Baetis (Rhodobaetis) issyksuvensis Brodsky, 1930

Sroka, Pavel, Godunko, Roman J., Novikova, Eugenia A. & Kluge, Nikita J., 2012, Contribution to the knowledge of the subgenus Rhodobaetis Jacob, 2003 (Ephemeroptera: Baetidae: Baetis) from Central Asia. Part 1, Zootaxa 3311, pp. 42-60 : 44-46

Baetis (Rhodobaetis) issyksuvensis Brodsky, 1930

Baëtis issyksuvensis Brodsky, 1930 : Zoologische Jahrbücher, 59: 688, figs 6–8

Baetis issyksuvensis apud Brodsky, 1935: Materialy k poznaniiu fauny gornykh potokov Srednei Azii, 1: 22 [faunistics] Baetis issyksuvensis Brodskii [sic!] apud Mani, 1968: Ecology and Biogeography of High Altitude Insects, 4: 266 [faunistics] Baetis issyksuvensis Brodsky, 1930 : Novikova, 1987b: Podenki semeistva Baetidae (Ephemeroptera) fauny SSSR, 73, figs 26.1–26.7 [description of larva and adults, discussion on taxonomy] (placed within subgenus Baetis ); Kluge, 1995: A catalogue of the type specimens in the collection of the Zoological Institute RAS, 13 [syntypes observation]; Godunko et al. 2004b: Acta Zoologica Cracoviensia, 47 (3–4): 242 [list of species]; Soldán & Godunko, 2008: Annales Zoologici, 58 (1): 100 [biogeographical analysis]

Distribution. Known only from type locality in Kyrgyzstan.

Type series. Brodsky (1930) did not designate the type specimen of B. issyksuvensis within 2 male imagos, 2 male subimagos, and a female subimago (these specimens represent syntypes according to Article 73.2 of the International Code of Zoological Nomenclature).

The location of the type series deposition was not specified by Brodsky (1930). Nevertheless, Kluge (1995: 13) reported one male imago in ethanol labeled as “р. Дюре у пер[евал] Дюре, Кунгей ала-тау, в[ысота] 3000 м, 9 VIII 1925, К. Бродский” [Diure River at Diure mountain pass, Kungei Alatau, 3000 m a.s.l., August 9, 1925, leg. K. Brodsky], microscopic slides of genitalia (treated with alkali), and wings of this specimen originally labeled as “ Baetis 3 Дюре”, deposited in the collection of ZIN RAS.

Comparison of the shape of genitalia and left hind wing of the male imago depicted by Brodsky (1930: 688– 689, figs 7, 8) with the material mounted on the microscopic slides mentioned by Kluge (1995), as also as analysis of the data on the original labels, confirmed that this specimen exactly had been described and figured by K. Brodsky and undoubtedly belongs to the syntype series of B. issyksuvensis .

Besides the male imago specified above, some additional material marked as B. issyksuvensis is deposited in the collection of ZIN RAS – 1 male imago, 3 male subimagos, and 3 female subimagos, all placed in the same tube, and originally labeled by K. Brodsky as follows: “N 15. І, 1. 11. VII 28. в инсектарии.” [in insectarium]; “K.[azakhskaja] SSR. Simiretschenkaj distr river Issyk near Almaty. VII–VIII 1928 leg. K Brodsky”. This material is reported in the original description as “13 Im., 23 Subim., 1Ƥ Subim. (diese Art?), Transiligebirge, Fluß Issyk, 1750 m ü. M., Aug. 1928 K. Brodsky” [Trans-Ili, or Zailiyskiy Alatau]. In any case, it seems to us that the determination of these additional adults as B. issyksuvensis is doubtful, because: (1) the male imago is considerably damaged, with wings, legs, genitalia and cerci absent, and possesses unicolorous light brown turbinate eyes; (2) the male and female subimagos both have a lighter body color (light brown) in comparison to the fresh material collected by N. J. Kluge; (3) the male subimago has damaged turbinate eyes.

On the other hand there are also numerous larvae of various species labeled as “Иссык, 1929” [Issyk] and supplied with numbers used by K. Brodsky for the material from his insectarium. These larvae are mentioned in the original description as “Nymphen dieser Art in großer Anzahl auf weitere Erstreckumg, beinahe von der Quelle bis zur Mündung des Flusses” [The nymphs of this species in great numbers are distributed almost from the source to the mouth of the river], but they are not listed among the material examined. According to personal communications by K. Brodsky, all his material from the Issyk River was collected in 1928 and 1929, and some errors in specimen numbers and/or dates are possible.

There is an obvious necessity to clarify the taxonomic status of B. issyksuvensis and to designate lectotype in order to allow the comparison of other Rhodobaetis species from Central Asia with B. issyksuvensis and avoid the misidentification of this species with Baetis taldybulaki sp. nov..

Lectotype and type locality designation. Within all the specimens mentioned above, only one syntype (male imago) from Kyrgyzstan, can be designated as a lectotype of B. issyksuvensis , because in the original description adults from Issyk were reported as questionably belonging to this species, and larvae from Issyk were not included in the material examined. We designate this syntype as the lectotype according to Articles 74.1., 74.7 and Recommendation 74B–74E of the International Code of Zoological Nomenclature.

Lectotype: male imago (preserved in 75% ethanol; genitals and left hind wing on slides), Kyrgyzstan, Issyk- Kul Region [Иссыкульская область], Tian Shan Mountains, Kungei-Ala-Too Ridge [Кюнгëй-Ала-Тоо], Diure- Suu [Дюре-Cyy] River, 3000 m a.s.l., approximately 42°43'40.41" N, 76°30'38.06" E, 09.viii.1925, leg. K. Brodsky ( Fig. 47 ).

Lectotype is housed at the collection of ZIN RAS.

Description of lectotype of Baetis issyksuvensis [in addition to Brodsky (1930) and Novikova (1987b)]. Size: body length: 6.3 mm; cerci lost. Turbinate eyes flattened due to fixation process, visible part of facetted surface uniformly dark reddish-brown, shaft color invisible.

Head and thorax uniformly brown. Dorsal surface of thorax with yellowish lateroparapsidal and medioparapsidal sutures. Lateral parts of thorax pale, yellowish-brown.

Legs yellowish-brown to brown, without spots. Forelegs light brown, darker than middle and hind ones. All wings hyaline, transparent. Pterostigma almost transparent, opaque with 4–5 cross veins. Hind wings 2.3 times longer than wide, with rounded apex. Costal projection well developed. Three longitudinal veins, cross veins absent. Third vein ends at approximately half of the wing length. Two small intercalaries between second and third veins ( Fig. 2 ). Venations of both wings yellowish-brown.

Abdomen uniformly brownish without spots or smudges. Genitalia yellow to light brown, unistyliger (term introduced by Kluge & Novikova 2011 (see p. 5); “basalglieder” in Müller-Liebenau 1969 and “gonostylar pedestal” in Kluge 2004) and gonostylus segment I darker than segment II and segment III. Unistyliger nearly as long as wide; gonostylus segment I with distinct subapical protuberance; segment II relatively short and wide; segment III distinctly elongated, with a length/width ratio of 3.0 ( Fig. 1 ).

Remarks. Some characters of the specimen studied are somewhat different from the original description made by Brodsky (1930), mainly the shape of the turbinate eyes, and the color of the head, thorax and abdominal segments. Most of the changes are caused by long-term storage in formaldehyde and ethanol.

Brodsky (1930) stated turbinate eyes in the shape of a “ship” from the dorsal view, with frontal and caudal parts pointed, as a diagnostic character of B. issyksuvensis . According to our investigation such an arrangement of the turbinate eyes is simply a consequence of the process of fixation, and in fact the species possesses turbinate eyes of the oval type widespread throughout the genus. In the same study as where the description of B. issyksuvensis was published several more examples of even more pronounced deformities caused most probably by fixation can be observed (e. g. p. 690: fig. 9 and p. 691: fig. 12 in Brodsky 1930, depicting turbinate eyes of B. transiliensis and B. mycetopis , respectively).

A further diagnostic character mentioned by Brodsky (1930), a distinct border between gonostylar segment I and II, is also the result of the deformation process caused probably by the fixation medium. Our study of the lectotype confirmed that such a border is indistinct at the very most. The structure of the hind wings mounted on a separate microscopic slide in Canada balsam is the same as in the publication of Brodsky (1930, fig. 8).

Figures

FIGURE 47. Diure-Suu river-valley (Kyrgyzstan) within type locality of Baetis issyksuvensis Brodsky, 1930. Approximately 3000 m a. s. l.

FIGURES 1 – 2. Baetis issyksuvensis Brodsky, 1930, male imago, lectotype: 1, genitals (ventral view); 2, left hind wing.