Trivia question for Sep-18-2011

Olivia chose these guys because they come in so many shapes and colors.  She was also amazed to see how they are only found on the eastern side of the America’s.  There are some 1,500 species of these invertebrates living today, and they are largely found in deep waters more than 1,650 feet down.

The mouth is rimmed with five jaws, and serves as an anus (egestion) as well as a mouth (ingestion). Behind the jaws is a short esophagus and a large, blind stomach cavity which occupies much of the dorsal half of the disk. Ophiuroids have neither a head nor an anus. Digestion occurs within 10 pouches or infolds of the stomach, which are essentially ceca, but unlike in sea stars, almost never extend into the arms.  They are generally sexually mature in 2 years, become full grown in 3 to 4 years, and live up to 5 years.

So here are Olivia’s questions:  Tell us what this invertebrate is and how they got their name?  Also, tell us how these guys are able to elude predators despite not having eyes?

Good Luck 😉

Answer:

Congratulations to Robert Fenton from Winter Park FL for being the first with the correct answer. The cool looking invertebrate we featured is the Common Brittle Star. Brittle stars or ophiuroids are echinoderms which are closely related to starfish. They crawl across the sea-floor using their flexible arms for locomotion. The ophiuroids generally have five long slender, whip-like arms which may reach up to 24 inches in length on the largest specimens. They are also known as serpent stars.

The name ‘brittle star’ refers to their easily-broken limbs, which can be regenerated.  Brittle stars compensate for a lack of eyes by relying on photosensitive nerves that guide them to crevices – essential for eluding predators.  Here is more on these elusive creatures: Common Brittle Star

Thanks for playing along 😉