Neoperla socia, 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 : 159-161

77. Neoperla socia n. sp.

( Figs. 439–442 )

Type material studied: Democratic Republic of the Congo: Holotype ♁, B. Congo Mutwanga [0.32N, 29.75E] 1200m, 23.9.57, Ross & Leech ( CASENT 8413116 ; NEOP307 ).

Paratypes. 22♁, same data as holotype ( CASENT 8413117 and SMNS: 6♁ in SMNS, Slides 18.08, 19.54). 1♁, Belg. Kongo, 39km S Walikale [-1.431718, 28.07478], 700m, 25.12.1957 Ross & Leech ( SMNS ex CAS; slide only! NEOP305 ). Democratic Republic of the Congo: 1♁, Kalengo-Bach [~ 2.2°S, 28.7°E] near Lwiro , 10km W of Lake Kivu on the western slopes of the Central African Rift Valley , 1750–1800m (Böttger 1975). 1♁: No. 5 Riv. Lwiru, Katana [2.24S, 28.83E] 12.12.49 G.Marlier (slide without number; SMNS) . 2♁: Coll. Mus. Congo Kivu: for. Blambwe, terr. Lubero [-0.188, 29.243] 950m XII-1956 R.P.M.J. Célis ( NEOP338 , slide Z19.45; MRAC); 1♁: Mus. Congo N. Kivu: Loashi [-1.359, 28.785] VIII-1937 J. Ghesquière; 1♁: Musée du Congo Masisi-Kisheryo (Kivu) 1935 H. Herman. 1♀, Musée du Congo Mutwanga pied du Ruwenzori 14-VIII-1932 L. Burgeon \ Neoperla africana Klap. det Navás S. J. \ R.det. 33 2969 ( MRAC, Slide Z 19.50, NEOP306 ) (all MRAC) . 1♁: Federal Democratic Republic of Ethiopia, Kaffa, Bonga [7.27N, 36.25E], 1800m, 26.x.1973, A.Vigna (coll. C. Consiglio, Rome ). 1♁, Republic of Uganda, Ruwenzori Range , Ibanda [-0.1565, 30.4946] 4700ft, 20–21.viii,1952, D.S.Fletcher ( BMNH) .

Habitus. WL 11.3–16.5mm. Bright yellowish ochre, a brown spot across the ocelli.

Male ( Figs. 439–440 ). Posterior sclerite of T7 transverse, raised, delimited by pale integument on the sides, caudally by a transverse fold or edge. SB stand in a row closely under that edge, plus many on the wide sclerite below it. A bulging brown band descends into the intersegmental fold T7/T8. Hook on T8 narrow in dorsal view, with some SB near tip 11. The hook stands opposite the bulge on the rear face of T7. The caudal face of the hook continues to the end of T8 as a narrow band. T9 is short, squeesed in between T8 and T10, its pilose lateral humps are transverse swellings. Antecosta of T9 medially interrupted, a small sclerite forms a low crest in front of the short and shallow median furrow which extends far back, almost to the epiproct. Mediobasal callus of HT10 rounded, concave, spoon-like, HT10 itself is a short angled spike.

Penis ( Fig. 440 ) a straight distally narrowing tube. Endophallus longer than the penis, its base is annulated, more distally the endophallus widens considerably, distally it turns into a long unarmed flagellum. The endophallic armature consists of only small sharp spines. Dorsally, a moderately wide spine band begins among the basal annuli and continues to the midlength of the wide section. On the concave ventral side is a slightly longer narrow band which locally consists of a single row of triangular spines. The ventral band may be divided into two or three sections.

11 Because of transparency of mounted specimens under transmitted light in Fig. 439 the anterior and posterior faces of the hook seem to be separate plates.

Female (presumed, Fig. 441 ). S8 with a short brown rounded nail which seems to have no counterpart in the floor of the vagina, there are no crests in front. Vagina slender, some small spinules stand laterally at some distance from the SSt insertion opoint. SSt curved, only little longer than the vagina, the base is wide, distally the SSt tapers much. Except for the membranous concave edge the entire SSt bears a dense carpet of scales.

Egg ( Fig. 442 ). Plump, oval, and with numerous straight striae. Costae are high sharp crests, the narrow sulci with two rows of micropunctures. The short sessile collar has two regular rows of small rounded cells, plus a ring of elongate cells whose long and slender ends lead into the sulci. Most striae continue to the top of the blunt operculum, a few are shorter. Only one micropyle was observed at the end of a short sulcus ( Fig. 442 , arrow).

DNA ( Figs. 491–492 , 498). The male holotype and three paratypes from the D. R. Congo were sequenced for the COX1 DNA barcode fragment and with the genome-skimming approach, respectively, resulting in only a partial DNA barcode for the holotype, but 8,388bp of an identical COX1 sequence and additional mitochondrial, protein-coding genes for a paratype; there is noticeable sequence divergence to the other two paratypes. Nevertheless, the monophyly of the species is maximally supported (100/100/100), as is its sister relationship to the N. sjostedti - complex (100/100/100).

Notes. Male tergal structures resemble N. crenulata n. sp. and N. sjostedti needhami . The great width of the endophallus, the smallness of its spines, and the short stout HT10 are unusual. Males of N. socia n. sp. from Mt. Kivu share these characters but the process on T8 is a little wider. A hand sketch and the description of a complete egg from Mutwanga were prepared in 1972. The only egg remaining was accidentally destroyed but there is a slide with fragments of the chorion with the characteristic high ribs.

Etymology. Neoperla socia is the colleague (Latin socia , a noun in apposition) of N. crenulata n. sp., N. tangana n. sp. and other species in the complex.

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 439–442. Neoperla socia n. sp., from Mutwanga. ♁ paratype (NEOP307): 439, abdominal tip, dorsal view, tergites and hemitergite 10 labeled; 440, penis with everted endophallus and detail of armature at site indicated by white arrow; the yellow arrow points at the annulated penis tip. ♀ paratype (NEOP306): 441, genital situs, sternites 7 and 8 labeled, the spermatheca happens to lie on top of the nail; 442, fragment of an egg with flanged costae; arrow indicates a micropyle in a sulcus. Scales are 100µm, unless differently indicated. n, nail; sa, spermatheca; SSt, spermathecal stalk; V, vagina.