scholarly journals Where should we draw the lines between dinocyst “species”? Morphological continua in Black Sea dinocysts

2019 ◽  
Vol 38 (1) ◽  
pp. 55-65 ◽  
Author(s):  
Thomas M. Hoyle ◽  
Manuel Sala-Pérez ◽  
Francesca Sangiorgi
Keyword(s):  
Black Sea ◽  
Genetic Difference ◽  
Morphological Variability ◽  
Intraspecific Variability ◽  
Nutrient Status ◽  
The Black Sea ◽  
Genetic Sequencing ◽  
Morphological Variations ◽  
Intermediate Phenotypes ◽  
Primary Driver

Abstract. The morphology of dinoflagellate cysts (dinocysts) is related not only to the genetics of the motile dinoflagellate from which it derives, but is also dependent on a range of environmental factors including salinity, temperature and nutrient status. Although this knowledge improves our understanding of the drivers behind dinocyst morphological variations, it makes the taxonomy governing their description somewhat complex. In basins such as the Black Sea, where environmental change can be extreme and occurs on relatively short (millennial) timescales, taxonomy becomes particularly challenging. Morphological continua can be observed between described forms, displaying a large range of intermediate phenotypes that do not necessarily correspond to any genetic difference. As these morphological nuances may preserve information about palaeoenvironments, it is important to find a systematic method of characterising morphotypes. Here, we show a dinocyst matrix within which dinocysts are described according to their similarity to (or difference from) described forms based on key descriptive parameters. In the example set out here, cyst shape and degree of process and/or ectophragm development are taken as two key parameters in Pyxidinopsis psilata and Spiniferites cruciformis, and can allow the description of intermediate forms even though the definitions do not overlap. We review some frequently occurring morphotypes and propose that using matrices to show the gradual variation between endmember forms is the most pragmatic approach until cyst–theca studies and genetic sequencing can be used to demonstrate relationships between genotypes and morphotypes. As prior studies propose salinity to be a primary driver of intraspecific variability, the endmembers presented may represent salinity extremes within an overall brackish environment. Although we cannot assign each morphotype to a value or a range of an environmental parameter (e.g. salinity) as the different morphotypes can occur in the same sample, using this matrix allows preservation of information about morphological variability without creating taxonomic categories that are likely to require alteration if genetic evidence becomes available.

The genus Cystoseira s.l. (Ochrophyta, Fucales, Sargassaceae) in the Black Sea: morphological variability and molecular taxonomy of Gongolaria barbata and endemic Ericaria crinita f. bosphorica comb. nov.

Phytotaxa ◽  
2021 ◽  
Vol 480 (1) ◽  
pp. 1-21
Author(s):  
SOFIA S. SADOGURSKA ◽  
JOÃO NEIVA ◽  
ANNALISA FALACE ◽  
ESTER A. SERRÃO ◽  
ÁLVARO ISRAEL
Keyword(s):  
Mediterranean Sea ◽  
Black Sea ◽  
Molecular Taxonomy ◽  
Morphological Variability ◽  
Morphological Characteristics ◽  
Molecular Data ◽  
Morphological Data ◽  
The Black Sea ◽  
Morphological Identification ◽  
Additional Tool

Brown algae of the genus Cystoseira sensu lato form the most diverse and productive marine ecosystems throughout the Mediterranean Sea and have equal roles also in the Black Sea where they have been decreasing in the recent years. The taxonomy of Cystoseira s.l. taxa from the Black Sea is still not well understood, and questions arise when related taxa have to be delimited. In addition to morphological descriptions, this study provides for the first time molecular data of the Black Sea Cystoseira s.l. distinct morphologies as an additional tool to clarify their identities and phylogenetic affinities. The analysis of two mitochondrial markers (cytochrome oxidase subunit 1—COI, and 23S-tRNAVal intergenic spacer—mt-spacer) showed that Cystoseira s.l. specimens from the Black Sea belong to two recently resurrected genera, namely Gongolaria and Ericaria. Molecular data confirm the morphological identification of G. barbata, which is characterized by high morphological plasticity in the Black Sea. The morphological data presented in this study support the transition of G. barbata to the genus Gongolaria, which was previously proposed based solely on genetic data. For the Black Sea endemic taxon C. bosphorica, sequence divergence suggests conspecificity with Mediterranean Sea species E. crinita and E. barbatula. However, considering original morphological characteristics of the taxon, its geographical isolation, and endemism, the new combination Ericaria crinita f. bosphorica comb. nov. is proposed.

New data on the morphological variability of the shell of Flexopecten glaber (Linnaeus, 1758) (Bivalvia, Pectinidae) in the Black Sea

2020 ◽  
Vol 30 (2) ◽  
pp. 103-113
Author(s):  
I. P. Bondarev
Keyword(s):  
Black Sea ◽  
Narrow Range ◽  
Shell Growth ◽  
Morphological Variability ◽  
The Black Sea ◽  
Habitat Conditions ◽  
Intraspecific Polymorphism ◽  
New Information ◽  
Quantitative Indicators ◽  
First Time

The morphological variability of the bivalve mollusc Flexopecten glaber was studied based on the analysis of 306 specimens from the Kazach’ya Bay (Sevastopol, Crimea) of the Black Sea. The sampling of mollusks was carried out with the help of skuba equipment in June-September of 2017-2018. For F. glaber, the age and size characteristics are given and the main trends in their ratios with the shell growth are considered. For the first time, quantitative indicators of thickness of the shell valves, their weight and height of the radial ribs are presented and discussed. A wide intraspecific polymorphism of the shell is shown in a relatively narrow range of habitat conditions. The obtained data expand the understanding of the morphological variability of F. glaber in the Black Sea and provide new information on the functional morphology of the species.

scholarly journals Morphological variation of two marine diatom species, Nitzschia ventricosa and Ardissonea crystallina (Bacillariophyta)

2016 ◽  
Vol 1 (4) ◽  
pp. 53-62
Author(s):  
K. I. Shorenko ◽  
Yu. A. Podunai ◽  
O. I. Davidovich ◽  
M. S. Kulikovskyi
Keyword(s):  
Hong Kong ◽  
Black Sea ◽  
Pure Culture ◽  
Morphological Variability ◽  
Natural Populations ◽  
Marine Diatom ◽  
The Black Sea ◽  
Pure Cultures ◽  
The Impact

The relevance of the article is caused by insufficient knowledge of the problem of understanding of the diatoms species scope, particularly in vitro. The aim of the research is to study the morphological variability in cultures of two species of marine pennate diatoms, Nitzschia ventricosa and Ardissonea crystallina using methods of light and scanning electron microscopy.  In addition we assessed the impact of salinity on morphological parameters of A. crystallina valves in the experiment, which is used in the diagnosis of the type. The material for investigation were isolates (algological pure cultures and clones) obtained in vitro. N. ventricosa isolates were received from natural populations collected at coasts of Canary Islands, Islands of Martinique and Texas (Gulf of Mexico). The clones of A. crystallina were allocated from benthic samples in Kazachya Bay (Sevastopol, the Black Sea). The culture was established with the micropipette way and grown in Petri dishes on ESAW media with natural light at a temperature of 20 °C. We refer to a clone (strain) as vegetative offspring derived from a single cell, while the algological pure culture is a group of clones of the same species. The algological pure culture of A. crystallina (consisting of several strains) was physically separated and grown in parallel with six levels of salinity (8, 12, 17, 30, 38 and 48 ‰) for two months. To obtain the required initial salinity the medium salinity (36 ‰) was diluted with the necessary amount of distilled water, or NaCl was added. The terms of keeping of cultures in artificial conditions until the preparation of drugs were no more than 2 months longer, in order to avoid teratological changes. The species Nitzschia ventricosa was originally discovered on the coast of Hong Kong and described in 1873 by the British naturalist F. Kitton. In the Black and Azov seas' benthos and plankton the species N. ventricosa was not observed. While studying the collected materials of the British Natural History Museum (London), the holotype of N. ventricosa was not marked by F. Kitton. The slide № 10365 from the collections of the British Museum (Collection Deby), with this type of material from Hong Kong, was studied. The material in the slide was decided to be authentic (specimina authentica). The material showed the proximity of morphometric characteristics of the valves. Data was compared to the ones given from other Pacific populations. The species Ardissonea crystallina (C. Agardh) Grunow was described by Swedish botanist C. Agardh in 1824 as Diatoma crystallinum C. Agardh. The type locality (locus typicus) are the waters of Sinus Codani, which corresponds to Kattegat Strait, located between the East coast of the Jutland peninsula and the south-western part of the Scandinavian Peninsula. Both species are widely distributed in the oceans and are found regularly in the benthos and plankton, however, they have not been studied in cultures. The following conclusions were obtained: 1. Morphological variability in cultures of N. ventricosa and A. crystallina was comparable with those obtained on the material from natural populations. 2. We managed to get both types of auxospore in the cultures that allowed us to estimate the upper limit of the size range of both types of cells. For N. ventricosa it was 616.0 µm, for A. crystallina the maximum length was 678.0 µm. 3. The variation of number of striae and fibulae in one clone of N. ventricosa was higher than in pure cultures. 4. It has been shown that A. crystallina was able to live while salinity was from 8 to 48 ‰. 5. The A. crystallina culture derived from natural population of the Black Sea, was close to the number of striae to the population from the coast of Canada (Shalёr Bay). 6. The content of the cultures at different rates of salinity for two months has not led to significant morphological changes of A. crystallina cells. There was no effect of salinity on qualitative morphological features of A. crystallina. With an increase of salinity in the experiment arrangement density of striae and areolae of A. crystallina tend to increase, and the width of the cell — to decrease. With the increase of salinity, an increase of the breadth ranges of the striae number variation was observed.

MÖSSBAUER AND CHEMICAL ANALYSES OF SOME SEDIMENTS FROM THE ROMANIAN SHORE OF THE BLACK SEA

1979 ◽  
Vol 40 (C2) ◽  
pp. C2-445-C2-448
Author(s):  
D. Barb ◽  
L. Diamandescu ◽  
M. Morariu ◽  
I. I. Georgescu
Keyword(s):  
Black Sea ◽  
The Black Sea ◽  
Chemical Analyses

Modeling of ecological conditions in the Euxine Basin in the Sarmatian and Maeotian by methods of diatom analysis

2019 ◽  
pp. 257-261
Author(s):  
Eleonora P. Radionova
Keyword(s):  
Black Sea ◽  
Late Miocene ◽  
The Black Sea ◽  
Subtidal Zone ◽  
Diatom Analysis ◽  
Diatom Flora ◽  
North West ◽  
Ecological Conditions ◽  
The North

The associations and ecological conditions of the existence of modern diatoms of the North-West (Pridneprovsky), Prikerchensky and Eastern regions of the subtidal zone of the Black Sea are considered. Based on the unity of the composition of the Present and Sarmatian-Meotian diatom flora, an attempt has been made to model some of the ecological c situation of the Late Miocene Euxinian basin.

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