Marin I.N.*, Palatov D.M. 2025. Two new species of the “Niphargus bzhidik” ingroup (Amphipoda: Niphargidae: Niphargus) from the southwestern foothills of the Great Caucasian Ridge // Invert. Zool. Vol.22. No.2: 320–339 [in English].
A.N. Severtsov Institute of Ecology and Evolution of RAS, Moscow 119071 Russia.
Ivan Marin: coralliodecapoda@mail.ru https://orcid.org/0000-0003-0552-8456
Dmitry Palatov: triops@yandex.ru https://orcid.org/0000-0002-8826-9316
* corresponding author
doi: 10.15298/invertzool.22.2.08
ABSTRACT. Two new species of the genus Niphargus Schiödte, 1849 (Amphipoda: Niphargidae), Niphargus olkhovik sp.n. and Niphargus natukhai sp.n., are described from the southwestern foothills of the Great Caucasian Ridge, Russia. Both species distinctly belong to the “puteanus” species group and are phylogenetically close related to the Caucasian Niphargus bzhidik Marin, Krylenko et Palatov, 2021. Together with N. bzhidik and two other undescribed species from Apsheronsk and Nebug, these newly discovered species form a district morphological and phylogenetically separated monophyletic clade (lineage), which we propose to name “Niphargus bzhidik” ingroup. The ingroup can be distinguished from other Caucasian species of the genus Niphargus by the presence of 2–3 hooks in the retinacules of the pleopods, different-sized rami of the uropod I both in ♂♂ and ♀♀, and relatively large inner ramus of the uropod III. Molecular dating suggests that this ingroup originated during the Late Miocene, at least 8 Mya, obviously somewhere within Euxinian basin of Paratethys.
KEY WORDS: diversity, phylogeny, Crustacea, taxonomy, Caucasus.