Six new epibioticProschkinia(Bacillariophyta) species and new insights into the genus phylogeny

Abstract

The diatom genus Proschkinia is a common element of biofilms covering diverse substrata in saline inland or shallow coastal environments. It can be distinguished from other naviculoid taxa by its lanceolate valves with a fistula located within the central area and numerous open girdle bands with a U-shaped cross-section and a single row of perforations on the internal side of the fold. Despite this distinct morphology, frustules of Proschkinia are typically weakly silicified and often overlooked when cleaned diatom material is analysed. The current paper describes six new species of Proschkinia: P. browderiana sp. nov., P. lacrimula sp. nov., P. maluszekiana sp. nov., P. sulcata sp. nov., P. torquata sp. nov. and P. vergostriata sp. nov., found in numerous samples of marine organisms, such as sea turtles (including sea turtle museum specimens), sea turtle-associated barnacles and seagrass from across the three oceans. Some of the newly described taxa were found on multiple individuals belonging to different sea turtle species, whereas others were in samples collected from different continents. Molecular phylogenetic analysis indicated that examined Proschkinia strains formed a monophyletic clade, sister to Fistulifera.

Geographical variation in the diatom communities associated with loggerhead sea turtles (Caretta caretta)

“…each other, but in general, maintaining a good separation among the different localities. Croatian samples showed the lowest group homogeneity, with the main group of three samples and a single group comprised of one sample(CRO-13) and one sample placed in a different cluster (CRO 19). An additional nMDS analysis performed only on the Greek carapace and skin samples showed good separation of the two groups (Fig 5B).…”

“…These taxa have not yet been found in epizoic samples from other localities and substrata. Similarly, the newly described Proschkinia species such as P. vergostriata Frankovich et al and P. sulcata Majewska et al have so far only been found on turtle carapaces and skin [19]. Thus, more sampling and analyses of marine benthic diatom communities from both biotic (including marine animals) and abiotic substrata will be necessary to determine the exact habitat preferences of these diatoms.…”

Analysis and critical evaluation of structural features in four Cymbellaceae taxa from New Caledonia

“…Especially since the other diagnositic features for Delicatophycus such as dorsiventral valves, areola foramina showing an undulated pattern (at least in part of their course), the steep inflexion of the raphe branches towards the ventral side approaching the middle of the valve, the dorsally deflected terminal raphe fissures and the absence of apical pore fields, fit entirely with the genus description. The presence of longitudinal ribs on the valve face and mantle is an uncommon feature in diatoms and only found in a few diatom genera: Proschkinia (Round et al 1990;Majewska et al 2019), Navicula (Sabbe et al 2019), Haslea (Simonsen 1974), Craticula (Lange-Bertalot 2001), Pinnularia (Lange-Bertalot et al 2003) and Navigiolum (Lange-Bertalot et al 2009). Two Stauroneis species, S. stodderi Greenleaf and S. staurolineata Reimer both possess very fine longitudinal ridges, running parallel from apex to apex (Patrick & Reimer 1966).…”

Biodiversity of carapace epibiont diatoms in loggerhead sea turtles (Caretta caretta Linnaeus 1758) in the Aegean Sea Turkish coast

“…Recently, diatoms associated with the Mediterranean loggerhead sea turtle population have been described. These included an Olifantiella species ( Kaleli et al, 2018 ) and six new species of Proschkinia ( Majewska et al, 2019 ), and a small celled Catenula taxon from the Adriatic Sea ( Robert, Bosak & Van de Vijver, 2019 ).…”