Cyclotella hinziae sp. nov. - a small Cyclotella (Bacillariophyceae) from subalpine lake Schliersee (Bavaria, Germany)

Abstract

Abstract:A small Cyclotella species (Thalassiosiraceae) from a subalpine lake Schliersee (Bavaria, Germany) is described. The species has characteristic valve morphology different from this of the other similar taxa. It differs from them especially with the presence of radially arranged ghost structures in the valve central part and with the presence and low number of transversal trabeculae inside the alveolus -maximally 6 in 1 μm. The valve morphology and ultrastructure of this taxon is described and its new name, Cyclotella hinziae, is proposed. Its valve morphology is compared and discussed with this of other similar taxa.

Two new fossil Cyclotella (Kützing) Brébisson species from Lake Ohrid, Macedonia/Albania

“…Houk et al 2010) show that the position of the rimoportula in Cyclotella (küTzing) de BRéBisson sensu lato is variable. In one of the most frequent freshwater species C. ocellata panToCsek the position of the rimoportula varies from at the valve face (Houk et al 2010, fig.…”

“…The species have high morphological variability with some being heterovalvar, thus identification is often problematic (Houk et al 2010). Three morphologically distinct groups within the genus were first proposed by loWe (1975) as the groups "meneghiniana", "comta" and "stelligera".…”

“…loginova (1990a) investigated more than 40 Cyclotella species and, based on several structural characteristics, the species were gathered into 12 groups. Houk et al (2010) divided the genus Cyclotella in three groups based on 58 Cyclotella species. The groups were separated by: 1) species with central area lacking areolae and single rimoportula within a ring of marginal fultoportulae; 2) species with central area without areolae and at least one rimoportula not within a ring of marginal fultoportulae and 3) species with central area with areolae and at least one rimoportula not within a ring of marginal fultoportulae, but on the valve face.…”

“…Therefore, revisions of the genus occur frequently (loginova 1990a;Håkansson 2002;Houk et al 2010;kHuRseviCH & koCiolek 2012). So far, several efforts to group the species based on their morphological features have been attempted.…”

“…loWe (1975) separated the genus into three groups, while loginova (1990a) divided the Cyclotella species into 12 groups. Houk et al (2010) distinguished three morphological groups within the genus Cyclotella. More recently, kHuRseviCH & koCiolek (2012) proposed new morphological groups for Cyclotella species and provided a more detailed explanation of the morphological and structural characters of 12 groups.…”