Which cnidarian class is the deadliest?
These, and even normally innocuous species, can be deadly in a massive dose or to a sensitive person, but the only cnidarians commonly fatal to humans are the cubomedusae, or box jellyfish.
What is the largest cnidarian?
The largest non-colonial cnidarian is the lion’s mane jellyfish. As mentioned above, the tentacles are thought to stretch more than 100 feet. The bell of this jellyfish can be over 8 feet across. Of colonial cnidarians, the longest is the giant siphonophore, which can grow to over 130 feet.
What is the only freshwater cnidarian?
Freshwater jellyfish, any medusa, or free-swimming form, of the genus Craspedacusta, class Hydrozoa (phylum Cnidaria). The Craspedacusta polyp is notable for its lack of tentacles. …
What are 5 examples of cnidarians?
- Anthozoa. Corals and sea anemones.
- Scyphozoa. Swimming Jellyfish.
- Staurozoa. Stalked Jellyfish.
- Cubozoa. Box jellyfish.
- Hydrozoa. Hydroids and siphonophores.
How are scyphozoans different from other cnidarians?
Scyphozoans include most of the jellyfish familiar to beach-goers; other similar organisms are classified in the Hydrozoa and Cubozoa, two other groups of cnidarians. True jellyfish are graceful, and sometimes deadly creatures. Their stings may cause skin rashes, muscle cramps, or even death.
Which is the most common muscle type in Cnidaria?
This variety is reflected in the large diversity of muscle organizations found in Cnidaria. Smooth epithelial muscle is thought to be the most common type, and is inferred to be the ancestral muscle type for Cnidaria, while striated muscle fibers and non-epithelial myocytes would have been convergently acquired within Cnidaria.
What kind of symmetry does a cnidarian have?
External Features Cnidarians exhibit primary radial symmetry. In the Hydrozoa and Scyphozoa all diameters are apolar (i.e. have like ends). Furthermore, any two diameters at right angles to each other are also alike, dividing the animal into symmetric halves. The Anthozoa are either biradial or bilateral.
How does the medusae develop in a cnidarian?
In most cnidarians where metagenesis is seen, the medusae (2n) or sexual individuals do not develop directly from the eggs but develop from the polyp (2n) by budding. The polyp form in Obelia develops asexually and it is diploid (2n) and does not contain sex organs. It represents the asexual generation.