Box jellyfish

Box jellyfish, named for their vaguely cube-shaped medusae, are a class of invertebrates belonging to the phylum cnidaria ("box jellyfish" is a common name for the notoriously dangerous Chironex fleckeri). Box jellyfish are known for the extremely potent venom produced by some species. Along with Chironex fleckeri, Carukia barnesi and Malo kingi are among the most venomous creatures in the world. Stings from these species are often fatal to prey animals, and extremely painful, but only occasionally fatal to humans.

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· 1 Nomenclature

· 2 Anatomy

· 3 Range

· 4 Defense and feeding mechanisms

· 5 Taxonomy

· 6 Treatment of stings

· 7 References

· 8 Bibliography

· 9 External links

Nomenclature

The ambiguous but commonly used terms "sea wasp," and "marine stinger" are somtimes applied to Cubozoans.

Anatomy

"Cubomedusae", from Ernst Haeckel's Kunstformen der Natur, 1904

Box jellyfish most visibly differ from the "true" or Scyphozoan jellyfish in that their umbrellas are cubic, rather than domed or crown-shaped. The underside of the umbrella includes a flap, or velum, concentrating and increasing the flow of water expelled from the umbrella. As a result, box jellyfish can move more rapidly than other jellyfish, with speeds of up to six metres per minute having been recorded.^[1]

Their nervous system is also more developed than that of many other jellyfish. Notably, they possess a nerve ring around the base of the umbrella that coordinates their pulsing movements; a feature found elsewhere only in the crown jellyfish. Whereas some other jellyfish do have simple pigment-cup ocelli, box jellyfish are unique in the possession of true eyes, complete with retinas, corneas and lenses. These enable them to see specific points of light, as opposed to simply distinguishing between light and dark.

Range

Various types of box jellies can be found in northern Australia, the Philippines, Indonesia, Hawaii,^[2] Vietnam, the Caribbean, and other tropical areas.

Defense and feeding mechanisms

Jellyfish/stinger net enclosure at Ellis Beach, Queensland

Box jellyfish venom is the deadliest in the animal kingdom^[^{citation needed}^] and has caused hundreds of recorded deaths since 1954^[^{citation needed}^]. Each tentacle has about 500,000 cnidocytes, harpoon-shaped needles that inject venom into the victim.^[3] Most often, these fatal envenomations are perpetrated by the largest species of box jelly, Chironex fleckeri, owing to its high concentration of nematocysts, although at least two deaths in Australia have been attributed to the thumbnail-sized Carukia barnesi.^[4] Those who fall victim to C. barnesi suffer severe physical and psychological symptoms known as Irukandji syndrome.^[5] The box jellyfish actively hunts its prey, rather than drifting as do true jellyfish. It is capable of achieving speeds of up to 4 knots (1.8 m/s).^[^{citation needed}^]

Box jellyfish are known as the "suckerpunch" of the sea not only because their sting is rarely detected until the venom is injected, but also because they are almost transparent.

The venom of cubozoans is very distinct from that of scyphozoans, and is used to catch prey (fish and small invertebrates which includes shrimp and bait fish) and for defense from predators, which include the Butterfish, Batfish ^[^{disambiguation needed}^], Rabbitfish, crabs (Blue Swimmer Crab) and various species of turtles (Hawksbill turtle, Flatback turtle). Sea turtles, however, are apparently unaffected by the sting and eat box jellies.

In northern Australia, the highest risk period for the box jellyfish is between October and May, but stings and specimens have been reported all months of the 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.

Taxonomy

As of 2007, at least 36 species of box jellyfish were known, grouped into two orders and six families^[6]:

Class Cubozoa

· Order Carybdeida

o Family Alatinidae

o Family Carybdeidae

o Family Tamoyidae

o Family Tripedaliidae

· Order Chirodropida

o Family Chirodropidae

o Family Chiropsalmidae

Treatment of stings

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. Once a tentacle of the box jellyfish adheres to skin, it pumps nematocysts with venom into the skin, causing the sting and agonizing pain. Following a sting, vinegar should be applied for a minimum of 30 seconds, resulting in the removal of any unfired nematocysts. 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^[8]; 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 separated 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.

Although commonly recommended in folklore and even some papers on sting treatment,^[9] there is no scientific evidence that urine, ammonia, meat tenderizer, sodium bicarbonate, boric acid, lemon juice, freshwater, steroid cream, alcohol, cold packs, papaya, or hydrogen peroxide will disable further stinging, and these substances may even hasten the release of venom.^[10] Pressure immobilization bandages, methylated spirits, or vodka should never be used for jelly stings.^[8]^[11]^[12]^[13] 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.

References

1. ^ Barnes, Robert D. (1982). Invertebrate Zoology. Philadelphia, PA: Holt-Saunders International. pp. 139-149. ISBN 0-03-056747-5.

2. ^ Jellyfish Predictions Waikiki, Hawai'i

3. ^ 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 North Wales Press Ltd. ISBN 0-86840-279-6.

4. ^ 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.

5. ^ 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.

6. ^ Daly, Marymegan; et al. (2007). "The phylum Cnidaria: A review of phylogenetic patterns and diversity 300 years after Linnaeus". Zootaxa (1668): 127-182. http://www.mapress.com/zootaxa/2007f/zt01668p182.pdf.

7. ^ 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.

8. ^ ^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.

9. ^ Zoltan T, Taylor K, Achar S (2005). "Health issues for surfers". Am Fam Physician 71 (12): 2313–7. PMID 15999868.

10. ^ Fenner P (2000). "Marine envenomation: An update – A presentation on the current status of marine envenomation first aid and medical treatments". Emerg Med Australasia 12 (4): 295–302. doi:10.1046/j.1442-2026.2000.00151.x.

11. ^ 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:10.1016/S0041-0101(02)00152-6. PMID 12368122.

12. ^ 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.

13. ^ 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.

Bibliography

· Daly, Marymegan; et al. (2007). "The phylum Cnidaria: A review of phylogenetic patterns and diversity 300 years after Linnaeus". Zootaxa (1668): 127–182. http://www.mapress.com/zootaxa/2007f/zt01668p182.pdf.

· 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.