Odhneripisidium сaucasus Bespalaya, Vinarski, Aksenova, Kondakov & Palatov, 2024

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 : 330

Odhneripisidium сaucasus Bespalaya, Vinarski, Aksenova, Kondakov & Palatov sp. nov.

( Fig. 11D )

Zoobank number: urn:lsid:zoobank.org:act:7F5E99C9-C0DB-4D05-8DE6-9F80CE7AAA99 .

Type series: The type series includes the holotype and 42 paratypes deposited in RMBH (accession numbers: RMBH MSph-296, MSph-327) .

Type locality: Russia, Krasnodar Region, Dolgaya Сave (43°36 ʹ 35.9″N 39°56 ʹ 54.5″E) .

Etymology: This species is named after the Caucasus Range.

Material examined: Abkhazia, Gudautsky District, spring near Psyrkha station II.2018, Palatov leg., 42 specimens (lot no. RMBH MSph-327), Russia, Krasnodar Region, Dolgaya Сave, IV.2015, Palatov leg., one specimen (lot no. RMBH MSph-296) .

Description: The shell is small (length 2.24 mm), round-oval in shape ( Fig. 11D ). The beaks are not prominent, located in the middle of the valves ( Fig. 11D, E ). The cardinal tooth of the right valve is slightly curved, its posterior end is branched. The inner cardinal tooth of the left valve is thickened, curved ( Fig. 12E ). The outer cardinal tooth of the left valve is short, thickened at the anterior end, slightly curved, and inclined towards the inner tooth ( Fig. 12E ).

Distribution: Caucasus.

Differential diagnosis: Odhneripisidium caucasus can be distinguished from its sister species, Odhneripisidium moitessierianum (Paladilhe, 1866) , Odhneripisidium tenuilineatum (Stelfox, 1918) , and Odhneripisidium stewarti (Preston, 1909) , by its shell morphology ( Fig. 11D ). In contrast with O. caucasus , the species O. moitessierianum and O. tenuilineatum have prominent beaks. The shell of O. stewarti is rather inflated with prominent beaks unlike that of O. caucasus .

Molecular diagnosis: The new species differs from its congeners by three fixed nucleotide substitutions in the 16S rRNA gene fragment (65 C, 66 G, and 71 G) and one fixed nucleotide substitution in the 28S rRNA gene fragment (691 C). The uncorrected 16S p-distance of the new species from other congeners is 4.8–10.6% and that based on 28S rRNA is 0.8–4.8%. The nearest congener is O. moitessierianum with the mean uncorrected 16S p-distance 6.5 ± 1.1%. The mean uncorrected 16S p-distance of the new species from O. stewarti and O. tenuilineatum is 7.8 ± 1.2% (± SD).

Figures

Figure 11. New species of Sphaeriinae described in this paper: (A) holotype of Euglesa kolymensis (RMBH No. MSph-787, Russia, Yakutia); (B) holotype of E.kyrgyzyca (RMBH No. MSph-331, Kyrgyzstan); (C) holotype of E. moroccana (RMBH No.MSph-775, Morocco); (D) holotype of Odhneripisidium caucasus (RMBH No. MSph-296, Russia, Krasnodar Region); (E) paratype of O.caucasus (RMBH No. MSph- 327, Abkhazia).Photos: O.V. Aksenova.Scale bar:1 mm.

Figure 12. Morphology and anatomy of new Sphaeriinae species described in this paper (teeth morphology and shell pores, anatomy of gills and siphons): (A) holotype of E. kyrgyzyca (RMBH No. MSph-331, Kyrgyzstan); (B) paratype of E. kyrgyzyca (RMBH No.MSph-331, Kyrgyzstan); (C) holotype of E. kolymensis (RMBH No. MSph-787, Russia, Yakutia); (D) holotype of E. moroccana (RMBH No. MSph-775, Morocco); (E) paratype of Odhneripisidium сaucasus (RMBH No. MSph-327, Abkhazia).Photos: O.V. Aksenova. Scale bars:0.5 mm.