; the spermatheca is concealed; V, vagina. Scales are 100µm.