Christmas Bells

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Christmas Bells - Blandfordia nobilis

Wednesday, September 24, 2008

Sydney Brown Trapdoor Spider (scary photo warning)

I trust that you have not opened this blog posting if you find close-up photos of spiders a bit scary.

This one is, by all accounts, not a dangerous spider. I hope so, as it was brought to me tonight by a neighbour, and after the "photo shoot" I released it outside my house.

The best identification I can come up with (and I am NOT a "spider" person) is the Sydney Brown Trapdoor Spider (Misgolas rapax). It was a soft bodied spider, and very placid in attitude.

It is NOT a male. Males of these Spiders have very large "palps" which look like "boxing gloves" being carried in front of the spider. I have seen such male Trapdoors before, but not recently. This one had large fangs, but not the prominent palps. If you count the "legs and feet" from the rear left side in to towards the mouth parts, you will find there appear to be 5 pairs of legs. Not correct, apparently. Spiders have 4 pairs of legs, plus the "palps" which are feeding structures - they apparently have one less joint than legs. In addition, the fangs are also just visible in the centre of the front of the Spider's mouth area.
Also, male Trapdoor Spiders have a distinctive spur on the inside of the front legs, but this one does not. So, she is a female.
Front-on view.
Side view of the Sydney Brown Trapdoor Spider.
You can see the hard "carapace" is shiny, compared to the soft abdomen.
A close-up view of the "cephalothorax" (or "carapace").
Note the four small eyes (on the front top of the "head")
and large vertically hinged fangs, ("Paraxial Fangs") which are black and hairy.
This is one of the "primitive spiders". These spiders are typical "lie in wait" Spiders, not the "see, run and catch" type hunting Spiders (such as the Wolf Spider), which have large eyes, very prominently positioned on the head.
Close-up of the fangs.
You can see that these fangs will strike in a vertical manner, as distinct from "modern" spiders, which have "diaxial fangs" which operate in a pincer movement. The eyes are also visible (above the top of the fangs).

The pale fleshy area above the fangs and below the eyes, is a "hinge" allowing the fangs to be moved. After all the "carapace or cephalothorax" (what we would loosely call the "head") has a hard shell, so joints are necessarily soft, to allow for movement.

Rear view of the soft abdomen, showing very small "spinnerets".


Gouldiae said...

G'day Denis,
Yet another beautifully detailed post. Great closeups - the warning is probably warranted to the arachnophobes(?).

Duncan said...

Impressive set of choppers Denis!

Mosura said...

Not dangerous? I reckon they could induce fainting in some people ....and to think as a kid I used to poke grass down their holes to make then come up ....shuderrrrrrrr.

William Archer said...

Unfortunately it does not look good for your Brown Trapdoor Spider as the females very rarely travel far from their burrow. I guess she was forced out by flooding or by a predator. They usually cannot reconstruct a new burrow and die from exposure. That is they need a humid environment for their book-lungs to operate efficiently and being trapped above ground this can rarely be achieved in the long run. A pity, but not much you can do.
Nice observations.
With best wishes,
William Archer

Denis Wilson said...

Thanks William.
I had not considered the prospect that she could only survive back in side her own home tunnel.
She had already been disturbed by my neighbours doing some gardening. And, to put not too fine a point on it, they did not want her back where she had been.
So I figured release in my yard was a good option. Lots of cover, as she was released into long grass.
Thanks for your advice.

AshleyyWithaWhy said...

Thanks, this really helps out. Nice photos too!
I caught one of these today, and I thought it was pretty nifty looking. They are beautiful; I've never seen a spider like the Sydney Brown Trapdoor Spider.

Denis Wilson said...

Hi Ashley with a Y
Good if it helped you identify your spider.
Most people assume large spiders are deadly.
Not all are.
Mind you I did not let her walk over my hand.
Glad you found my site to have been of assistance.
One of the joys of blogging. The original post was nearly 2 years old, but it stays there, and can still be found via a Search Engine.

Anonymous said...

I found one of these tonight in my house, I was very disturbed. Do i need to look for it's home to she if there a nest of eggs?

Denis Wilson said...

Thanks for the question.
I know these thing normally live in burrows, so probably you would not find its nest or eggs anyway.
My advice is generally leave well alone.
Be grateful it was not a Sydney Funnel-web Spider
- they are potentially dangerous. They get flooded out of their burrows (after heavy rain). Males also go roaming. looking for females.