Pleurobrachia bachei
| Pleurobrachia bachei | |
|---|---|
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| Pleurobrachia bachei with its oral end down. | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Ctenophora |
| Class: | Tentaculata |
| Order: | Cydippida |
| Family: | Pleurobrachiidae |
| Genus: | Pleurobrachia |
| Species: | P. bachei |
| Binomial name | |
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Pleurobrachia bachei A. Agassiz, 1860 |
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Pleurobrachia bachei is a member of the phylum Ctenophora and is commonly referred to as a sea gooseberry. These comb jellies are often mistaken for medusoid Cnidaria, but are not dangerous to handle.
Traditionally, Ctenophora has been thought to represent an ancient metazoan phylum. Recent genetic data suggests that all extant Ctenophora taxa may have evolved from a relatively recent common ancestor and that this ancestral ctenophore was tentaculate and cydippid-like. Because of the virtual absence of ctenophores in the fossil record, their evolutionary history holds many more questions than answers.
An individual sea gooseberry's body length can reach up to 20 mm (0.79 in) with each of the two tentacles stretching 150 mm (5.9 in). Their gelatinous globular bodies are composed of 99% water. They have eight rows of well-developed comb plates consisting of thousands of fused macrocilia controlled by an apical organ. Unlike most other ctenophores, Pleurobrachia lacks a conventional photoprotein and is therefore incapable of producing light. Their bodies are virtually transparent and the many cilia refract the light, producing rainbow-like colors that can give the false appearance of bioluminescence. The branched tentacles can be white, yellow, pink or orange. They have no (stinging cells). Instead, the two long extensile branched tentacles are armed with colloblasts: specialized adhesive cells with which to ensnare their prey.
The sea gooseberry is only alive for around 4–6 months.
Pleurobrachia lack any sessile (attached) stages and are wholly planktonic in their life cycle. They are self-fertile hermaphrodites that spawn eggs and sperm freely into the sea, and develop thereafter without any parental protection with direct development.
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Wikipedia