Glossodoris atromarginata

Geographic Range

Glossodoris atromarginata is a common species of marine nudibranch native to the Pacific and Indian Oceans. (Fontana, et al., 1999; Ellis, 1999)


Glossodoris atromarginata may be found in marine habitats such as reefs, inter-tidal areas and the deep ocean. However, it is generally found in shallow water. Most individuals live near or even on the surface of the water. (Banks, 2006; Fontana, et al., 1999)

  • Range depth
    0 to 28 m
    0.00 to 91.86 ft

Physical Description

Glossodoris atromarginata is an elongate sea slug that is white to creamish with a dark band down the dorsal midline. The mantle edge is very sinuous and has a dark brown to black margin. This sea slug has dark rhinophore clubs on the dorsal surface. Gills range in number from 14-22. The simple gills are also long, cream colored and have a dark margin. Glossodoris atromarginata will grow to 50-60 mm in length. (Ellis, 1999; Fontana, et al., 1999; Rudman, 1998)

  • Range length
    60 (high) mm
    2.36 (high) in
  • Average length
    40-45 mm


In its early stages of life Glossodoris atromarginata looks very different from the adult. A free-swimming, shelled larva called a veliger is released from the egg. Shortly after hatching the shell is lost. While initially planktonic, the veliger eventually settles on the ocean floor where it metamorphoses into a juvenile. Development time can vary with water temperature. (Banks, 2006; Ellis, 1999; Fontana, et al., 1999; Karlsson and Haase, 2002; Valdés and Adams, 2005)


In general, nudibranchs are simultaneous hermaphrodites and produce both sperm and eggs. Two nudibranchs will exchange sperm sacs with each other to mate. Eggs are typically deposited on sponges. Gestation occurs over 5 to 50 days and in warmer waters, egg maturation occurs sooner. (Karlsson and Haase, 2002)

  • Range gestation period
    5 to 50 days
  • Range age at sexual or reproductive maturity (female)
    2 to 4 months
  • Range age at sexual or reproductive maturity (male)
    2 to 4 months

Larvae are free-living, and thus drift unprotected by either parent. (Karlsson and Haase, 2002)

  • Parental Investment
  • no parental involvement
  • pre-hatching/birth
    • provisioning


Glossodoris atromarginata has a life expectancy of 1 year in the wild. If captured, the life expectancy varies due to the conditions of the new environment and whether or not the species can adapt. Generally the expected lifespan for G. atromarginata is the same as for in the wild: 1 year. (Banks, 2006; Ellis, 1999; Fontana, et al., 1999; Karlsson and Haase, 2002; Valdés and Adams, 2005)

  • Range lifespan
    Status: wild
    4.5 (high) years
  • Range lifespan
    Status: captivity
    6 (high) years
  • Typical lifespan
    Status: wild
    less than 1 to 1 years
  • Typical lifespan
    Status: captivity
    less than 1 to 1 years


Glossodoris atromarginata is mostly active during the day. It "crawls" along the surface of rocks and sponges, moving its body in a wave-like pattern as it goes. When not moving, it is known to coil its body up. Sea slugs in general live relatively sedentary lives, and some species spend their entire life on one prey organism such as a sponge or coral reef. (Banks, 2006; Ellis, 1999; Fontana, et al., 1999; Karlsson and Haase, 2002; Valdés and Adams, 2005)

Home Range

Glossodoris atromarginata is found in the tropical Indo-Pacific. (Banks, 2006; Ellis, 1999; Fontana, et al., 1999; Karlsson and Haase, 2002; Valdés and Adams, 2005)

Communication and Perception

Glossodoris atromarginata has cephalic tentacles on its head. These tentacles are sensitive to touch, taste, and smell. It has aposematic coloring to warn predators that it is poisonous. (Banks, 2006; Ellis, 1999; Fontana, et al., 1999; Karlsson and Haase, 2002; Ruigómez, 2007; Valdés and Adams, 2005)

  • Other Communication Modes
  • mimicry

Food Habits

Glossodoris atromarginata is a carnivore, eating corals or sponges, particularly Hyatella. (Banks, 2006; Ellis, 1999; Fontana, et al., 1999; Karlsson and Haase, 2002; Valdés and Adams, 2005)

  • Primary Diet
  • carnivore
    • eats other marine invertebrates
  • Animal Foods
  • cnidarians
  • other marine invertebrates


Sea slugs in general are preyed upon by crabs, lobsters, sea spiders, and other predatory sea slugs (e.g. Navanax inermis).

Sea slugs in general have been able to develop several defense mechanisms, including the ability to secrete toxic chemicals. It does this by retaining stinging cells from the animals that it ingests. Nudibranchs are also able to camoflouge themselves by taking on the color of anything they have eaten. These mechanisms can be used to scare off predators or inflict harm on the predator. (Cimino, et al., 1999; Fontana, et al., 1999; Rudman, 1998; Ruigómez, 2007)

Ecosystem Roles

Glossodoris atromarginata will live on a sponge or coral its whole life. Sea slugs in general are hosts to parasitic copepods. (Banks, 2006; Ellis, 1999; Fontana, et al., 1999; Karlsson and Haase, 2002; Ruigómez, 2007; Valdés and Adams, 2005)

Commensal/Parasitic Species
  • Parasitic copepods, Copepoda

Economic Importance for Humans: Positive

Glossodoris atromarginata is aesthetically appealing to snorklers and divers, and add to the beauty and diversity of marine life. However beyond their aesthetic appeal it has little to no significance to humans.

Economic Importance for Humans: Negative

There are no known adverse effects of Glossodoris atromarginata on humans.

Conservation Status

Glossodoris atromarginata is not considered threatened or endangered. G. atromarginata is not listed by the IUCN. (Banks, 2006; Fontana, et al., 1999; Ellis, 1999; Karlsson and Haase, 2002; Valdés and Adams, 2005)


Melanie Kuehl (author), Rutgers University, Joanne Sountis (author), Rutgers University, Christy Young (author), Rutgers University, Craig Zagata (author), Rutgers University, David V. Howe (editor), Rutgers University, Renee Mulcrone (editor), Special Projects.


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.

World Map


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.

bilateral symmetry

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


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.

  1. active during the day, 2. lasting for one day.

humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.


animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature


union of egg and spermatozoan


having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

internal fertilization

fertilization takes place within the female's body

intertidal or littoral

the area of shoreline influenced mainly by the tides, between the highest and lowest reaches of the tide. An aquatic habitat.


A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.


imitates a communication signal or appearance of another kind of organism


having the capacity to move from one place to another.


specialized for swimming

native range

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 aquatic biome consisting of the open ocean, far from land, does not include sea bottom (benthic zone).


the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.


structure produced by the calcium carbonate skeletons of coral polyps (Class Anthozoa). Coral reefs are found in warm, shallow oceans with low nutrient availability. They form the basis for rich communities of other invertebrates, plants, fish, and protists. The polyps live only on the reef surface. Because they depend on symbiotic photosynthetic algae, zooxanthellae, they cannot live where light does not penetrate.

saltwater or marine

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


uses touch to communicate


the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.


uses sight to communicate


Banks, I. 2006. "Black-margined Glossodoris" (On-line). Diving the Gold Coast. Accessed December 02, 2010 at

Cimino, G., S. De Rosa, S. De Stefano, G. Sodano, G. Villani. 1999. Dorid nudibranch elaborates its own chemical defense. Science, 219: 1237-1238.

Ellis, W. 1999. "Australasian Nudibranch News" (On-line pdf). Accessed December 02, 2010 at

Fontana, A., P. Cavaliere, N. Ungur, L. D'Souza, P. Parameswaram, G. Cimino. 1999. New scalaranes from the nudibranch Glossodoris atromarginata and its sponge prey. Journal of Natural Products, 62/10: 1367 -1370.

Karlsson, A., M. Haase. 2002. The enigmatic mating behaviour and reproduction of a simultaneous hermaphrodite, the nudibranch Aeolidiella glauca (Gastropoda, Opisthobranchia). Canadian Journal of Zoology, 80/2: 260-270. Accessed December 02, 2010 at

Rudman, W. 1998. "Glossodoris atromarginata (Cuvier, 1804)" (On-line). Sea Slug Forum. Accessed February 23, 2011 at

Ruigómez, V. 2007. "Nudibranchs: Beautiful but dangerous marine creatures" (On-line). Advanced aquarist's online magazine. Accessed February 23, 2011 at

Valdés, A., M. Adams. 2005. A new species of Glossodoris (Mollusca: Nudibranchia), of the Glossodoris atromarginata color group, from Indonesia. Pacific science, Volume 59/Issue 4: 603-608. Accessed December 02, 2010 at