Skeleton Shrimp, Feather Duster Worm, and 18-scaled worm

There are two skeleton shrimp on top of the piece of kelp in the center of the container in this video. The one to the left is carrying many, many juvenile skeleton shrimp on its body while the one above seems to check on the other. Perhaps a pair? Or a curious neighbor? There is something curiously cute about these skeleton shrimp and their mannerism.

To the left you can see a feather duster worm and maybe a nereid worm?
 

 This is an 18-scale worm upside down, followed by a video of it right side up revealing its scales. It's "feet" are broom-like. It must be used for filtering or some other purpose.

 

 This is the feather duster worm's radioles? radioli?

 

Revisiting Creek & Vernal Pool Collections

Since our visits to the creek and the duck-weed pond late last year, I've kept a container of the water with some of the aquatic plants in it as a sort of aquarium with whatever creatures are living in it. I covered the containers and left them outside for about 2 months. 

Additionally, I collected a handful of dry vernal pool soil and added dechloronated water to it to see what might appear. This is our third dry year of drought in California and it makes me wonder what can survive these conditions and how. 

A couple nights ago, I brought these samples in and spent several hours looking at them under a microscope. Here is a video of the creatures I found in the drops of water and bottom debris on a standard size glass slide. You can see them with the naked eye and, for the record, none of the creatures I've been able to identify, including the flatworm, are parastic. I have, however, seen leeches in the creek so that's not to say there isn't anything parasitic there. 

Here's a closer look:

Clam Shrimp (conchostraca)

Unidentified hairy sac
The similarity in shape makes me wonder if it isn't a molt or an egg casing of the clam shrimp

Aelosoma

 

Cyclopoid Copepod

This is hardly visible, but it is a clear worm - unidentified

This creature, a gastrotrich, was found in the vernal pool soil that I added water to. According to Encyclopedia Britannica, gastrotrich lay "opsiblastic" eggs, which remain inactive for long periods and can survive dry and freezing conditions. Certainly explains things doesn't it?

gastrotrich

Here is a video showing the movement of these creatures - some are squinchy, some are frenzied, some are seeking - all very interesting and unique. A whole world we obliviously step right through on our hikes!

Thornback Ray on a Zero Tide

The warm weather and low tide brought us back to the beach today. It was a zero tide, which, a tide-pool docent explained is calculated as the point between the highest and lowest tides of the year. This zero tide brought us a very rare treat - a Thornback Ray. 

 According to an article on California Diving News, "the thornback's genus name, Platyrhinoidis, comes from the Greek platys, meaning broad, and rhinos, meaning snout. The species name, triseriata, is Latin for three rows and refers to the parallel rows of "thorns" that run from the middle of the creature's back to just before its tail."

Here's an unanswered question: What causes these sand pile holes? My guess is some kind of worm. I've observed them as they are made, but the animal can not be seen. I have also tried to dig up the hole to find the creature, and it evades me. I have read that lug worms create a crater with a hole in it, but this is a pile with a hole in it. Maybe a similar species?

You can just catch a glimpse of one of the holes being cleared out in this video

Marine Invertebrates in Kelp Holdfasts

Holdfast of Giant Kelp (Macrocystis Pyrifera)

Growth pattern of Giant Kelp (Macrocystis Pyrifera)

Brooding Sea Anemone (Epiactis Prolifera) it's spitting something out

Unidentified Crab Megalops Larvae

California Sea Hare (Aplysia Californica)

Striped Sea Hare (Navanax inermis)

Sandcastle Worm? (phragmatopoma californica)

Unidentified - egg sac?

Peanut Worm? (Sipuncula)

Eighteen Scaled Worm? (Halosydna brevisetosa) you can also see the 'foot' of the mussel sticking out

Purple Star (Pisaster Ochraceus)

Ghost Shrimp?

Larval Octopus (look close you can see it's suckers)

Purple Sea Star and Unidentified Brittle Star

western spiny brittle star (ophiothrix spiculata) - September 5, 2013
"ophio" meaning snake or serpent, "thrix" meaning hair, and "spicula" meaning needle. These stars can be found entangled in the washed up holdfasts of the majestic Giant Kelp (macrocystis pyrifera). We have observed it "milk" a whitish substance once and this time one of the stars released an orange colored cloudy substance; eggs?

Here are its spines under the microscope... amazing.