Chiropsella bronzie

Chiropsella bronzie is a species of box jellyfish that has a medusae form with a cubic bell and branching tentacles from each corner. This species belongs to the order Chirodropida, which can be distinguished from other box jellyfish by the presence of muscular masses on the medusae's four corners and saccules found in the gastrovascular cavity. The adult bell of the Chiropsella bronzie is small and rounded, and ranges from 3 to 5 cm in diameter,not exceeding 8 cm high and wide. The species was previously misidentified in 1880 as Chiropsalmus quadrigata, an Indian Ocean cubazoan of the same order. It was later correctly identified as a new species by Gershwin in 2006. The species name bronzie is named after the Royal Life Saving Society's bronze medallion award for a qualified Life Saver.

Each corner of the C. bronzie medusae holds up to 9 tentacles on each stalk, or pedalium. The venom contained in C. bronzie’s cnidocytes is much less potent than other cubozoans, and has shown to be harmless to humans with no past evidence of a lethal sting. Box jellyfish tend to move much faster than other jellyfish, with Chiropsella bronzie having a maximum speed of 7-8 cm per second against a 1 cm per second current.

Chiropsella bronzie and other box jellyfish have very developed eyes and sensory structures. Box jellyfish posses true eyes, which are found in clusters called rhopalia. The Chiropsella bronzie has 24 eyes and 4 morphologically different types on rhopalia, Two of these eyes are camera type eyes, which consist of one upper lens and one lower lens eyes, and two pigment slit eyes. However, similar to T. cystophora, Chriposella bronzie have shown to have weaker eyes than other cubazoa species due to weaker lenses to focus images on the retina. This is most likely due to eyes being ellipsoid in shape and very soft, unlike the spherical shape of other cubozoa that contain more sensory power. Research also suggests that C. bronzie are most likely color blind, a factor that does not inhibit obstacle avoidance. This variation in box jellyfish is expected due to the wide range of habitat cubozoa occupy, including sandy beaches, mangroves, kelp forests, the open ocean, and coal reefs. The complexity of box jellyfish eyes allows for more advanced swimming and navigational behavior, such as increased awareness of surroundings and directional swimming.

Description

Description/anatomy and appearance

-manubrium -size/length

Ecology

-age and growth/life cycle

-Additionally, the habitat of the polyps is unknown (Gordon et al. 2004) , suggests additional habitats to beaches such as mangroves

Behavior

-hunt using complex eyes rather than float like true jellyfish

-prey: -where they feed on shrimps (Acetes australis)

Distribution and Habitat

Cubozoan distribution is mainly restricted to Indo-Pacific regions, with C. bronzie specifically located in shallow waters near Queensland, Australia, specifically from Cooktown to Townsville Australia. These beach habitats contain mangrove trees, sandy beaches, and coral reefs. After heavy rainfalls, C. bronzie habitats include sunken natural debris, such as branches and large rocks, that jellyfish need to navigate.

Taxonomy

Classification:

Biota Animalia (Kingdom) Cnidaria (Phylum) Cubozoa (Class) Chirodropida (Order) Chiropsellidae (Family) Chiropsella (Genus) Chiropsella bronzie (Species)

-environment: marine

The order Chirodropida broken down in to three major families: Chirodropidae, Chiropsalmidae, and Chiropsellidae containing genuses Meteorona and Chiropsella. Out of all cubazoan relationships, research has shown that the Meteorona kishinouyei and Chiropsella bronzie are the closest relatives as they are the most phylogenically similar. Both species have similar morphological traits, such as an unbranched gastrovascular cavity saccule, whereas most other cubazoans' gastro cavity saccules are branched. Morphological traits used to distinguish the two species are differences in number of tentacles and pedalium shape.

A morphological exception that C. bronzie holds compared to other members of the order Chirodropida is the presence of gastric filaments in its stomach, where other members lack these structures. Because of this exception, there has been proposals of adjusting Chirodropida taxonomy and the potential addition of another family.

Sting and Toxocity

There has been no evidence that C. bronzie can deliver a lethal sting to a human. However, studies have shown that the venom of C. broznie has adversely affected the cardiovascular system of anesthetized rats in laboratory settings, by greatly lowering their heart rate. The venom of C. bronzie may be very similar to that of C. fleckeri, but potentially less potent. This could be confirmed by the fact C. bronzie are more abundant than C. fleckeri, but have no history to be the cause of human fatalities. A stronger venom would also allow C. bronzie to feed on fish, while their diet is limited to smaller prey, like shrimp. More research is need to increase understanding of just how harmful the venom of C. broznie can be to humans.