Carybdea sivickisi | INFORMATION | Animal Diversity Web

Scientific Classification

Rank	Scientific Name
Kingdom	Animalia animals
Phylum	Cnidaria corals, sea anemones, jellyfish, and relatives
Class	Cubozoa
Order	Cubomedusae
Family	Carybdeidae
Genus	Carybdea
Species	Carybdea sivickisi

By Roshni Patel and Kimberly Rutledge

Geographic Range

Carybdea sivickisi has been found in many temperate, tropical, and subtropical locations in the western Pacific from Japan in the north, the Indo-Pacific, to New Zealand in the south. Most specimens have been found in temperate regions around the end of August, and subtropical regions between April and August. These regions seem to have native strains of Carybdea sivickisi .

Biogeographic Regions
oceanic islands
- native

Habitat

Carybdea sivickisi is generally found in the shallower waters of the ocean, especially during the summer months due to their mating rituals. However, box jellies travel to deeper depths in open marine waters in search of food. This species resides in marine saltwater, mild temperate, tropical, and subtropical regions.

Aquatic Biomes
pelagic
benthic

Physical Description

Carybdea sivickisi is a small, bell shaped, transparent creature, with a bell diameter of about 1-4 mm, sometimes up to 14 mm, and a height of 7 mm. This species has four interradial compressed corners, each with pedalia (muscular adhesive pads) and yellow tentacles coming from them. The tentacles have nematocyst rings and swellings on the end. Also visible in the specimen are the velarial canals, manubrium, nerve ring, rhopalia, and the radial cyst. Females are distinguishable from males because they have orange spots on their bell. Cnidarians in general are polymorphic with alternating polyp and medusa stages.

Other Physical Features
ectothermic
radial symmetry
polymorphic

Sexual Dimorphism
sexes colored or patterned differently
female more colorful

Development

Carybdea sivickisi females have a long, gelatin like strand where they house their embryos that form only a few hours after fertilization. These embryos become planulae that swim for a few days and then settle on a substrate. After settling, they metamorphose into a sessile polyp. The polyps then form a creeper stage after a few more days. The creeper stage then eventually forms a juvenile medusa.

Development - Life Cycle
metamorphosis

Reproduction

The mating behavior of Carybdea sivickisi differs from most jellyfish. In what is termed 'the wedding dance', the male moves the female through the water by her tentacle. He positions her so their manubria (orifices) are close together and passes her a sac full of brightly colored red sperm. She then eats this sac and the eggs are fertilized. Males can pass a sperm sac to many different females, and females can accept many different sperm sacs from many males. Males may be able to choose their females based on their bright orange spots.

Mating System
polygynandrous (promiscuous)

Carybdea sivickisi tends to mate in the spring and summer when the water is warmer. The gestational period is an average of 55 hours, and the embryos produced from a single fertilization event are approximately 3,000 in each strand. Each embryo strand weighs approximately 55 mg, and there is evidence that Carybdea sivickisi females only produce one embryo strand and die 16 days after. These embryos are held in the embryo strand for approximately 4 days and are released as planulae as the strand decomposes.

Carybdea sivickisi puts effort into parental care through the formation of an embryo strand. This gelatinous strand holds all of the embryos together inside the female and ensures they are able to develop before they are released on their own to swim and attach to a surface to metamorphose.

Parental Investment
no parental involvement
female parental care
pre-hatching/birth
- provisioning
  - female
- protecting
  - female

Lifespan/Longevity

The life cycle of this organism includes four days for embryonic development into a planula, four days of swimming around, and eight days for the planula to settle on a substrate to metamorphose. The actual metamorphosis process to become a polyp is 24 hours. The sessile polyp lives approximately 2-6 weeks after it settles on the substrate before they die. This makes a total of 4-8 weeks. Some organisms are able to survive the polyp stage, and after another three days become an elongated "creeper" stage which eventually metamorphs into a juvenile medusae stage. In lab experiments, the transitions from polyp to creeper and then to medusa was not observed, however it has been reported that the medusae die shortly after sexual reproduction.

Behavior

A medusa of Carybdea sivickisi spends most of its days attached by its bell to the undersides of rocks. They have the ability to compact their bodies by folding their four tentacles inside their bells or by flattening. They swim to a surface, make contact with it using their adhesive pads, and then quickly stick to the surface. While stuck to the surface they are motionless and their tentacles are relaxed. They can remain like this for varied amounts of time. They detach either spontaneously or by some sort of stimulus and continue to swim. The reason for attaching to substrates and remaining immobile is to save energy and to avoid predators. They are usually attached to a substrate during the day and then free swimming during the night.

Key Behaviors
motile

Communication and Perception

Vision plays a role on what surfaces Carybdea sivickisi attaches. The developed rhopalial eyes have not been studied completely, but have a role in their reproductive behavior. These box jellies also have sexually dimorphic pigmentation patterns and distinctive banding patterns on their tentacles that may have a role in mate recognition.

Communication Channels
visual
tactile

Perception Channels
visual
tactile
chemical

Food Habits

Because Carybdea sivickisi is free swimming during the night, it feeds mainly on night swarming benthic organisms. This includes heteronereids, cumaceans, gammarid amphiods, and isopods. This jellyfish stings its prey to capture it.

Primary Diet
carnivore
- eats non-insect arthropods

Animal Foods
aquatic or marine worms
aquatic crustaceans
other marine invertebrates
zooplankton

Predation

To avoid predators Carybdea sivickisi attaches to surfaces.

Anti-predator Adaptations
cryptic

Ecosystem Roles

There are no published studies on the role of Carybdea sivickisi on the ecosystem, but it feeds on benthic organisms and therefore is part of the food web for benthic populations.

Economic Importance for Humans: Positive

Carybdea sivickisi is of special importance to scientists because of its unique mating rituals. This species is one of the only cubozoans to exhibit this "intimate" mating ritual. This species has also helped scientists study the rhopalia eyes found in cubozoans.

Positive Impacts
research and education

Economic Importance for Humans: Negative

Like many species of Cubozoa, Carybdea sivickisi have cnidocytes that sting organisms. The cnidocytes are used to catch prey and can be harmful to humans, if they are stung. However, the stings are not known to be fatal for humans.

Negative Impacts
injures humans
- bites or stings

Conservation Status

Carybdea sivickisi requires no special conservation efforts.

Additional Links

Encyclopedia of Life

Contributors

Roshni Patel (author), Rutgers University, Kimberly Rutledge (author), Rutgers University, David V. Howe (editor), Rutgers University, Renee Mulcrone (editor), Special Projects.

oceanic islands: islands that are not part of continental shelf areas, they are not, and have never been, connected to a continental land mass, most typically these are volcanic islands.

native range: the area in which the animal is naturally found, the region in which it is endemic.

temperate: 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).

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

saltwater or marine: mainly lives in oceans, seas, or other bodies of salt water.

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

benthic: 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.

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

radial symmetry: a form of body symmetry in which the parts of an animal are arranged concentrically around a central oral/aboral axis and more than one imaginary plane through this axis results in halves that are mirror-images of each other. Examples are cnidarians (Phylum Cnidaria, jellyfish, anemones, and corals).

polymorphic: "many forms." A species is polymorphic if its individuals can be divided into two or more easily recognized groups, based on structure, color, or other similar characteristics. The term only applies when the distinct groups can be found in the same area; graded or clinal variation throughout the range of a species (e.g. a north-to-south decrease in size) is not polymorphism. Polymorphic characteristics may be inherited because the differences have a genetic basis, or they may be the result of environmental influences. We do not consider sexual differences (i.e. sexual dimorphism), seasonal changes (e.g. change in fur color), or age-related changes to be polymorphic. Polymorphism in a local population can be an adaptation to prevent density-dependent predation, where predators preferentially prey on the most common morph.

metamorphosis: 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.

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

year-round breeding: breeding takes place throughout the year

fertilization: union of egg and spermatozoan

internal fertilization: fertilization takes place within the female's body

ovoviviparous: reproduction in which eggs develop within the maternal body without additional nourishment from the parent and hatch within the parent or immediately after laying.

female parental care: parental care is carried out by females

motile: having the capacity to move from one place to another.

visual: uses sight to communicate

tactile: uses touch to communicate

visual: uses sight to communicate

tactile: uses touch to communicate

chemical: uses smells or other chemicals to communicate

zooplankton: animal constituent of plankton; mainly small crustaceans and fish larvae. (Compare to phytoplankton.)

cryptic: 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.

carnivore: an animal that mainly eats meat

References

Hartwick, R. 1991. Observations on the anatomy, behaviour, reproduction and life cycle of the cubozoan Carybdea sivickisi . Hydrobiologia , 216-217: 171-179.

Hoekenga, C. 2011. "Jellyfish romance-( Carybdea sivickisi )" (On-line). Smithsonian Natural Museum of Natural History. Accessed February 23, 2013 at http://invertebrates.si.edu/jellyfish/index.html .

Hoverd, W. 1985. Occurance of the order Cubomedusae (Cnidaria, Scyphozoa) in New Zealand: collection and laboratory observations of Carybdea sivickisi . New Zealand Journal of Zoology , 12: 107-110. Accessed February 23, 2013 at http://www.tandfonline.com/doi/pdf/10.1080/03014223.1985.10428267 .

Lewis, C., S. Kubota, A. Migotto, A. Collins. 2008. Sexually dimorphic culjomedusa Carybdea sivickisi . Publ. Seto Mar. Biol. Lab , 40: 1-8. Accessed February 23, 2013 at http://si-pddr.si.edu/jspui/bitstream/10088/6250/1/Lewis_etal_2008.pdf .

Lewis, C., T. Long. 2005. Courtship and reproduction in Carybdea sivickisi (Cnidaria: Cubozoa). Marine Biology , 147: 477–483. Accessed February 23, 2013 at http://www.wlu.ca/documents/44351/Lewis_Long_2005.pdf .

Shapiro, L. 2011. " Carybdea sivickisi " (On-line). EOL species rapid response. Accessed February 23, 2013 at http://eolspecies.lifedesks.org/pages/15888 .