Carboniferous Marine Life

[Jennifer_P]

I was learning about blastoids in my lab today, and guess what! Their heyday was the Carboniferous--the Mississippian Carboniferous to be precise. So I figured I'd record what I'd learned in case some day I end up adding a marine section to this Age. Which will probably be a long time from now, since I'd have to get the land foliage near perfect first, plus I really couldn't live without animations and real water if I was going to do a seascape. Perhaps some kind of glass tunnel you could walk through would be best...hm. The crinoid arms that look like chicken feet might make a good puzzle, if I drew them in as the feet of a chicken like animal and then for some reason made the player figure out that the picture was deceptive, by studying the real live crinoids.

It was a good time to be an echinoderm (starfish, sand dollars, sea urchins, crinoids, blastoids and friends) in the Carboniferous. In particular, it was a good time to be a crinoid or blastoid, the two major groups at that time. If you've ever wondered (maybe even right now!) what a crinoid or a blastoid is, then this is your lucky day!
Crinoids: Imagine flipping a starfish upside down and mounting it on a stick. You've pretty much got a crinoid, in terms of body plan. They grab food out of the water flowing by with their little suctiony feet (which starfish use to walk on) and then carry it down to their mouth in the center of the arms. Crinoids could get pretty tall back in the day, over a meter at least. Now their arms weren't a meter long--they were pretty short, actually. What gave them their height was their tall column (the stick). In terms of their arms, they had many different variations: some of them looked like branching chicken feet, others like a cluster of feather pens. I can't think of a way to describe the other forms. Modern crinoids go by the name of sea lilies, but they've lost that cool stalk-like column that they once used to raise themselves off the sea floor. On the plus side, they're mobile.
Blastoids: Since these guys evolved from crinoids, they share a lot of the same body plan. Blastoids just are what you'd get if you stuck a bud on a stick. They had smaller, more delicate filtering strands that came out of their body instead of arms. Blastoids have an awesome name.

Now the crinoids and blastoids ruled the sea with a fist of calcite. There are crinoidal limestones which are made up mostly of crinoids! There were meadows full of crinoids and blastoids, and the "foliage" was tiered as jungles are. Bryozoans, which are coral-looking organisms (actually they're more closely related to brachiopods), shared space with them. These guys didn't like rough tidal areas, nopesireepop. They liked gentle waters, particularly the mud-bottomed lagoons and the sorts of shallow seas that were common in the Carboniferous.