Loreto Diving - Sea Stars & Urchins

I finally finished going through several thousand diving photos from our recent trip to Baja. Only a small fraction are any good; that's the nature of (my) underwater photos. It took me even longer than usual because I was posting many of them on iNaturalist, which means I was trying to identify the species. The amount and variety of life on a good dive is a bit overwhelming, which makes it hard to know where to start with taking photos. My first mini-project was to get photos of the common sea stars (aka starfish). There are a lot more kinds, but these are the ones you're likely to see. 

The most common are the Panamic Cushion Stars:

At one point our dive master called us over to look at something. It was one of these common cushion stars and I could not figure out why he was pointing it out. He was holding his hand out with the fingers spread out, but what did that mean? Finally I realized it had six legs instead of the usual five. Perhaps it had been damaged and regrown two legs in place of one?

A less common cushion star is the Chocolate Chip Sea Star:

Then there are ones with skinnier arms:

Crown of Thorns feeds on coral, and in large numbers they can threaten coral reefs (as they did on the Great Barrier Reef). But there isn't a lot of hard coral around Loreto and (therefore?) not a lot of these. Like brittle and basket stars, they have more legs and lack the five way symmetry of most star fish. Their spines are sharp and venomous. Generally, "look but don't touch" is good idea in diving.

Sea urchins are related to sea stars and have the same five way symmetry, although often the symmetry is more visible in the shells than when they're alive. (like the Sand Dollars we have further north) Urchins are primarily herbivores whereas sea stars are mostly carnivores.

Flower Urchins are fairly common. They cover themselves with rocks and shells, possibly for camouflage or protection. Another theory is that it serves as "ballast" to stop them getting moved by waves. They are also venomous.

Sea Eggs are another common kind of urchin. They are often quite large, roughly 6 inches in diameter.

Slate Pencil Urchins are usually hiding in holes in the rocks, like this one. They are a more "primitive" urchin in the sense that they evolved earlier.

There are other fairly common kinds of sea urchins but for some reason I didn't take any photos of them this trip. I also saw a few brittle stars but they were always mostly hidden so I couldn't get a decent photo.