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 "Cubomedusae", from Ernst Haeckel's Kunstformen der Natur, 1904
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Box jellyfish are invertebrates belonging to the class Cubozoa, named for their cube-shaped medusae. Cubozoans are categorized separately from other types of jellyfish and are considered more complex than Scyphozoans. Likewise, Chironex fleckeri (sometimes simply called "the Box Jellyfish"), the best-known species of box jellyfish, is only one of a category which actually contains about 19 different species. The name sea wasp is also applied to some species of Cubozoans, including the aforementioned Chironex fleckeri and Carybdea alata. Box jellies can be found in Australia, the Philippines, Hawaii1, Vietnam, and many other tropical areas. Box jellyfish are extremely venomous and can kill humans.
Box jellyfish are best known for the extremely powerful venom possessed by some of their species. The Chironex fleckeri and the Carukia barnesi (Irukandji) species are amongst the most venomous creatures in the world. Stings from such species are excruciatingly painful, either initially or as an after-effect, and are often fatal to their prey and sometimes even for humans. However not all species of Box Jellyfish are this dangerous to humans.2
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Defense and feeding mechanisms
Box jellyfish venom is the most deadly in the animal kingdom and has caused at least 5,567 recorded deaths since 1954.2 Most often, these fatal envenomations are perpetrated by the largest species of box jelly, Chironex fleckeri, owing to its high concentration of nematocysts, though at least two deaths in Australia have been attributed to the thumbnail-sized irukandji jellyfish (Carukia barnesi).3 Those who fall victim to Carukia barnesi suffer several severe symptoms known as Irukandji syndrome.4
The box jellyfish actively hunts its prey, rather than drifting as do true jellyfish. It is capable of achieving speeds of up to 3.5 knots (1.8 m/s).
The venom of cubozoans is very distinct from that of scyphozoans, and is used to catch prey (fish and small invertebrates) and for defense from predators. Sea turtles, however, are apparently unaffected by the sting and eat box jellies.
The highest risk period for the box jellyfish is between October to May, but stings and specimens have been reported all months of the year. Thus, it is possible to be stung any time of year. Similarly, the highest risk conditions are those with calm water and a light, onshore breeze; however, stings and specimens have been reported in all conditions. Thus, it is possible to be stung in any conditions.
Box jellyfish are abundant in the warm waters of northern Australia. However, the swarms generally disappear during the Australian winter (though occasional individuals are found throughout the year). Australian researchers using ultrasonic tagging reported that these creatures sleep on the ocean floor between 3 pm and dawn; it was believed that they sleep to conserve energy and to avoid predators. However, this 'sleep' hypothesis was challenged by many other researchers, and analysis of sting patterns demonstrated that a reasonably high proportion of fatal and non-fatal stings occur within this time period. Furthermore, the small sample size in the "sleep experiment" (i.e., 1 of 3 total tested actually 'slept'), combined with the unusual feature of a large, metal sensor potentially weighting down the animals, lead researchers to discount the hypothesis of sleep.
Vision
The box jellyfish is the only jellyfish with an active visual system. It possesses four sets of eyes, in clusters known as "rhopalia", one centered on each of the four lateral faces of its bell.
Each cluster consists of six eyes: Four simple photoreceptors capable of distinguishing light from dark, and two more sophisticated "camera eyes"--an "upper" and a "lower"--both comprising a cornea, lens and retina. The lower camera eye also possesses a mobile iris, which expands and contracts in response to light.
Structural analysis of this camera eye reveals a spherical lens capable of forming a near-perfect, almost distortion-free image. Despite this, box jellyfish are curiously farsighted because the focal length of this lens is longer than the distance between the lens and retina, producing a blurred image5.
It is not currently known how this visual information is processed by Cubozoa, as they lack a central nervous system, although they seem to have four brain-like organs.6 Some scientists have proposed that jellies have a “nerve net” that would allow the processing of visual cues.
Treatment of stings
First aid
If swimming at a beach where box jellyfish are known to be present, a bottle of vinegar is an extremely useful addition to the first aid kit. Following a sting, vinegar should be applied for a minimum of 30 seconds. A box jellyfish sting can kill a human.7 Acetic acid, found in vinegar, disables the box jelly's nematocysts that have not yet discharged into the bloodstream (though it will not alleviate the pain). Vinegar may also be applied to adherent tentacles, which should then be removed immediately; this should be done with the use of a towel or glove to avoid bringing the tentacles into further contact with the skin. These tentacles will still sting if separate from the bell, or if the creature is dead. Removing the tentacles without first applying vinegar may cause unfired nematocysts to come into contact with the skin and fire, resulting in a greater degree of envenomation. If no vinegar is available, a heat pack has been proven for moderate pain relief.8 However, careful removal of the tentacles by hand is recommended.9 Vinegar has helped save dozens of lives on Australian beaches. Although commonly recommended in folklore and even some papers on sting treatment,10 there is no scientific evidence that urine, ammonia, meat tenderizer, sodium bicarbonate, boric acid, lemon juice, freshwater, steroid cream, alcohol, cold packs or papaya will disable further stinging, and these substances may even hasten the release of venom.11 Pressure immobilization bandages, methylated spirits, or vodka should never be used for jelly stings.9121314 Often in severe Chironex fleckeri stings cardiac arrest occurs quickly, so Cardiopulmonary resuscitation (CPR) can be life saving and takes priority over all other treatment options (including application of vinegar). Activate the emergency medical system for immediate transport to the hospital.
Classification
There are two orders of Cubozoans, Chirodropida and Carybdeida (previously recognised as families Chirodropidae and Carybdaidae), containing at least 30 species between them. Box Jellyfish of the Chirodropida, which contains the Chironex fleckeri species, are distinguished by being generally larger than those of Carybdeida and having numerous tentacles trailing from the corners of their bells. Carybdeida, which contains the Irukandji species, are smaller, and only have a single tentacle trailing from each corner of their bells. A phylogenic analysis of the relationships between these two families is yet to be published.
- Phylum [1]Cnidaria
- Order Chirodropida
- Chironex fleckeri
- Chiropsoides buitendijki
- Chiropsoides quadrigatus (previously in the genus Chiropsalmus)
- Chirodropus gorilla
- Chirodropus palmatus
- Chiropsalmus quadrumanus
- Chiropsalmus zygonema
- Chiropsalmus alipes
- Chiropsella bronzie
- Chiropsella bart
- Chirodectes maculatus
- Order Carybdeida
- Carukia barnesi
- Carukia shinju
- Manokia stiasnyi
- Tripedalia binata
- Tripedalia cystophora
- Tamoya haplonema
- Tamoya gargantua
- Carybdea alata (= species complex, now the genus Alatina)
- Carybdea xaymacana
- Carybdea sivicksi
- Carybdea rastonii
- Carybdea marsupialis
- Carybdea aurifera
- Malo maxima
- Malo kingi
- Gerongia rifkinae
- Alatina mordens
- Alatina rainensis
- Alatina moseri
- Alatina alata
- and others in the genus Alatina, of uncertain status
Footnotes
- ^ Jellyfish Predictions Waikiki, Hawai'i
- ^ a b Williamson JA, Fenner P J, Burnett JW, Rifkin J., ed. (1996). Venomous and poisonous marine animals: a medical and biological handbook, Surf Life Saving Australia and University of New South Wales Press Ltd. ISBN 0-86840-279-6.
- ^ Fenner P, Hadok J (2002). "Fatal envenomation by jellyfish causing Irukandji syndrome". Med J Aust 177 (7): 362–3. PMID 12358578, http://mja.com.au/public/issues/177_07_071002/fen10297_fm.pdf.
- ^ Little M, Mulcahy R (1998). "A year's experience of Irukandji envenomation in far north Queensland". Med J Aust 169 (11-12): 638–41. PMID 9887916, https://www.mja.com.au/public/issues/xmas98/little/little.html.
- ^ "Pharyngula: Jellyfish eyes".
- ^ Nilsson, D. E., et al. (2005). "Advanced optics in a jellyfish eye". Nature 435 (May 12): 201–205. doi:.
- ^ Fenner P, Williamson J, Blenkin J (1989). "Successful use of Chironex antivenom by members of the Queensland Ambulance Transport Brigade". Med J Aust 151 (11-12): 708–10. PMID 2574410.
- ^ Taylor, G. (2000). "Are some jellyfish toxins heat labile?". South Pacific Underwater Medicdfl;ghksdpohkr]ytrjudgiine Society journal 30 (2). ISSN 0813-1988. OCLC 16986801, http://archive.rubicon-foundation.org/5843. Retrieved on 16 June 2008.
- ^ a b Hartwick R, Callanan V, Williamson J (1980). "Disarming the box-jellyfish: nematocyst inhibition in Chironex fleckeri". Med J Aust 1 (1): 15–20. PMID 6102347.
- ^ Zoltan T, Taylor K, Achar S (2005). "Health issues for surfers". Am Fam Physician 71 (12): 2313–7. PMID 15999868.
- ^ Fenner P (2000). "Marine envenomation: An update - A presentation on the current status of marine envenomation first aid and medical treatments". Emerg Med Australas 12 (4): 295–302. doi:.
- ^ Seymour J, Carrette T, Cullen P, Little M, Mulcahy R, Pereira P (2002). "The use of pressure immobilization bandages in the first aid management of cubozoan envenomings". Toxicon 40 (10): 1503–5. doi:. PMID 12368122.
- ^ Little M (June 2002). "Is there a role for the use of pressure immobilization bandages in the treatment of jellyfish envenomation in Australia?". Emerg Med (Fremantle) 14 (2): 171–4. PMID 12164167.
- ^ Pereira PL, Carrette T, Cullen P, Mulcahy RF, Little M, Seymour J (2000). "Pressure immobilisation bandages in first-aid treatment of jellyfish envenomation: current recommendations reconsidered". Med. J. Aust. 173 (11-12): 650–2. PMID 11379519, http://www.mja.com.au/public/issues/173_11_041200/pereira/pereira.html.
References
Gershwin, L. 2005a. Taxonomy and phylogeny of Australian Cubozoa. PhD, School of Marine Biology and Aquaculture, James Cook University, Townsville, Queensland.
Gershwin, L. 2005b. Two new species of jellyfishes (Cnidaria: Cubozoa: Carybdeida) from tropical Western Australia, presumed to cause Irukandji Syndrome. Zootaxa 1084: 1–30.
Gershwin, L. 2005c. Carybdea alata auct. and Manokia stiasnyi, reclassification to a new family with description of a new genus and two new species. Memoirs of the Queensland Museum 51(2): 501–523.
Gershwin, L. 2006a. Comments on Chiropsalmus (Cnidaria: Cubozoa: Chirodropida): a preliminary revision of the Chiropsalmidae, with descriptions of two new species. Zootaxa 1231: 1–42.
Gershwin, L. 2006b. Nematocysts of the Cubozoa. Zootaxa 1232: 1–57.
Gershwin, L. 2007. Malo kingi: A new species of Irukandji jellyfish (Cnidaria: Cubozoa: Carybdeida), possibly lethal to humans. Zootaxa 1659: 55–68.
Gershwin, L. & Alderslade, P. 2006. Chiropsella bart, n. sp., a new box jellyfish (Cnidaria: Cubozoa: Chirodropida) from the Northern Territory, Australia. The Beagle 22: 15–21.
External links
- Cubozoa classification
- ThinkQuest: Box jellyfish, Boxfish, Deadly sea wasp
- Box Jelly Fish, dangers on the great barrier reef
- Jellyfish eyes
- Jellyfish Predictions Waikiki, Hawai'i
Wikipedia content modification information:
- This page was last modified on 3 December 2008, at 00:16.
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