Neoperla transvaalensis (Enderlein, 1909)

II. The Neoperla transvaalensis View in CoL -group (= clade A)

Male tergites: T7 process a flat tongue-shaped lobe or triangular process. T8 flat with some sensilla basiconica (SB) on a weak median sclerite. The antecosta T9 is divided in front of a median membranous area. The sclerotised sides of T9 form humps with long pilosity and some SB, between them runs a shallow furrow with weakly sclerotised floor. HT10 with large dorsally flat mediobasal callus and straight spike-like or slightly curved process (e.g., Figs 1 View FIGURES 1–5 , 11 View FIGURES 11–15 ). Penis stout, sclerotised around the basal opening and on a triangular dorsal area, remainder membranous. Endophallus wide, as long as or little longer than penis tube, spines on dorsal and ventral sides a little different but dispersed, not separated by bare lateral strips (e.g., Figs 137 View FIGURES 135–142 , 317 View FIGURES 313–322 , 376 View FIGURES 373–385 ).

Female S 8 unmodified, no distinct subgenital plate. Vagina large, dorsally with stacks of U-shaped folds in front of which originates the SSt. The SSt is a flat slightly curved sac which is bent sideward and rests on the sternite. Opening into the vagina very wide, the cuticle on the convex side is thick, the concave side contains undulating longitudinal folds suggesting the SSt is extensible, the cuticle is thinner. The armature of microtrichia or tiny scales is weak and pale ( Fig. 6 View FIGURES 6–10 ). Only N. kalengonis has a long flat SSt which is bent back and armed with a dense pelt of long reddish microtrichia ( Fig. 28 View FIGURES 26–32 ). The smooth narrow spermathecal duct (SD) is eccentrically inserted, close to the convex side. Spermatheca elongate, curled or winding.

Eggs have 6 to 16, mostly around 12 longitudinal ridges; egg cross sections resemble cog-wheels ( Fig. 21 View FIGURES 18–25 ). Micropyles in the wide shallowly concave sections between the ridges are exposed and freely visible. Striae do not extend onto the operculum which is a low cap, in side view a flat triangle, the egg contour has an angle at the operculum base. Except for the collar, the entire chorion is punctate, surface structure is essentially the same everywhere. The mushroom-shaped anchor has a solid stem and a large cap.

In species with large punctures the egg surface is coarse, punctures stand in transverse rows, groups of 4–5 rows are separated by a narrow bare strip. The bare strips extend across the concave sections and up the sides to the top of the ridge where various ornaments, including denticles, pearls, and knobs, may occur. Ornaments on left- and right-hand sides of a ridge are displaced by half a diameter (resembling, e.g., Fig. 10 View FIGURES 6–10 ). In Neoperla spectabilis egg costae bear high flanges.

DNA ( Figs 491–493 View FIGURE 491 View FIGURE 492 View FIGURE 493 ). Within the limits of taxon sampling, molecular evidence provides very strong support (100/96/93) for the N. transvaalensis -clade (= clade A), but its phylogenetic placement within Neoperla is unresolved. The monophyly of multiple-sampled species is always strongly supported, but support for phylogenetic relationships between species is limited. Strong support exists only for N. rostrata n. sp. + N. costata n. sp. and for N. lujana Navás + N. kalengonis n. sp..

Notes. The flat, sac-shaped SSt with weak pale armature seems to be an apomorphy, apomorphies of males are not known. Species known only from males are provisionally included, and those presently known have weakly sclerotised penis tubes.

The N. transvaalensis-clade exhibits several plesiomorphic characters (e.g. the entirely punctate egg surface, including the ridges). A flat lappet-like process of male T7 occurs only in this group. The flat T8 resembles genus Phanoperla and the only partial or weak sclerotisation of the penis and the undifferentiated endophallic armature resemble the so-called Asian N. montivaga -group.

In females, the wide opening between vagina and SSt resembles the American N. occipitalis (Pictet) , N. clymene (Newman) , and their close Nearctic relatives but also some Asian Neoperla species (P. Zwick, in prep.). However, in the transvaalensis- clade the spermatheca is a delicate curled structure like it is in all other African species and only in them. Identification of egg-bearing females is usually no problem, egg cross sections resemble cog-wheels ( Figs. 21–22 View FIGURES 18–25 ). Identification of males is often difficult because tergites and endophallus are uniform and simple. If minor morphological differences indicate intraspecific variation or presence of cryptic species is unknown. The low cap-like operculum of the egg may also be an apomorphy of the transvaalensis- group which single members of the N. decorata- and africana -complexes share, possibly as an atavism.

Keys to species in the N. transvaalensis -clade, and to similar species of uncertain relations

Males

1 Penis wide, largely soft, dorsally only a triangular sclerite (e.g., Figs. 3 View FIGURES 1–5 , 43 View FIGURES 42–49 )....................................... 2

1' Penis tube-shaped, generally sclerotised (e.g., Fig. 57 View FIGURES 56–58 )........................................................ 7

2 Everted endophallus stands at right angle to penis tube, armature consists almost entirely of large hooks ( Fig. 5 View FIGURES 1–5 )............................................................................................ 2 N. laticollis View in CoL Klapálek

2' Direction of penis tube and everted endophallus similar, armature mixed, includes also many small spines (e.g., Fig. 3 View FIGURES 1–5 ).... 3

3 Subapical patches of external spinules on penis tube, endophallic armature includes large flat triangular spines with re-curved small apical hooklet ( Figs. 42–45 View FIGURES 42–49 )........................................................ 9 N. spectabilis n. sp.

3' No external spine patches on penis....................................................................... 4

4 Penis and everted endophallus differ in direction ( Figs 12, 15 View FIGURES 11–15 ) or are sinuous...................................... 5

4' Penis and everted endophallus together are approximately straight or curve in the same direction...................... 6

5 Penis curved, dorsal side ends in a bare hump, base of the thick sausage-shaped endophallus displaced to the ventral side ( Fig. 12 View FIGURES 11–15 )................................................................................... 4 N. costata n. sp.

5' Penis tip without hump, everted endophallus basally wide, turning ventrad and bears dorsally many closely set spines, the ventral side is bare. Terminal section directed caudad and densely covered with spines on all sides ( Fig. 15 View FIGURES 11–15 )................................................................................................... 5 N. serrula n. sp.

5' Everted endophallus a plump sac standing in straight continuation of penis tube, basal dorsal and ventral sides not much different............................................................................................ 6

6 Distal half of penis tube and base of endophallus bare, only a ventrolateral band of spines connects to many small spines in distal half of endophallus ( Fig. 3 View FIGURES 1–5 )................................................ 1 N. transvaalensis (Enderlein) View in CoL

6' Paired swellings at base of endophallus densely covered with small spines. More distally follows a section with only few spines, distal half with many large spines ( Figs. 13–14 View FIGURES 11–15 )............................................... 3 N. lujana Navás View in CoL

7 Process of T7 with 2 small points. Small spines between tip of penis and base of curved endophallus, with many spines on the convex side, concave side bare ( Figs. 56–58 View FIGURES 56–58 ).............................................. 11 N. ivanloebli n. sp.

7' Process of T7 with single tip, endophallus different.......................................................... 8

8 Penis tube dorsodistally with patch of external spines. Base of endophallus dorsally with large curved hooks, ventral side bare ( Figs. 37–41 View FIGURES 33–41 )......................................................................... 8 N. luhohonis n. sp.

8' No external spines on penis tube, endophallus different....................................................... 9

9 Endophallus curved near base, exiting from penis subterminally on ventral side, the armature consists of stout triangular spines without order ( Figs. 33–36 View FIGURES 33–41 )............................................................... 7 N. rostrata n. sp.

9' Endophallus protrudes terminally from penis tube and is almost straight......................................... 10

10 Apex of penis tube unmodified. Endophallus covered by short conical spines ( Figs. 91–93 View FIGURES 91–95 )........ 17 N. planidorsum n. sp.

10' A bare membranous nipple dorsally on penis apex, endophallus long and straight, with armature of long needles ( Figs. 26–28 View FIGURES 26–32 ).................................................................................. 6 N. kalengonis n. sp.

Females (unknown of N. luhohonis , N. ivanloebli and N. rostrata )

1 Spermathecal stalk (SSt) U-shaped, the forward-directed base wide, with large folds, the back-curved distal section is smooth, finger-like. Eggs with approximately20 straight to slightly oblique strongly flanged ridges ( Figs. 46–49 View FIGURES 42–49 ).................................................................................................... 9 N. spectabilis n. sp

1' SSt entirely wide, base directed forward, curving sideward distally. Eggs variable.................................. 2

2 Vagina and base of SSt without large stacks of folds, SSt long and parallel, U-shaped, the two sections of similar length, full of elongate reddish spinules. Egg collar large, wide and inflated, cup-like ( Figs. 28–32 View FIGURES 26–32 )................ 6 N. kalengonis n. sp

2' Vagina and/or base of SSt with many large folds. SSt bent, the forward-directed section much shorter than the sideward section, armature colourless and hard to see. Egg collar narrow........................................................ 3

3 Anchor pole truncate, collar contracted, short, sometimes ring-like, no distinct cells ( Figs. 6, 8 View FIGURES 6–10 ). Eggs with approximately 12, of one morph with up to 16 ridges........................................................................ 4

3' Egg gradually narrowing towards collar which is either long or bears cells with high walls........................... 5

4 Folds on vagina form a pack behind base of SSt which is moderately long. Egg ridges without large ornaments ( Fig. 7 View FIGURES 6–10 )............................................................................... 1 N. transvaalensis (Enderlein) View in CoL

4' The largest folds on vagina behind attachment of long SSt project on the sides. Egg ridges with double row of large spheres ( Figs 9–10 View FIGURES 6–10 )........................................................................ 2 N. laticollis Klapálek View in CoL

5 No subgenital plate. Vagina short and wide, lateral sclerites far in front of genital opening ( Fig. 16 View FIGURES 16–17 ). SSt about as long as vagina, curved, no major folds, basal 2/3 with delicate scales. Egg ridges with blunt rounded top ( Fig. 21 View FIGURES 18–25 ), collar elongate, long to very long ( Figs. 18–20 View FIGURES 18–25 ), with rudimentary cells................................................... 3 N. lujana Navás View in CoL

5' Small, variable subgenital plate on S8. Egg with sharp ridges ( Fig. 22 View FIGURES 18–25 ), collar with distinct cells ( Figs 23–24 View FIGURES 18–25 )............ 6

6 S8 caudally rounded, vagina long and narrow ( Fig. 17 View FIGURES 16–17 ). Egg an elongate ovoid, or sides nearly parallel, ridges are smooth, cells on collar flanged ( Figs. 23–24 View FIGURES 18–25 )............................................................ 4 N. costata n. sp.

6' An indistinct transverse subgenital plate, vagina not elongated. Egg much wider near operculum than near collar, side view almost wedge-shaped, ridges finely serrate ( Fig. 25 View FIGURES 18–25 )............................................ 5 N. serrula n. sp.