Does anyone else look at this and think echinoderm version of a worm? 

 

 

Appears annelid to me, though most worms aren't spiny.

Echinoderms are more about "hard skin" than spines. Even some echinoderms have soft skin (ie) sea cucumber. Many have no spines at all (no less functional ones)

20 minutes ago, rangerx said:

Appears annelid to me, though most worms aren't spiny.

Echinoderms are more about "hard skin" than spines. Even some echinoderms have soft skin (ie) sea cucumber. Many have no spines at all (no less functional ones)

To me it looks like an echinoderm version of an annelid. Just stretch out a sea urchin vertically, spins, feet with little nippers, lots of waving tentacles. It was when life forms were just getting started and lots of things didn't really fit in today's shapes... Actually lots of annelids are spiny, mostly little tiny spines like glass shards. Most echinoderms are spiny, even sea stars most often have spines and the hooked feet and waving tentacles. I live near the beach, I've been collecting and keeping echinoderms for many years. The sea cucumbers are soft but some still have spines and they have the tube feet and tentacles...    

Agreed, we're not claiming it to be an echinoderm insomuch as observing similarities.  Echinoderms are radial skeletal, generally with five distinct interconnected segments whereas annelids are not. Sunflower stars may present with up to sixteen segments, while bat stars may present with six or seven.

Echinoderms vary broadly from each other. Some spawn into the water column, while others by asexual separation (or both).

The video didn't specify whether the spines were calcareous or chitinous, but it's known that some annelids have nacreous linings to the calcareous tubes they inhabit. Nacre is not exclusive to mollusks.

Also agreed, are the tubed feet which seem more common across the phylum than the hard skin does.
 

Edited December 17, 20178 yr by rangerx

Echinoderms can be thought of as non vertebrates with internal skeletons. Kind of an odd thing. I was thinking of it as radial but more like a sea cucumber in that respect. Interesting to think of in that time. Lots of odd things came and went in that time with no modern ties really...