Oh, hello there!

 

 

While taking a break from a task I was working on at the coast this afternoon (1 July 2023), I turned over a couple pieces of driftwood and noticed this little pseudoscorpion!  

 

Note the scorpion-like claws, but the lack of a scorpion-like tail.  This individual was only ~5 mm long.

 

I don't know much about pseudoscorpions.  This might be Garypus californicus, but if anyone can help confirm the i.d., let me know!

Fantastically spinose

 

Recently, Maddy found several of these sea spiders (pycnogonids) living among low intertidal tunicates on Bodega Head.   This species is very distinctive among our local sea spiders because of the many spines covering its body.  Below is a close-up view of the top surface of the sea spider.  Notice the numerous cactus-like spines around the legs and abdomen:

 

As Joel Hedgpeth noted in his 1951 paper on the sea spiders of Dillon Beach, this species is “fantastically spinose” and so it seems appropriate that it is named Nymphopsis spinosissimum!  

The drawing below from Hilton (1942) shows the spiny body plan of this species.  You can also see another important distinguishing feature of this species — the three tubercles (tower-like structures) in a row on the upper surface of the sea spider:

Modified from: Hilton, W.A. (1942) Pycnogonids from the Allan Hancock Expeditions. Reports of the Allan Hancock Pacific Expedition 5 (9): 277–339.

In the side view below, you can see the spiny abdomen in the back (it looks like a finger pointing to the left), then the three spiny tubercles in a row, and lastly the ocular tubercle at the front (the projection on the right side with reddish coloration bearing the shiny eyes). 

Finally, here’s a head-on view of the sea spider, showing its grasping claws (chelicerae) and the ocular tubercle above:

 

It seems possible that all of these sharp spines might help defend the sea spider against being eaten, but very little is known about the biology of this species.    

Many thanks to Maddy for finding these sea spiders and Eric for taking the excellent photographs! 

Leggy

A couple of nights ago I promised to share more information about this sea spider:

 

We're slowly trying to document the diversity of local sea spiders.  Maddy spotted this one in July and we hadn't knowingly observed this species yet, so Eric took some photos for the record.  Meet Ammothea hilgendorfi!  The entire sea spider is ~12 mm across (from leg tip to leg tip).

 

Sea spiders aren't necessarily easy to photograph, but these are terrific shots (thanks to Eric's patience!).

Below is a series of images showing some of the distinguishing features used to identify Ammothea hilgendorfi to species.  First, a diagram so you know what to look for:

Modified from Cole, Leon J. 1904. Pycnogonida of the west coast of North America. Harriman Alaska Expedition, Volume 10: pp. 249-298. 

Look for the eyes (two are visible from the side, a pair of circles on a small raised cone) and the abdomen (also a raised projection, at the end opposite the eyes):

 

Next, here's a view of the proboscis.  Look for the large white tubular structure projecting forward — it's below and extends out in front of the eyes.  The proboscis is used in feeding (suctioning and pumping). Although it's not visible, there's a small, triangular mouth at the far end of the proboscis.  (Sea spiders are parasitic on other animals like hydroids, bryozoans, and sea anemones.)

 

Eric also captured a nice view of one of the claws (at the tip of a leg).  It reminded me of the claw of a sloth — useful for grasping limbs.  In this case the sea spider might hold on to the branches of colonial animals such as hydroids:

 

You can compare the photos of these features to the diagram above to see that they are a good match for this species.

Many thanks to Maddy for spotting this intriguing pycnogonid and to Eric for the photos!

 

Celebrating eight

For 8/8: a beautiful local pycnogonid (sea spider)!

 

I'm running out of time tonight, but we'll share more information about this species soon!

Little pups

We went for a short beach walk at the end of the day today (28 May 2018).  Eric noticed a spider that looked a little different:

 

Did you notice how the abdomen looks "fuzzy"?  This spider is carrying its young, so those are tiny little spiderlings clinging to their mother. 

Some of the young spiders let go and started running (and I mean running!) among the sand grains.

One stopped briefly in an empty mussel shell:

 

Here's an even closer view of this spiderling that's smaller than a sand grain (an admittedly large sand grain):

 

I'm not sure about the identity of this spider, but I'm guessing it's a species of wolf spider (Family Lycosidae).  If you're familiar with it, I'd love to learn which species it is.

 

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!

 

 

Different mates

In January I mentioned that there is male parental care in sea spiders.  Here are a few pictures to continue that story.

This is Pycnogonum stearnsi, a common local sea spider often associated with sea anemones.  Its legs are pulled in, and it's "hiding" a large mass of fertilized eggs — the white mass barely visible below the sea spider.  Males have specialized legs (ovigers) for carrying the developing embryos.  [For orientation, the anterior or head end (note the brown eyes) is pointing towards the top of the image.]

 

Viewed from below you can see the impressive number of embryos.  And if you look very carefully, you should be able to see something else that's notable.  Not all of the embryos are alike!

 

It may help if I zoom in.  (And remember that you can click on the picture for a larger version.)

 

Can you see that there are two different masses of embryos, in different developmental stages?  The uppermost embryos have reddish spots and are more mature...while the lowermost embryos are pure white, lack those spots, and are younger.

Here's an even closer view of the uppermost embryos (below).  The reddish spots are eyespots.

 

Male sea spiders often gather different egg masses from multiple females.  It's possible that the two egg masses are from the same female, but in a study done where they tested this (extensively), it was much more likely that different egg masses carried by one male were from different mates.  (The egg masses could be from up to 4 different females, but more often they were from 1-3 females.)

The males will carry the embryos for 1-2 months until the larvae hatch.

Facts above from:  Barreto, F.S. and J.C. Avise. 2010. Quantitative measures of sexual selection reveal no evidence for sex-role reversal in a sea spider with prolonged paternal care.  Proc. R. Soc. B 277: 2951-2956.

Along came a sea spider

In late April, I was looking through a microscope trying to photograph a local hydroid when I was distracted by something orange with long legs:

 

I zoomed in for a closer look:

 

This is a pycnogonid, or sea spider.  It's a little hard to make everything out at first, but I just had to post these pictures because this animal is so unusual.  

This sea spider is mostly transparent.  The orange lines are branches of the gut that extend throughout the body and into each leg.  (Somehow this patterning made the sea spider look like some sort of Halloween skeleton to me!)

The head is on the left side and if you look carefully you can see small silvery spots that are the eyes. [There are four eyes, but all four are not always visible.]  The two arching appendages on either side of the eyes are chelicerae — the presence of chelicerae tells you that sea spiders are related to horseshoe crabs, spiders, and scorpions.

After that, the body (or trunk) is narrow, but there are very long legs extending out to either side.  In the next photo, the sea spider has turned to face away from the camera and is now crawling along a branch of the hydroid.  Note the sharp curved claws at the tips of its legs for holding on (reminiscent of a sloth).

 

Close-up of leg and claw wrapped around hydroid branch:

 

I believe this sea spider had just eaten one of the hydroid polyps — see the pink mass next to the sea spider in the following image.  The sea spider has a long proboscis that it uses to suck fluids out of its prey.

 

There are many other interesting facts to share about sea spiders, but I'll save those for another night. 

For now, since you've become familiar with what this sea spider looks like, can you find it in the photo below?  The transparent-and-orange coloration is effective camouflage against the backdrop of the hydroid, but I think you'll be able to find it if you search carefully.

 

The sea spider is in the lower right corner, at the lower end of the rightmost brown hydroid branch.