Onchidiidae

{{Short description|Family of gastropods}} {{Use dmy dates|date=October 2020}} {{Automatic taxobox | image = Onchidella.jpg | image_caption = A live but partially retracted individual of ''Onchidella'' sp. | image2 = Onchidella nigricans.png | image2_caption = A live and active individual of ''Onchidella nigricans'' | parent_authority = Rafinesque, 1815 | taxon = Onchidiidae | authority = Rafinesque, 1815<ref name="Rafinesque1815">{{cite book |last1=Rafinesque |first1=C.S. |title=Analyse de la nature ou tableau de l'univers et des corps organises |date=1815 |publisher=[Privately printed] |location=Palermo |pages=224 pp |url=https://www.biodiversitylibrary.org/item/188066#page/11/mode/1up |access-date=24 May 2023}}</ref> | subdivision_ranks = Genera | subdivision = See text | synonyms = * Hoffmannolidae Starobogatov, 1976 * Onchidinidae Starobogatov, 1976 * Onchidellidae Labbé, 1934 * Peroniidae Keferstein, 1865 * Peroninidae Starobogatov, 1976 * Platevindecidae Starobogatov, 1976 * Quoyellidae Starobogatov, 1976 * Scaphidae Labbé, 1934 }}

'''Onchidiidae''' are a family of small, air-breathing sea (and land) slugs. They are shell-less marine (except for two species)<ref name="Dayrat 2009">{{cite journal|author=Dayrat B.|year=2009|title=Review of the current knowledge of the systematics of Onchidiidae (Mollusca: Gastropoda: Pulmonata) with a checklist of nominal species|journal=Zootaxa|volume=2068|pages=1–26|doi=10.11646/zootaxa.2068.1.1|s2cid=4821033}}, [http://www.mapress.com/zootaxa/2009/f/z02068p026f.pdf preview].</ref> pulmonate gastropod molluscs. Onchidiidae is the only family within the superfamily '''Onchidioidea'''.

These animals are quite unusual in that they are emphatically not opisthobranchs with gills, as are almost all of the sea slugs. Instead these creatures are pulmonates. They are more closely related to air-breathing land and freshwater snails and slugs than they are to most other sea snails and sea slugs.

This family has no subfamilies (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005).

143 species names were created within the Onchidiidae,<ref name="Dayrat 2009"/> but until recently few species could be identified. In the late 1920s Hoffmann revised the family (based on the descriptions), and classified the described species into genera.<ref>{{Cite journal|last=Hoffmann|first=H.|date=1928|title=Zur Kenntnis der Oncidiiden|journal=Zoologische Jahrbücher |volume=55|pages=29–118}}</ref> Labbé later continued the revision and named many new genera in his classification of onchidiid slugs.<ref>{{Cite journal|last=Labbé|first=A.|date=1934|title=Les Silicodermés (Labbé) du Museum d'Histoire Naturelle de Paris. Première partie: Classification, formes nouvelles ou peu connues|journal=Annales de l'Institut Océanographique de Monaco |volume=14|pages=73–246}}</ref> Labbé also made mistakes in describing the anatomy of some species,<ref name=":0">{{Cite journal|last1=Goulding|first1=Tricia C. |last2=Khalil |first2=Munawar |last3=Tan |first3=Shau Hwai |last4=Dayrat|first4=Benoît|date=2018-06-04|title=Integrative taxonomy of a new and highly-diverse genus of onchidiid slugs from the Coral Triangle (Gastropoda, Pulmonata, Onchidiidae)|url=https://zookeys.pensoft.net/article/21252/|journal=ZooKeys|issue=763 |pages=1–111|doi=10.3897/zookeys.763.21252|pmid=29896045 |pmc=5996013 |issn=1313-2970|doi-access=free }}</ref> and the Onchidiidae was not revised again for over 80 years. The genus ''Onchidium'' was revised in 2016 based on natural history, comparative anatomy, and DNA sequences.<ref name=":1">{{Cite journal|last1=Dayrat|first1=Benoît|last2=Goulding|first2=Tricia C.|last3=Apte|first3=Deepak|last4=Bhave|first4=Vishal|last5=Comendador|first5=Joseph|last6=Quang|first6=Ngô Xuân|last7=Tan|first7=Siong Kiat|last8=Tan|first8=Shau Hwai|date=2016-11-24|title=Integrative taxonomy of the genus Onchidium Buchannan, 1800 (Mollusca, Gastropoda, Pulmonata, Onchidiidae) |journal=ZooKeys|issue=636|pages=1–40|doi=10.3897/zookeys.636.8879 |pmc=5126514 |pmid=27917062|doi-access=free}}</ref> This was followed by revisions of the other onchidiid genera<ref>{{Cite journal|last1=Goulding|first1=Tricia C.|last2=Tan|first2=Shau Hwai|last3=Tan|first3=Siong Kiat|last4=Apte|first4=Deepak|last5=Bhave|first5=Vishal|last6=Narayana|first6=Sumantha|last7=Salunkhe|first7=Rahul|last8=Dayrat|first8=Benoît|date=2018-08-16|title=A revision of Peronina Plate, 1893 (Gastropoda : Euthyneura : Onchidiidae) based on mitochondrial and nuclear DNA sequences, morphology and natural history|url=https://www.publish.csiro.au/is/IS17094|journal=Invertebrate Systematics|language=en|volume=32|issue=4|pages=803–826|doi=10.1071/IS17094|s2cid=91784082|issn=1447-2600|url-access=subscription}}</ref><ref name=":7">{{Cite journal|last1=Goulding|first1=Tricia C.|last2=Bourke|first2=Adam J.|last3=Comendador|first3=Joseph|last4=Khalil|first4=Munawar|last5=Quang|first5=Ngo Xuan|last6=Tan|first6=Shau Hwai|last7=Tan|first7=Siong Kiat|last8=Dayrat|first8=Benoît|date=2021-03-08|title=Systematic revision of Platevindex Baker, 1938 (Gastropoda: Euthyneura: Onchidiidae)|url=https://europeanjournaloftaxonomy.eu/index.php/ejt/article/view/1259|journal=European Journal of Taxonomy|language=en|issue=737|pages=1–133|doi=10.5852/ejt.2021.737.1259|s2cid=233797267|issn=2118-9773|doi-access=free}}</ref><ref name=":6">{{Cite journal|last1=Dayrat|first1=Benoît|last2=Goulding|first2=Tricia C.|last3=Apte|first3=Deepak|last4=Aslam|first4=Sadar|last5=Bourke|first5=Adam|last6=Comendador|first6=Joseph|last7=Khalil|first7=Munawar|last8=Ngô|first8=Xuân Quảng|last9=Tan|first9=Siong Kiat|last10=Tan|first10=Shau Hwai|date=2020-10-01|title=Systematic revision of the genus Peronia Fleming, 1822 (Gastropoda, Euthyneura, Pulmonata, Onchidiidae)|url=https://zookeys.pensoft.net/article/52853/|journal=ZooKeys|issue=972|pages=1–224|doi=10.3897/zookeys.972.52853|issn=1313-2970|pmc=7544732|pmid=33071542|doi-access=free}}</ref><ref name=":4">{{Cite journal|last1=Dayrat|first1=Benoît|last2=Goulding|first2=Tricia C.|date=2017-06-29|title=Systematics of the onchidiid slug Onchidina australis (Mollusca: Gastropoda: Pulmonata)|journal=Archiv für Molluskenkunde|volume=146|pages=121–133|doi=10.1127/arch.moll/146/121-133}}</ref>'','' and the descriptions of onchidiid species in several new genera.<ref name=":0" /><ref name=":2">{{Cite journal|last1=Goulding|first1=Tricia|last2=Khalil|first2=Munawar|last3=Tan|first3=Shau Hwai|last4=Dayrat|first4=Benoit|date=2018|title=A new genus and a new species of onchidiid slugs from eastern Indonesia (Gastropoda: Euthyneura: Onchidiidae)|journal=Raffles Bulletin of Zoology|volume=66|pages=337–349}}</ref><ref name=":3">{{Cite journal|last1=Dayrat|first1=Benoît|last2=Goulding|first2=Tricia C.|last3=Apte|first3=Deepak|last4=Bhave|first4=Vishal|last5=Ngô Xuân|first5=Quảng|date=2017-07-27|title=A new genus and four new species of onchidiid slugs from South-East Asia (Mollusca: Gastropoda: Pulmonata: Onchidiidae)|journal=Journal of Natural History|volume=51|issue=31–32|pages=1851–1897|doi=10.1080/00222933.2017.1347297|s2cid=91153309|issn=0022-2933}}</ref><ref>{{Cite journal|last1=Dayrat|first1=Benoît|last2=Goulding|first2=Tricia C.|last3=Khalil|first3=Munawar|last4=Apte|first4=Deepak|last5=Bourke|first5=Adam J.|last6=Comendador|first6=Joseph|last7=Tan|first7=Shau Hwai|date=2019-02-22|title=A new genus and three new species of mangrove slugs from the Indo-West Pacific (Mollusca: Gastropoda: Euthyneura: Onchidiidae)|url=https://europeanjournaloftaxonomy.eu/index.php/ejt/article/view/643|journal=European Journal of Taxonomy|language=en|issue=500|doi=10.5852/ejt.2019.500|issn=2118-9773|doi-access=free}}</ref><ref>{{Cite journal|last1=Dayrat|first1=Benoît|last2=Goulding|first2=Tricia C.|last3=Khalil|first3=Munawar|last4=Comendador|first4=Joseph|last5=Xuân|first5=Quảng Ngô|last6=Tan|first6=Siong Kiat|last7=Tan|first7=Shau Hwai|date=2019-02-09|title=A new genus of air-breathing marine slugs from South-East Asia (Gastropoda, Pulmonata, Onchidiidae)|url=https://zookeys.pensoft.net/article/36698/|journal=ZooKeys|language=en|issue=877|pages=31–80|doi=10.3897/zookeys.877.36698|issn=1313-2970|pmc=6775175|pmid=31592220|doi-access=free}}</ref><ref>Dayrat, B.; Goulding T.C.; Khalil, M.; Lozouet, P., Tan, S.H. (2018) Systematic revision one clade at a time: A new genus of onchidiid slugs from the Indo-West Pacific (Gastropoda: Euthyneura: Onchidiidae). ''Raffles Bulletin of Zoology'' 66: 814–837.</ref>

== Anatomy == Adult onchidiids lack a shell, although a shell<ref>{{Cite book|url=https://books.google.com/books?id=YM_OqfVV_ygC&q=onchidiid+larvae+shell&pg=PA220|title=Reproduction of Marine Invertebrates V4: Molluscs: Gastropods and Cephalopods|last=Berry|first=A.J.|isbn=9780323153058|editor-last=Giese|editor-first=A|pages=220|date=2012-12-02|publisher=Elsevier }}</ref> and operculum is present at the larval stage. The mantle cavity is reduced to the point of absence, correlating with a loss of gills, raphes, and other characters usually found in the mantle cavity. The organism is completely detorted.<ref>{{cite book | url = https://books.google.com/books?id=hbqVv5r3FgsC&pg=PA719 | title = The Marine Flora and Fauna of Hong Kong and Southern China III___ Fouling and pollution, morphology, behaviour and physiology, Hoi Ha Wan | publisher = Hong Kong University Press | isbn = 978-962-209-295-2 | author1 = Morton, Brian | year = 1992}}</ref>

Slugs in this family make and use love darts made of chitin.<ref name="Chung Hawaii">Chung D. J. D.: ''Molluscan 'Love darts'?'' Hawaiian Shell News, 1986 May, Vol 34(5), pages 3–4. http://s190418054.onlinehome.us/HSN/1980/8605.pdf{{dead link|date=March 2018 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

== Genetics == In this family, the number of haploid chromosomes lies between 16 and 20 (according to the values in this table).<ref name="Barker">Barker G. M.: Gastropods on Land: ''Phylogeny, Diversity and Adaptive Morphology''. in Barker G. M. (ed.): ''[https://books.google.com/books?id=WlvX-9Wt0toC&hl The biology of terrestrial molluscs]''. CABI Publishing, Oxon, UK, 2001, {{ISBN|0-85199-318-4}}. 1–146, cited pages: 139 and 142.</ref>

==Habitat== Most of the species in this family are marine and are found in the intertidal zone. Many species live on rocky coasts, while others live in mangrove forests which may be marine or brackish.<ref name=":1" /> ''Onchidium stuxbergi'' (as ''E. ajuthiae'', synonym in literature) was previously considered to be a fresh water species, but the species is now recognized to be found in brackish water habitats.<ref name=":1" />

Remarkably, some onchidiid species are completely terrestrial.<ref name=":5">{{Cite journal|last=Dayrat|first=Benoît|date=January 2010|title=Anatomical Re-Description of the Terrestrial Onchidiid SlugSemperoncis montana(Plate, 1893)|journal=Malacologia|volume=52|issue=1|pages=1–20|doi=10.4002/040.052.0101|s2cid=84799367|issn=0076-2997|url=https://www.biodiversitylibrary.org/part/386431 }}</ref> ''Semperoncis montana'' (synonym in literature: ''Platevindex apoikistes'' and ''Semperella montana'') and ''Platevindex ponsonbyi'' are the only known terrestrial species in the Onchidiidae.<ref name="Dayrat 2009"/> They live in high-elevation rainforests in Borneo and the Philippines.<ref name="Dayrat 2009"/>

==Life habits== All these slugs breathe air. The marine ones breathe and move around and feed during low tide, when the water recedes and the slugs are exposed to the air.

==Genera== Genera in the family Onchidiidae include: *''Alionchis'' Goulding and Dayrat, 2018<ref name=":2" /> *''Hoffmannola'' Strand, 1932 *''Laspionchis'' Dayrat & Goulding, 2019 *''Marmaronchis'' Dayrat & Goulding, 2018 *''Melayonchis'' Dayrat and Goulding, 2017<ref name=":3" /> *''Onchidella'' Gray, 1850<ref>{{ITIS |id=78761 |taxon=Onchidella}}, accessed 13 September 2010.</ref> *''Onchidina'' Semper, 1885<ref name=":4" /> *''Onchidium'' Buchanan, 1800 - type genus<ref name=":1" /> *''Paromoionchis'' Dayrat & Goulding, 2019 *''Peronia'' Fleming, 1822 *''Peronina'' Plate, 1893 *''Platevindex'' Baker, 1938 *''Semperoncis'' Starobogatov, 1976<ref name=":5" /> *''Wallaconchis'' Goulding and Dayrat, 2018<ref name=":0" />

; ;Synonymized genera : *''Arctonchis '' Dall, 1910: synonym of ''Onchidella'' J. E. Gray, 1850 *''Elophilus'' Labbé, 1935: synonym of ''Onchidium'' Buchanan, 1800<ref name=":1" /> *''Eudrastus'' Gistel, 1848: synonym of ''Peronia'' Fleming, 1822<ref name=":6" /> *''Labbella'' Starobogatov, 1976: synonym of ''Onchidium'' Buchanan, 1800<ref name=":1" /> *''Lessonia'' Labbé, 1934: synonym of ''Peronia'' Fleming, 1822<ref name=":6" /> *''Lessonina'' Starobogatov, 1976: synonym of ''Peronia'' Fleming, 1822<ref name=":0" /><ref name=":6" /> *''Occidentella'' Hoffmann, 1929: synonym of ''Onchidella'' J. E. Gray, 1850 *''Oncidiella'' P. Fischer & Crosse, 1878: synonym of ''Onchidella'' J.E. Gray, 1850 *''Oncidina'' Plate, 1893: synonym of ''Onchidina'' Semper, 1882<ref name=":4" /> *''Oncis'' Plate, 1893: synonym of ''Platevindex'' H. B. Baker, 1938<ref name=":7" /><ref>{{Cite web|url=http://www.marinespecies.org/aphia.php?p=taxdetails&id=424032|title=WoRMS - World Register of Marine Species - Platevindex H. B. Baker, 1938|website=www.marinespecies.org|access-date=2018-07-18}}</ref> *''Paraoncidium'' Labbé, 1934: synonym of ''Onchidina'' Semper, 1882<ref name=":4" /> *''Paraperonia'' Labbé, 1934: synonym of ''Peronia'' Fleming, 1822<ref name=":6" /> *''Peronella'' Mörch, 1863: synonym of ''Onchidella'' J.E. Gray, 1850 *''Peroniella'' Starobogatov, 1976 : synonym of ''Onchidella'' J. E. Gray, 1850 *''Quoya'' Labbé, 1934: synonym of ''Peronia'' J. Fleming, 1822<ref name=":6" /> *''Quoyella'' Starobogatov, 1976: ''Peronia'' J. Fleming, 1822<ref name=":6" /> *''Scaphis'' Labbé, 1934: synonym of ''Peronia'' J. Fleming, 1822<ref name=":6" /> *''Semperella'' Labbé, 1934 synonym of ''Semperoncis'' Starobogatov, 1976 *''Watsoniella'' Hoffmann, 1928: synonym of ''Hoffmannola'' Strand, 1932

== References == {{Reflist}}

==External links== *{{commons category-inline|Onchidiidae}}

Category:Onchidiidae Category:Gastropod families Category:Taxa named by Constantine Samuel Rafinesque