Onchidoris bilamellata

{{Use dmy dates|date=May 2017}} {{Speciesbox | image = Onchidoris bilamellata.jpg | image_caption = A live individual of ''Onchidoris bilamellata'', head end towards the right | taxon = Onchidoris bilamellata | authority = (Linnaeus, 1767) | synonyms_ref = <ref name="WoRMS" /><ref>{{Gastropods.com|key=9|id=50469|title=''Onchidoris bilamellata''|access-date=5 November 2010}}</ref> | synonyms = *''Doris bilamellata'' <small>(Linnaeus, 1758)</small> *''Doris fusca'' <small>Müller, 1776</small> * ''Doris verrucosa'' Pennant, T., 1777 * ''Onchidoris elfortiana'' Blainville, H.M.D. de, 1816 * ''Doris leachii'' Blainville, H.M.D. de, 1816 * ''Doris affinis'' Thompson, W., 1840 * ''Doris lamellosa'' Johnston, G., 1842 * ''Doris liturata'' Beck, H.H. in Möller, H.P.C., 1842 * ''Doris echinata'' Lovén, S.L., 1846 * ''Doris coronata'' Agassiz, L., 1850 * ''Doris vulgaris'' Leach, W.E. in Gray, J.E., 1852 * ''Onchidoris bilamellata liturata'' (f) Beck, H.H. in Bergh, L.S.R., 1878 * ''Onchidoris bilamellata pacifica'' (f) Bergh, L.S.R., 1880 * ''Ancylodoris baicalensis'' Dybowski, W., 1900 }}

'''''Onchidoris bilamellata''''', common name the '''rough-mantled doris''', is a species of sea slug, a dorid nudibranch, a shell-less marine gastropod mollusk in the family Onchidorididae.<ref name="WoRMS">Gofas, S. (2010). Onchidoris fusca (Müller O.F., 1776). In: Bouchet, P.; Gofas, S.; Rosenberg, G. (2010) World Marine Mollusca database. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=140638 on 2010-11-05</ref>

== Distribution == This nudibranch has a wide distribution, mostly in colder intertidal waters to a depth of about 20 m. It has been found in the North Atlantic and the North Sea from Britain and France to the Norwegian Sea, Iceland and Greenland; along the North American coast as far south as Connecticut. It has also been recorded in the North Pacific in the Bering Sea, and from Alaska south to northern California.

These sea slugs sometimes occur in abundant numbers during breeding time, swarming with over 1,000 individuals per square metre, as has been observed on numerous occasions.<ref name="Distribution">{{in lang|fr}} Pelseneer P. (1922). {{cite journal|title=Sur une habitude de ''Doris bilamellata''| journal=Annales de la Société royale zoologique de Belgique| year=1922| volume=53| page=[https://archive.org/stream/annalesdelasoci5322soci#page/28/mode/2up/ 28]-32| url=https://archive.org/stream/annalesdelasoci5322soci/annalesdelasoci5322soci_djvu.txt}}</ref><ref>{{cite journal|author=Thompson T. E.|year=1984|title=Migrations of ''Onchidoris bilamellata'' during tidal emersion: a refutation|journal=Journal of Molluscan Studies|volume=50|page=123|url=http://mollus.oxfordjournals.org/cgi/pdf_extract/50/2/123-a|archive-url=https://archive.today/20120717035044/http://mollus.oxfordjournals.org/cgi/pdf_extract/50/2/123-a|url-status=dead|archive-date=2012-07-17|issue=2|doi=10.1093/oxfordjournals.mollus.a065851|url-access=subscription}}</ref><ref>{{Cite web|url=http://www.seaslugforum.net/message/8252|title=.''Onchidoris bilamellata'' - swarming in Scotland again|accessdate=2009-12-13|publisher=Sea Slug Forum|year=2002|author=Jim Anderson}}</ref><ref>{{cite web|url=http://www.seaslugforum.net/message/22650|title=''Onchidoris bilamellata'' aggregation in Maine, USA|publisher=Sea Slug Forum|accessdate=17 December 2009}}</ref> These swarms are all oriented in the same direction, determined by the flow of the tide. They follow each other at the same speed, forming columns, in different close-knitted rows.

== Description == thumb|left|''Onchidoris bilamellata'' with a rusty brown pattern The maximum recorded body length is 38 mm.<ref name="Welch 2010">Welch J. J. (2010). "The “Island Rule” and Deep-Sea Gastropods: Re-Examining the Evidence". ''PLoS ONE'' '''5'''(1): e8776. doi:10.1371/journal.pone.0008776.</ref> They mostly show an abundant rusty brown pigment. But some individuals display a mixed pattern of colours, from a lighter brown colour to dark brown. Even fewer individuals are white, with brown color only in the rhinophores and the gills. A rare few are completely white, and yet they are not albinos, as their eyes are pigmented.

''Onchidoris bilamellata'' has a broadly oval shape with its back covered with short, knobby papillae. Their antennae are comblike. The gills are arranged in two half rings on the back at the rear end and consist of 16 to 32 simple featherlike plumes.

The branchial ganglia are fused in ''Onchidoris bilamellata''.<ref name="Alder 1951 Annals">Alder J. & Hancock A. (October 1851). "Descriptions of two new species of nudibranchiate Mollusca, one of them forming the type of a new genus". ''Annals and Magazine of Natural History'' [https://archive.org/details/annalsmagazineof28lond (series 2)'''8'''](46): [https://archive.org/stream/annalsmagazineof28lond#page/290/mode/2up 290]-302, pls. 9-10.</ref>

== Habitat == Minimum recorded depth is 0 m.<ref name="Welch 2010"/> Maximum recorded depth is 55 m.<ref name="Welch 2010"/>

== Feeding habits == ''Onchidoris bilamellata'' feeds mainly on acorn barnacles in the genera ''Elminius'' and ''Balanus''. It uses its rachidian tooth to chew away at the top plates of the barnacles and then sucks out the soft body.<ref name="Naylor">Naylor, Paul. 2005. ''Great British Marine Animals 2nd Edition'', Deltor. {{ISBN|0-9522831-5-8}}</ref>

==References== {{Reflist}}

== External links == {{Commons category|Onchidoris bilamellata}} *[http://www.seaslugforum.net/factsheet.cfm?base=onchbila Onchidoris bilamellata (Linnaeus, 1767) at Seaslugforum] {{Webarchive|url=https://web.archive.org/web/20100615072229/http://seaslugforum.net/factsheet.cfm?base=onchbila |date=15 June 2010 }} *[http://www.scottishnudibranchs.co.uk/onchidoris-bilamellata.html Onchidoris bilamellata (Linnaeus, 1767) at Scottishnudibranchs] *[https://www.youtube.com/watch?v=Z9gjAWC-2-Q Video of O. bilamellata in Puget Sound]

Category:Onchidorididae Category:Gastropods described in 1767 Category:Animal taxa named by Carl Linnaeus