Cassiopea
| Cassiopea | |
|---|---|
| |
| Cassiopea sp. | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Cnidaria |
| Class: | Scyphozoa |
| Order: | Rhizostomeae |
| Family: | Cassiopeidae Agassiz, 1862 |
| Genus: | Cassiopea Péron & Lesueur, 1809 |
| Species | |
|
8 species, see text | |
| Synonyms | |
Cassiopea (upside-down jellyfish) is a genus of true jellyfish and members of the family Cassiopeidae.[3] They are found in warmer coastal regions around the world, including shallow mangrove swamps, mudflats, canals, and turtle grass flats in Florida, the Caribbean and Micronesia. The medusa usually lives upside-down on the sea floor in shallow areas, which has earned them their common name. These jellyfish partake in a symbiotic relationship with photosynthetic dinoflagellates and therefore, must lie upside-down in areas with sufficient light penetration to fuel their energy source, which also involves certain elements and minerals such as carbon.[4] Where found, there may be numerous individuals with varying shades of white, blue, green and brown. Furthermore, these creatures have unique characteristics involving significant aspects of reproducing with their oral disc, processes in their sleep state, and the use of water currents while swimming that set them a part from many other species. [4]
Species
[edit]According to the World Register of Marine Species, this genus includes 8 species:[5]
- Cassiopea andromeda (Forsskål, 1775)—Indo-Pacific, introduced in the Mediterranean
- Cassiopea depressa Haeckel, 1880—Western Indian Ocean off the African coast
- Cassiopea frondosa (Pallas, 1774)—Western Atlantic, Caribbean Sea
- Cassiopea maremetens Gershwin, Zeidler & Davie, 2010—Western Pacific Ocean, off the Australian Coast
- Cassiopea medusa Light, 1914—Pacific Ocean, Philippines and Palau Region
- Cassiopea mertensi Brandt, 1838—Pacific Ocean Southern Micronesia
- Cassiopea ndrosia Agassiz & Mayer, 1899—Pacific Ocean, Australia and Fiji
- Cassiopea ornata Haeckel, 1880—Pacific Ocean, Palau, Philippines, Okinawa
- Cassiopea xamachana Bigelow, 1892—Caribbean Sea and the Northern Atlantic Area of the West indies
Sex Life
[edit]Cassiopea individuals are either strictly male or female, also known as being gonochoristic. Unlike humans, this species has a gastrovascular cavity, meaning their digestive system only has one opening. This is where the fertilization of their babies primarily occurs, and happens at a decently quick rate. After fertilized, the embryos are expelled and attached onto their oral disc, which is commonly known as their mouth. The eggs are present on this surface for 48 hours after they are fertilized. By the 96-hour mark, they elongate and become polyps, meaning they already are beginning to look like their species.[4]
Sleep State
[edit]Certain species of Cassiopea have been observed to enter a sleep state and displays three primarily characteristics during that time. These are quiescence, also known as a state of inactivity or dormancy, delayed responsiveness to stimuli (or sensory depression), and being able to partake in homeostatic regulation whilst asleep, or not being highly affected by the outside environment and remaining stable. Furthermore, they are the first animals with no central nervous system to have been observed sleeping.[4]
Swimming
[edit]The process of Cassiopea swimming is quite unique to jellyfish themselves. They create their own water currents to propel when changing direction through the use of contracting a part of their body called the bell, which is the mushroom-shaped structure. This contraction originates a whirlpool at the bell and are broken through the pressure exerted on the oral arms. Also, the jellyfish move in a constant flow, which pushes towards the animal and having a upward flow above them.[4]
Nutritional Requirements
[edit]These jellyfish are more unusual than most species regarding their nutrition. Upside down jellyfish do not gain much nutrients from feeding from the waters around them, rather they need a significant amount of minerals to support their carbohydrates and lipids. This allows for them to continue to grow and prolong sexual reproduction. Even so, the process behind them feeding is still relatively unknown to many. The major gap of knowledge is how there is an ongoing process of biosynthesis and carbon flow, which are believed to be complex metabolic modifications within the jellyfish. Furthermore, they have endosymbiotic algae living inside of them, allowing them to photosynthesize as a whole organism. Recently, the jellyfish have been more widely known for this symbiotic relationship because of them being able to autotrophically assimilate with the element, carbon. With everything aside, glycerol is the dominant photosynthetic that they are producing, specifically glucose.[4]
References
[edit]- ^ IRMNG (2021). Cassiopeia Gistl, 1848. Accessed on 2023-05-29.
- ^ IRMNG (2021). Cassiopeja Schultze, 1898. Accessed on 2023-05-29.
- ^ "Cassiopeidae". WoRMS. World Register of Marine Species. Retrieved 3 August 2012.
- ^ a b c d e f Ohdera Aki H.; Abrams Michael J.; Ames Cheryl L.; Baker David M.; Suescún-Bolívar Luis P.; Collins Allen G.; Freeman Christopher J.; Gamero-Mora Edgar; Goulet Tamar L.; Hofmann Dietrich K.; Jaimes-Becerra Adrian; Long Paul F.; Marques Antonio C.; Miller Laura A.; Mydlarz Laura D.; Morandini Andre C.; Newkirk Casandra R.; Putri Sastia P.; Samson Julia E.; Stampar Sérgio N.; Steinworth Bailey; Templeman Michelle; Thomé Patricia E.; Vlok Marli; Woodley Cheryl M.; Wong Jane C.Y.; Martindale Mark Q.; Fitt William K.; Medina Mónica (2018). "Upside-Down but Headed in the Right Direction: Review of the Highly Versatile Cassiopea xamachana System". Frontiers in Ecology and Evolution. 6: 35. doi:10.3389/fevo.2018.00035. hdl:11449/176281.
- ^ "Cassiopea". WoRMS. World Register of Marine Species. Retrieved 3 August 2012.
External links
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