''Sanderia malayensis'' is a

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

jellyfish Jellyfish and sea jellies are the informal common names given to the medusa-phase of certain gelatinous members of the subphylum Medusozoa, a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animals with umbrella- ...

in the family

Pelagiidae The Pelagiidae are a family of jellyfish. Members of the family ''Pelagiidae'' have no ring canal, and the marginal tentacles arise from umbrella margin. Genera There are four genera currently recognized: *Genus ''Chrysaora'' – (14 species) *G ...

, native to the tropical

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

. It has a complex

life cycle Life cycle, life-cycle, or lifecycle may refer to: Science and academia * Biological life cycle, the sequence of life stages that an organism undergoes from birth to reproduction ending with the production of the offspring * Life-cycle hypothesi ...

and is thought to be

venom Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a ...

ous and to have caused injuries to humans.

Description

The medusa phase of ''S. malayensis'' is distinguished from other related species by having 32 marginal lappets at the edge of the transparent bell, and 16

tentacle In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work main ...

s alternating with 16

rhopalia Rhopalia (singular: rhopalium) are small sensory structures of certain Scyphozoan (true jellyfish) and Cubozoan (box jellyfish) species. Description The structures typically occur in multiples of four, are bell shaped and face outward from invag ...

. The edge of the bell has a short vertical "skirt", about as wide as one sixth of the bell. The stomach has four heart-shaped radial pouches each edged with up to 40 finger-like gonadal papillae. The bell is topped by a number of warts laden with nematocytes. This jellyfish is transparent, and may be yellowish or tinged violet. Sometimes there are radiating rows of reddish spots on the bell or on the mouth-arms. The diameter of the bell can be as large as , but a more normal size is . The marginal tentacles can be long with the frilled mouth-arms being long.

Distribution

The species is native to the tropical Indo-Pacific region. Its range includes the

Red Sea The Red Sea ( ar, البحر الأحمر - بحر القلزم, translit=Modern: al-Baḥr al-ʾAḥmar, Medieval: Baḥr al-Qulzum; or ; Coptic: ⲫⲓⲟⲙ ⲛ̀ϩⲁϩ ''Phiom Enhah'' or ⲫⲓⲟⲙ ⲛ̀ϣⲁⲣⲓ ''Phiom ǹšari''; ...

and Suez Canal, Pakistan, Malaysia, the Philippines and Japan.

Life cycle

''Sanderia malayensis'' has a complex life cycle with a number of types of asexual reproduction. New polyps can bud off existing polyps, with a moveable

stolon In biology, stolons (from Latin '' stolō'', genitive ''stolōnis'' – "branch"), also known as runners, are horizontal connections between organisms. They may be part of the organism, or of its skeleton; typically, animal stolons are external ...

developing at the same time on the opposite side of the mother polyp. These stolons may develop a knobbed end, curl up and attach themselves to the substrate, before detaching from the mother polyp and developing into a new polyp.

Strobilation Strobilisation or transverse fission is a form of asexual reproduction consisting of the spontaneous transverse segmentation of the body. It is observed in certain cnidarians and helminths. This mode of reproduction is characterized by high offspr ...

of the polyp may occur with ephyrae being formed which separate from the mother polyp. Sexual reproduction can also occur with eggs being liberated into the sea by the adult medusa. When fertilised, these develop into a free-living

planula A planula is the free-swimming, flattened, ciliated, bilaterally symmetric larval form of various cnidarian species and also in some species of Ctenophores. Some groups of Nemerteans also produce larvae that are very similar to the planula, whi ...

, then to a scyphistoma, to a strobila, and lastly to a free-living young medusa.

Venom

''S. malayensis'' is believed to be a

ous species of jellyfish with reports stating that it causes injury to humans. One report from the

Persian Gulf The Persian Gulf ( fa, خلیج فارس, translit=xalij-e fârs, lit=Gulf of Fars, ), sometimes called the ( ar, اَلْخَلِيْجُ ٱلْعَرَبِيُّ, Al-Khalīj al-ˁArabī), is a mediterranean sea in Western Asia. The bo ...

near Kuwait stated that it caused severe stings with

necrosis Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. Necrosis is caused by factors external to the cell or tissue, such as infection, or trauma which result in the unregulated dig ...

of the skin. Other reports describe it as causing "peripheral vasospasm" and "peripheral tissue necrosis", and some describe it as being moderately to severely potent. The venom has been little studied. In 2020, a proteomic study identified 51 putative toxins form the venom of ''S. malayensis'' which dominated by the hemostasis-impairing toxins and proteases toxins ''.'' First aid treatment includes removing any still-adhering tissue; this is of a very glutinous nature indicating that the nematocytes are continuing to discharge.

References

{{Taxonbar , from = Q3385945 Pelagiidae Fauna of the Indian Ocean Fauna of the Pacific Ocean Animals described in 1886