Euglesa kolymensis Bespalaya, Aksenova & Bolotov 2024, sp. nov.
Creators: name: Bespalaya, Yulia V.
name: Vinarski, Maxim V.
name: Aksenova, Olga V.
name: Babushkin, Evgeniy S.
name: Gofarov, Mikhail Yu.
name: Kondakov, Alexander V.
name: Konopleva, Ekaterina S.
name: Kropotin, Alexander V.
name: Mabrouki, Youness
name: Ovchankova, Nadezda B.
name: Palatov, Dmitry M.
name: Sokolova, Svetlana E.
name: Shevchenko, Alexander R.
name: Travina, Oksana V.
name: Taybi, Abdelkhaleq F.
name: Soboleva, Alena A.
name: Zubrii, Natalia A.
name: Bolotov, Ivan N.
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Bivalvia
Sphaeriida
Sphaeriidae
Euglesa
Euglesa kolymensis

description: Euglesa kolymensis Bespalaya, Aksenova & Bolotov sp. nov.
(Fig. 11A)
Zoobank number: urn:lsid:zoobank.org:act: BDC94015-12D0- 42CB-B21E-F7C950E94EFD.
Type series: The holotype is deposited in RMBH (accession number: MSph-787). The type series includes one holotype.
Type locality: Russia: Yakutia, Srednekolymsk, lake next to the oil depot, Kolyma River Basin, [67°27 ʹ 29″N 153°42 ʹ 22″E], 25. VI.2021, Sokolova & Zubrii leg.
Etymology: This species is named after the Kolyma River.
Description: Shell round-oval in shape, its length is 4.7 mm (Fig.11A). The beaks are rounded and slightly protruding, somewhat shifted to the posterior edge of the shell (Fig.11A). The cardinal tooth of the right valve slightly curved has a thickening at the ends, the posterior end is branched. The cardinal teeth of the left valve are straight parallel to each other (Fig. 12C). The inner cardinal tooth of the left valve is thickened.
Distribution: Eastern Siberia, Kolyma River Basin.
Comments: The 16S and 28S rRNA sequences of this species have no analogues in GenBank and form a clade sister to the E. globularis group (Fig. 2). Considering that E. kolymensis was found in the Kolyma River Basin, we also analysed the original descriptions, and compared our material with the type specimens of some nominal species described from the same river basin: Euglesa czerskii (Starobogatov & Streletskaja, 1967), Euglesa jacutica (Starobogatov & Streletskaja, 1967), and Euglesa rotundicostata (Starobogatov & Streletskaja, 1967) (Supporting Information, Fig. S1A, L, M). The original morphological descriptions and features of these type specimens do not correspond to those of our specimen from the Kolyma River. In addition, all the listed species were subsequently assigned to the genera Henslowiana, Cingulipisidium, and Cyclocalyx according to Korniushin (1996) that are clearly different from the E. globularis group (see Vinarski and Kantor 2016).
Differential diagnosis: The new species can be distinguished from its sister species E. globularis and E. khurbaensis by having a more developed regular ribbing on shell surface, and different shape of the cardinal teeth. Thus, the cardinal teeth of the left valve of the E. globularis are distinctly curved, whereas those of E. kolymensis are straight (Fig. 11A). The cardinal tooth of the right valve of the E. globularis and E. khurbaensis is noticeably curved, unlike that of E. kolymensis (Fig. 11A).
Molecular diagnosis: The new species also differs from its congeners by two fixed nucleotide substitutions in the 16S rRNA gene fragment (280 C, 291 A). The uncorrected rRNA 16S p-distance of the new species from other congeners is 3.4–8.9% and those based on 28S rRNA is 0.1–4.8 %. The nearest congener of E. kolymensis is E. khurbaensis with the mean uncorrected 16S rRNA p-distance of 4.1 ± 0.8% (± SD).
description: Published as part of 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), pp. 305-338 in Zoological Journal of the Linnean Society 201 (2) on pages 323-326, DOI: 10.1093/zoolinnean/zlad139, http://zenodo.org/record/13220074