Urceolus cyclostomus
{{Short description|Species of flagellate}}
{{Speciesbox
| image = Stein 1878 Tafel XXIII Phialonema cropped.png
| image_caption = The first illustrations of Urceolus cyclostomus by Friedrich Stein (1878)
| taxon = Urceolus cyclostomus
| authority = (Stein, 1878) Mereschkowsky, 1881
| synonyms =
{{center|Phialonema cyclostomum{{br}}{{au|Stein, 1878}}}}
}}
Urceolus cyclostomus is a species of heterotrophic flagellates. It was initially described by Friedrich Stein in 1878 as Phialonema cyclostomum, from an unknown location. Due to its morphological similarities to Urceolus alenizini, the author of the latter, Konstantin Mereschkowsky, transferred it to the genus Urceolus in 1881. Like other species of the genus, its cells have a neck and a wide aperture to a canal that hosts a single flagellum and its feeding apparatus. It is distinguished from other species by a significantly more rigid cell shape, among other traits. It can be found in the bottom sediment of freshwater and brackish water bodies, as a consumer of algae.
Description
Urceolus cyclostomus is a species of flagellate, a single-celled protist that exhibits an emergent flagellum for movement. Members of the genus Urceolus are distinguished by the presence of a 'neck' at the anterior end of their oval-shaped cell, followed by a wide aperture or 'mouth' into a deep canal where the feeding groove and the flagellum originate. In addition, like other euglenids, the cell surface or pellicle is spiral-striped. In particular, U. cyclostomus is distinguished from other species of the genus by its more or less rigid and regular body shape, a less developed 'ingestive organelle' or feeding apparatus, and a more conspicuous 'hatching' (i.e. more pronounced stripes) of the pellicle. The posterior end of the cell is narrow, as is common in other euglenids. The cells are ovate, measuring 14–30 μm long and 4–18 μm wide. The cells move by crawling through the substrate, with the posterior end raised. The flagellum is around 1.5 times longer than the cell itself, 40–50 μm.{{cite Q|Q104049037}}{{cite Q|Q119981891}}
Distribution and habitat
Urceolus cyclostomus inhabits the bottom sediment of freshwater bodies with a wide distribution. It has been recorded in bogs of the Central Russian forest-steppe region and numerous ponds in the Czech Republic, where it feeds on epipelic cyanobacteria and other kinds of algae.{{cite Q|Q119649001}} It is also present in brackish waters, such as salt marshes and intertidal sand of England.{{cite journal|title=An Ecological Study of Brackish Water Ciliates|author1=Marjorie G. Webb|date=1956|volume=25|issue=1|pages=148–175|journal=Journal of Animal Ecology|doi=10.2307/1856|url=https://www.jstor.org/stable/1856}}{{cite journal|title=Microscopic Algae And Protozoa In The waters near Plymouth in August 1962|author1=James B. Lackey|author2=Elsie W. Lackey|journal=Journal of the Marine Biological Association of the United Kingdom|volume=43|issue=3|date=1963|pages=797–805|doi=10.1017/S0025315400025698}}
Taxonomy
The species Urceolus cyclostomus was initially described by German zoologist Friedrich Stein in his 1878 book Der Organismus der Infusionthiere. He named the species as Phialonema cyclostomum, without specifying the location in which it was discovered. He described this new genus and species through a series of illustrations.{{cite book|title=Der Organismus der Infusionsthiere. III. Abtheilung. Der Organismus der Flagellaten nach eigenen Forschungen in Systematischer Reihenfolge. I. Hälfte, Den noch nicht abgeschlossenen allgemeinen Theil nebst Erklärung der sämmtlichen Abbildungen enthaltend |language=german|trans-title=The Infusoria Organism. Volume III. The Flagellate Organism according to our own research in a systematic order. Part I, Containing the general part, which has not yet been completed, along with an explanation of all the illustrations |doi=10.5962/bhl.title.3933|publisher=W. Engelmann|publication-place=Lepizig|date=1878|author1=Friedrich Ritter von Stein|author1-link=Samuel Friedrich Stein|url=https://www.biodiversitylibrary.org/page/42377676|page=plate XXIII, figures 42–48|no-pp=yes|doi-access=free|access-date=2024-04-17|oclc=475289589}} Later, Russian biologist Konstantin Mereschkowsky compared Stein's illustrations of P. cyclostomum with the description of his own genus and species, Urceolus alenizini, which he published the previous year in 1877.{{cite journal|author1=K. S. Mereschkowsky|author1-link=Konstantin Mereschkowski|title=Etyudy nad prosteyshimi zhivotnymi severa Rossii|script-title=ru:Этюды над простейшими животными севера России|trans-title=Studies on protozoa of northern Russia|work=Trudy S.-Peterburgskago Obshchestva Estestvoispytatelei|script-work=ru:Труды Санкт-Петербургскаго Общества естествоиспытателей|trans-work=Proceedings of the St. Petersburg Society of Naturalists|volume=8|pages=203–376|language=Russian|date=1877}} Mereschkowsky noticed the extreme similarities, particularly the 'neck' with a wide aperture where the flagellum originates. In 1881, he transferred this new species to Urceolus under the name of U. cyclostomus, rendering Phialonema a junior synonym of his genus.{{cite journal|author1=C. Mereschkowsky|author1-link=Konstantin Mereschkowski|title=XVIII.—On some new or little-known Infusoria|journal=Annals and Magazine of Natural History|volume=7|issue=39|pages=209-219|date=1881|doi=10.1080/00222938109459496|url=https://www.biodiversitylibrary.org/item/79589|series=Fifth series}}