Oligoneuriopsis orontensis (Koch, 1980) Barber-James & Zrelli & Yanai & Sartori, 2020

Barber-James, Helen M., Zrelli, Sonia, Yanai, Zohar & Sartori, Michel, 2020, A reassessment of the genus Oligoneuriopsis Crass, 1947 (Ephemeroptera, Oligoneuriidae, Oligoneuriellini), ZooKeys 985, pp. 15-47 : 15

Oligoneuriopsis orontensis (Koch, 1980) comb. nov. Figures 9B , 10B , 11D-F , 12B , 14F

Oligoneuriella orontensis Koch, 1980: 154, figs 1-4 (nymph).

Material examined.

Israel • 1N; Jordan River, Ateret Fortress; 33.0032°N, 35.6286°E; alt. 63 m a.s.l.; 7 May 1990; H. Glassmann & M. Sartori leg.; MZL • 1N; same locality; 7 May 1991; H. Glassmann & M. Sartori leg.; MZL • 5N; same locality; 8 Dec. 2014; Z. Yanai leg.; SMNH • 15N, 3♂; same locality; 29 Oct. 2015; Z. Yanai & Y. Brenner leg.; SMNH • 14N; same locality; 16 May 2016; Z. Yanai & A. Charvet leg.; SMNH • 8N; same locality; 2 Jun. 2016; Y. Hershkovitz & T. Eshcoly leg.; SMNH • 3N (1N - GBIFCH00759464 - sequenced); same locality; 11 Mar. 2017; Z. Yanai & J.-L. Gattolliat leg.; MZL, SMNH • 4N (2N - GBIFCH00664952, GBIFCH006759463 - sequenced); same locality; 27 Mar. 2019; Z. Yanai leg.; MZL, SMNH • 2N; Dan Stream, st. 6; 33.1320°N, 35.3845°E; alt. 120 m a.s.l.; 10 May 1990; A. Reuven & M. Sartori leg.; MZL • 4N; Senir (Hasbani) Stream, upstream Ma’ayan Barukh Bridge; 33.2253°N, 35.6152°E; alt. 103 m a.s.l.; 10 May 1990; A. Reuven & M. Sartori leg.; MZL • 1N; same locality; 10 May 1991; A. Reuven & M. Sartori leg.; MZL • 2N; Senir (Hasbani) Stream, downstream 'En Barukh; 33.2308°N, 35.6209°E; alt. 119 m a.s.l.; 10 May 1990; A. Reuven & M. Sartori leg.; MZL • 2s♀, 1♂; same locality; 25 Jul. 1990; A. Reuven leg.; MZL • 4s♀, 3♂; same locality; 10 May 1991; A. Reuven & M. Sartori leg.; MZL • 4N; Hermon (Banyas) Stream, Kefar Szold; 33.1301°N, 35.3832°E; alt. 100 m a.s.l.; 8 May 1991; A. Reuven & M. Sartori leg.; MZL • 1N; Jordan River, haDodot Bridge; 32.9318°N, 35.6226°E; alt. -161 m a.s.l.; 29 Jul. 2015; Y. Hershkovitz & T. Eshcoly leg.; SMNH • 2N; Jordan River, Park haYarden; 32.9091°N, 35.6235°E; alt. -203 m a.s.l.; 2 Jun. 2016; Y. Hershkovitz & T. Eshcoly leg.; SMNH • 2s♂; Senir (Hasbani) Stream, Beth Hillel; 33.1989°N, 35.6108°E; alt. 82 m a.s.l.; 6 Aug. 2020; Z. Yanai & A. Hershko leg.; SMNH.

Male imago.

Lengths. Body: up to 18 mm; forewing: up to 17 mm; cerci: up to 15 mm; caudal filament: up to 13 mm.

Vertex light brown, frontoclypeus yellowish, compound eyes greyish black, base of ocelli black, ocelli whitish, antennae with pedicel light brown and flagellum medium brown.

Pronotum light brown, washed with grey. Pterothorax light brown, with a large mesonotal suture yellowish. Forelegs with outer margin of femora, tibiae and tarsi medium brown, inner margin yellowish; mid- and hindlegs yellowish, with distinct inner brown maculae on the femoro-tibial articulation; wings, when folded, light brown, almost whitish when unfolded.

Abdominal segments uniformly yellowish, without distinct patterns, except sides of tergite IX, tergite X and sternite IX light brown; gonostyli and cerci whitish.

Forelegs functional, tibiae and tarsi of middle and hind legs weakly sclerotized and non- functional. Tarsal claws blunt. Forewing typical of the genus, with 5 groups of veins: Sc+RA, RSa+iRS, RSp+MA1, MA2+MP1, and a forked MP2+CuA - CuP vein. Subcostal field with numerous transversal veins, those issued from RA not reaching iRS in the distal forth of the length, those between iRS and MA1 only present in the proximal half.

Gonostyli 4-segmented, the basal one ca. 4 × the length of segments 2 to 4 combined; a fifth segment can sometimes be present (Fig. 9B ). Penis lobes with characteristic sclerotized proximal process ending in a bifid projection; lateral longitudinal lobe ending in a distinct club-shaped sclerite more than 2 × larger than the lateral lobe. Cerci with whorls of long setae at each junction.

Female subimago.

Lengths. Body: up to 23 mm; forewing: up to 21 mm; cerci: up to 7 mm; caudal filament: up to 5.5 mm.

Colouration as in the male, except antennal pedicel entirely medium brown, forefemora with outer margin sepia, tibiae and tarsi of all legs atrophied, twisted on forelegs; tarsal claws reduced to a single pointed and unsclerotized filament. Cerci light to medium brown. Posterior margin of sternite IX deeply concave and rounded.

Nymph

(Fig. 10B ). First described by Koch (1980) sub nomen Oligoneuriella orontensis .

Lengths. Body up to 14 mm and 19 mm in male and female nymphs respectively; cerci (and caudal filament) up to 7 mm (5 mm) and 9 mm (7 mm) in male and female nymphs respectively.

General colouration light to medium brown, always lighter in male nymphs. Head medium brown, yellowish between the compound eyes. Pronotum medium brown, with yellowish areas sublaterally. Pterothorax medium brown, with yellowish maculae very characteristic (see Koch, 1980, fig. 4). Legs light brown, femora medium brown in the proximal half, lighter distally; femoro-tibial articulation darker, especially notable in mature nymphs. Setae on the outer margin of hind femora well developed, but not reaching the apex (if reaching it, then much smaller than the proximal ones) (Fig. 14F ). Outer margin of hind tibiae without a row of long and thin setae (Fig. 12B ). Abdominal tergites uniformly medium brown, each with a pair of light spots in the middle and one or two light maculae laterally; sternites with four spots on a transverse line and two elongated maculae anteriorly, altogether six spots creating sort of a circle (most notable in mature nymphs). Gills II-VII almost subequal in size, gill I smaller, ventral. On all gills, fibrillae shorter or subequal to lamella length. Lamellae II-VII with long and thin setae on their distal inner margin. Posteromedially sternal patch of long and thin setae present on segments II-IV(V). Posterolateral spines of the abdomen increasing in size posteriorly. Cerci uniformly dark brown, sometimes medium brown with a wide median dark band or with apex light brown.

Eggs.

General shape rhomboid, ca. 300 µm long and 270 µm wide, chorionic surface finely granulated (Fig. 11D ), micropyle tagenoform, smooth, sperm guide well apparent (Fig. 11E ), KCT’s rather regularly arranged, ca. 10 µm of diameter, formed by coil-thread ending in a leaf-like and flat structure (Fig. 11F ).

Affinities.

In male imagos, O. orontensis differ from all other known species by the apex of the lateral sclerite of the penis, which is greatly enlarged, even more than in O. dobbsi , and the proximal process of the penis which is bifid. Nymphs are characterized by a row of setae on the outer margin of hind femora which does not reach the apex compared to other species studied, except O. jessicae to some extent, and differs to all other known species by the absence of a row of setae on hind tibiae.

Habitat preference.

In Israel, found in well-oxygenized streams with high water discharge and current velocity ( Yanai et al. 2020). The scarcity of these habitats in the Levant may be the reason for its recent decline in Israel, and perhaps in other countries, although no recent data are available.

Known distribution.

Israel, Lebanon, Syria, Turkey.

Comments.

Al-Zubaidi and Al-Kayatt (1986) reported on " Oligoneuriopsis sp." from northern Iraq (later cited by Abdul-Rassoul 2020). These individuals may belong either to O. orontensis or O. villosus , thus pushing distribution slightly eastwards or westwards, respectively. While both alternatives are possible in terms of ecology and geography, it is very likely that these specimens were misidentified and in fact belong to the genus Oligoneuriella , the only oligoneuriid reported by the authors in the following year ( Al-Zubaidi et al. 1987). Until further information is available, we ignore this report from Iraq.

Figures

Figure 9. Genitalia of Oligoneuriopsis in ventral view A O. skhounate B O. orontensis. Black arrows: Apex of the lateral longitudinal lobe of penis. White arrows: Proximal process of penis. Scale bar: 1 mm.

Figure 10. Habitus of Oligoneuriopsis nymphs in dorsal view A O. skhounate B O. orontensis. Scale bar: 5 mm.

Figure 11. O. skhounate (A-C) and O. orontensis (D-F) A, D shape of the egg B, E micropyle C, F KCT's.

Figure 12. Hind legs of Oligoneuriopsis in dorsal view, showing femoral and tibial setation A O. skhounate B O. orontensis. Scale bar: 1 mm.

Figure 14. Hind femora of representative Oligoneuriella (A-C) and Oligoneuriopsis (D-F) species A Oligoneuriella rhenana B Oligoneuriella pallida C Oligoneuriella skoura D Oligoneuriopsis lawrencei E Oligoneuriopsis skhounate F Oligoneuriopsis orontensis.