Creature Feature: Brittle Star.

Echinoderms are darn strange compared to what we usually think of as animals. They have pentaradial  symmetry (that is, the creature is split into 5 even sides instead of two), mouths on the bottom of their bodies, no real cephalization to speak of, and have "tentacle rape" written all over them. Or "Facehugger," take your pick.

In conclusion: This blog needs more starfish, dammit!


(Yes, they can be legally kept as pets.)

That's a rather strange starfish, no? Brittle stars (Ophiuroidea) do not look like Patrick or any other friendly starfish you can name. With their spindly legs, quick movements, and bands, they almost look more like five snakes joined at the cloaca (those stars above have "serpent" in their name, for example). They are found everywhere in the ocean, from reefs to the deepsea abyss. A few even live in brackish water. Some of the abyssal ones glow in the dark!

No two are exactly alike!

 

Brittle stars are so named because their arms are, well...brittle. Unlike more fleshy starfish, the arms of brittle stars are covered in segmented armor. These arms have no tube feet, and can break off easily to allow the star to escape.

These starfish are the unholy eldritch lords of regeneration. Starfish, as a general rule, can regenerate their limbs. Brittle stars are the masters of this, being able to regenerate segment-by-segment unless all arms are lost. A certain group of brittle stars called Amphiuridae can regenerate sexual organs and innards. Some can even perform binary fission with little harm. In other words, brittle stars make themselves very hard to kill.

MWAHAHA, they're gonna take over the world!

Fun fact: Although brittle stars are not toxic, they are among the few animals that humans have not yet found a way to eat. Trust us, the list is very small.

Creature Feature: Purple and Orange Starfish.

Y'know what? This entry does not need a fancy intro. There have been so many people asking what the hell this starfish is, or if it is even real, that mere confirmation of its status as a real animal merits a blog entry. After all, who would believe that an animal could naturally be orange and purple?

Well, this one is. The purple and orange starfish's scientific name is Astropecten articulatus- no reference to its bizarre coloration at all. It is also called the royal starfish, which is likely a reference to purple being a regal color. It is fairly common along the southeastern U.S. coast and, like all starfish, is predatory.

That is really all that is special about this particular starfish. Oh, wait...starfish are pretty darn weird anyways. No, we are not talking about Patrick's desire to taste the rainbow.

There's nothing REMOTELY suspect about this image. Nope.

On an embryonic level, starfish are much closer to us than most other invertebrates. They are deuterosomes; that is, the first opening of a baby starfish and a baby vertebrate becomes the anus, whereas in most others it becomes the mouth. We both start life wanting to crap before eating; lovely.

Starfish, like all echindoderms, exhibit pentaradial symmetry- that is, their body is divided into five fairly-even chunks instead of two. There are a few starfish species that break this rule, but otherwise, it's solid. It is safe to say that everything one arm has, the others usually do as well. Yes, this includes starfish junk and eyes.

The appendages are lined with tube feet on the bottom, allowing the starfish to move about and pry open bivalves. They are also part of the starfish's hydraulic circulatory system; basically, starfish use a dot in the center of themselves called a madreporite to gather the water that they use for moving, respiration and digestion.

The mouth is in the center of those arms. Starfish wrap themselves around potential prey and work from there, usually extending their own stomachs outwards towards their food. One of the few notable things about the royal starfish besides it wacky colors is that it, unlike other starfish, swallows its food whole; the food is already slightly digested by the time that it gets to the starfish's stomach. Oh, and it's purple, but haven't we covered that enough already?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

No. No, we have not.

For a starfish, this colorful specimen is hardly weird. That is not saying much; starfish are pretty weird themselves.

Tomorrow: An animal so intense that it merits its own energy drink...or at least a Powerthirst reference. For some reason, the most fearless animal in nature has neither.

Also, lots of pics came from this awesome page. Thanks SO much for being an informative source as opposed to "OMG A PURPLE AND ORANGE STARFISH!"