Carybdea marsupialis

Carybdea marsupialis
File:Carybdea marsupialis.jpg
Scientific classification
Kingdom:	Animalia
Phylum:	Cnidaria
Class:	Cubozoa
Order:	Carybdeida
Family:	Carybdeidae
Genus:	Carybdea
Species:	C. marsupialis
Binomial name
Carybdea marsupialis (Linnaeus, 1758)

File:Carybdea marsupialis draw.jpg

C. marsupialis

Carybdea marsupialis, the sea wasp, is a mildly venomous species of cnidarian, in the small family Carybdeidae within the class Cubozoa.

Description

Carybdea marsupialis is a small transparent jellyfish with a box-shaped bell about 3 cm (1 in) across, at the four lower corners of which are four elongated tentacles up to 30 cm (12 in) long. The bell has a number of small white or yellowish warts with stinging cells, and near the margin, equidistant from the tentacles, are four rhopalia (sensory structures with ocelli). This species can be distinguished from other similar species by the red banding on the tentacles.

Distribution

C. marsupialis is found in the tropical and subtropical waters of the eastern Indo-Pacific, its range including southeastern Asia, Japan, the Philippines, Australia and Polynesia. It is also known from the northern Pacific Ocean, off California and the northern Atlantic Ocean. It was first detected in the Mediterranean Sea and Adriatic Sea in 1957. It is pelagic and is present in the upper few metres of the sea.

Biology

File:Medusae of world-vol03 pl58.jpg

C. marsupialis, illustration from Medusae of the World, vol. 3, by A.G. Mayer

Carybdea marsupialis is a predator and feeds on invertebrates and even small fish which it captures with the nematocysts (stinging cells) in its tentacles, often in shallow waters. It swims by making rapid contractions of the bell and can move at a speed of between 3 to 6 m (10 to 20 ft) per minute. Like other species in its genus it has comparatively sophisticated eyes with lenses. With their help it can detect obstacles such as posts or a ship's rudder and avoid them. It often occurs in small groups. The sting is mildly venomous to humans but some swimmers do not notice any painful sensation.

The life history of this box jellyfish is complex. The sexes are separate and sexual reproduction takes place with the emission of gametes into the open water. After fertilisation, a planula larva forms which later develops into a cubopolyp with a few tentacles. This can reproduce asexually by budding, the buds soon becoming detached. At first they creep across the substrate with the tentacular region leading. During this mobile stage, pieces may become detached or the cubopolyp may split transversely; these fragments regenerate their missing parts within 72 hours. The resulting polyps then attach themselves to the substrate and grow a full complement of 24 tentacles. About a month later they become detached, the multiple tentacles are reabsorbed and the four tentacles typical of the medusa phase develop.