Neoperla usambara, 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 : 112-115

50. Neoperla usambara n. sp.

( Figs. 278–284 , 289–291 )

Types and aditional material taken with them: United Republic of Tanzania: Tanga region W. Usambara Mts., Mazumbai, ZMB’s Tanzania Exp, (after Andersen & Johansen 1992): Kaputu stream on Kwagoroto Hill, from 1770m down to 1400m (see Notes): Site A: 1♀, 3.– 4.11.1990; 1♀ paratype, 4.– 9.11.1990; 3♁ paratypes, 4.– 13.2.1990; 4♀, 4.– 12.2.1991. Site B: 6♀, 2.– 3.11.1990; 1♁ paratype, 1♀, 3.– 4.11.1990, ♁ holotype, 4.– 6.11.1990, 1♁, 1♀, 6.– 9.11.1990. Site bW, below/beyond waterfall, 4♁, 4♀ paratypes, 6. 12.11.1990; 1♀, 6.– 12.11.1990. Site F, 1♀ 2.– 6.11.1990. Site G, 1♁ paratype, 1♀, 30.10.– 6.11.1990. Sites I, J, L, M: 1♁, 4♀, 4.11.–54.12.1990. Site N: 1♀ paratype, 3 ♀, 20.– 26.11.1990. 1♁ paratype, United Republic of Tanzania: Tanga region W. Usambara Mts. , Mpoude forest 30.11.– 6.12.1990 Malaise trap. Holotype in ZMBN, paratypes and additional material in ZMBN, some also in SMNS.

Aditional material studied. United Republic of Tanzania: 1♀: Tanganjika , Usambara-Berge, Sakatani 1500m lg. Lindemann und Pavlitzki, 10.xi.1952 ( ZSM, pinned slide of genitalia, no egg) .

Habitus. WL of males 11.7–14.2mm (n=6), of females 15.2–16.7mm. Yellowish, a dark heart-shaped macula over the ocelli. Flagellum and outer edge of tibiae dark. Wings turbid, yellowish.

Male ( Figs. 278–284 ). T7 with small erect caudal process. A broad swelling with SB on T8 opposite the vertical posterior face of T7. T8 caudally bare, weakly sclerotised, flat. T9 unmodified. HT10 short, straight, mediobasal callus rounded ( Figs. 278–279 ).

The stout penis ( Figs. 280–284 ) has a rhomboid apex covered with small blunt teeth, the lateral corners of the rhombus project, each with some spines directed towards base. More distally the endophallus resembles a garden hose of about 25% the width of the penis tube and approximately three times as long. Endophallus with a single row of slender spines and two rows of much smaller spines. End of endophallus coiled, from its tip a narrow terminal tube (tt in Figs. 280–281 ) leads back into the penis, exits through the basal penis opening, and is attached to the ejaculatory duct (ed in Fig. 284 ).

Female ( Fig. 289 ). S8 largely brown, with a pale anchor-pattern near the caudal edge. Vagina slender, with faint basolateral sclerites and anterodorsally with a forward-directed cone formed by many concentric folds to which the SSt attaches from in front. SSt very long and narrow, entirely scaly, with two slender bands of spines projecting into the cone (arrow in Fig. 289 ).

Egg ( Figs. 290–291 ).Average size 365*208µm, ovoid, widest near midlength. Many straight striae with smooth costae twice as wide as the sulci.Along each side of the narrow sulcus runs one line of punctures but in the widenings around micropyles (arrow in Fig. 291 ) the punctation is irregular. The operculum is parabolic, only a small apical area has some cells. The sessile collar is wide and short, with one ring of cells. Anchor mushroom-shaped, the stem rises from a moderately deep bowl-shaped cavity ( Fig. 290 ).

DNA. No data.

Notes. The penis of the holotype was naturally fully everted, the entire specimen was slide mounted, to preserve this condition.

Neoperla usambara n. sp. is known only from the Usambara Mountains where it co-occurs with N. sambarua n. sp. The two species are similar in male and female genitalia, but eggs are very different. An expedition report (Andersen & Johansen 1992) marked 11 Malaise trap sites along Kaputu stream on Kwagoroto Hill by numbers, from 1770m down to 1400m where the stream enters a small lake. However, the Plecoptera locality labels distinguish 13 sites by letters. Most specimens of N. usambara n. sp. and N. sambarua n. sp. were collected at sites A, B, and ‘ beyond \ below waterfall ’, presumably the uppermost sites. Information to match the different codes is no longer available (T. Andersen, in a letter).

Phenology of the two species agreed. Operation of emergence traps began in early November, numerous individuals were taken until mid-November, much fewer until mid-December. In January and February, after the hottest season, numbers increased again.

Etymology. The species is named after the Usambara mountains, the name is a noun in apposition.

Figures

FIGURES 278–288. Neoperla usambara n. sp. and N. sambarua n. sp., ♁ holotypes: N. usambara: 278, 279, abdominal tip, dorsal and lateral views; 280–283, naturally fully everted penis, photograph of the holotype whole mount with enlarged details, corresponding structures are connected by lines; 284, connection of penis base to the mesodermal ejaculatory duct (ed) via the thin recurrent tube (rt). N. sambarua: 285, 286, abdominal tip, dorsal and lateral views 287, penis, beginning eversion of endophallus; 288, enlarged apex of same. ed, ejaculatory duct; rt, recurrent tube; tergites and HT10 are labeled.

FIGURES 289–293. Neoperla usambara n. sp. and N. sambarua n. sp., ♀ ♀. N. usambara: 289, genital situs, vagina and the coiled spermathecal stalk flipped back to expose anchor pattern on S8; 290, egg; 291, detail of striae with a micropyle in a sulcus (full arrow). N. sambarua: 292, genital situs with diagrammatic indication of border between S7/S8; 293, egg, variable thickness of chorion indicated by inner contour on right hand side. Open arrows show divergent spinule bands at entry of SSt into vagina. Scales as indicated. A, anchor; c, collar; co, costa; ls, lateral sclerite; mi, micropyle; mic, micropylar canal; sa, spermatheca; SSt, spermathecal stalk.