76 research outputs found
typifying four Ehrenberg names and a preliminary checklist of the African taxa
To comply with the new phylogeny within the Surirellales as supported by
molecular and morphological data, re-evaluations and re-combinations of taxa
from and within the genera Surirella, Cymatopleura, and Stenopterobia and with
the re-established genus Iconella are necessary. Since the African diatom
flora is rich with taxa from these genera, especially Iconella, and the
authors have studied these taxa recently, describing also new taxa, a
preliminary checklist of African Iconella and Surirella is here presented. 94
names are contained on this list. 57 taxa have been transferred to Iconella;
55 taxa were formerly ranked within Surirella and two taxa within
Stenopterobia. 10 taxa have stayed within Surirella and six taxa have been
transferred from Cymatopleura to Surirella. 20 Surirella and 1 Stenopterobia
names are listed which are either unrevised or unrevisable since morphological
data is missing. Four names and taxa described by Ehrenberg are here typified.
Two had been transferred to Iconella already: Iconella bifrons (Ehrenb.) Ruck
& Nakov and Iconella splendida (Ehrenb.) Ruck & Nakov. Two are re-transferred
from Cymatopleura to Surirella: Surirella librile (Ehrenb.) Ehrenb. and
Surirella undulata (Ehrenb.) Ehrenb.; both taxa are currently known by their
younger synonyms: Cymatopleura solea (Bréb.) W. Smith and Cymatopleura
elliptica (Bréb. ex Kützing) W. Smith. Lectotypes for Iconella bifrons, I.
splendida, Surirella librile, and S. undulata were designated
Red list and checklist of the limnic red algae and brown algae
Für Berlin wurden bisher sieben Arten limnischer Rotalgen (Rhodophyta) sicher nachgewiesen, davon sind zwei Bestandteil der Roten Liste. Diese Neufassung der Gesamtartenliste weist einige wesentliche Veränderungen gegenüber der Vorgängerliste auf, weil neben Zufallsfunden erstmalig auch mehrjährige Nachuntersuchungen von Rotalgenstandorten einbezogen werden konnten. Eine verschollene Rotalge wurde wiedergefunden, zwei Arten wurden im Untersuchungszeitraum erstmals nachgewiesen. Die Liste der limnischen Braunalgen (Phaeophyceae) enthält nach wie vor nur eine verschollene Art.The checklist of Berlin includes seven species of limnic red algae (Rhodophyta), two of them are part of the Red List. In comparison with the previous list now multi-annual findings are included besides single records. One extinct or missing species was found again and two species were discovered for the first time in Berlin. The list of limnic brown algae (Phaeophyceae) for Berlin still includes only one extinct species
Red list and checklist of the stoneworts
Für Berlin wurden seit dem 18. Jahrhundert 21 Arten limnischer Armleuchteralgen (Characeae) in den Gattungen Chara, Lychnothamnus, Nitella, Nitellopsis und Tolypella nachgewiesen. Davon sind 11 Arten ausgestorben oder verschollen, weitere vier Arten sind als bestandsgefährdet eingestuft und auch Bestandteil der Roten Liste. Diese Neufassung der Gesamtartenliste weist einige Veränderungen gegenüber der Vorgängerliste auf, weil durch Kartierungsergebnisse der Flächenbezug der Artvorkommen im Stadtstaat visualisiert und der Einfluss der Urbanisierung auf die Arten stärker berücksichtigt wird.The checklist of Berlin (Germany) includes 21 species of stoneworts (Characeae) in the genera Chara, Lychnothamnus, Nitella, Nitellopsis, and Tolypella. 11 of them are extinct or lost, 4 further species are part of the Red List as endangered species. In comparison with the previous list, this list includes mapped floristic data to visualize and discuss the effects of urbanization on the distribution of Characeae
A Best Practice Example from Diatom Research
DNA barcoding uses a short fragment of a DNA sequence to identify a taxon.
After obtaining the target sequence it is compared to reference sequences
stored in a database to assign an organism name to it. The quality of data in
the reference database is the key to the success of the analysis. In the here
presented study, multiple types of data have been combined and critically
examined in order to create best practice guidelines for taxonomic reference
libraries for environmental barcoding. 70 unialgal diatom strains from Berlin
waters have been established and cultured to obtain morphological and
molecular data. The strains were sequenced for 18S V4 rDNA (the pre-Barcode
for protists) as well as rbcL data, and identified by microscopy. LM and for
some strains also SEM pictures were taken and physical vouchers deposited at
the BGBM. 37 freshwater taxa from 15 naviculoid diatom genera were identified.
Four taxa from the genera Amphora, Mayamaea, Planothidium and Stauroneis are
described here as new. Names, molecular, morphological and habitat data as
well as additional images of living cells are also available electronically in
the AlgaTerra Information System. All reference sequences (or reference
barcodes) presented here are linked to voucher specimens in order to provide a
complete chain of evidence back to the formal taxonomic literature
Integrative taxonomic description of two new species of the Cocconeis placentula group (Bacillariophyceae) from Korea based on unialgal strains
Cocconeis coreana and C. sijunghoensis are described as new based on micromorphological and molecular data C. coreana is represented by five unialgal cultures from four different freshwater bodies, two from North Korea and three from South Korea. C. sijunghoensis is represented by two unialgal cultures from a brackish water body in North Korea. Except for one, all of the strains auxosporulated and showed an almost quadrupling of size in length and width. Morphologically, these species with their two different elliptical valves belong to the Cocconeis placentula group. The raphe valve has striae with uniseriate areolae continuing across a pronounced submarginal hyaline rim to the edge of the valve. The sternum valve has uniseriate dash-like areolae continuously from the valve face until the valve edge. Micromorphologically, these species possess two different open valvocopulae: only the raphe valvocopula has fimbriae; the sternum valvocopula has none. Based on p-distances of currently available DNA sequence data, i.e., rbcL and 18SV4, both species are pronouncedly different from the epitype strain of C. placentula, with C. coreana closest to the published molecular data of the strain UTEX FD23 named C. placentula from Iowa, USA, while C. sijunghoensis is closest but not the same as the publ is hed molecular data of strain D36_012, the epitype strain of C. placentula from Berlin, Germany. Based on scanning elect ron microscope observations, differentiating features are discussed concerning valvocopula fimbriae, central area, areolation of the sternum valve and on the raphe valve especially between the submarginal hyaline rim and edge
PLATE PATTERN CLARIFICATION OF THE MARINE DINOPHYTE HETEROCAPSA TRIQUETRA SENSU STEIN (DINOPHYCEAE) COLLECTED AT THE KIEL FJORD (GERMANY)
One of the most common marine dinophytes is a
species known as Heterocapsa triquetra. When Stein
introduced the taxon Heterocapsa, he formally based
the type species H. triquetra on the basionym
Glenodinium triquetrum. The latter was described by
Ehrenberg and is most likely a species of
Kryptoperidinium. In addition to that currently
unresolved nomenclatural situation, the thecal plate
composition of H. triquetra sensu Stein (1883) was
controversial in the past. To clarify the debate, we
collected material and established the strain UTKG7
from the Baltic Sea off Kiel (Germany, the same
locality as Stein had studied), which was investigated
using light and electron microscopy, and whose
systematic position was inferred using molecular
phylogenetics. The small motile cells (18–26 µm in
length) had a biconical through fusiform shape and
typically were characterized by a short asymmetrically
shaped, horn-like protuberance at the antapex. A
large spherical nucleus was located in the episome,
whereas a single pyrenoid laid in the lower cingular
plane. The predominant plate pattern was identified
as apical pore complex (Po, cp?, X), 4', 2a, 6'', 6c,
5s, 5''', 2''''. The triradiate body scales were
254–306 nm in diameter, had 6 ridges radiating from
a central spine, 9 peripheral and 3 radiating spines,
and 12 peripheral bars as well as a central depression
in the basal plate. Our work provides a clarification
of morphological characters and a new, validly
published name for this important but yet formally
undescribed species of Heterocapsa: H. steinii sp. nov
A Gordian knot: Nomenclature and taxonomy of Heterocapsa triquetra (Peridiniales: Heterocapsaceae)
In the course of polyphasic taxonomic work in the dinophytes, we became aware of a fundamental misapplication
of the name Glenodinium triquetrum (now represented conceptually by a species of Kryptoperidinium), when Stein assigned it to Heterocapsa. Possible solutions involve a conflict between retaining Ehrenberg’s epithet in its correct application in the interest of priority and preserving current usage of Heterocapsa. However, we do not achieve a consensus on how to disentangle this Gordian knot, underlining that this is not a regular case of taxonomic confusion. We intend to stimulate a more general discussion about best practices in such cases, balancing between the interest of nomenclatural practicability and the respectful acknowledgement of scientific work, even if it was conducted many years ago
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