The unexpected diversity in Amphora sensu lato (Bacillariophyta) at Sozopol Bay, the western Black Sea

Abstract

During a survey of benthic diatoms from the Bulgarian Black Sea coast near the historic town of Sozopol, we found a high diversity of Amphora sensu lato taxa at a single site and on a single type of artificial substratum. A total of 40 taxa from the current genera Amphora, Halamphora, Seminavis and Tetramphora were recognized during light microscopy (LM) and scanning electron microscopy (SEM) observations. We were able to identify with a high degree of certainty only 6 taxa based on the literature, whereas for 19 taxa (or almost 50% of all taxa) we could not find even sufficiently similar species, and they remained unidentified to species level. Many of the species had small valve dimensions. The paper presents all taxa with short morphometric data and microphotographs under LM and SEM, where possible. All taxa are discussed and compared with similar known taxa. The illustrative materials in earlier works from the Black Sea and species descriptions, where such were available, were also consulted. Diversity of Amphora sensu lato in the Black Sea coastal waters seems to be underestimated, whereas some of the past records are uncertain. A discussion on the current state of knowledge of Amphora sensu lato species from the Black Sea is given.

Taxonomic Structure and Diversity of Benthic Diatoms (Bacillariophyta) in the Northern Shelf of the Black Sea

“…There are also reports of new phytoplankton species found off the southern Black Sea [24,25]. Moreover, data on the discovery of new benthic diatom species found off the Black Sea coast of Turkey and Bulgaria appeared at the time of writing this manuscript [26][27][28].…”

Craspedostauros nazmii sp. nov., a new diatom species (Bacillariophyta) from the Turkish Coast of the Black Sea

“…The Black Sea is inhabited by what seems to be an endemic taxon of the blue-pigment producing diatom, Haslea karadagensis Davidovich, Gastineau and Mouget ( Davidovich et al 2012a ; Gastineau et al 2012a , 2012b ). An increasing number of studies on the biodiversity and species richness of the Black Sea diatoms have been published in recent years ( Nevrova 2022 , 2023 ; Nevrova and Petrov 2019a , 2019b ; Zidarova et al 2022b ). Strains of diatoms from the Black Sea have also been used to investigate either their patterns of auxosporulating ( Podunay et al 2021 ; Davidovich et al 2012b , 2017a , 2017b , 2019 ; Kaczmarska et al 2018 ), physiology ( Bedoshvili et al 2021 ; Davidovich et al 2016 , 2018 ; Podunay et al 2016 ) or genomic peculiarities ( Gastineau et al 2021 ).…”