Wikipedia

Urceolus

This article is about a protist. For the fungus alternatively known as Urceolus, see Resupinatus.

Urceolus (from Latin urceolus 'flask', 'pitcher') is a genus of heterotrophic flagellates belonging to the Euglenozoa, a phylum of single-celled eukaryotes or protists. Described by Russian biologist Konstantin Mereschkowsky in 1877, its type species is Urceolus alenizini. Species of this genus are characterized by deformable flask-shaped cells that exhibit at least one flagellum that is active at the tip, arising from a neck-like structure that also hosts the feeding apparatus. They are found in a variety of water body sediments across the globe. According to evolutionary studies, Urceolus belongs to a group of Euglenozoa known as peranemids, closely related to the euglenophyte algae.

Urceolus
Illustration of U. alenizini by Mereschkowsky (1879)[1]
Scientific classification Edit this classification
Domain: Eukaryota
Phylum: Euglenozoa
Class: Euglenida
Order: Peranemida
Family: Peranemidae
Genus: Urceolus
Mereschkowsky 1877 ["1879"][a]
Type species
Urceolus alenizini
Mereschkowsky 1877 ["1879"][a]
Species
Synonyms[4]
  • Phialonema Stein 1878[6]
  • Urceolopsis Stokes 1887[7]

Description

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Urceolus species are single-celled eukaryotes or protists. Their cells are sack-shaped, narrow at the anterior end and expanded at the posterior end. The cells exhibit flexibility and squirming movements, more vigorous in some species. Like other phagotrophic protists, they present an organelle for ingestion known as a 'feeding apparatus',[8] an arrangement of microtubules beneath a concave portion of the cell membrane used for ingesting prey through phagocytosis.[9] Their cell body is deformable, but can be distinguished from other euglenids by a flared collar[10] or 'neck' in the anterior region, which hosts a canal where the feeding apparatus and the flagellum are located.[2] very small in some species. They have one emergent flagellum, but it is mostly active only at the tip. A rudimentary second flagellum is present in U. cyclostomus.[4]

Ecology and distribution

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Urceolus species are heterotrophic, and feed on algae through phagocytosis.[11] They have been reported in marine and freshwater sediments of various locations, both temperate and tropical, such as the Norwegian Oslofjord,[12] lake Tämnaren [sv] in Sweden,[13] the Danish portion of the Wadden Sea,[3] numerous ponds and wetlands in Czech Republic[11] and Russia,[8] tropical Australia,[14][15] the Juma River in China,[16] and Fiji.[4] Like most peranemids, they live on the bottom mud of various water bodies, and only occasionally find their way into the water column, drifting among the plankton.[13]

Evolution

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Urceolus is a genus of phagotrophic flagellates belonging to the Euglenida, a highly diverse group that also contains the phototrophic euglenophyte algae. One trait that has been used to investigate the evolution from heterotrophic euglenids towards their phototrophic counterpart is the number of strips within the feeding canal. In Urceolus cyclostomus, the canal has a number of strips equivalent to the number of strips along the entire exterior of the cell (around 40). In contrast, more 'basal' heterotrophic euglenids such as Dinema have half as many strips in the canal as the cell exterior (around 20). This is known as the 'second strip duplication event', an evolutionary innovation that presumably led to more plastic movement (metaboly) and an increase in cell size for a clade uniting Urceolus, Peranema and the phototrophic euglenophytes,[17] known as Spirocuta.[10][18]

Further morphological traits seen in Urceolus, such as a swelling around the flagellum that resembles a photoreceptor, and a stigma that resembles the eyespot of euglenophyte algae, led to the hypothesis that Urceolus was the sister group of the euglenophytes.[17] Phylogenetic analyses through DNA sequences place all peranemids (e.g., Urceolus, Peranema and others) as a whole as the sister group to euglenophytes, rather than any particular genus. The following cladogram, based on a study published in 2021, represents these findings:[18]

Euglenida

Systematics

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Taxonomic history

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The illustrations drawn by Friedrich Stein to describe Phialonema cyclostomum (1878)[6]

The genus Urceolus was first described by Russian biologist Konstantin Mereschkowsky in 1877,[a] in a memoir on the protozoa of the north of Russia.[2] He described it to accommodate a rare species of flagellate that he discovered that same year in the White Sea, near the Solovetsky Monastery, named U. alenizini. He characterized this new genus by the unique urn or pitcher-shaped cells, and accordingly named it urceolus meaning 'pitcher' in Latin.[19][1] The next year, German zoologist Friderich Stein described a new flagellate by the name of Phialonema cyclostomum, the first species of its genus.[6] Upon comparing the two species, Mereschkowsky concluded that the appearance and description of P. cyclostomum matched his description of Urceolus, and he transferred it to his genus as U. cyclostomus. Consequently, Phialonema became a junior synonym of Urceolus in 1881.[2]

In 1887, American protozoologist Alfred Cheatham Stokes described the genus Urceolopsis to accommodate the species U. sabulosus. This genus is essentially equal in appearance to Urceolus, with the only difference being that the cell surface is covered in adherent sand grains.[7][20] It was later synonimised to Urceolus for that reason.[4][12]

Urceolus and other colorless, non-photosynthetic flexible flagellates such as Heteronema, Peranema and Anisonema were initially lumped together in the family Peranemidae, while similar but phototrophic, green-coloured algae such as Euglena composed the family Euglenidae. Both families belong to the Euglenida,[21] one of the major groups within the phylum Euglenozoa, a basal group of eukaryotes.[10] The taxonomic status of Peranemidae has changed through the years: first classified in the paraphyletic order Heteronematales,[3][4] it later became the sole family of the order Peranemida, regarded as the closest relatives of the photosynthetic euglenids.[18][22] Many colorless euglenids were transferred from Peranemidae to other groups, but Urceolus is one of the few genera that remains in the family.[23]

Classification

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Urceolus contains the following species:[3][4]

Several authors note that there is considerable ambiguity in the identification of Urceolus species, because most original descriptions are inadequate and confident identification is not always possible. In addition, detail is often obscured by adhering particles of detritus.[4][14]

Notes

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  1. ^ a b c d Some online resources, such as AlgaeBase, attribute the original description of Urceolus to a 1879 article in the German journal Archiv für Mikroskopische Anatomie.[1] However, according to Mereschkowsky himself[2] and posterior articles,[3][4] this is a translation of an article published two years earlier in a Russian journal.[5] This explains the priority of Urceolus over Phialonema, a junior synonym described in 1878.[3]

References

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  1. ^ a b c C. von Mereschkowsky (1879). "Studien über Protozoen des nördlichen Russland" [Studies on protozoa of northern Russia]. Archiv für Mikroskopische Anatomie (in German). 16: 153–248.
  2. ^ a b c d C. Mereschkowsky (1881). "XVIII.—On some new or little-known Infusoria". Annals and Magazine of Natural History. Fifth series. 7 (39): 209–219. doi:10.1080/00222938109459496.
  3. ^ a b c d e f g h i Jacob Larsen (December 1987). "Algal studies of the Danish Wadden Sea. IV. A taxonomic study of the interstitial euglenoid flagellates". Nordic Journal of Botany. 7 (5): 589–607. doi:10.1111/J.1756-1051.1987.TB02028.X. ISSN 0107-055X. Wikidata Q104049037.
  4. ^ a b c d e f g h i j Jacob Larsen; David J. Patterson (August 1990). "Some flagellates (Protista) from tropical marine sediments". Journal of Natural History. 24 (4): 801–937. doi:10.1080/00222939000770571. ISSN 0022-2933. Wikidata Q54494137.
  5. ^ K. S. Mereschkowsky (1877). "Etyudy nad prosteyshimi zhivotnymi severa Rossii" Этюды над простейшими животными севера России [Studies on protozoa of northern Russia]. Trudy S.-Peterburgskago Obshchestva Estestvoispytatelei Труды Санкт-Петербургскаго Общества естествоиспытателей [Proceedings of the St. Petersburg Society of Naturalists] (in Russian). 8: 203–376.
  6. ^ a b c Friedrich Ritter von Stein (1878). 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 [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] (in German). Lepizig: W. Engelmann. plate XXIII, figures 42–48. doi:10.5962/bhl.title.3933. OCLC 475289589. Retrieved 2024-04-17.
  7. ^ a b Alfred C. Stokes (1887). "Notices of New Fresh-Water Infusoria". Proceedings of the American Philosophical Society. 24 (126): 244–255.
  8. ^ a b K. I. Prokina (July 2019). "Heterotrophic Flagellates from Sphagnum Bogs and Terrace-Forest and Floodplain Water Bodies of the Central Russian Forest-Steppe". Inland Water Biology. 12 (3): 276–289. doi:10.1134/S199508291903012X. ISSN 1995-0829. Wikidata Q119981891.
  9. ^ Brian S Leander; Heather J Esson; Susana A Breglia (1 October 2007). "Macroevolution of complex cytoskeletal systems in euglenids". BioEssays. 29 (10): 987–1000. doi:10.1002/BIES.20645. ISSN 0265-9247. PMID 17876783. Wikidata Q33299331.
  10. ^ a b c Gordon Lax; Alastair G. B. Simpson (16 August 2020). "The Molecular Diversity of Phagotrophic Euglenids Examined Using Single-cell Methods". Protist. 171 (5): 125757. doi:10.1016/J.PROTIS.2020.125757. ISSN 1434-4610. PMID 33126020. Wikidata Q101127864.
  11. ^ a b Petr Hašler; Jana Štěpánková; Jana Špačková; et al. (1 September 2008). "Epipelic cyanobacteria and algae: a case study from Czech ponds". Fottea (Praha). 8 (2): 133–146. doi:10.5507/FOT.2008.012. ISSN 1802-5439. Wikidata Q119649001.
  12. ^ a b c Eider Zubizarreta Garai (2005). Diversity of sandflagellates in the Oslofjord (Master thesis). Universitetet i Oslo.
  13. ^ a b c H. Skuja (1956). "Taxonomische und Biologische Studien das Phytoplankton Schwedischer Binnengewasser" [Taxonomic and biological studies of the phytoplankton of Swedish inland waters] (PDF). Nova Acta Regiae Societatis Scientiarum Uppsaliensis. 4th series (in German). 16: 1–403.
  14. ^ a b Won J. Lee; Alastair G. B. Simpson; David J. Patterson (2005). "Free-living Heterotrophic Flagellates from Freshwater Sites in Tasmania (Australia), a Field Survey" (PDF). Acta Protozoologica. 44 (4): 321–250. ISSN 0065-1583. Wikidata Q124695486.
  15. ^ Won Je Lee (June 2006). "Heterotrophic Euglenids from Marine Sediments of Cape Tribulation, Tropical Australia" (PDF). Ocean science journal : OSJ. 41 (2): 59–73. doi:10.1007/BF03022412. ISSN 1738-5261. Wikidata Q104428258.
  16. ^ Fengchao Li; Xianjiang Kang; Wenbo Yang; Yueqiang Guan; Xiaohui Zhang; Weiwei Liu; Gongming Shen; Jilong Li; Hongwei Wang (2006). "Protozoan community character in relation to trophic level in the Beijing section of the Juma River". Biodiversity Science. 14 (4): 327–332. doi:10.1360/biodiv.060004.
  17. ^ a b Brian S. Leander; Richard E. Triemer; Mark A. Farmer (2001). "Character evolution in heterotrophic euglenids". European Journal of Protistology. 37 (3): 337–356. doi:10.1078/0932-4739-00842. ISSN 0932-4739. Wikidata Q124711495.
  18. ^ a b c Lax G, Kolisko M, Eglit Y, Lee WJ, Yubuki N, Karnkowska A, Leander BS, Burger G, Keeling PJ, Simpson AGB (2021). "Multigene phylogenetics of euglenids based on single-cell transcriptomics of diverse phagotrophs". Molecular Phylogenetics and Evolution. 159 (107088). doi:10.1016/j.ympev.2021.107088.
  19. ^ "Urceolus". Merriam-Webster.com Dictionary. Merriam-Webster. Retrieved 2024-04-24.
  20. ^ H.W. Conn; C.H. Edmondson (1918). "Chapter IX. Flagellate and Ciliate Protozoa (Mastigophora et Infusoria)". In Henry Baldwin Ward; George Chandler Whipple (eds.). Fresh-water biology. New York: John Wiley & Sons. pp. 238–300. doi:10.5962/bhl.title.160213.
  21. ^ Theodore Louis Jahn (1 September 1946). "The euglenoid flagellates". The Quarterly Review of Biology. 21 (3): 246–274. doi:10.1086/395316. ISSN 0033-5770. PMID 20274710. Wikidata Q83295819.
  22. ^ Lax G, Cho A, Keeling PJ (2023). "Phylogenomics of novel ploeotid taxa contribute to the backbone of the euglenid tree". The Journal of Eukaryotic Microbiology. 70 (e12973): e12973. doi:10.1111/jeu.12973. PMID 36912454.
  23. ^ Thomas Cavalier-Smith (15 September 2016). "Higher classification and phylogeny of Euglenozoa". European Journal of Protistology. 56: 250–276. doi:10.1016/J.EJOP.2016.09.003. ISSN 0932-4739. PMID 27889663. Wikidata Q39151632.
  24. ^ B. W. Skvortzow. "Neue oder wenig bekannte Protisten. XI. Neue oder wenig bekannte Flagellaten. X. Farblose Euglenaceen aus Nord-Mandschurei (China)" [New or little-known protists. XI. New or little-known flagellates. X. Colorless Euglenaceae from North Manchuria (China)] (PDF). Archiv für Protistenkunde (in German). 48 (1): 180–186.
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