{{Short description|Genus of gastropods}} {{Automatic taxobox | image = Calma glaucoides 303641128.jpg | image_caption = ''Calma glaucoides'' | taxon = Calma | display_parents = 3 | parent_authority = Iredale & O'Donoghue, 1923 | authority = Alder & Hancock, 1855 | type_species = ''Calma glaucoides'' | type_species_authority = (Alder & Hancock, 1854) | synonyms_ref = | synonyms = ''Forestia'' <small>Trinchese, 1881</small> }}

'''''Calma''''' is a genus of nudibranchs, shell-less marine gastropod molluscs or sea slugs, and the only member of the family '''Calmidae'''.<ref name="WoRMS"/> It is characterized by the lacks of an anus and radular teeth mostly fused into a band-like radular ribbon, a trait unique within a majority of the order Nudibranchia. These adaptations are largely a result of their diet of teleost eggs.<ref name=Cella/><ref name=Korshunova_et_al2025/>

== Species == The genus contains two species:<ref name="WoRMS"/> * Species ''Calma glaucoides'' <small>(Alder and Hancock, 1854)</small> * Species ''Calma gobioophaga'' <small>Calado and Urgorri, 2002</small>

==Taxonomic history== In 2016, a molecular phylogenetics study by Cella and colleagues placed various fionoid taxa in the family Fionidae, among them ''Calma''.<ref name=Cella/> In 2017, Korshunova and colleagues found this "super-lumping" of taxa inside the family Fionidae, as “Fionidae” sensu latissimo, to contain fundamental errors in its list of synapomorphies and to not provide a reliable morphological delineation or definition of the taxa it contained. The latter authors argue that various taxa lumped into this family presented considerable morphological and molecular pattern differences from each other, such as the unique radula of ''Calma'', and that such differences should grant the usage of more narrowly-defined families, reinstating, among other families, the family Calmidae.<ref name=Ontogeny/><ref name=Korshunova_et_al2025/>

[[File:AlderHancockFam3Plate22.jpg|thumb|Illustration of ''Calma glaucoides'']]

==References== <references>

<ref name=Ontogeny>{{Cite journal |last=Korshunova |first=Tatiana |last2=Martynov |first2=Alexander |last3=Picton |first3=Bernard |date=2017-09-26 |title=Ontogeny as an important part of integrative taxonomy in tergipedid aeolidaceans (Gastropoda: Nudibranchia) with a description of a new genus and species from the Barents Sea |url=https://www.mapress.com/zt/article/view/zootaxa.4324.1.1 |journal=Zootaxa |language=en |volume=4324 |issue=1 |pages=1–22 |doi=10.11646/zootaxa.4324.1.1 |issn=1175-5334}}</ref>

<ref name=Cella>Cella, K; Carmona Barnosi, L.; Ekimova, I; Chichvarkhin, A; Schepetov, D; Gosliner, T. M. (2016). [https://dx.doi.org/10.1371/journal.pone.0167800 ''A radical solution: The phylogeny of the nudibranch family Fionidae.''] PLoS ONE. 11(12): e0167800.</ref>

<ref name="WoRMS">Gofas, S. (2015). [http://www.marinespecies.org/aphia.php/aphia.php?p=taxdetails&id=137720 ''Calma'' Alder & Hancock, 1855.] In: MolluscaBase (2015). Accessed through: World Register of Marine Species on 2015-10-14</ref>

<ref name=Korshunova_et_al2025>{{Cite journal |last=Korshunova |first=Tatiana |last2=Fletcher |first2=Karin |last3=Martynov |first3=Alexander |date=2025-08-01 |title=The endless forms are the most differentiated—how taxonomic pseudo-optimization masked natural diversity and evolution: the nudibranch case |url=https://academic.oup.com/zoolinnean/article/doi/10.1093/zoolinnean/zlaf057/8237533 |journal=Zoological Journal of the Linnean Society |language=en |volume=204 |issue=4 |doi=10.1093/zoolinnean/zlaf057 |issn=0024-4082|url-access=subscription }}</ref>

</references>

== See also == * Gofas, S.; Le Renard, J.; Bouchet, P. (2001). Mollusca. in: Costello, M.J. et al. (Ed.) (2001). ''European register of marine species: a check-list of the marine species in Europe and a bibliography of guides to their identification''. Collection Patrimoines Naturels. 50: pp.&nbsp;180–213. * {{cite journal |author1=Bouchet, P. |author2=Rocroi, J.-P. | year = 2005 | title = Classification and Nomenclator of Gastropod Families | journal = Malacologia | volume =47 | issue = 1–2 | pages = | issn = | doi = }} * [http://animaldiversity.ummz.umich.edu/site/accounts/classification/Calmidae.html/ Animal Diversity - University of Michigan] * Vaught, K.C. (1989). A classification of the living Mollusca. American Malacologists: Melbourne, FL (USA). {{ISBN|0-915826-22-4}}. XII, 195 pp. * [http://www.marinespecies.org/aphia.php?p=taxdetails&id=22996/ Marine species database] * Proc. malac. Soc. London 15: 200

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Category:Calma (gastropod) Category:Gastropod genera Category:Taxa named by Joshua Alder Category:Taxa named by Albany Hancock

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