Baetis (Tenuibaetis) ursinus Kazlauskas 1963

Kluge, Nikita, Srinivasan, Pandiarajan, Sivaruban, T., Barathy, S. & Isack, Rajasekaran, 2023, Contribution to the knowledge of the subgenus Tenuibaetis Kang & Yang 1994 (Ephemeroptera, Baetidae, Baetis s. l.), Zootaxa 5277 (2), pp. 201-258 : 208-212

1. Baetis (Tenuibaetis) ursinus Kazlauskas 1963

( Figs 22–43 )

Baetis ursinus Kazlauskas 1963: 585 (larva); Kluge 1983: 70 (♁ imago, larva); Kluge 1995: 17 (type specimens).

Baetiella ursina: Waltz & McCafferty 1987: 563 .

Baetis ursinus ursinus: Novikova 1991 : figs 18–30 (larva).

Baetis (Baetis) ursinus ursinus: Kluge 1997b: 194 (larva).

Baetis (Rhodobaetis) ursinus: Jacob 2003: 120 .

Baetis (Tenuibaetis) ursinus : Kluge 2022: 166 (subimago).

Material examined ( ZIN). Holotype: Irkutsk province, stream falling in river Angara 2 km upstream Zajarsk, 9. VII.1955: parts of larva . Other material: RUSSIA: Khabarovskiy Kray: railway station Bira, 8. IX.1980, coll. N. Kluge: L-S-I♁. Primorskiy Kray: river Ussuri near Bulyga-Fadeevka and Breevka , 1–12. VIII.1980, coll. N. Kluge: L-S-I♁, 3 L-S♁, 3 L-S ♀, 5 larvae ; Lazovskiy natural reserve, stream Sukhoy, 23. VIII.1980, coll. N. Kluge: L-S/I♁. Ussuriyskiy natural reserve, river Komarovka , 22. VIII.1983, coll. T. Vshivkova: 1 larva ; same locality, 27–28. VIII.1980, coll. N. Kluge: L-S-I♁, L-S-I ♀ ; area of natural reserve «Kedrovaya Pad’» including river Narva , 13–26. VII.1980, coll. N. Kluge: L-S-I♁, 2 L-S♁, 16 larvae ; river Barabashevka near Barabash , 15. VII.1976, coll. N. Sinitshenkova & V. Zherikhin: 1 larva . MONGOLIA: river Orkhon WE Bulgan, 16–20. VIII.1997, coll. N. Kluge: L-S-I♁, 8 larvae ; river Ider-Gol 40 km downstream Jargalt, 25. VIII.1997, coll. N. Kluge: 1 larva ; basin of river Selenga, 19. VIII.1997, coll. N. Kluge: L-S♁; river Orkhon near Kharkhorin, L-S♁, L-S-♁, 1 larva .

Additional descriptions

Larva. CUTICULAR COLORATION ( Figs 24–29 ): Described and figured by Novikova (1991: figs 18–30); pronotum with lighter sigilla on darker background ( Fig. 28 ; Novikova 1991: figs 18–19).

HYPODERMAL COLORATION: Not expressed.

SHAPE AND SETATION: Labrum of medium proportions ( Fig. 22 ; Kluge 1983: fig. 41). Mandibles as in original description ( Kazlauskas 1963: figs 21–22). Labial glossae, paraglossae and palp as in original description ( Fig. 23 ; Kazlauskas 1963: fig. 23).

Hind protoptera present (as in Fig. 2 ). Two-channel setae forming row along outer side of femur (including two subapical setae) elongate, blunt, distally widened and flattened ( Fig. 31 ; Kluge 1983: fig. 43). Stout setae on anterior side of femur two-channel, from moderately long to short ( Fig. 31 ).

Tibia of each leg with small, stout two-channel setae on inner side and along patella-tibial suture; stout setae on outer side of tibia extremely small, with length subequal to cuticle thickness ( Fig. 32 ), more numerous on middle and hind tibiae, sparser or absent on fore tibiae.

Denticles on posterior margins of terga I–X bluntly triangular ( Kluge 1983: fig. 44; Novikova 1991: 17). Denticles on posterior margin of sternum small and irregular, present only on sternum IX, sometimes also on sterna VIII and VII; in male, row of denticles not interrupted by protogonostyli; paraproct with denticles on most part of inner margin ( Fig. 30 ). Paracercus significantly smaller than cerci ( Fig. 24 ; Kazlauskas 1963: fig. 20).

Subimago. CUTICULAR COLORATION:Head colorless,antennae brown.Pronotum light brown.Mesonotum with ochre, light brownish and dark brown areas ( Fig. 33 ). Thoracic pleura and sterna with light brownish and dark brown areas (as in Fig. 215 ). Legs of all pairs with femur colorless, tibia and tarsus brownish ( Figs 39–40 ). Abdominal terga I– VIII light brownish, darker laterally; terga IX –X colorless (as in Fig. 172 ). Cerci light brown.

HYPODERMAL COLORATION: As in imago.

Imago, male ( Figs 34, 36–38 ). Described by Kluge (1983). Middle and hind tarsi with 2 apical spines (on 1st+2nd and 3rd segments). Gonovectes bent under right angle, brown; sterno-styligeral muscle vestigial ( Figs 42–43 ).

Imago, female ( Fig. 41 ). Head and thorax ochre with brown. Wings slightly tinged with brownish. Hind wing narrower than in male ( Fig. 35 ). All tarsi with 2 apical spines (fore tarsus on 2nd and 3rd segments, middle and hind tarsi on 1st+2nd and 3rd segments). Abdominal terga ochre medially, brownish laterally; sterna uniformly lighter ochre.

Dimension. Forewing length 4–5 mm.

Distribution. East Siberia, Mongolia and Russian Far East.

Comments. Larva from Korea described and figured by Bae & Park (1998) under the name ́Baetis ursinus » does not belong to this species, since it has no V-shaped blank on mesonotum, has colorless fore protoptera and different coloration of abdominal terga; these authors referred to the publication by Kluge (1983) where male imago was described, but stated that ́Male adult. Unknown».

Figures

FIGURES 22–30. Baetis (Tenuibaetis) ursinus, larval exuviae (24–29, one and the same magnification). 22, labrum; 23, maxilla and labium; 24, abdomen, 25–27, middle and hind legs; 28, half of pronotum and mesonotum; 29, head; 30, paraproct.

FIGURES 31–32. Baetis (Tenuibaetis) ursinus, larval exuviae of fore leg. 31, part of femur; 32, part of tibia. Abbreviation: 2-can, two-channel setae.

FIGURES 33–41. Baetis (Tenuibaetis) ursinus. 33, subimaginal exuviae of half of mesonotum; 34, hind wing of male; 35, hind wing of female; 36, male imago and its spread abdomen; 37–38, its fore and middle legs; 39–40, their subimaginal exuviae (the same magnification); 41, female imago.

FIGURES 42–43. Baetis (Tenuibaetis) ursinus, genitalia of male imagines. Abbreviations: 1, 2, 3, segments of gonostylus; gd, gonoduct; gv, gonovectis; m.gs, gonostylar muscle; m.gv, muscle of gonovectis; s.s, sterno-styligeral muscle; us, unistyliger.

FIGURES 1–4. Setae on larval legs of Baetis (Tenuibaetis) bialatus sp. n.. 1, two-channel and hirudiform setae on outer side of middle tibia under scanning electron microscope; 2–3, hirudiform seta; 4, two-channel seta on anterior side of femur in transmitted light. Abbreviations: 2-can, two-channel seta; hirud, hirudiform seta.

FIGURES 215–224. Baetis (Tenuibaetis) bialatus sp. n. 215, subimaginal exuviae of mesopleuron; 216, subimaginal exuviae of half of mesonotum; 217–218, exuviae of fore and hind legs of male subimago; 219–220, fore and middle legs of male imago; 221, male imago; 222, female imago; 223, subimaginal exuviae of abdominal segments VIII–IX; 224, egg (215–220, holotype).

FIGURES 169–180. Baetis (Tenuibaetis) kaltenbachi sp. n. 169–170, male imago; 171, female imago; 172, subimaginal exuviae of abdomen; 173–174, fore and middle legs of male imago; 175–176, their subimaginal exuviae; 177, subimaginal exuviae of half of mesonotum; 178, hind wing of male imago; 179, the same, female; 180, blunt microlepides on fore tarsus of male subimago (169–170, 172–178, 180, holotype).