Euglesa nordenskioldi (Clessin, 1876)

Bespalaya, Yulia V., Vinarski, Maxim V., Aksenova, Olga V., Babushkin, Evgeniy S., Gofarov, Mikhail Yu., Kondakov, Alexander V., Konopleva, Ekaterina S., Kropotin, Alexander V., Mabrouki, Youness, Ovchankova, Nadezda B., Palatov, Dmitry M., Sokolova, Svetlana E., Shevchenko, Alexander R., Travina, Oksana V., Taybi, Abdelkhaleq F., Soboleva, Alena A., Zubrii, Natalia A. & Bolotov, Ivan N., 2024, Phylogeny, taxonomy, and biogeography of the Sphaeriinae (Bivalvia: Sphaeriidae), Zoological Journal of the Linnean Society 201 (2), pp. 305-338 : 329

Euglesa nordenskioldi (Clessin in Westerlund, 1876)

( Fig. 9H )

Pisidium nordenskioldi Westerlund, 1876: 68–69 , pl., fig. 20.

Type series: Not traced, probably lost.

Type locality: Russia, Krasnoyarsk Territory (northern part) and Tyumen Region. The syntypes were collected in several localities ["Jenissei, vid Dudino, (lat. 69°15 ʹ), Surgutskoj (lat. 62°50 ʹ), Worogowa Selo (lat. 69°50 ʹ)"; Westerlund 1877: 69].

Material examined: Vashutkiny lakes, VIII.2016, Aksenova, Aksenov, Bespaliy, Sokolova & Shevchenko leg., 94 specimens (lot nos RMBH MSph 184, 263), Vaigach Island , VIII.2010, Aksenova & Bespalaya, leg., 68 specimens; Yugorsky Peninsula, VI.2015, Spitsyn leg., four specimens (lot no. RMBH MSph 86-3) .

Description: The shell is medium sized (mean length ± SE 2.9 ± 0.6 mm), round-oval in shape ( Fig. 9H ), distinctly and regularly striated. The beaks are rounded and prominent, located in the middle of the valves ( Fig. 9H ). The cardinal tooth of the right valve is slightly curved, with a weaker split at the posterior end. The inner cardinal tooth of the left valve is straight. The outer cardinal tooth of the left valve is thin, slightly curved ( Fig. 10E ). The lateral teeth are long.

Distribution: Northern European Russia and Siberia.

Comment: The 16S and 28S rRNA sequences of this species have no analogues in GenBank and are more closely related to the E. henslowana group ( Fig. 2 ). We analysed the original descriptions and type specimens of some nominal species of this group from close localities (Supporting Information, Fig. S1A–D ), that is, Euglesa nordenskioldi (Clessin in Westerlund, 1877), Euglesa ostroumovi Pirogov & Starobogatov, 1974 , Euglesa polonica Anistratenko & Starobogatov, 1990 , Euglesa sibirica (Clessin in Westerlund, 1877), and Euglesa suecica (Clessin in Westerlund, 1873). The original morphological description of Pisidium nordenskioldi Clessin published in Westerlund (1876) corresponds well to the morphological features of specimens from our samples. In addition, Korniushin (1996) noted the presence of E. nordenskioldi in the lakes of the Bolshezemelskaya Tundra. According to morphological features, this species can be classified as E. nordenskioldi . At the same time, the type specimens of E. polonica , E. ostroumovi , and E. suecica , studied by us, can be distinguished from E. nordenskioldi by having narrow and prominent beaks, offset to the posterior edge of the valves and with oblique folds ( Fig. 9 ; Supporting Information, Fig. S2A–D ). Therefore, we do not have sufficient grounds to synonymize the listed species with E. nordenskioldi .

Figures

Figure 1.Spatial distributionofthe numberofavailable 16S rRNA sequences (A), and species richness of thesubfamily Sphaeriinae (B), in theworld.

Figure 2. The phylogeny of the subfamily Sphaeriinae recovered from ML analysis (W-IQ-TREE) and obtained for the complete dataset of mitochondrial and nuclear sequences (16S rRNA+28S rRNA). Black numbers near nodes are bootstrap support values (BS)/ Bayesian posterior probabilities (BPP). The new taxa are highlighted in red. Subgenera are marked by curly brackets.

Figure 9. Shells of species, re-described in this research: (A) Euglesa khurbaensis (RMBH No. MSph-707, Russia, Primorsky Territory); (B) E. khurbaensis (RMBH No.MSph-707/2, Russia, Primorsky Territory); (C) E.lindholmi (RMBH No. MSph-370, Russia, Gydan Peninsula); (D) E. ljovushkini (RMBH No. MSph-335, Abkhazia); (E) E. ljovushkini (RMBH No. MSph-335/2, Abkhazia); (F) E. hinzi (RMBH No. MSph- 366, Russia, Gydan Peninsula); (G) E. subterranea (RMBH No. MSph-295, Georgia, Imereti); (H) E. nordenskioldi (Russia, Vaygach Island). Photos: O.V. Aksenova.Scale bar: 1 mm.

Figure 10. Morphology and anatomy of re-described species discussed in this research (teeth morphology and shell pores, anatomy of gills and siphons): (A) Euglesa hinzi (RMBH No. MSph-366, Russia, Gydan Peninsula); (B) E. khurbaensis (RMBH No. MSph-707/2, Russia, Primorsky Territory); (C) E.lindholmi (RMBH No.MSph-370, Russia, Gydan Peninsula); (D) E. ljovushkini (RMBH No. MSph-335, Abkhazia); (E) E. nordenskioldi (Russia, Vaygach Island); (F) E.subterranea (RMBH No. MSph-295, Georgia, Imereti). Photos: O.V. Aksenova. Scale bar: 0.5 mm.