Torleya padunica Kazlauskas, 1963

Gorovaya, E. A. & Semenchenko, A. A., 2024, MORPHOLOGICAL REDESCRIPTION AND DNA BARCODING OF TORLEYA PADUNICA KAZLAUSKAS, 1963 (EPHEMEROPTERA, EPHEMERELLIDAE) FROM THE EAST PALAEARCTIC REGION, Far Eastern Entomologist 501, pp. 1-16 : 4-12

Torleya padunica Kazlauskas, 1963

Figs 1–35

Torleya padunica Kazlauskas, 1963: 584 , figs 13–19 (holotype and paratype – mature larvae, Russia: Irkutskaya Oblast; lost); Kluge, 1995: 42; Tiunova, 1995: 56, figs 10–16; Jacobus et al., 2004: 170; Jacobus & McCafferty, 2008: 202. Ephemerella (Torleya) padunica Kluge, 1997: 213 .

TYPE MATERIAL. Neotype – male imago (reared from larva), Russia: Primorsky Krai, Khasansky district, Amba River , 01.VII 2020, coll. E. Gorovaya, here designated; deposited in the collection FSC Biodiversity (Vladivostok).

OTHER MATERIAL EXAMINATED. Russia: Primorsky Krai, Khasansky district, Amba River, 01.VII 2020, 13 larvae, 1 female subimago, 6 females imago, 1 male subimago and 8 males imago (all reared) ( EG); same locality, 06.VII 2020, 4 females subimago, 5 males subimago and 3 male imago (light) ( EG); Republic of Sakha (Yakutiya), Aldan River basin, Ungra River , 28.VII 2006, 1 larva, 6 mails imago ( TT); Zabaikalsky Krai, Chornaya River , 29–30.VII 2005, 1 mail imago ( TT); Amurskaya Oblast , Bolshoi Oldoi River , 31.VII 2005, 6 mails imago ( TT); Republic of Buryatiya, Vitim River , 57 km from the mouth of the Baisa River , 20VII 1960, 1 larva (I. Sukachova) (one claw of mid leg on slide) [collection of N. Kluge] .

DESCRIPTION. MALE IMAGO (in alcohol). General body color yellowish ( Figs 1, 2 ). Length (mm): body 4.8–5.6; forewings 5.1–5.6, cerci 5.3–6.0.

Head: upper portion of the eyes brown (while alive ginger); lower one black.

Thorax: yellowish with light brown tint. Forewings hyaline, pterostigma and area between Sc and R dull white. Veins unpainted, poorly visualized ( Fig. 3 ). Hind wings hyaline ( Fig.4 ). Legs creamy white. Length (mm) of foreleg segments: femora 1.2; tibiae 2.4–2.6; tarsal segments 0.6–0.7, 0.5–0.6, 0.3–0.4, 0.2, 0.05 ( Fig. 5 ). No maculation on femora surface.

Abdomen creamy white; terga I–VI hyaline. Styliger, gonostyli and penis creamy white, slightly hyaline ( Fig. 6 ). Styliger with wide low rounded protrusion ( Fig.7 ). Gonostyli tartareous, with papillae on inner surface. Gonostyli segments 1 and 2 poorly separated, segment 3 elongate, oval-shaped, slightly expanded at the base ( Figs 7–9 ). Penis lobes wider in upper part, divided by less than a quarter, outer edges rounded, tops pointed ( Figs 9 –11). Each lobes with acute dorsal projection: low part triangular, slightly elongated ( Fig. 9 ); on ventral side bear well developed spines in apical part ( Figs.10 , 11). Cerci creamy white, subequal to medial filament.

MALE SUBIMAGO. Measurements and body color similar to those in male imago; abdomen and forewings creamy white, opaque.

FEMALE IMAGO (in alcohol). Length (mm): body 5.0–5.2; forewings 6.0–6.2; cerci 4.6. General color of body similar to that in male imago, but abdomen dark creamy due to transculent eggs. Eyes grey with ochroid tint. Subanal plate convex, roundish (Fig. 12).

FEMALE SUBIMAGO. Measurements and body color similar to those in female imago; abdomen no hyaline. Forewings creamy white, opaque.

MATURE LARVA (in alcohol). Length (mm): body 3.7–4.4; cerci and paracercus 1.7–2.0. General body color creamy white (alive larvae with pale yellow tint) with light brown maculation ( Figs 13, 14 ). All sclerotized structures abundantly covered with micro-thin transparent hairs.

Head: without tubercles or projections, creamy white, with big brownish spot above labrum and sometimes, with small brownish mosaic spots between eyes ( Fig. 15 ). Upper part of eyes of male brown (while alive ginger), lower one black. Antennae long, creamy white.

Mouthparts: Labrum pale, brownish; dorsal surface densely covered with long hairlike setae, ventral – small spikes; length to width ratio 1:2 anteromedian emargination well-marked ( Fig.16 ). Hypopharynx wide, rounded, apical part densely covered with small spikes; superlinguae uniformly wide, with long thick setae along anterior and inner margins ( Fig. 17 ). Mandible broad; right incisor with three ( Fig. 18 ) rounded teeth; left incisor with three tapering teeth ( Fig. 19 ). Maxilla wide, apex pointed with three teeth and some long thin setae near its base on external margin of maxilla ( Fig. 20 ). Massing of multitudinal long thin setae is absent. Inner margin of maxilla with rows of strong dentiform setae. Maxillary palp 2-segmented with single thin setae on apex. Glossae closely approximate, some narrower and longer than paraglossae; both with long strong setae on distal parts. Labial palpus 3-segmented ( Fig. 21 ); 1st and 2nd segments of labial palpus wide, rectangle; 3rd segment conical; transition from 2nd to 3rd segment smooth.

Thorax: Pronotum light brown with small creamy white roundish spots. Mesonotum and rudiments of fore wings maculation ( Fig. 22 ). All legs creamy white with light brown belts: more clearly expressed on femurs and tarsi, less – on tibiae (especially hind leg); densely covered by long setae and hairs ( Figs 23–25 ). Length (mm) of segments of legs (femur; tibia; tarsus): fore: 0.5–0.7; 0.4–0.5; 0.25–0.35; mid: 0.6–0.8; 0.4–0.5; 0.3–0.35; hind: 0.7–0.8; 0.4–0.5; 0.25–0.35. Femurs of fore leg wide, oval; femurs of mid and hind legs more elongate. All claws with two rows of denticles: three to four short basal denticles and preapical palisade with four to five long denticles ( Figs 26–28 ).

Abdomen: Tergites I–IV, VI light brown with small creamy white roundish spots along middle line, terga V lighter, tergites VII–X all over creamy white. Tergites III–IIX with well-developed acuminate creamy white posterolateral projections. Lateral margins of tergites II–IX with strong, long and middle setae and hairs. Abdominal tergal paired spines absent; on its position long, thin, hard setae. Posterior margins of abdominal tergites V–IIX with paired tufts of long, thin, hard setae ( Fig. 29 ). Sternites creamy white without maculation. Abdominal gills on tergites IV–VII imbricated. Length of gills of larvae 5 mm (mm): I, II–0.7; III – 0.5; IV – 0.35; V – 0.1. Gill V consists of two large and three small but quite wide plate ( Figs 30–34 ). Caudal filaments creamy white; every fourth segment brownish ( Figs 13, 14 ).

Egg (Taken from imago). Measurements: length 157−166 μm; width 100−109 μm. Shape oviform with one polar cap. Form of polar cap depends from the quality of cleaning and can be wide and flat or a bit fastigiate ( Fig. 35 ). Surface of the chorion with geometric relief: wide reticulation with mesh about 11.4–12.3 μm formed by raised porous ridges with thickness 4.5–4.9 μm. Bottom of each mesh unit hillocky. Papillae of inner margin of ridges are not explicitly expressed. Lateral attachment structures represented by multitreads-folded with terminal fibre cluster (MFT) which widely-spaced all over the surface. Micropyle (two to three in the field of vision) pear shaped with narrower part near micropylar opening in shape. All micropyles with porous rim and situated in the equatorial part of egg.

DISTRIBUTION. Russia: Irkutskaya Oblast , Republic of Buryatiya, Zabaikalsky Krai, Republic of Sakha (Yakutiya), Amurskaya Oblast, Jewish Autonomous Oblast, Khabarovsky Krai, Primorsky Krai.

TAXONOMIC NOTES. Larvae only five species of the genus Torleya have relatively well-developed maxillary palp: T. padunica , T. cohery ( Allen et Edmunds, 1963) (Oriental region), T. dibruensis Selvakumar, Martynov et Jacobus, 2021 (Oriental region), T. elissa (Jacobus, Zhou, et McCafferty, 2009) (East Palaearctic region) and T. major Klapálek, 1905 (West Palaearctic region). All these species differs well from T. padunica in a number of characters. So, T. cohery has special form of mandibles and labium; tarsal claws with a significant number of long denticles in palisade (more than five); abdominal segment 8 with a narrow acute posterior projection, posterolateral projection on segment 9 extends posterolaterally beyond margin of segment 10 ( Allen & Edmunds, 1963: figs 15, 17–19; Martynov et al., 2021: fig. 10). T. dibruensis has terga IV–VII and IX with paired posterior protuberances and dorsal lamella of gill III which extending to middle of tergum VIII ( Tiunova, 2024: fig. 12B). T. elissa has maxillary palp with three segments, specific form and location of the denticles on claws ( Martynov et al., 2023: figs 7, 9d, 9e). Micro-thin transparent hairs on all sclerotized structures are absent ( Jacobus et al., 2009). Claws of T. major without palisade of the denticles ( Jacobus &McCafferty, 2008: fig. 41), gill V consists of two large and six small plates (Mikulskij, 1936: fig. 114b).

Form of styliger and genitals of male’s imago T. padunica close to the ones of T. naga Jacobus et McCafferty, 2004 (Oriental region). But apical parts of penis lobes of T. naga very narrow, widely spaced; the outer edges of the penis straight; the third segment of gonostyles is curved, and its base strongly narrowed ( Jacobus et al., 2004: fig. 6). The greatest similarity male imago T. padunica has with T. mikhaili Tiunova, 1995 from East Palaearctic ( Figs 36–39 ). But T. mikhaili has styliger with high conical rounded protrusion ( Fig. 36 ), third segment of gonostyles oval-shaped with narrow base, the outer edge of the penis lobes with a hollow ( Tiunova, 2024: figs 3–5) and spines on ventral side of penis lobes smaller ones ( Fig. 39 ).

All known eggs of the genus Torleya have close to oval shape and one polar cap. But eggs of T. lutosa Kang et Yang, 1995 , T. nepalica ( Allen et Edmunds, 1963) (= T. glareosa Kang et Yang, 1995 , synonymized by Jacobus & McCafferty, 2008) (both from East Palaearctic and Oriental regions) have teardrop-shaped micropyle and high ridges ( Kang & Yang, 1995: figs 20–24), that are wider than those of T. padunica . The eggs of T. major also have wide, but only slightly raised ridges ( Ubero-Pascal & Puig 2009: fig. 4c). The ridges of reticulation of T. naga very narrow, micropyle oval or teardrop-shaped ( Jacobus & McCafferty, 2004: fig. 5). The eggs of T. mikhaili are smaller and ridges are more subtle with numerous papillae on inner margin ( Tiunova, 2024: figs 23–26).

Figures

Figs 1–2. Male imago of Torleya padunica, habitus. 1 – lateral view; 2 – dorsal view.

Figs 3–5. Male imago of Torleya padunica. 3 – fore wing; 4 – hind wing; 5 – fore leg.

Figs 6–10. Torleya padunica: 6–11 male imago; 12 – female imago. 6 – genitalia; 7 – styliger and gonostyli; 8 – 3rd segment of gonostyli; 9 – genitalia; 10, 11 – penis; 12 – subanal plate. 6 – lateral view, 7, 10–12 – ventral view; 8, 9 – dorsal view.

Figs 13–14. Larvae of Torleya padunica, habitus. 13 – dorsal view; 14 – ventral view.

Figs 15–21. Larvae of Torleya padunica. 15 – head; 16 – labrum; 17 –hypopharynx and superlinguas; 18, 19 – mandibles, ventral view (18 – right, 19 – left); 20 – maxilla; 21 – labium.

Figs 22–34. Larvae of Torleya padunica. 22 – pro- and mesonotum; 23–25 – legs (23 – fore, 24 – mid, 25 – hind); 26–28 claws (26 – fore leg, 27 – mid leg, 28 – hind leg); 29 – abdomen, dorsal view; 30– gill I pair; 31–34 gills, sketchily (31 – II pair, 32 – III pair, 33 – IV pair, 34 – V pair). 9

Fig. 35. Eggs of Torleya padunica. The arrows indicate the micropyles.

Figs 36–39. Torleya mikhaili, genitalia. 36 – styliger and gonostyli; 37 – penis; 38 – penis and gonostyli; 39 – penis lobes. 36, 38–39 – ventral view; 37 – dorsal view.