Electrogena gibedede Godunko & Sroka, sp. nov.
Creators: name: Sroka, Pavel
name: Godunko, Roman J.
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Ephemeroptera
Heptageniidae
Electrogena
Electrogena gibedede

description: Electrogena gibedede Godunko & Sroka, sp. nov.   
Figures 1–34  
 Description. Male imago. Size: body length 7.5–8.0 mm, forewing length 8.0–9.0 mm, cerci length 20.0–24.0 mm (approximately 2.5 times longer than body).   
Head brown with paler clypeal part; compound eyes divided grayish dorsally and black ventrally (Figs. 1, 17). No stripes or bands on head. Ocelli black. Antennae pale brownish.  
Prothorax brown dorsally, paler in central part; ventrally dark brown (Fig. 17). Meso- and metahorax brown dorsally with light yellowish smudges; ventrally dark brown. Thorax laterally pale, yellowish with brownish sclerites (Fig. 17).  
Legs slender, all pairs with 5–segmented tarsus with one sharp and one blunt claw. Forelegs generally darker than other legs. Forefemur proximally pale brown, with darker margins. Distinct dark brown transversal band approximately at 2/3 of femur length (Fig. 17). Distal part of forefemur brownish. Dark brown transversal band also at distal end of femora, at articulation with tibia. Foretibia brown, darker than femur. Tarsal segments I–IV brown, slightly paler than tibia. Last tarsal segment darker, brown. Tarsal claws brown. Middle and hind legs of same coloration as forelegs; femora pale brown, with darker brown spot situated approximately at 2/3 of femur length. Tibia and tarsi brownish, darker than femur.  
 Wings hyaline, transparent, with easily visible brown venation. Costal and subcostal field slightly milky colored (mainly in pterostigmatic area). Pterostigma with several cross veins. Wings with typical of Electrogena venations.   
Abdominal tergites laterally brown with whitish pattern, consisting of pale triangles visible on laterocaudal portions of each tergite. Additionally, pairs of elongated pale spots situated dorsally on tergites, to side of central thin longitudinal pale line (Figs. 2, 3, 19). Sternites pale brownish, with very indistinct whitish pattern in central part, consisting of two oblique elongated spots situated frontally and two dots caudally. Distal part of sternite IX white. Neural ganglion visible in sternite VII.  
Cerci dark brown basally, towards distal end getting paler, with dark bands following individual articulations. Every second articulation more pronounced, accompanied by more distinct dark band than those between them. These differences are visible mainly in central part of cerci. All surface covered with dark hairs. Paracercus vestigial.  
 Genitalia: Styliger plate with apparent rounded projections on posterior margin. Forceps brown, on the proximal portion darker. Surface of forceps with numerous tiny rounded projections on inner side (Fig. 4). Penis with contrasting brown pigmentation. Penis lobes somewhat squared basally with abrupt step at outer margin of basal parts of penis lobes. Lobes separated distally with wide interspace, U or V–shaped (Figs. 5, 6, 21, 22). On dorsal side of penis lobes 1–2 larger teeth situated near lateral margin, may be accompanied by 1–2 smaller teeth, reaching length of approximately 1/3 of larger ones (Fig. 6). Titillators with small teeth apically.   
 Female imago. Size: body length 8–8.5 mm, forewing length 9–10.2 mm, cerci length 16–18 mm (approximately 2 times longer than body).   
Head brown, compound eyes and ocelli black (Fig. 18). Antennae brown, paler basally.  
Thorax dorsally and ventrally dark brown. Lateral portions yellowish. Legs more robust than in male imago. Femora and tibiae of similar coloration as in male imago. Tarsi uniformly dark brown. In some specimens middle and hind tarsi paler centrally (segments III and IV). Wings hyaline, transparent, with well visible brown venation. Costal and subcostal field slightly milky (mainly in pterostigmatic area).  
Color pattern of abdomen similar to those in male imago, slightly paler (Fig. 20). Neural ganglion visible on sternite VII. Subgenital plate widely rounded, reaching articulation of segment IX. Subanal plate distinctly bent.  
Cerci dark brown basally. Towards distal end getting paler, with dark bands following individual articulations. Every second articulation more pronounced, accompanied by more distinct dark band than those between them.  
These differences more distinct than in male imago and disappear only in distal third of cerci. All surface covered with dark hairs. Paracercus vestigial.  
 Male subimago Size: body length 8 mm, forewing length 8–9 mm, cerci length unknown.   
Head and antennae dark brown.  
Prothorax brownish. Mesothorax dorsally pale yellowish (especially in central part), with dark brown areas frontally, caudally and laterally. Lateral portions of mesothorax between wing insertion and coxae pale yellowish, with occasional darker sclerites. Ventral side of thorax mainly uniformly brownish or yellowish brown.  
Forefemora brown, with darker margins and two darker transversal bands distally (at approximately 2/3 of the femur length and near articulation with tibia). Foretibiae uniformly brown, slightly darker at articulations. Tarsi 5– segmented, with one sharp and one blunt claw. Tarsal segments I–IV of the same color as tibia, segment V and claws darker. Middle and hind legs generally paler than forelegs. Middle femora yellowish brown, with brown patch at approximately 3/5 of femur length. Further area dark brown. Middle tibia of same color as middle femur, dark brown only at articulation with femur. Middle tarsus 5–segmented, with one sharp and one blunt claw. Tarsal segments brownish, most distal segment and claws darker. Hind legs of same arrangement and color pattern as middle ones. Wings dull brownish with dark brown venation. No patches of darker coloration. Hind margin with row of tiny hairs.  
 Abdominal tergites I–X brown with two hooked, approximately L –shaped whitish spots situated laterally near the tergo-sternal suture. Longitudinal part of each L –shaped spot is pointing caudally. On tergites I, IX and X, these spots are not pronounced in some specimens. L –shaped spot may be accompanied at its caudal end by a single pale dot. Presence of further two longitudinally elongated whitish spots in central part of tergites IV–X. These spots situated near fore margin of each tergite. Central part of tergites I–III paler, thus elongated spots are not apparent. Sternites II–VIII yellowish brown with white pattern in central part, consisting of two oblique elongated spots situated frontally and two white dots caudally. Sternites IX and X brownish, sternite I whitish.   
 Genitalia: Penis lobes yellowish, titillators dark brown. Otherwise penis lobes without any dark markings. Incision between penis lobes indistinct. Typical shape of penis (squared, with abrupt, almost square-angled step at outer margin of basal parts of penis lobes) already well apparent. Titillators with teeth. Penis lobes, styliger plate and forceps densely covered with short hairs. On surface of forceps tiny articulated spines also present.   
Cerci dark brown, covered with short hairs. Individual articulations of segments with dark bands.  
 Female subimago. Size: body length 8 mm, forewing length 9.5–10 mm, cerci length 11 mm (approximately as long as body).   
Head and antennae dark brown.  
Dorsal side of prothorax brown, whitish posteromedially. Mesothorax of same color pattern as in male imago. Metathorax pale brown, darker at base of hind wings.  
Legs of same arrangement and color pattern as in male imago. Wings uniformly dull brownish with dark brown venation. No patches of darker coloration. Hind margin with row of tiny hairs.  
Abdominal color pattern same as in male subimago.  
Cerci dark brown, evenly covered with short hairs. Darker bands at individual articulations.  
 Mature larva. Size: body length (slightly differs between males and females): in male 5.8–6.9 mm; cerci length 7.6–8.2 mm, paracercus length 8.6–9.0 mm; in female 7.0–8.0 mm, cerci length 10.0 mm, paracercus length 11.0 mm.   
Head brownish with apparent light pattern, consisting of two spots near fore margin approximately in front of lateral ocelli. Further two light spots elongated transversally, situated near antennal bases (Figs. 7, 15). Lateral margins of head light colored.  
Prothorax yellowish with dark brown pattern. Lateral margins whitish. Longitudinal pale line in middle, extending towards its ends. Dark smudges laterally from this line, interrupted by pale areas near fore and hind margins of prothorax. Meso- and metathorax yellowish with darker brown smudges (Fig. 15).  
 Legs yellowish, with dark brown pattern. Femora with four distinct elongated dark spots dorsally; distal two spots partly fused near tibia insertion (Fig. 12). Tibiae uniformly yellowish, sometimes with dark smudge in central part. Tarsi brownish, indistinctly darker apically. Shape of bristles on dorsal surface of femora in Electrogena gibedede sp. nov. differs depending on leg pair and exact location of particular bristle on surface of respective femur. Bristles on forefemora unique among representatives of genus Electrogena, rounded and widened distally (Figs. 23, 24). Bristles of middle and hind femora more bluntly pointed or pointed, spine-like (Figs. 25, 26). Middle and hind tibiae with rows of hairs, approximately as long as tibia width. Hind tibiae with rows of hairs accompanied by short pointed bristles.   
Abdominal tergites with pronounced dark brown pattern and only several isolated spots of yellowish color. Each tergite with two light spots placed centrally and further two spots situated more posterolaterally, near hind margin of respective tergite. Moreover, another light smudge may appear posteromedially. This smudge may fuse with two light spots in central part of tergite and connect them together in some cases. Sometimes this light smudge extends even to further two posterolateral spots, forming band of lighter coloration along hind margin of tergite. Extension of posteromedial smudge is common mainly on tergites I–II, IV–V and VII–IX. Therefore tergites III, VI and X appears darker than rest of abdomen (tergite X sometimes even completely dark, without any lighter pattern) (Fig. 15). Isolated broad lighter areas present also laterally, near gill insertions. Abdominal sternites yellowish, well visible neural ganglion in segment VII; brown pattern of sternites mainly absent (Fig. 16). Posterior margin of tergites with the dense row of large spines pointed apically (Figs. 27, 28). Gills whitish with pale brownish tracheization; marginal areas transparent (Figs. 13, 14). Cerci yellow to yellowish-brown.  
 A set of standard larval diagnostic characteristics for identification of Electrogena species is provided below. In the present study we provide states and values for 30 characteristics of Electrogena gibedede sp. nov. Several features treated in the present study had not previously been used for the genus Electrogena, but Haybach (1999) used them for the differentiation of some species of the genus Ecdyonurus Eaton, 1868 (E. venosus species-group). The set comprises namely four characteristics concerning setae on the maxillary palp (N_PLS, N_PLBas, N_VEN, N_LPH). Since the structure of the maxilla of the genus Electrogena is very similar to that of representatives of the E. venosus species-group, these characteristics are used for the genus Electrogena here as well. One new characteristic (S_1GI) is added to the series of the standard diagnostic characteristics. It describes the shape of the first gill plate, which is unique in some Electrogena species (see below).   
Quantitative characteristics were measured in 13 specimens. Most features states are compared with the related species (focusing mainly on the species from the closely situated geographical regions, e.g. Caucasus Mts., Crimean Peninsula and Anatolia) and respective differences are pointed out.  
 Representatives of the genus Electrogena with known larvae, mostly recorded from the Caucasus Mts. and/or adjacent areas, which were taken for comparison in the list of the standard diagnostic features below, encompass the following species: E. affinis (Eaton, 1883), E. antalyensis (Braasch & Kazancı, 1986), E. armeniaca (Braasch, 1983), E. azerbajdshanica (Braasch, 1978), E. braaschi (Sowa, 1984), E. galileae (Demoulin, 1973), E. kuraensis (Braasch, 1978), E. lateralis (Curtis, 1834), E. malickyi (Braasch, 1983), E. necatii (Kazancı, 1987), E. pseudaffinis (Braasch, 1980), E. squamata (Braasch, 1978) and E. zimmermanni (Sowa, 1984).   
 Due to the general lack of knowledge of the species of the genus Electrogena in the Caucasus Mts., ratio values of quantitative characteristics used in the present study for comparison with Electrogena gibedede sp. nov.   
were in some cases derived from the original drawings. Thus, they can be taken only as a pointer to the most pronounced differences. Moreover, the states of maxillae structure are unknown in most Caucasian species; since descriptions of the species do not often contain any specification of maxillae arrangement.  
 Recent redescriptions of two species (E. galileae and E. antalyensis, see Belfiore & Sartori 1999 and Belfiore et al. 2000, respectively) are most useful for the comparative study.   
Mean, range and variance are presented for each quantitative characteristic.  
 Quantitative characteristics:   
1. N_PLP – 15.07, 14–16, 0.46  
 The number of hairs near the fore margin of the first segment of maxillary palp (Fig. 11). Non-overlaping range has E. antalyensis (0–6). Range overlaps with E. galileae (7–19) and E. lateralis (7–21). 2. N_PLH – 0, 0–0, 0   
 Long hairs on the hind margin of the first segment of maxillary palp missing. Such long hairs present only in E. affinis.   
3. N_OUT – 0, 0–0, 0  
 Bristles on the outer margin of galea-lacinia are always missing. This characteristic is shared with E. galileae and E. malickyi. In other representatives of the genus bristles are present at least in some specimens (E. affinis 0–1; E. lateralis 0–10). In E. antalyensis, the number of bristles is particularly high (mean 6.5–24). 4. N_CBS – 14.23, 12–16, 1.10   
 The number of comb-shaped bristles on the fore margin of galea-lacinia is low. E. antalyensis and E. lateralis have a slightly higher number of bristles (means 15.93 and 17.30, respectively). E. galileae is a non-overlapping species (19–21.5).   
5. N_TCB – 7.42, 7–8, 0.20  
 The number of pointed teeth on the 5th comb-shaped bristle is low. E. galileae has a non-overlapping range (13–16). E. antalyensis has an overlapping range, but a generally higher number of teeth (10.34). E. lateralis has an overlapping range (7–13).   
6. N_CLW – 2, 2–2, 0  
 The species always posses 2 teeth on the tarsal claws (Figs. 29, 30). This characteristic is shared by numerous Electrogena species, only E. antalyensis posses more teeth (4–9 in two rows). Some specimens of E. galileae have up to 4 teeth (2–4). Invariably one tooth is present in E. lateralis and E. squamata. 7. N_BVF – 30.08, 25–34, 8.076   
 The number of bristles on the ventral side of femora near the hind margin is high. Other species with a high number of bristles is E. galileae (22.45). The maximum number of bristles shared by other species is 3. Bristles are short and pointed apically, which is a characteristic shared by all other species except for E. galileae with the bristles rounded apically.   
8. N_HFF – 0, 0–0, 0  
 The number of long hairs (at least twice as long as neighboring bristles) on the fore margin of femora. Electrogena galileae sp. nov. has three very long hairs near the base of femora. E. affinis has 8–58 such hairs along the femoral margin.   
 Four more meristic characteristics were measured for Electrogena gibedede sp. nov. The characteristics proved to be useful for the taxonomy of the related E. venosus species-group (Haybach 1999) and are proposed here for the genus Electrogena for the first time.   
9. N_PLS – 33.077, 25–41, 14.80  
The number of bristles on the hind margin of the first segment of the maxillary palp. 10. N_PLBas – 7.63, 6–11, 4.59  
The number of hairs at the base of the maxillary palp.  
11. N_VEN – 13.88, 10–19, 10.01  
The number of hairs on the ventral surface of galea-lacinia.  
12. N_LPH – 20.05, 17–24, 5.66  
The number of bristles on the hind margin of the first segment of the labial palp. Several of these bristles form a separate group at the distal part of the hind margin, near the articulation of the second segment. This group contains 2–7 bristles.  
 Qualitative characteristics:   
 13. S_HLB – The tips of hypopharyngeal superlinguae are covered with hairs shorter than those on the fore margin of superlinguae (Fig. 8). Most of the hairs on the tips are no longer than 1/3 of the length of the fore hairs. However, several individual hairs approximately as long as 1/2 of the fore hairs may occur. This arrangement is unique and different from the species with very short hairs of the same length on the tips, in those cases not exceeding 1/4 of the fore hair length (E. lateralis, E. galileae), or from all other species with hairs of the same length as fore hairs situated on the superlingual tips.   
 14. S_GLO – The shape of glossae quadrangular, Ecdyonurus -like, in contrast to the subtriangular shape of glossae in E. antalyensis (Fig. 10). This characteristic is shared with all other Electrogena species.   
 15. S_PGL – The paraglossae are widely rounded laterally. In another Caucasian species E. pseudaffinis the lateral parts of paraglossae are almost straight, whereas in E. galileae they are somewhat pointed.   
 16. S_PNT – The hind corners of the pronotum are smoothly rounded, in contrast to the abrupt step present in related Caucasian species, especially in E. squamata or some specimens of E. antalyensis.   
 17. S_BFE – The bristles on the upper surface of forefemora are spatulate, extended towards the apex and rounded apically. This is a rare arrangement among the genus, shared only with E. galileae. Most Electrogena species posses long and pointed or bluntly pointed bristles of forefemora. Such an arrangement is typical for all other Caucasian species.   
 18. S_BFF – The bristles arranged in a row on the hind margin of femora are long, their length is approximately equal to 1/2 of the maximal femur width in all leg pairs. This characteristic state can be observed in almost all other Electrogena species. A different arrangement with very short bristles may be found in E. antalyensis. 19. S_TAR – The dark band on tarsi is indistinct and situated apically.   
 20. S_1GI – The shape of the first gill is slightly curved, with convex, almost parallel margins, steeply converging and rounded apically, forming a “hump” on the fore margin (Fig. 14). It differs from species with margins converging throughout the gill length (e. g. E. azerbajdshanica, E. pseudaffinis, E. kuraensis, E. squamata). It is similar to the gill shape of E. malickyi and E. affinis. The convexity of the fore margin is less pronounced in some specimens. 21. S_7GI – The shape of the seventh gill gradually narrows towards the apex (Fig. 13), differring from species with a broad proximal part of the gill, suddenly narrowing at the apex; see E. zimmermanni in Sowa (1984: Fig. 37). The gill plate is rounded apically, with a distinct row of short hairs along the distal 1/3 of the fore margin. 22. S_PLB – The bristles on the hind margin of the first segment of the maxillary palp are distributed in three irregular rows. The length of bristles is approximately 1/3 of the segment width. This is shared by all other Electrogena species except for two species with shorter bristles: E. galileae (about 1/4–1/5) and about 1/ 4 in E. zebrata (Hagen, 1864).   
 23. S_LBB – The paramedian bristles on the ventral surface of the labrum are arranged in a single row. Such an arrangement is present in most other species, with the exception of E. galileae, which exhibits two rows of bristles. 24. S_HEM – The head is brownish, with light but clear markings (Fig. 7). There are two light spots on the fore margin of the head capsule (distance between these spots approximately equal to distance between lateral ocelli). There are further areas of lighter coloration along the lateral margins, anterior to the antennal insertions and along the posterior margin. Presence of a narrow light stripe anterior to the median ocellum and dark brown spots in the area of the lateral ocelli and eyes. Among other representatives of the genus, similar light markings are present only in E. affinis, E. galileae and E. pseudaffinis, but the arrangement is different in E. affinis (light spot along posterior margin of head is missing).   
 25. S_HEA – The shape of the head capsule is symmetrical and oval, without distinct narrowing in the fore part (contrary to E. antalyensis).   
 Ratio characteristics:   
26. R_1GI – 2.06, 1.89–2.14, 0.005  
 Length/width ratio of the first gill plate. It differs from that of species with a distinctly narrower first gill (E. squamata, the ratio – 4.45 and E. zimmermanni, the ratio – 2.67), and from that of species with a distinctly wider first gill (E. necatii, the ratio – 1.57; E. antalyensis, the ratio mean – 1.60 and E. armeniaca, the ratio – 1.78). 27. R_7GI – 2.24, 2.0–2.55, 0.043   
 Length/width ratio of seventh gill plate. It differs from that of species with a distinctly wider seventh gill (E. armeniaca, the ratio – 1.83 and E. braaschi, the ratio – 1.84).   
28. R_LBR – 4.72, 4.55–5.25, 0.049  
 Total width of labrum/mean width of the lateral lobe of labrum. The value of this ratio is approximately shared by most species from the genus Electrogena, occurring in the Caucasus Mts. and adjacent territories (Fig. 9). E. galileae (the ratio – 3.86) and E. braaschi (the ratio – 4) posses significantly more pronounced lateral lobes of labrum.   
29. R_GLA – 3.83, 3.46–4.56, 0.124  
 Distance between glossae. This feature differs in species with an apparently narrower distance between glossae (E. necatii, the ratio – 6).   
30. R_GLB – 2.74, 2.55–3.06, 0.017  
 Width of glossae. Glossae are moderately wide among all Electrogena species.   
 Egg (Figs. 31–34). Size: length 110–160 μm; width 70–95 μm. Egg oval, slightly elongated (Fig. 31). The chorionic surface only with rare KCTs attachment structures, which are assembled in small groups (15–30 KCTs) in the subequatorial region or in the region of the pole cap (Fig. 34). The chorionic surface covered with numerous small rounded tubercles (1.2–1.8 μm) and delicate granules (granular ground matrix) (Figs. 32, 33). Two to three micropyles are visible in the subequatorial region; micropylar rim is absent (Fig. 32).   
 Haybach (2008) used the word “naked” for the description of the eggs with lacking attachment structures. The same structure of chorion is known in E. gridelii (Grandi, 1953), E. fallax (Hagen, 1864) and E. antalyensis (see Gaino et al. 1987; Belfiore et al. 2000), in contrast to another species of Electrogena (e.g. E. affinis; see Belfiore et al. 1999) with numerous adhesive elements on the chorionic surface.   
 Etymology. The species epithet refers to the name of the Russian State Inspection of Road Safety (acronym GIBDD).The species is named in honor of those few honest officers of the Russian road police whom we have met during our travels while collecting the new species.   
 Affinities. Comparison of Electrogena gibedede sp. nov. with the related Caucasian species is particularly difficult due to the very poor available descriptions of almost all possibly sympatric species (the values of standard diagnostic characteristics are mostly unknown and only some of them can be roughly estimated from the original drawings). Conclusions about the closeness of relationships between individual Caucasian species of Electrogena based on morphological similarities can therefore be only very restricted.   
 Most morphological differences in the larval stage between Electrogena gibedede sp. nov. and other individual species of the genus Electrogena occurring in the area of question have been mentioned above in the descriptions of the individual standard diagnostic characteristics. Nevertheless we can generalize that from all species of the genus with known larvae, occurring in the area of question, Electrogena gibedede sp. nov. can be easily distinguished according to the current knowledge mainly by the combination of characteristics, as follows: (i) shape and color pattern of the head capsule (Fig. 7); (ii) shape of paraglossae, rounded laterally; (iii) setation of superlinguae with long hairs on the tips (Fig. 8); (iv) joint between pronotum and mesonotum smooth, without abrupt step (Fig. 15); (v) unique shape of bristles on upper surface of forefemora, widened towards the apex and rounded (Figs. 23, 24); (vi) presence of two teeth on the tarsal claws (Figs. 29, 30); (vii) shape of gill I with subparallel margins for most of the gill length (Fig. 14); (viii) shape of gill VII, gradually narrowing towards apex (Fig. 13).   
 At the imaginal stage males of Electrogena gibedede sp. nov. exhibit a unique arrangement of genitalia with almost square angled proximal parts of penis lobes. These diagnostic characteristics distinctly differentiate the new species from all other representatives of the genus Electrogena described so far, the latter displaying penis lobes mostly rounded or sub-triangular.   
 The coloration of the adult abdomen, consisting of a triangular pattern from the lateral point of view, is also characteristic for Electrogena gibedede sp. nov., shared only by E. armeniaca, E. ressli and E. dirmil. The characteristic coloration of abdominal tergites together with the absence of distinct coloration of the sternites can also be used in discriminating females and subimagines.
description: Published as part of Sroka, Pavel & Godunko, Roman J., 2012, Mayflies of the Caucasus Mountains. I. A new species of the genus Electrogena Zurwerra & Tomka, 1985, pp. 28-45 in Zootaxa 3222 on pages 29-42, DOI: 10.5281/zenodo.280262