''Phyllodesmium'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

predatory Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill ...

sea slug Sea slug is a common name for some Marine biology, marine invertebrates with varying levels of resemblance to terrestrial Slug, slugs. Most creatures known as sea slugs are gastropods, i.e. they are Sea snail, sea snails (marine gastropod moll ...

s, aeolid

nudibranch Nudibranchs () are a group of soft-bodied marine gastropod molluscs, belonging to the order Nudibranchia, that shed their shells after their larval stage. They are noted for their often extraordinary colours and striking forms, and they have b ...

s, marine

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

mollusc Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

s in the family Myrrhinidae.Bouchet, P. (2012). ''Phyllodesmium'' Ehrenberg, 1831. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=204424 on 2012-06-05 These nudibranchs occur in the tropical

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

Ocean and warm temperate waters of Japan, Tasmania and South Africa. The nudibranchs in this genus often show extraordinary

mimicry In evolutionary biology, mimicry is an evolved resemblance between an organism and another object, often an organism of another species. Mimicry may evolve between different species, or between individuals of the same species. In the simples ...

, each species very closely resembling its prey species, which are octocorals, a kind of

soft coral Alcyonacea is the old scientific order name for the informal group known as "soft corals". It is now an unaccepted name for class Octocorallia. It became deprecated . The following text should be considered a historical, outdated way of treatin ...

.Moore E. & Gosliner T. (18 August 2009)
"Three new species of ''Phyllodesmium'' Ehrenberg (Gastropoda: Nudibranchia: Aeolidoidea), and a revised phylogenetic analysis"
''

Zootaxa ''Zootaxa'' is a peer-reviewed scientific mega journal for animal taxonomists. It is published by Magnolia Press (Auckland, New Zealand). The journal was established by Zhi-Qiang Zhang in 2001 and new issues are published multiple times a week ...

'' 2201: 30–48. Some of the species are also unusual in that they are able to utilize

zooxanthellae Zooxanthellae (; zooxanthella) is a colloquial term for single-celled photosynthetic organisms that are able to live in symbiosis with diverse marine invertebrates including corals, jellyfish, demosponges, and nudibranchs. Most known zooxanthell ...

from their prey, in a symbiotic relationship that provides them with extra nutrition from

photosynthesis Photosynthesis ( ) is a system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their metabo ...

, hence they are commonly called "solar-powered" sea slugs (also see the

Sacoglossa Sacoglossa are a superorder of small sea slugs and sea snails, marine gastropod mollusks that belong to the clade Heterobranchia known as sacoglossans. There are 284 valid species recognized within this superorder. Sacoglossans live by ingestin ...

Species

Species within the genus ''Phyllodesmium'' include: * '' Phyllodesmium acanthorhinum'' Moore & Gosliner, 2014 * '' Phyllodesmium briareum'' (Bergh, 1896) * '' Phyllodesmium colemani'' Rudman, 1991 * '' Phyllodesmium crypticum'' Rudman, 1981Rudman W. B. (1981). "The anatomy and biology of alcyonarian-feeding aeolid opisthobranch molluscs and their development of symbiosis with zooxanthellae". ''

Zoological Journal of the Linnean Society The ''Zoological Journal of the Linnean Society'' is a monthly peer-reviewed scientific journal covering zoology published by Oxford University Press on behalf of the Linnean Society. The editor-in-chief is Maarten Christenhusz (Linnean Society) ...

'' 72(3): 219-262. . * '' Phyllodesmium fastuosum'' Ehrenberg, 1831 * ''

Phyllodesmium guamense ''Phyllodesmium guamense'' is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusc in the family Facelinidae.Bouchet, P. (2010)''Phyllodesmium guamense'' Avila, Ballesteros, Slattery, Starmer & Paul, 1998.In: Bouchet, P.; Gofa ...

'' C. Ávila, Ballesteros, Slattery, Starmer & Paul, 1998 * '' Phyllodesmium horridum'' (Macnae, 1954) * '' Phyllodesmium hyalinum'' (Ehrenberg, 1831) - type species * '' Phyllodesmium iriomotense'' Baba, 1991Baba K. (1991). "Taxonomical study of some species of the genus ''Phyllodesmium'' from Cape Muroto-misaki, Shikoku, and Okinawa Province, Southern Japan (Nudibranchia: Facelinidae)". ''Venus'' 50(2): 109-124. * '' Phyllodesmium jakobsenae'' Burghardt & Wägele, 2004Burghardt I. & Wägele H. (2004). "A new solar powered species of the genus ''Phyllodesmium'' Ehrenberg, 1831 (Mollusca: Nudibranchia: Aeolidoidea) from Indonesia with analysis of its photosynthetic activity and notes on biology". ''

'' 596: 1-18
PDFt
* '' Phyllodesmium kabiranum'' Baba, 1991 * '' Phyllodesmium karenae'' Moore & Gosliner, 2009 * ''

Phyllodesmium koehleri ''Phyllodesmium koehleri'' is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusc in the family Facelinidae. Distribution Known from southern Queensland, Australia; Okinawa, Japan; Sulawesi, Indonesia, New Britain, Papua N ...

'' Burghardt, Schrödl & Wägele, 2008 * '' Phyllodesmium lembehense'' Burghardt, Schrödl & Wägele, 2008 * '' Phyllodesmium lizardense'' Burghardt, Schrödl & Wägele, 2008Burghardt I., Schrödl M. & Wägele H. (2008). "Three new solar-powered species of the genus ''Phyllodesmium'' Ehrenberg, 1831 (Mollusca: Nudibranchia: Aeolidioidea) from the tropical Indo-Pacific, with analysis of their photosynthetic activity and notes on biology". ''

Journal of Molluscan Studies The ''Journal of Molluscan Studies'' is the peer-reviewed scientific journal of the Malacological Society of London, covering research in malacology.

'' 74(3): 277-292.
abstract
* '' Phyllodesmium longicirrum'' (Bergh, 1905) * '' Phyllodesmium macphersonae'' (Burn, 1962) * '' Phyllodesmium magnum'' Rudman, 1991Rudman W. B. (1991). "Further studies on the taxonomy and biology of the octocoral-feeding genus ''Phyllodesmium'' Ehrenberg, 1831 (Nudibranchia: Aeolidacea)". ''Journal of Molluscan Studies'' 57(2): 167–203
abstract
* '' Phyllodesmium opalescens'' Rudman, 1991 * '' Phyllodesmium parangatum'' Ortiz & Gosliner, 2003 * '' Phyllodesmium pecten'' Rudman, 1981 * '' Phyllodesmium pinnatum'' Moore & Gosliner, 2009 * '' Phyllodesmium poindimiei'' (Risbec, 1928) * '' Phyllodesmium rudmani'' Burghardt & Gosliner, 2006Burghardt I. & Gosliner T. M. (2006). "''Phyllodesmium rudmani'' (Mollusca: Nudibranchia: Aeolidoidea), a new solar powered species from the Indo-West Pacific with data on its symbiosis with zooxanthellae". ''

'' 1308: 31-47
abstractfull PDF
* '' Phyllodesmium serratum'' (Baba, 1949) * '' Phyllodesmium tuberculatum'' Moore & Gosliner, 2009 * '' Phyllodesmium undulatum'' Moore & Gosliner, 2014 ;Species brought into synonymy: * ''Phyllodesmium xeniae'' Gohar & Aboul-Ela, 1957: synonym of ''Phyllodesmium hyalinum'' Ehrenberg, 1831 ;Species with unknown placement: * '' Phyllodesmium orientale'' Baba, 1991 File:Phyllodesmium crypticum.jpg, '' Phyllodesmium crypticum'' File:Phyllodesmium kabiranum.jpg, '' Phyllodesmium kabiranum'' File:Phyllodesmium longicirrum.jpg, '' Phyllodesmium longicirrum''

Ecology

Phyllodesmium briareum and Briareum violacea

Species of the genus ''Phyllodesmium'' are

carnivorous A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose nutrition and energy requirements are met by consumption of animal tissues (mainly mu ...

and feed on

octocoral Octocorallia, along with Hexacorallia, is one of the two extant classes of Anthozoa. It comprises over 3,000 species of marine and brackish animals consisting of colonial polyps with 8-fold symmetry, commonly referred informally as "soft cora ...

s (for example, in the family

Xeniidae Xeniidae is a family of soft coral in the order Alcyonacea. Predators Predatory sea slugs of the genus ''Phyllodesmium'' are reported to feed on Xeniidae species. Representatives of this family have been observed to provide shelter to juvenile ...

). This is a unique feature within the

Aeolidida The Aeolidida is a taxonomic clade of sea slugs, specifically aeolid nudibranchs, marine gastropod molluscs in the clade Cladobranchia. They are distinguished from other nudibranchs by their possession of cerata containing cnidosac A cnidosac ...

. Some of these nudibranchs contain

endosymbiotic An endosymbiont or endobiont is an organism that lives within the body or cells of another organism. Typically the two organisms are in a mutualistic relationship. Examples are nitrogen-fixing bacteria (called rhizobia), which live in the root ...

, which are in effect single-celled plants. Zooxanthellae are one kind of

dinoflagellate The Dinoflagellates (), also called Dinophytes, are a monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and are usually considered protists. Dinoflagellates are mostly marine plankton, but they are also commo ...

protist A protist ( ) or protoctist is any eukaryotic organism that is not an animal, land plant, or fungus. Protists do not form a natural group, or clade, but are a paraphyletic grouping of all descendants of the last eukaryotic common ancest ...

s and they live only within other organisms, most notably in corals. The nudibranchs in this genus obtain zooxanthellae from their food, the soft corals. As they previously did within the corals, the zooxanthellae provide the nudibranch with a supply of food in the form of the products of

. The nudibranchs are able to avoid digesting these protists, and sequester them in their tissues instead. This process is somewhat reminiscent of the relationship between the

n sea slugs and the living

chloroplast A chloroplast () is a type of membrane-bound organelle, organelle known as a plastid that conducts photosynthesis mostly in plant cell, plant and algae, algal cells. Chloroplasts have a high concentration of chlorophyll pigments which captur ...

s that they are able to sequester. Both these nudibranchs and the sacoglossans have been referred to as "solar-powered sea slugs".Rudman, W.B., 1998 (October 11
Solar-powered sea slugs.
n/nowiki> Sea Slug Forum. Australian Museum, Sydney. Many other species of nudibranchs have

aposematic Aposematism is the Advertising in biology, advertising by an animal, whether terrestrial or marine, to potential predation, predators that it is not worth attacking or eating. This unprofitability may consist of any defenses which make the pr ...

coloring in order to warn away would-be predators, giving them brilliant colors. This is because they contain in their tissues many examples of an organ called the

cnidosac A cnidosac is an anatomical feature that is found in the group of sea slugs known as aeolid nudibranchs, a clade of marine (ocean), marine opisthobranch gastropod mollusk, molluscs. A cnidosac contains cnidocytes, stinging cells that are also known ...

which contains undischarged

cnidocyte A cnidocyte (also known as a cnidoblast) is a type of cell containing a large secretory organelle called a ''cnidocyst'', that can deliver a sting to other organisms as a way to capture prey and defend against predators. A cnidocyte explosively ...

s (also known as

nematocyst A cnidocyte (also known as a cnidoblast) is a type of cell containing a large secretory organelle called a ''cnidocyst'', that can deliver a sting to other organisms as a way to capture prey and defend against predators. A cnidocyte explosively ...

s). These are stinging cells that the nudibranchs obtain from the tissues of the

cnidaria Cnidaria ( ) is a phylum under kingdom Animalia containing over 11,000 species of aquatic invertebrates found both in fresh water, freshwater and marine environments (predominantly the latter), including jellyfish, hydroid (zoology), hydroids, ...

ns they eat. Thus, the very brightly colored nudibranchs are quite unpalatable for predators. Some nudibranchs, such as ''

Glaucus atlanticus ''Glaucus atlanticus'' (common names include the blue sea dragon, sea swallow, blue angel, blue glaucus, dragon slug, blue dragon, blue sea slug, and blue ocean slug) is a species of sea slug in the family Glaucidae. These sea slugs live in ...

'', are even capable of giving humans painful stings. The nudibranchs in this genus, however, use an opposite tactic. They do not have cnidosacs, and thus they would in reality be palatable to eat for various predators, however they are almost all extremely well camouflaged, so that they resemble almost perfectly the soft coral on which they live and feed, not only in color but also in form. The shape and form of the nudibranch's cerata in each individual species very closely resembles the tentacles of the species of soft coral polyp on which that species feeds. This excellent camouflage also makes these nudibranchs difficult for humans to notice, and it is likely that several species in this genus have not yet been discovered, described, and named scientifically. Another tactic these nudibranchs use to protect themselves is that when threatened by a predator, they can drop one or more of their

cerata :''The tortrix moth genus ''Cerata'' is considered a junior synonym of ''Cydia (genus), Cydia. Cerata, singular ceras, are anatomical structures found externally in nudibranch sea slugs, especially in aeolid nudibranchs, marine animal, marine opi ...

. These organs will wiggle for some time after being cast off, hopefully distracting a predator away from the animal itself.''Phyllodesmium magnum Rudman, 1991
. Sea Slug Forum, accessed 26 September 2009. This is an example of a defensive technique known as

autotomy Autotomy (from the Greek ''auto-'', "self-" and ''tome'', "severing", αὐτοτομία) or 'self-amputation', is the behaviour whereby an animal sheds or discards an appendage, usually as a self-defense mechanism to elude a predator's grasp ...

. A

molecular phylogeny Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

study of ''Phyllodesmium'' by Moore and Gosliner (2011)Moore E. J. & Gosliner T. M. (2011). "Molecular phylogeny and evolution of symbiosis in a clade of Indopacific nudibranchs". ''

Molecular Phylogenetics and Evolution ''Molecular Phylogenetics and Evolution'' is a peer-reviewed scientific journal of evolutionary biology and phylogenetics. The journal is edited by E.A. Zimmer. Indexing The journal is indexed in: * EMBiology *Journal Citation Reports *Scopus ...

'' Volume 58, Issue 1, January 2011, Pages 116–123 . accessed 17 December 2010. demonstrated that the non-symbiotic species of ''Phyllodesmium'' evolved separately from the symbiotic species of ''Phyllodesmium''. However, there is one exception: '' Phyllodesmium karenae'' evolved in the symbiotic clade and subsequently lost its zooxanthellae.

References

External links

* {{Taxonbar, from=Q3901735 Myrrhinidae Taxa named by Christian Gottfried Ehrenberg