39 or 3+9

On the way to work this morning, the outdoor thermometer in our car registered 39°F in the town of Bodega — a chilly temperature for August!

At work, a friend asked me about whether I'd ever seen juvenile Gumboot Chitons (Cryptochiton stelleri).  I have a few photos of them, and since many people have only seen the larger adults, I decided it would be fun to share a couple of photos of juveniles.

Here's a small Gumboot Chiton from Bodega Head that was ~10-12 mm long (it's in a mussel shell).

 

Note that at this size, you can see a hint of the white plates exposed along the back.  (This isn't true for adults, as you'll see below).  The juveniles I've found are also paler in color than the adults.

Here's a different juvenile photographed under a microscope.  Check out the clusters (or fascicles) of spines.

 

Now here's a reminder about what the adults look like.  You may have encountered them in intertidal boulder fields.  Sometimes they look like big red blobs among the algae.  The first image was taken near Mendocino, the second along the Big Sur coast.

 

 

The outer covering is relatively soft and leathery.  As adults, their eight plates are hidden (hence the "Crypto" part of their name).  

Gumboot Chitons can reach lengths up to 12 inches.  See below for scale.  (Eric's boot is conveniently ~12 inches long!)

 

You might be wondering about the title of this post.  I know this is a S-T-R-E-T-C-H, but it's the first title that came to me.  39 degrees (an impressive summer temperature) and 3+9 = 12 inches (an impressive length for a chiton, but fun to see what they look like at 12 mm!).