Phyllodesmium

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Phyllodesmium
Phyllodesmium briareum 2.jpg
A live individual of Phyllodesmium briareum , head end towards the front
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Subclass: Heterobranchia
Order: Nudibranchia
Clade: Dexiarchia
Suborder: Cladobranchia
Superfamily: Aeolidioidea
Family: Myrrhinidae
Genus: Phyllodesmium
Ehrenberg, 1831 (1828) [1]
Type species
Phyllodesmium hyalinumEhrenberg, 1831
Diversity
27 species (in this list)
Synonyms
  • EnnoiaBergh, 1896
  • MyrrhineBergh, 1905

Phyllodesmium is a genus of predatory sea slugs, aeolid nudibranchs, marine gastropod molluscs in the family Myrrhinidae. [2]

Contents

These nudibranchs occur in the tropical Indo-Pacific Ocean and warm temperate waters of Japan, Tasmania and South Africa.

The nudibranchs in this genus often show extraordinary mimicry, each species very closely resembling its prey species, which are octocorals, a kind of soft coral. [3]

Some of the species are also unusual in that they are able to utilize zooxanthellae from their prey, in a symbiotic relationship that provides them with extra nutrition from photosynthesis, hence they are commonly called "solar-powered" sea slugs (also see the Sacoglossa). [4]

Species

Species within the genus Phyllodesmium include:

Species brought into synonymy
Species with unknown placement

Ecology

Phyllodesmium briareum (one specimen at the bottom of the image) and its food species, the coral Briareum violaceum (at the top of the image), showing how closely the nudibranch resembles its food source. It camouflages itself well from predators. Phyllodesmium briareum and Briareum violacea.jpg
Phyllodesmium briareum (one specimen at the bottom of the image) and its food species, the coral Briareum violaceum (at the top of the image), showing how closely the nudibranch resembles its food source. It camouflages itself well from predators.

Species of the genus Phyllodesmium are carnivorous and feed on octocorals [5] (for example, in the family Xeniidae [10] ). This is a unique feature within the Aeolidida. [5]

Some of these nudibranchs contain endosymbiotic zooxanthellae, which are in effect single-celled plants. [5] Zooxanthellae are one kind of dinoflagellate protists and they live only within other organisms, most notably in corals. The nudibranchs in this genus obtain zooxanthellae from their food, the soft corals. [6] [5] As they previously did within the corals, the zooxanthellae provide the nudibranch with a supply of food in the form of the products of photosynthesis. 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 Sacoglossan sea slugs and the living chloroplasts that they are able to sequester. Both these nudibranchs and the sacoglossans have been referred to as "solar-powered sea slugs". [4] [10]

Many other species of nudibranchs have aposematic 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 [13] which contains undischarged cnidocytes (also known as nematocysts). These are stinging cells that the nudibranchs obtain from the tissues of the cnidarians they eat. Thus, the very brightly colored nudibranchs are quite unpalatable for predators. Some nudibranchs, such as Glaucus atlanticus , 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. These organs will wiggle for some time after being cast off, hopefully distracting a predator away from the animal itself. [14] This is an example of a defensive technique known as autotomy.

A molecular phylogeny study of Phyllodesmium by Moore and Gosliner (2011) [15] demonstrated that the non-symbiotic species of Phyllodesmium evolved separately from the symbiotic species of Phyllodesmium. [15] However, there is one exception: Phyllodesmium karenae evolved in the symbiotic clade and subsequently lost its zooxanthellae. [15]

Related Research Articles

<span class="mw-page-title-main">Nudibranch</span> Order of gastropods

Nudibranchs belong to the order Nudibranchia, a group of soft-bodied marine gastropod molluscs that shed their shells after their larval stage. They are noted for their often extraordinary colours and striking forms, and they have been given colourful nicknames to match, such as "clown", "marigold", "splendid", "dancer", "dragon", and "sea rabbit". Currently, about 3,000 valid species of nudibranchs are known.

<span class="mw-page-title-main">Hepatopancreas</span>

The hepatopancreas, digestive gland or midgut gland is an organ of the digestive tract of arthropods and molluscs. It provides the functions which in mammals are provided separately by the liver and pancreas, including the production of digestive enzymes, and absorption of digested food.

<i>Phyllodesmium briareum</i> Species of gastropod

Phyllodesmium briareum is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusc in the family Facelinidae.

<i>Phyllodesmium serratum</i> Species of gastropod

Phyllodesmium serratum is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusc in the family Facelinidae.

<i>Phyllodesmium longicirrum</i> Species of gastropod

Phyllodesmium longicirrum, common name the solar-powered phyllodesmium, is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusc in the family Facelinidae.

<i>Phyllodesmium kabiranum</i> Species of gastropod

Phyllodesmium kabiranum is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusc in the family Facelinidae.

<i>Phyllodesmium horridum</i> Species of gastropod

Phyllodesmium horridum, the coral nudibranch, is a species of sea slug, specifically an aeolid nudibranch. It is a marine gastropod mollusc in the family Facelinidae.

<i>Phyllodesmium rudmani</i> Species of gastropod

Phyllodesmium rudmani is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusc in the family Facelinidae.

<i>Phyllodesmium colemani</i> Species of gastropod

Phyllodesmium colemani is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusc in the family Facelinidae.

Phyllodesmium hyalinum is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusc in the family Facelinidae.

<i>Phyllodesmium iriomotense</i> Species of gastropod

Phyllodesmium iriomotense is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusc in the family Facelinidae.

<i>Phyllodesmium jakobsenae</i> Species of gastropod

Phyllodesmium jakobsenae is a species of sea slug, an aolid nudibranch, a marine gastropod mollusk in the family Facelinidae.

<i>Phyllodesmium magnum</i> Species of gastropod

Phyllodesmium magnum is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusc in the family Facelinidae.

<i>Phyllodesmium opalescens</i> Species of gastropod

Phyllodesmium opalescens is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusc in the family Facelinidae.

Phyllodesmium parangatum is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusc in the family Facelinidae.

<i>Phyllodesmium koehleri</i> Species of gastropod

Phyllodesmium koehleri is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusc in the family Facelinidae.

Phyllodesmium lembehense is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusc in the family Facelinidae.

<i>Phyllodesmium lizardense</i> Species of gastropod

Phyllodesmium lizardense is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusc in the family Facelinidae.

Baeolidia harrietae is a species of sea slug, an aeolid nudibranch. It is a marine gastropod mollusc in the family Aeolidiidae.

<i>Phyllodesmium poindimiei</i> Species of gastropod

Phyllodesmium poindimiei is an Alcyonacea feeding, aeolid nudibranch Gastropod belonging to the family Facelinidae. Cerata are important in this clade in terms of their physical defense and efficient metabolic processes. This species is spread sporadically along tropical coastal regions such as Australia, Hawaii, and the Indo-Pacific living in diverse marine habitats such as coral reefs. Unlike other species in the Opisthobranch Mollusca clade, P. poindimiei’s lush pink cerata are used for defensive purposes other than Nematocyst (dinoflagellate) capture and toxin release. Organismal ties within these thriving, tropical ecosystems can be determinants of environment change, which affects massive coral ecosystems. Continuously changing marine ecosystems, such as coral reefs, are directly linked to the evolution of organisms that live and thrive in the tropics such as the soft nudibrach P. poindimiei.

References

  1. ↑ Ehrenberg C. G. (1831). Sym. Phys., Moll., sign. h. (plates are from 1828.)
  2. ↑ 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
  3. 1 2 3 4 Moore E. & Gosliner T. (18 August 2009). "Three new species of Phyllodesmium Ehrenberg (Gastropoda: Nudibranchia: Aeolidoidea), and a revised phylogenetic analysis". Zootaxa 2201: 30–48.
  4. 1 2 Rudman, W.B., 1998 (October 11) Solar-powered sea slugs. [In] Sea Slug Forum. Australian Museum, Sydney.
  5. 1 2 3 4 5 6 7 Rudman W. B. (1991). "Further studies on the taxonomy and biology of the octocoral-feeding genus Phyllodesmium Ehrenberg, 1831 (Nudibranchia: Aeolidacea)". Journal of Molluscan Studies57(2): 167–203. abstract.
  6. 1 2 3 Rudman 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 72(3): 219-262. doi : 10.1111/j.1096-3642.1981.tb01571.x.
  7. ↑ Avila C., Ballesteros M., Slattery M., Starmer J. & Paul V. J. (1998). "Phyllodesmium guamensis (Nudibranchia: Aeolidoidea), a new species from Guam (Micronesia)". Journal of Molluscan Studies 64: 147–160. abstract.
  8. 1 2 Burghardt 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". Zootaxa 596: 1-18. PDFt.
  9. 1 2 3 Baba K. (1991). "Taxonomical study of some species of the genus Phyllodesmium from Cape Muroto-misaki, Shikoku, and Okinawa Province, Southern Japan (Nudibranchia: Facelinidae)". Venus50(2): 109-124. abstract.
  10. 1 2 3 4 5 Burghardt 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 74(3): 277-292. doi : 10.1093/mollus/eyn016, abstract.
  11. ↑ Ortiz D. M. & Gosliner T. M. (31 July 2003). "A New Species of Phyllodesmium Ehrenberg, 1831 (Mollusca, Nudibranchia) from the Tropical Indo-Pacific". Proceedings of the California Academy of Sciences 54(9): 161–168, 5 figs.
  12. ↑ Burghardt 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". Zootaxa 1308: 31-47. abstract. full PDF. (subscription required)
  13. ↑ Aeolid cnidosac Archived 2009-11-09 at the Wayback Machine . Sea Slug Forum, accessed 26 September 2009.
  14. ↑ Phyllodesmium magnum Rudman, 1991 Archived 2012-03-13 at the Wayback Machine . Sea Slug Forum, accessed 26 September 2009.
  15. 1 2 3 Moore E. J. & Gosliner T. M. (2011). "Molecular phylogeny and evolution of symbiosis in a clade of Indopacific nudibranchs". Molecular Phylogenetics and Evolution Volume 58, Issue 1, January 2011, Pages 116–123 doi : 10.1016/j.ympev.2010.11.008. accessed 17 December 2010.
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