Compsoneuria spectabilis Eaton, 1881

Sartori, Michel, 2014, The concept of Compsoneuria Eaton, 1881 revisited in light of historical and new material from the Sunda Islands (Ephemeroptera: Heptageniidae: Ecdyonurinae), Zootaxa 3835 (1), pp. 1-32 : 4-11

Compsoneuria spectabilis Eaton, 1881

Compsoneuriella thienemanni Ulmer, 1939 , Arch. Hydrobiol. Suppl. 16, p. 672, nymph (pro parte)

Compsoneuriella thienemanni Gillies, 1984 , Proc. 4th Int. Conf. Ephemeroptera, p. 21, nymph

nec Compsoneuria thienemanni Braasch & Soldán, 1986 , Reichenbachia 24(3), p. 41, adult, nymph

Material examined. Specimens in ethanol

1 male imago, Buitenzorg, 13.2.32. Lieftinck leg. [ ZMH]

1 male (one fore- and one hind legs on slide) and 1 female imagos, Buitenzorg, XI. 1919, Karny leg. [ ZMH]

1 female subimago, Buitenzorg, VII. 1929, Lampe , Thienemann leg. [ ZMH]

2 female imago and 1 male subimago, Buitenzorg, I. 1929, Lampe, Thienemann leg. [ ZMH]

4 nymphs (two mounted on slides), Indonesia, Java, Buitenzorg [ Bogor ], in Tjiliwung [ Ciliwung ] River , 25.V.1929, FB3, Prof. Thienemann leg [ ZMH, MZL] (sub. nom. C. thienemanni )

4 nymphs, Indonesia, West Java, Fish ponds south of the Puntjak pass , 13.IX.1928, B13, Prof. Thienemann leg [ ZMH] (sub. nom. C. thienemanni )

1 nymph, Indonesia, West Java, Buitenzorg, Pakantjilan River , 16.IX.1928, B7, Prof. Thienemann leg [ ZMH] (sub. nom. C. thienemanni )

8 nymphs (one mounted on slide), Indonesia, Sumatra Barat, Ombilin River , Talawi , 277 m., 00° 34.147’S 100° 43.543’E, 8.XI.2011, UN4, M. Balke leg [ MZL, ZMH, LIPI]

1 nymph, Indonesia, Sumatra Barat, stream near Lubuk Sikaping , 440 m., 0° 10.839’S 100° 08.533’E, 29.IX.2009, SUM12, M. Balke & D. Amran leg. [ MZL]

Pinned specimen. One male imago, Buitenzorg, Java. K. Kraepelin leg. 24.II–12.III.1904

Comments on the material examined of C. spectabilis . The pinned specimen is the one observed and mentioned by Klapálek (1905, p. 107) and illustrated by Ulmer (1924, fig. 53A, fig. 55C). In figure 53A the segment V of Klapálek’s specimen does not possess a sagittal dark banding, i.e. these marks are present only on segments III–IV and VI–VII. This drawing is thus an interpretation by Ulmer (1924, p. 86): “auf Tergit V manchmal undeutlich oder fehlend”.

Genitalia and legs of the 1919 male imago have been illustrated by Ulmer (1924, figs 56–58); the attribution of the specimen to coll. Jacobson in the legends is a probable mistake since the original label bears the name of Karny.

Sequence data. One specimen has been used for the study by Vuataz et al. (2013) under the name “ Heptageniidae 2” in figures and “ Heptageniidae sp. 2” in table S1, with one mitochondrial (CO1) and two nuclear genes (H3, wg) sequenced. Access numbers in GenBank are for CO1: HF536606 , for wg: HF536599 , for H3: HF 536592 .

Description. Male imago description based on the 1932 specimen. General coloration faded, with legs yellowish, thorax and compound eyes brownish-orange, wings translucent, costal and subcostal fields milky, abdomen translucent with ventral nerve cord whitish, gonopods yellowish, cerci whitish, some junctions between segments lightly tinted in orange, suggesting cerci originally banded with darker color.

Measurements: Body length: ca 6.5 mm; Forewing length: 6.9 mm; Gonopods length: 0.9 mm; Cerci length: ca. 14 mm

Head: Compound eyes large, meeting in middle at distance equal to distance between lateral ocelli; lateral ocelli two times larger than front one. Frons translucent with well-marked carina.

Thorax: Transversal suture on mesothorax present but barely visible; medial depression of furcasternum of mesothorax subparallel. Forewing ( Fig. 1 ) with few crossveins, arranged roughly in several rows; costal field with ca. 10 crossveins, subcostal field with only 6; hindwing as in Fig. 2 . Foreleg ( Fig. 3 ) with tibia ca 1.3x length of femur, and tarsi subequal or slightly longer than tibia; tarsal segment 1 very short, 4.5x shorter than second; segment 3 and 4 subequal, 0.8x length of segment 2, segment 5 0.5x length of segment 4; tarsal claw dissimilar, one obtuse, one hooked. Hind leg with tibia subequal to femur, tarsi shorter than tibia, tarsal segments 1 and 2 subequal, segment 4 the shortest, segments 3 and 5 subequal and slightly shorter than segments 1 and 2.

Abdomen (genitalia): styliger plate ( Fig. 6 ) almost straight, slightly emarginated adjacent to bases of gonopods.; basal segment rounded, 2x longer than wide; segment 1 short and broad, segments 3 and 4 subequal in length, together about ⅓ length of segment 2; segment 2 with small rounded inner projection at base. Penis lobes separated by V shape in ventral view ( Fig. 7 ) and U shape in dorsal view; lobes expanded laterally; apical sclerite long, extending to half length of lobe, with distinct subapical spine; base of apical sclerite tinted in orange brown, suggesting strong chitinization. In dorsal view, lateral sclerite broad and rounded, not constricted at apex, basal sclerite weakly developed, with small and acute spine directed inwards on outer margin. Titillators small but present, visible in ventral view, but barely visible in dorsal view.

Nymph. (Note: The nymph of C. spectabilis has been described by Ulmer (1939) under the name Compsoneuriella thienemanni (figs 442–454). It is redescribed here anyway for comparative purposes.)

Size: body length between 5.7 and 7.9 mm.

Coloration ( Fig. 79 ): head uniformly dark brown, except white spot around ocelli and transverse white line starting from lateral ocelli and reaching margin of head in front of compound eyes in perpendicular orientation; prothorax medium brown with two whitish spots, one proximal, one distal, on median part of each hemi-thorax, sometimes linked together with light line; dorsal face of femora greyish brown, with three elongated maculae on outer margin, sometimes less visible on inner margin, apices of femora and tibiae dark brown, tibiae uniformly medium brown, sometimes slightly banded; abdominal tergites medium brown, with markings, as follows: segments III, IV, VI and VII with double sagittal blackish line crossing whole segment, on segment V, diffuse yellowish macula in middle, on segments VIII and IX, elongate transverse yellowish macula crossed in middle by sagittal dark brown line, sometimes incomplete; posterior margin of tergites II–VII with blackish line enlarging when reaching sides; abdominal sternites uniformly whitish; cerci medium brown with dark brown banding every two segments.

Head: Labrum ( Fig. 8 ) greatly extended laterally, with narrow tips slightly turned posteriorly; anterior margin almost straight, covered by numerous long and simple setae; ventral surface with row of small stout setae; dorsal surface with scattered long and simple setae directed medially. Mandibles strongly arched, both with lateral margin covered with several rows of long and thin setae; right mandible ( Fig. 9 ) with outer incisor saw-like on its inner margin, composed of ca. 9 teeth, and with subapical tooth in ventral position; inner incisor trifid; presence of 4 fimbriate setae below incisors and 4 long and simple setae below mola; left mandible ( Fig. 10 ) with outer incisor saw-like on its inner margin, composed of ca. 6 teeth, and with subapical tooth in ventral position; inner incisor slender and pointed, bearing 4–5 setae-like structures arising from ventral face; 4 fimbriate setae present below incisors, followed by tuft of short setae above mola, and 8 long and simple setae below mola. Maxillae with row of ca. 13 comb-shaped setae on anterior margin, medial comb-shaped setae bearing 12–13 teeth ( Fig. 47 ); ventral surface of galea covered by scattered fimbriate setae ( Figs 45–46 ); proximal dentiseta bifid and fimbriate, first (outer) distal one fimbriate, second (inner) distal one entire ( Figs 43–44 ). Hypopharynx ( Fig. 11 ) with welldeveloped superlinguae, densely covered with long and simple setae on lateral margin, ending below rounded apex of lobes; lingua with tuft of small setae. Labium ( Fig. 12 ) characterized by well-separated glossae, somewhat rhomboid; paraglossae very large, and extending laterally, more than two times longer than wide.

Thorax: Leg ornamentation rather similar among fore-, mid- and hindlegs. Supracoxal spurs weakly developed on forelegs, apparent on mid- and hindlegs, rounded apically. Hindleg ( Figs 13 , 60 ) with femur bearing row of long and simple setae on its outer margin; inner margin with row of stout spines directed toward apex, and an incomplete submarginal row of stout spines; bristles on upper face of femora elongated ( Figs 14 , 62 ), with rounded apex; tibiae each with two rows of long and very thin setae, one on outer margin, one on lateral ridge ( Figs 13 , 61 ); inner margin with only 5–6 short spines regularly arranged. Tarsal claw hooked, with 3–4 subapical denticles ( Fig. 63 ).

Abdomen: Posterolateral projections weakly developed on segments I–IV, more pronounced on segments V–IX. Gills broadly oval ( Figs 16–18 ), fibrillate part well-developed on gills I–VI, absent on gill VII; plate gills with tracheation barely visible, strongly colored with purple gray on most of plate, except in apical region and close to margins. Posterior margin of tergites ( Fig. 19 ) with few but very large spines, with 2– 3 intercalary small pointed spines. Cerci with whorl of stout and pointed setae on each segment.

Eggs (from mature nymph and female): Size: 115–130 µm x 80 –95µm; chorion smoothly granulated, covered by polygonal ridges ( Fig. 21 a), and KCTs arranged in polygonal mesh with ridges joining them. KCTs on one pole regularly arranged and three times larger than those on other part of egg ( Fig. 21 b). Micropyles located in equatorial area, with prominent double margins ( Fig. 21 c).

Discussion. The specimens housed in ZMH completely fit the diagnosis proposed by Eaton (1885) and Ulmer (1924), especially concerning wing venation and leg proportions. Fig. 1 of the forewing is almost identical to Fig. 55 A in Ulmer (1924) of a female imago also from Buitenzorg. Figs 3 and 4 of the legs are identical to those proposed by Ulmer (1924) in Fig. 58 for another male imago from Buitenzorg. Genitalia are basically comparable in the general shape; Ulmer’s drawing ( Ulmer 1924, Fig. 56 ) exhibits the characteristic apical sclerite, although he did not draw the spine in ventral view, but mentioned it in the text and illustrated it in lateral view ( Ulmer 1924, Fig. 57 B). Major differences between the two drawings are the stem of the lobes which are clearly convex in our specimen but concave in Ulmer’s drawing, and the shape of the styliger plate which is not flat but concave with a pointed process in the middle.

As the specimen drawn by Ulmer (1924, Figs 56–58 ) is also deposited in the collections of ZMH, it has been re-studied and a complementary description and interpretation is given. The contour of the genitalia of the 1919 specimen in ventral and dorsal view is in accordance with Ulmer’s drawing, except the stem of the penis which is clearly convex. The shape of the styliger plate is undoubtedly different but results of a partial drying of the specimen which has folded the plate, hence making this “pointed process” apparent but not real. The basal segments of the gonopods are not in the same plane as the styliger because of the folding. Penis lobes are somewhat distorted and the lateral sclerites are not well visible but the two small spines at the base of the sclerites are noticeable as are those of the apical sclerites in lateral view ( Ulmer 1924, Fig. 57 B). Therefore, there is no clear difference between these two specimens, taking into account that the 1919 specimen is less well preserved than the 1932 one.

The major difference is the presence of concealed and hard to see titillators in C. spectabilis , as well as the presence of subapical spines on the ventral side of the penis lobes; these two structures were evidently overlooked by Ulmer (1924) in his redescription.

The slide preparation of fore- and hind legs made by Ulmer is presented in Figs 4 and 5 . Foreleg ( Fig. 4 ) with coloration patterns very characteristic; the dorsal face of the femur is covered by small and dark maculae in the distal part; apex of the femur with two dark maculae near the inner and the outer margins; proximal part of the tibia dark brown, becoming lighter distally on a short distance; apex of tibia medium brown, as are the distal outer part of each tarsal segments. Hindleg ( Fig. 5 ) with coloration patterns as in the foreleg.

There is a third male imago available in the ZMH collections, pinned and mentioned by Klapálek (1905), and also coming from Buitenzorg. The observation of the genitalia is difficult because of the twisted gonopods, but the general shape is in accordance with the two others, the apical sclerite with the median spine is present, the lateral sclerite has the same shape, but the minute spine at the base of the sclerite cannot be seen. Wing venation is in agreement with the one of the described specimen. This specimen is therefore also considered as belonging to C. spectabilis . It is the only one that gives an idea of the color patterns of the thorax and the abdomen.

The nymph of C. spectabilis described here is the only one known to belong to the genus Compsoneuria at the moment (but see discussion, and Fig. 80 ). The generic diagnosis therefore applies to the species C. spectabilis .

Figures

FIGURES 1 – 7. Compsoneuria spectabilis Eaton, male imago. Fig. 1: Forewing; Fig. 2: Hindwing; Fig. 3: Foreleg; Figs 4 – 5: Fore- and hindlegs of a 1919 specimen mounted on slide by Ulmer; Fig. 6: Genitalia; Fig. 7: Penis structure in ventral (left) and dorsal (right) view. Abbreviations: as: apical sclerite; ass: spine on the apical sclerite; bss: basal sclerite spine; ls: lateral sclerite; sas: subapical spine; tit: titillator

FIGURES 79–82. General overview of the nymphs, with emphasize on their supracoxal spurs (midleg). Fig. 79: Compsoneuria spectabilis; Fig. 80: Compsoneuria sp. from Sulawesi; Fig. 81: Compsoneuriella thienemanni; Fig. 82: Compsoneuriella tagbanua.

FIGURES 8 – 12. Compsoneuria spectabilis, nymphal mouthparts. Fig. 8: Labrum, with structure on the dorsal face (left) and ventral face (right); Fig. 9: Right mandible; Fig. 10: Left mandible; a: general view, b: details of the incisors; Fig. 11: Hypopharynx (left side); Fig. 12: Labium (left side).

FIGURES 43 – 47. Nymphal maxillae details of Compsoneuria spectabilis. Fig. 43: SEM view of the dentisetae, proximal dentiseta in red, distal dentisetae in yellow, with first one fimbriate; Fig 44: Same view in optical microscope; Fig. 45: SEM view of fimbriate scattered setae on the ventral face of the galea; Fig. 46: Same view in optical microscope; Fig. 47: SEM view of the comb-shape setae on the crown of the galea; abbreviations: dp: proximal dentiseta, dd 1, first distal dentiseta, dd 2 second distal dentiseta.

FIGURES 13 – 19. Compsoneuria spectabilis, thoracic and abdominal parts. Fig. 13: Hind leg; Fig. 14: Bristles on the upper face of hind femora; Fig. 15: Schematic cross section of the tibia and the respective position of the two rows of setae; Fig. 16: Gill I (only the plate drawn); Fig. 17: Gill V (only the plate drawn); Fig. 18: Gill VII; Fig. 19: Posterior margin of tergite IV.

FIGURES 60 – 67. Nymphal leg structures of Compsoneuria spectabilis (Figs 60 - 63) and Compsoneuriella thienemanni (Figs 64 - 67) with SEM. Figs 60 and 64: Dorsal view of the hind leg; Figs 61 and 65: Detail view of the posterior margin of the hind femur and the hind tibia; Figs 62 and 66: Bristle on the upper face of femora; Figs 63 and 67: Tarsal claw.

FIGURES 20 – 21. SEM pictures of eggs extracted from a female imago (Fig. 20) and from mature nymph (Fig. 21) of Compsoneuria spectabilis. Fig. 20: Female imago from Java, Buitenzorg, XI. 1919, Karny leg; Fig. 21: Female nymph (UN 4) from Sumatra, Ombilin River, Talawi, 8. XI. 2011, Balke leg.; a: egg in toto; b: detail of the pole; c: micropyle and detail of the chorionic structure.

FIGURES 55 – 59. Nymphal maxillae details of Notonurus sp. from Madagascar. Fig. 55: SEM view of the dentisetae, proximal dentiseta in red, distal dentisetae in yellow; Fig. 56: Same view in optical microscope; Fig. 57: SEM view of scattered setae on the ventral face of the galea; Fig. 58: Same view in optical microscope; Fig. 59: SEM view of the comb-shape setae on the crown of the galea.