The spotted jelly (Mastigias papua), lagoon jelly, golden medusa, or Papuan jellyfish, is a species of jellyfish from the Indo-Pacific oceans. Like corals, sea anemones, and other sea jellies, it belongs to the phylumCnidaria. Mastigias papua is one of the numerous marine animals living in symbiosis with zooxanthellae, a photosynthetic alga.[2]
The spotted jelly has distinctive spots atop its bell, and vary in colouration, from greenish blue to olive green, which can be attributed to the zooxanthellae which reside within their tissues.[4]
They have 8 frilled oral arms, which end in a clublike appendage. The upper surfaces of these arms are covered in stinging cells called cnidocytes.[5] Unlike many other jellies, spotted jellyfish have numerous mouths along the bottom of their oral arms.
There are eight rhopalia, which act as the sensory organs of the jellyfish, on the margin of the bell.[5]
They average 10cm (4 in) in diameter, but can grow as large as 30 cm (12 in).[2]
Feeding
These jellies feed on zooplankton and other tiny organisms using their stinging cells, called cnidocytes. The spotted jelly has several small mouths used to grab animal plankton.
Spotted jellies also acquire much of their nutrition via an endosymbiotic relationship with photosynthetic zooxathellae, such as those of the genus Cladocopium.[5][6] The zooxathellae provide the jellyfish with nutrients, and in return the zooxanthellae get a safe place to live. This symbiotic relationship is not unique to the spotted jellyfish, and can also be observed in species such as the upside-down jellyfish.
During the night, these jellyfish stay lower in the water column and migrate each day, rising to the waters surface, and following the sun east to west, to allow their zooxanthellae access to the light they need to photosynthesize.[5][7][8]
Habitat
Spotted jellies range throughout the Indo-Pacific, from the Fijian Islands to the western Indian Ocean, and from Japan to Australia.[9]
Some populations of spotted jellies in Palau have been found to occur in huge groups (called "smacks"), which have become tourist attractions.[8] The most famous spot to admire them is the Ongeim’l Tketau Lake in Palau, also known as Jellyfish Lake.[10][8]
Predators
Spotted jellies are predated upon by the sea anemone Entacmaea medusivora, which capture the jellyfish in their tentacles. While the jellyfish is captured by the anemone, an enterprising gastropod or fish may scavenge upon the captured jellyfish before the anemone is finished consuming it.[11]
Footnotes
↑ Collins, A.G.; Morandini, A.C. (2023). World List of Scyphozoa. Mastigias papua (Lesson, 1830). Accessed through WoRMS on 2023-05-29.
Cnidaria is a phylum under kingdom Animalia containing over 11,000 species of aquatic animals found both in fresh water and marine environments, including jellyfish, hydroids, sea anemones, corals and some of the smallest marine parasites. Their distinguishing features are a decentralized nervous system distributed throughout a gelatinous body and the presence of cnidocytes or cnidoblasts, specialized cells with ejectable flagella used mainly for envenomation and capturing prey. Their bodies consist of mesoglea, a non-living, jelly-like substance, sandwiched between two layers of epithelium that are mostly one cell thick. Cnidarians are also some of the only animals that can reproduce both sexually and asexually.
Jellyfish, also known as sea jellies, are the medusa-phase of certain gelatinous members of the subphylum Medusozoa, which is a major part of the phylum Cnidaria.
The Scyphozoa are an exclusively marine class of the phylum Cnidaria, referred to as the true jellyfish.
A cnidocyte is an explosive cell containing one large secretory organelle called a cnidocyst that can deliver a sting to other organisms. The presence of this cell defines the phylum Cnidaria. Cnidae are used to capture prey and as a defense against predators. A cnidocyte fires a structure that contains a toxin within the cnidocyst; this is responsible for the stings delivered by a cnidarian. Cnidocytes are single-use cells that need to be continuously replaced.
Rhizostomeae is an order of jellyfish. Species of this order have neither tentacles nor other structures at the bell's edges. Instead, they have eight highly branched oral arms, along which there are suctorial minimouth orifices. These oral arms become fused as they approach the central part of the jellyfish. The mouth of the animal is also subdivided into minute pores that are linked to coelenteron.
Medusozoa is a clade in the phylum Cnidaria, and is often considered a subphylum. It includes the classes Hydrozoa, Scyphozoa, Staurozoa and Cubozoa, and possibly the parasitic Polypodiozoa. Medusozoans are distinguished by having a medusa stage in their often complex life cycle, a medusa typically being an umbrella-shaped body with stinging tentacles around the edge. With the exception of some Hydrozoa, all are called jellyfish in their free-swimming medusa phase.
Jellyfish Lake is a marine lake located on Eil Malk island in Palau. Eil Malk is part of the Rock Islands, a group of small, rocky, mostly uninhabited islands in Palau's Southern Lagoon, between Koror and Peleliu. There are about 70 other marine lakes located throughout the Rock Islands. Millions of golden jellyfish migrate horizontally across the lake daily.
Mastigiidae is a family of true jellyfish. The family is native to the Indo-Pacific, but a species of Mastigias has been introduced to the West Atlantic, and Phyllorhiza punctata has been introduced to the West Atlantic and Mediterranean Sea.
Cotylorhiza tuberculata is a species of jellyfish of the phylum Cnidaria, also known as the Mediterranean jellyfish, Mediterranean jelly, or fried egg jellyfish. It is commonly found in the Mediterranean Sea, Aegean Sea, and Adriatic Sea.
Cotylorhiza is a genus of true jellyfish from the family Cepheidae. The genus is found in the central-east Atlantic, Mediterranean, and western Indian Ocean.
Mastigias is a genus of true jellyfish in the family Mastigiidae. It contains seven described species. Members of this genus are found widely in coastal regions of the Indo-Pacific, including saline lakes of Palau, but there are also records from the West Atlantic at Florida and Puerto Rico. The West Atlantic records are most likely the result of accidental introductions by humans.
Aurelia is a genus of jellyfish that are commonly called moon jellies, which are in the class Scyphozoa. There are currently 25 accepted species and many that are still not formally described.
Catostylus mosaicus is also known as the jelly blubber or blue blubber jellyfish. The jelly blubber is distinguishable by its color, which ranges from light blue to a dark blue or purple, and its large (250-300mm), rounded bell which pulses in a staccato rhythm. It occurs along the coastline of Eastern Australia in estuaries and shallow bays, and often blooms to high abundance.
Cassiopea andromeda is one of many cnidarian species called the upside-down jellyfish. It usually lives in intertidal sand or mudflats, shallow lagoons, and around mangroves. This jellyfish, often mistaken for a sea anemone, usually keeps its mouth facing upward. Its yellow-brown bell, which has white or pale streaks and spots, pulsates to run water through its arms for respiration and to gather food.
Clear Lake is a marine lake located on Eil Malk island in Palau. Eil Malk is part of the Rock Islands, a group of small, rocky, mostly uninhabited islands in Palau's Southern Lagoon, between Koror and Peleliu. There are about 70 other marine lakes located throughout the Rock Islands. Clear Lake is notable for endemic subspecies of golden jellyfish and is one of five marine lakes in Palau used for several scientific researches in evolutionary biology, the other lakes being Jellyfish Lake, Goby Lake, Uet era Ngermeuangel, Uet era Ongael.
Goby Lake is a marine lake located on Koror island in Palau. There are about 70 other marine lakes located throughout the Rock Islands and Koror. Goby Lake is notable for endemic subspecies of golden jellyfish and is one of five marine lakes in Palau used for several scientific researches in evolutionary biology the other lakes being Jellyfish Lake, Clear Lake (Palau), Uet era Ngermeuangel, Uet era Ongael.
Uet era Ngermeuangel is a marine lake located on Koror island in Palau. There are about 70 other marine lakes located throughout the Rock Islands and Koror. Uet era Ngermeuangel is notable for endemic subspecies of golden jellyfish and is one of five marine lakes in Palau used for several scientific researches in evolutionary biology the other lakes being Jellyfish Lake, Clear Lake (Palau), Goby Lake, Uet era Ongael.
Uet era Ongael is a marine lake located on Ongael Island, Koror, in Palau. There are about 70 other marine lakes located throughout the Rock Islands and Koror. Uet era Ongael is notable for endemic subspecies of golden jellyfish and is one of five marine lakes in Palau used for several scientific researches in evolutionary biology, the other lakes being Jellyfish Lake, Clear Lake, Uet era Ngermeuangel and Goby Lake.
Cassiopea ornata are one of many Cnidarian species called the upside-down jellyfish. This pelagic jellyfish primarily lives in tropical waters, off the coast of Australia in shallow lagoons and around mangrove trees. The name "upside-down jellyfish" comes from the fact that it appears to be upside-down in its natural state—resting on its bell. Its bell is a golden/brown color and the tentacles vary with different shades of yellow. While the sighting of this particular species is rare, it is usually mistaken for vegetation like the other species in genus Cassiopea.
The golden jellyfish is a subspecies of spotted jellyfish that inhabits Jellyfish Lake on Eil Malk island in Palau in the western Pacific Ocean. Like the nominate subspecies, it derives part of its nutrition from symbiotic algae (Zooxanthellae) that live in their tissues and part of their nutrition from captured zooplankton.
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