This genus of nudibranchs (also known as sea slugs) has approximately 50 described species, which are commonly divided into two major clades. Eastern Pacific and Atlantic nudibranchs are often grouped together into a single clade, which is a sister clade to the Indo-Pacific nudibranchs. It is thought that these two groups reflect allopatric divergence events, such as the formation of the Panama isthmus and the expansion of the Pacific Ocean (Valdes, 2001). The effects of vicariance often appear in the form of color - the eastern Pacific and Atlantic clade often have a dark blue base color and a variety of spot and stripe patterns. They are found in both the Pacific and Atlantic coasts of North and South America, and in the Atlantic coasts of Europe and Africa. Morphologically, they have larger sperm storage structures than those in their sister clade. The Indo-Pacific species vary more in their coloration and have more compact sperm storage structures (Alejandrino and Valdes, 2006; Gosliner and Johnson, 1999). (Alejandrino and Valdes, 2006; Gosliner and Johnson, 1999; Valdes, 2001)
The genusis comprised of bilaterally symmetrical, soft-bodied slugs without shells. They are known for their vibrant colors and patterns. The east Pacific and Atlantic clade tend to be blue with spots or stripes of numerous colors, excluding red. Species in the Indo-Pacific clade are more varied in their coloration - they range from pink/purple to orange/yellow, and also have a wide variety of spot and stripe patterns. Because these two clades are thought to have diverged after an allopatric speciation event, is a genus that scientists use to study the effects of vicariance on the evolution of color patterns (Alejandrino and Valdes, 2006; Galvao et. al., 2015; Gosliner and Johnson, 1999).
Morphologically, members of this genus have a high body profile and laterally-opening glands along the edge of the mantle. Generally, they have teeth with curved points which include bicuspid lateral teeth, however (Alejandrino and Valdes, 2006; Galvao, et al., 2015; Gosliner and Johnson, 1999; Rudman, 1984)lacks a rachidian row of radular teeth. This genus has branched vestibular glands, which are primarily used for lubrication of female sex organs. Nudibranchs are also characterized by the presence of receptaculum seminis, or sperm storage structures, that open in the middle of the vaginal duct. The eastern Pacific and Atlantic clade are thought to have larger receptaculum seminis than the Indo-Pacific clade (Rudman, 1984).
Sea slugs are simultaneous hermaphrodites, but do not often self-fertilize because they have the ability to store sperm. Copulation is preceded by what is thought to be courtship behavior, which is expressed in a variety of behaviors such as head contact, or contact with the edges of the mantle (Hamel, Sargent, and Mercier, 2008; Pola and Gonzalez Duarte, 2008). (Hamel, et al., 2008; Pola and González Duarte, 2008)
Sea slugs are internally-fertilized simultaneous hermaphrodites. During copulation, a mating pair will align their gonopores to exchange gametes. Individuals are usually in fixed position side-by-side during copulation, and have been observed both during the day and at night. Egg dispersal is low, and survival rates of egg clutches is approximately 5-7% (Hamel, Sargent, and Mercier, 2008; Pola and Gonzalez Duarte, 2008). (Hamel, et al., 2008; Pola and González Duarte, 2008)
Nudibranchs lay egg ribbons that are often attached to rocks or sessile marine organisms. Other than choosing suitable locations for egg masses, nudibranchs are not known to have parental investment in their offspring (Hamel, Sargent, and Mercier, 2008; Pola and Gonzalez Duarte, 2008). (Hamel, et al., 2008; Pola and González Duarte, 2008)
Sea slugs have a lifespan of up to 1 year in the wild and 1 month in captivity. Their reduced lifespan in captivity is attributed to the components of their diet that are difficult to rear in captivity because of their toxicity and danger to other organisms (e.g. sponges, hydroids) (National Geographic Society, 2018; Willin and Coleman, 1984). (National Geographic Society, 2018; Willin and Coleman, 1984)
Nudibranchs in the genusare known for their bright aposematic or warning coloration. This coloration is used as a visual cue to warn predators that most of is toxic if ingested. Several species of are considered Müllerian mimics, meaning that they share similar coloration with another species, but each species is equipped with its own chemical defense mechanism. Typically, chemical defenses in are derived from their diet, but can also be produced internally. Defensive allomones are typically located in the mantle and have toxic properties that deter other animals from feeding on nudibranchs. However, some species in do not have chemical deterrents and some are considered to be Bayesian mimics of other species (Avila et. al., 1991; Haber et. al., 2010)
Despite using visual signals to communicate with predators, sea slugs have relatively low visual acuity. Tactile signals are more commonly used for communication with conspecifics, specifically during mating behaviors. Nudibranchs approach other individuals by touching their head, tail, or the sides of the body. Species in (Avila, et al., 1991; Haber, et al., 2010; Wyeth and Willows, 2006)often utilize chemoreception structures, called rhinopores, to obtain information about the location of food and mates. Slugs intraspecifically communicate their location in the form of pheromones, which are 1000x stronger than pheromones found in the human bloodstream (Wyeth and Willows, 2006).
Sea slugs are specialized carnivores that feed on sessile animals that are not heavily exploited by other taxa - such as sponges, corals, bryozoans, or hydroids. Some species are cannibalistic and will feed on other nudibranchs. Typically, sea slugs practice stenophagy, meaning that different species have a specialized diet of one or two kinds of food. Nudibranchs appear to graze on sessile food items and strike at more formidable prey, such as cnidarians (Megino and Cervera, 2003; National Geographic Society, 2018; Wagner, Kahng, and Toonen, 2009; Wyeth and Willows, 2006). (Megino and Cervera, 2003; National Geographic Society, 2018; Wagner, et al., 2009; Wyeth and Willows, 2006)
Despite their lack of a protective shell, nudibranchs display a wide variety of anti-predatator strategies. Several species use crypsis as a form of predator avoidance, but most sea slugs are known for their striking aposematic coloration. Some scientists suggest that several species in (Avila, et al., 1991; Fontana, et al., 1993; Haber, et al., 2010; Harris, 1973)form a Mullerian mimetic circle, which indicates that many species in this taxa are poisonous to predators. Some species, however, use Bayesian mimicry in order to benefit from the toxicity of other species without synthesizing chemical defenses themselves (Haber et. al., 2010). Most nudibranchs rely on chemical defenses that are typically derived from their diet, and have the ability to select food items containing furanosesquiterpenoids, or toxic essential oils. The combination of chemical defenses and aposematic coloration in is why they are rarely predated on, except by other cannibalistic species of sea slugs (Avila et. al., 1991; Harris, 1973;
Several FDA-approved chemical products were originally isolated from mollusks and are further used in drugs and in clinical trials. The genus Hypselodoris jacksoni is first known natural source of the metabolite (−)-(5R,6Z)-dendrolasin-5-acetate. Sea slugs have much to offer in terms of unexplored chemical synthesis research, which has many applications in education and medicine (Mudianta et. al., 2013).is of interest to scientists because of the chemical properties of their toxic oils, and
Recent research has suggested that total nudibranch abundance along the coast of California is highly correlated with warming. This relationship suggests the potential use of nudibranchs as an indicator taxa of climate change (Goddard, Pearse, and Gosliner, 2011). (Goddard, et al., 2011; Mudianta, et al., 2013)
There are no known adverse effects ofon humans.
There is no listing of the conservation status of, nor any of its species.
Sea slugs are used in the aquarium trade and are typically recommended for advanced aquarists because of the difficulty involved with rearing supporting organisms (e.g. sponges, hydroids, and byrozoans) (Willin and Coleman, 1984).
Nudibranchs do not often appear in museum collections because there is no known technique to preserving the shape, size, or color of a non-living specimen. Because color morphology is so distinct in (Willin and Coleman, 1984), it is recommended that a color photograph of a living specimen be included along with the preserved specimen (Willin and Coleman, 1984).
Megan Jones (author), Colorado State University, Tanya Dewey (editor), University of Michigan-Ann Arbor.
the body of water between Africa, Europe, the southern ocean (above 60 degrees south latitude), and the western hemisphere. It is the second largest ocean in the world after the Pacific Ocean.
body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.
having coloration that serves a protective function for the animal, usually used to refer to animals with colors that warn predators of their toxicity. For example: animals with bright red or yellow coloration are often toxic or distasteful.
Referring to an animal that lives on or near the bottom of a body of water. Also an aquatic biome consisting of the ocean bottom below the pelagic and coastal zones. Bottom habitats in the very deepest oceans (below 9000 m) are sometimes referred to as the abyssal zone. see also oceanic vent.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
an animal that mainly eats meat
uses smells or other chemicals to communicate
the nearshore aquatic habitats near a coast, or shoreline.
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
a substance used for the diagnosis, cure, mitigation, treatment, or prevention of disease
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
union of egg and spermatozoan
fertilization takes place within the female's body
imitates a communication signal or appearance of another kind of organism
having the capacity to move from one place to another.
the area in which the animal is naturally found, the region in which it is endemic.
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
an organism that obtains nutrients from other organisms in a harmful way that doesn't cause immediate death
chemicals released into air or water that are detected by and responded to by other animals of the same species
mainly lives in oceans, seas, or other bodies of salt water.
remains in the same area
reproduction that includes combining the genetic contribution of two individuals, a male and a female
mature spermatozoa are stored by females following copulation. Male sperm storage also occurs, as sperm are retained in the male epididymes (in mammals) for a period that can, in some cases, extend over several weeks or more, but here we use the term to refer only to sperm storage by females.
uses touch to communicate
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
uses sight to communicate
2018. "Catalogue of Life" (On-line). Accessed March 26, 2018 at http://www.catalogueoflife.org/col/browse/tree/id/3daf232c2e6973f70fc0a0e15d9017d4.
2018. "World Register of Marine Species" (On-line). Accessed March 26, 2018 at http://www.marinespecies.org/aphia.php?p=taxdetails&id=137784.
Alejandrino, A., A. Valdes. 2006. PHYLOGENY AND BIOGEOGRAPHY OF THE ATLANTIC AND EASTERN PACIFIC HYPSELODORIS STIMPSON, 1855 (NUDIBRANCHIA, CHROMODORIDIDAE) WITH THE DESCRIPTION OF A NEW SPECIES FROM THE CARIBBEAN SEA. Journal of Molluscan Studies, 72/2: 189/198. Accessed January 31, 2018 at https://academic-oup-com.ezproxy2.library.colostate.edu/mollus/article/72/2/189/1256423.
Avila, C., G. Cimino, A. Fontana, M. Gavagnin, J. Ortega, E. Trivellone. 1991. Defensive strategy of two Hypselodoris nudibranchs from Italian and Spanish coasts. Journal of Chemical Ecology, 17/3: 625-636. Accessed January 31, 2018 at https://www.researchgate.net/profile/Jesus_Ortea_Rato/publication/258824563_Defensive_strategy_of_two_Hypselodoris_nudibranchs_from_Italian_and_Spanish_coasts/links/56c3a16308aee3dcd4166940.pdf?inViewer=0&pdfJsDownload=0&origin=publication_detail.
Cummins, S. 2008. How Sea Slugs Fall in Love. Australasian Science, 29/2: 33-35. Accessed February 26, 2018 at https://search-proquest-com.ezproxy2.library.colostate.edu/docview/223698682/fulltextPDF/AB9BF91F71574953PQ/1?accountid=10223.
Fontana, A., C. Avila, E. Martinez, J. Ortea, E. Trivellone, G. Cimino. 1993. DEFENSIVE ALLOMONES IN THREE SPECIES OF Hypselodoris (GASTROPODA: NUDIBRANCHIA) FROM THE CANTABRIAN SEA. Journal of Chemical Ecology, 19/2: 339-356. Accessed February 02, 2018 at https://link-springer-com.ezproxy2.library.colostate.edu/content/pdf/10.1007%2FBF00993700.pdf.
Galvao, F., H. Araujo, A. Silva, V. Azevedo, C. Mierelles. 2015. Sea slugs (Gastropoda: Heterobranchia) from a poorly known area in North-east Brazil: filling gaps in Atlantic distributions.. Marine Biodiversity Records, 8: n/a. Accessed February 17, 2018 at https://search-proquest-com.ezproxy2.library.colostate.edu/cv_643462/docview/1826099753/A373CCB9925247ACPQ/2?accountid=10223.
Goddard, J., J. Pearse, T. Gosliner. 2011. "Sea Slugs as Brilliant Indicators of Climate Change in Central California" (On-line pdf). Accessed March 05, 2018 at https://caseagrant.ucsd.edu/sites/default/files/R-OPCENV-08-Goddard.pdf.
Gosliner, T., R. Johnson. 1999. Phylogeny of Hypselodoris (Nudibranchia: Chromodorididae) with a review of the monophyletic clade of Indo‐Pacific species, including descriptions of twelve new species. Zoological Journal of the Linnean Society, 125/1: 1-114. Accessed January 31, 2018 at http://onlinelibrary.wiley.com.ezproxy2.library.colostate.edu/doi/10.1111/j.1096-3642.1999.tb00586.x/full.
Haber, M., S. Cerfeda, M. Carbone, G. Calado, H. Gaspar, R. Neves, V. Maharajan, G. Cimino, M. Gavagnin, M. Ghiselin, E. Mollo. 2010. Coloration and Defense in the Nudibranch Gastropod Hypselodoris fontandraui. The Biological Bulletin, 218/2: 181-188. Accessed January 31, 2018 at http://www.journals.uchicago.edu/doi/full/10.1086/BBLv218n2p181.
Hamel, J., P. Sargent, A. Mercier. 2008. Diet, reproduction, settlement and growth of Palio dubia (Nudibranchia: Polyceridae) in the north-west Atlantic. Journal of the Marine Biological Association of the United Kingdom, 88/1: 365-374. Accessed February 18, 2018 at https://search-proquest-com.ezproxy2.library.colostate.edu/cv_643462/docview/224140032/fulltextPDF/775ACECEFA134D22PQ/5?accountid=10223.
Harris, L. 1973. Nudibranch associations. Current Topics in Comparative Pathobiology, 2: 275-277.
Johnson, R., T. Gosliner. 2012. Traditional Taxonomic Groupings Mask Evolutionary History: A Molecular Phylogeny and New Classification of the Chromodorid Nudibranchs: e33479. PLoS One, 7/4: e33479. Accessed February 02, 2018 at https://search-proquest-com.ezproxy2.library.colostate.edu/zoologicalrecord/docview/1324444342/fulltext/CD3BA87B32B04B44PQ/2?accountid=10223.
Lawrence, K., W. Watson. 2002. Swimming Behavior of the Nudibranch Melibe leonina. Biological Bulletin, 203/2: 144-151. Accessed February 26, 2018 at http://www.jstor.org.ezproxy2.library.colostate.edu/stable/pdf/1543383.pdf?refreqid=excelsior%3A26009695ddc12129dab680831da7b81f.
MacLeod, P., I. Valiela. 1975. The Effect of Density and mutual Interference by a Predator: A Laboratory Study of Predation by the Nudibranch Coryphella rufibranchialis on the hydroid Tubularia larynx. Hydrobiologia, 47/3: 339-346. Accessed February 26, 2018 at https://link-springer-com.ezproxy2.library.colostate.edu/content/pdf/10.1007%2FBF00039581.pdf.
Megino, C., J. Cervera. 2003. Diet, prey selection and cannibalism in the hunter opisthobranch Roboastra europaea. Journal of the Marine Biological Association of the United Kingdom, 83/3: 489-495. Accessed February 18, 2018 at https://search-proquest-com.ezproxy2.library.colostate.edu/cv_643462/docview/224156901/fulltextPDF/C564C483D9094C4FPQ/2?accountid=10223.
Mudianta, W., V. Challinor, A. Winters, K. Cheney, J. De Voss, M. Garson. 2013. Synthesis and determination of the absolute configuration of (−)-(5R,6Z)-dendrolasin-5-acetate from the nudibranch Hypselodoris jacksoni. Beilstein Journal of Organic Chemistry, 9: 2925–2933. Accessed March 05, 2018 at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3896254/.
National Geographic Society, 2018. "Nudibranchs" (On-line). Accessed February 25, 2018 at https://www.nationalgeographic.com/animals/invertebrates/group/nudibranchs/.
Pola, M., M. González Duarte. 2008. Is self-fertilization possible in nudibranchs?. Journal of Molluscan Studies, 74/3: 305-308. Accessed February 18, 2018 at https://academic-oup-com.ezproxy2.library.colostate.edu/mollus/article/74/3/305/1022306.
Rudman, W. 1984. The Chromodorididae (Opisthobranchia: Mollusca) of the Indo-West Pacific: a review of the genera. Zoological Journal of the Linnean Society, 81/2: 115-273. Accessed February 02, 2018 at http://onlinelibrary.wiley.com/doi/10.1111/j.1096-3642.1984.tb01174.x/abstract.
Tronosco, J., F. Garcia, V. Urgorri. 1998. Anatomical data on a rare Hypselodoris Picta (Schultz, 1836) (Gastropoda, Doridacea) from the Coast of Brazil with Description of a new Subspecies. Bulletin of Marine Science, 63/1: 133-141. Accessed February 01, 2018 at http://docserver.ingentaconnect.com.ezproxy2.library.colostate.edu/deliver/connect/umrsmas/00074977/v63n1/s10.pdf?expires=1517513410&id=0000&titleid=10983&checksum=D2C67637B04A99079EA16711C6D4C441.
Turner, L., N. Wilson. 2007. Polyphyly across oceans: a molecular phylogeny of the Chromodorididae (Mollusca, Nudibranchia). Zoologica Scripta, 37/1: 23-42. Accessed February 02, 2018 at http://onlinelibrary.wiley.com.ezproxy2.library.colostate.edu/doi/10.1111/j.1463-6409.2007.00310.x/full.
Valdes, A. 2001. Depth-related adaptations, speciation processes and evolution of color in the genus Phyllidiopsis (Mollusca: Nudibranchia). Marine Biology, 139/3: 485-496. Accessed February 10, 2018 at https://www.researchgate.net/publication/226449193_Depth-related_adaptations_speciation_processes_and_evolution_of_color_in_the_genus_Phyllidiopsis_Mollusca_Nudibranchia.
Wagele, H., R. Willan. 2000. Phylogeny of Nudibranchia. Zoological Journal of the Linnean Society, 130/1: 83-181. Accessed March 26, 2018 at https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1096-3642.2000.tb02196.x.
Wagner, D., S. Kahng, R. Toonen. 2009. Observations on the life history and feeding ecology of a specialized nudibranch predator (Phyllodesmium poindimiei), with implications for biocontrol of an invasive octocoral (Carijoa riisei) in Hawaii. Journal of Experimental Marine Biology and Ecology, 372/1: 64-74. Accessed February 12, 2018 at https://www-sciencedirect-com.ezproxy2.library.colostate.edu/science/article/pii/S0022098109000744?_rdoc=1&_fmt=high&_origin=gateway&_docanchor=&md5=b8429449ccfc9c30159a5f9aeaa92ffb&ccp=y.
Willin, R., N. Coleman. 1984. Nudibranchs of Australasia. Sydney: Caringbah. Accessed February 25, 2018 at http://www.nudibranch.com.au/aboutnudibranchs.html.
Wyeth, R., D. Willows. 2006. Field Behavior of the Nudibranch Mollusc Tritonia diomedea. Biological Bulletin, 210/1: 81-96. Accessed February 26, 2018 at http://www.jstor.org.ezproxy2.library.colostate.edu/stable/pdf/4134598.pdf?refreqid=excelsior%3Ad89c3d52562cc5ce687375c7dcf9093e.