Two different visitors

Last night there were two visitors waiting for us when we got home.  We walked into the kitchen and were a little surprised to look up at the ceiling to see one of these:

 

We moved this scorpion to an outdoor railing for a photo, and then released it onto a nearby log.  It quickly crawled underneath a loose piece of bark.

 

For more about California Forest Scorpions (Uroctonus mordax), see the post from 13 March 2012.

When photographing the scorpion, we also noticed this small, shiny, metallic beetle.  It was only ~7 mm long.

 

I wish I knew the identify of this beetle.  Here are two more views.  If you're familiar with it, let me know!

 

 

Mordax

Can you guess whose eyes these are?

Here's another clue: an impressive claw-like pedipalp.

And another (this one gives it away)...

This is the stinger of a California Forest Scorpion (Uroctonus mordax).  The sharp barb is called an aculeus. 

Here's a view from above:

Scorpions are chelicerates, a subphylum of arthropods that includes three classes — horseshoe crabs, arachnids (scorpions/spiders/ticks/mites) and sea spiders (more about them in future posts!).

They all have three basic types of appendages: the first pair are called chelicerae — small appendages near the mouth that are used for holding and tearing.  The second pair are the pedipalps (greatly enlarged in scorpions).  And then come 4 pairs of walking legs.

If you zoom in to the front of scorpion's carapace, you can see the distinctive chelicerae.  There are two of them, like miniature claws, lined with triangular teeth.  Scorpions lack mandibles, so they tear their food with the chelicerae before ingesting it.

We've encountered these scorpions under logs in the woods (and under doormats and plant pots) in Sebastopol.  They're about 4 cm long.  

I've been trying to find out the derivation of the scientific name.  Mordax apparently means to bite or sting.  Uroctonus has been more challenging to track down.  "Uro" might mean tail, and "ctonus" might mean murderer.  So all together, perhaps this is the Stinger that Murders with its Tail?

I'm not sure exactly why, but Mordax just seems like the perfect name for a scorpion.  It, like all of their anatomy, somehow says, "Beware."  I'm glad I don't live under a log.