User:Chaotic Enby/sandbox/Salinella
| Chaotic Enby/sandbox/Salinella | |
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| Johannes Frenzel's illustrations, 1892 | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Clade: | Platytrochozoa R. Blackwelder, 1963 |
| Phylum: | Monoblastozoa |
| Genus: | Salinella J. Frenzel, 1891[1] |
| Species: | S. salve
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| Binomial name | |
| Salinella salve | |
Salinella salve is a dubious species of a very simple animal which some have named as the sole member of the phylum Monoblastozoa. Its body is reported to consist of a single layer of cells, covered in cilia externally and internally, surrounding a tube-shaped gut with a mouth at one end and an anus at the other. It was discovered in 1892 by Johannes Frenzel in the salt pans of Córdoba Province, Argentina and cultivated in a laboratory by him. This animal has not been found since and its real existence is considered as doubtful.[2][3] A project involving Michael Schrödl from the Zoological State Collection in Munich searched for Salinella in salt lakes across Argentina and Chile, but failed to find any specimens.[4][5][6]
Discovery
Salinella was discovered in soil samples from salt pans around Río Cuarto, Córdoba Province, Argentina, although the exact type locality was never specified.[7] Salinella's discoverer Frenzel did not collect the soil samples himself, but received them from a geologist friend in 1890 or 1891.[4] The samples were placed in a freshwater aquarium, resulting in a 2% saline solution, and were left unattended for weeks. Later observations by Frenzel revealed organisms around 2 millimetres (0.079 in) on the walls and substrate. Reproduction by fission was observed, as well as conjoined adults and possible unicellular larvae.[7]
[This should be expanded into two paragraphs, describing how specimens were studied, with any useful Frenzel commentary that posterity judged relevant]
[And then the publishing of the successive articles in 1891-92]
Description
[Old description] According to Frenzel's description, S. salve is more organized than Protozoa, but still very primitive for a multicellular organism. They are characterised by their distinct anterior/posterior parts and being densely ciliated, especially around the "mouth" and "anus". They have only one layer of cells, and reproduce asexually by transverse fission of their bodies. Although sexual reproduction was suspected, Frenzel did not observe it.[8]
[This can be expanded more if possible]
[MI's rewrite] According to Frenzel's description, S. salve is a multicellular tube-shaped and bilateral organism that is somewhat pointed in at both ends, flattened underneath and arched from above, appearing to be semicircular when viewed from the side. The body consists of a single layer of large almost cuboid cells of nearly equal size, surrounding a tube-shaped intestinal cavity with an oral opening at the front end and a smaller anal opening at the rear end. The ventral side of the body is covered in cilia, which the animal uses to move along, while the dorsal and lateral sides are instead more sparsely covered in short setae. At the oral opening are longer and thicker cirri (long thin tentacle-like structures), which are used to whirl food into the mouth.[9]
Taxonomy
[Here we can have all of the debates about the position in the tree of life, with its tentative placement in "Mesozoa", the new phylum, etc.]
In 189?, French zoologist Yves Delage argued that Salinella's growth was evidence for the transition from unicellular to multicellular organisms happening through differentiation of a single cell, rather than from colonial protozoans growing together. Delage claimed that the structure of the single-celled Salinella larva was homologous to the multicellular adult form, and proposed a mechanism through which fragments of the multinucleate cell migrated to the periphery of the larva and differentiated into distinct cells, leaving an internal digestive cavity.[10]
In 1963, American biologist Richard E. Blackwelder established the new phylum Monoblastozoa, containing only the genus Salinella and species S. salve, in his Classification of the Animal Kingdom.[11]
Later searches
In 2012, German malacologist Michael Schrödl from the Bavarian State Collection of Zoology led an expedition to Córdoba Province, Argentina with colleagues in order to recover specimens of Salinella. However, the location specified by Frenzel, originally described as a salt pan, was found to have been transformed into arable land. As Schrödl believed that Salinella could have been transported as a wind-borne spore, the expedition collected samples from various salt lakes across Córdoba Province. After searching in Argentina, the expedition also collected samples from salt lakes in Chile. While replication of Frenzel's protocol was attempted, no specimens of Salinella were found throughout the cultured samples.[4][6][5]
See also
- Mesotardigrada – another high rank taxon whose sole member has not been independently verified to exist
References
- ^ a b Acosta 2015, p. 89.
- ^ Brusca, R. C.; Brusca, G. J. (2005). Invertebrados (2nd ed.). Madrid: McGraw-Hill-Interamericana. ISBN 978-0-87893-097-5.
- ^ Taylor, Christopher (June 27, 2007). "Salinella - what the crap was it?". Catalogue of Organisms.
- ^ a b c Dunning, Hayley (October 1, 2012). "Gone Missing, circa 1892". The Scientist.
- ^ a b Viering, Kerstin (November 23, 2012). "Jäger der verborgenen Art". Spektrum.
- ^ a b Tihelka & Cai 2021, p. 1071.
- ^ a b Tihelka & Cai 2021, p. 1070.
- ^ Frenzel, Johannes (1892). "Untersuchungen über die mikroskopische Fauna Argentiniens". Archiv für Naturgeschichte (in German). 58: 66–96, Plate VII.
- ^ Frenzel, J. (1892). "A multicellular infusorian-like animal". Annals and Magazine of Natural History. 8. 9: 109–111.
- ^ Boutan 1897, p. 26–27.
- ^ Blackwelder, R.E. (1963). Classification of the Animal Kingdom. Carbondale, Illinois: Southern Illinois University Press. p. 27.
Bibliography
- Acosta, Luis Eduardo (March 2015). "Historia de la Zoología en la Universidad de Córdoba: los primeros años (1872-1916)" [History of Zoology at the University of Córdoba: the beginning years (1872-1916)]. Revista de la Facultad de Ciencias Exactas, Físicas y Naturales (in Spanish). 2 (1). ISSN 0373-9686.
- Boutan, Louis (1897). Cours de zoologie (in French). Octave Doin.
- Tihelka, Erik; Cai, Chenyang (2021-09-27). "Salinella". Current Biology. 31 (18): R1070–R1071. doi:10.1016/j.cub.2021.07.013.
