Two spiny spiders

Black spiny spider with white pattern
Spiny spider 1

When I was a ten-year-old living on a farm in South Gippsland, Victoria, I would go down to the reedy swampy paddock at the foot of a steep hill and marvel at the enormous number of webs of a beautiful small spiky spider. On a dewy morning I could see them as an endless sparkling net stretched over the reed tips for yards at a time. (This was long before metres were invented, of course.)

I would encourage individual spiders onto my hand and watch them walk around, spinning their incredibly tough silk as they went, and I would examine their webs to see what they had caught. They were my favourite spiders – completely harmless, much prettier than the clever little leaf-curling spiders, and not big enough to be scary like the huntsmen.

black spiny spider with white pattern
Spiny spider 2

When I came to North Queensland I was pleased to find them up here as well – not so many of them, true, but just the same as the ones I remembered from my childhood. In my garden they make orb webs between the shrubs, often about face height (oops! sorry, spidey!) but sometimes a couple of metres higher. Their webs are often interlinked in loose colonies, although never in such masses as I remember from my childhood.

I never even considered doubting that they were the same species. I was wrong, though.

Spiny spider 1 is Austracantha minax, the Australian Jewel or Christmas Spider, and is found (according to the World Spider Catalogue) in “Australia, Tasmania and the Montebello Islands,” the latter being a small group off the WA coast near Karratha. It is the only species in its genus.

Spiny spider 2 is Gasteracantha sacerdotalis and it doesn’t appear to have a recognised common name. On the other hand, it has lots of other species in its genus, all of them spiny and many of them weirdly beautiful  – click here for examples from around the world. The World Spider Catalogue gives its range as “New Guinea, Queensland, New Caledonia”.

Spiny spider 1, Austracantha minax, is the one I knew and loved as a child in Victoria. It may also live in North Queensland but I have to say that I haven’t seen one here – all of mine here are Spiny spider 2, Gasteracantha sacerdotalis. Learning to tell them apart took me a while but here are the differences as I see them:

Austracantha minax (the southerner)

  • Back: the white pattern can be seen as a “V” with a few dots between the open ends.
  • Spines: rather long and unevenly spaced around the carapace – there are two very close together at each side.
  • Underside: bright yellow spots on a very dark background.
  • Legs: distinctly orange-brown

Gasteracantha sacerdotalis (the northerner)

  • Back: the white pattern can be seen as “M!M” with the outer legs of each “m” extended downwards. The outer part of the pattern varies somewhat but the centreline is constant enough to distinguish the two species.
  • Spines: rather short and more evenly spaced around the carapace.
  • Legs: usually black or very dark brown, often banded.
  • Underside: indistinct concentric bands of orange-brown.
Black spiny spider with white pattern
Austracantha minax
black spiny spider with white pattern
Gasteracantha sacerdotalis

These photos and descriptions all apply to the females. The males are much smaller (about 3-4 mm to the females’ 8 mm), less vividly coloured and rarely noticed. More pictures of females, and some of males, are here:

 

• Thanks to Volker Framenau, who alerted me to my mistake in the first place via comments on my photos on Flickr, and to Rob Whyte for use of his photo here and his ongoing encouragement of my arachnological pursuits.

4 thoughts on “Two spiny spiders”

  1. Chris, a member of the Wildlife North Queensland facebook group, recently posted a photo of Austracantha minax (which I called “the southerner”) in Townsville – more specifically in Douglas. He also shared a photo from White Mountains NP which appears to show the same species, although it’s not clear enough to be quite sure.
    So we do have both species here in the North and they may be quite widespread. I will be checking every spiny spider I meet until I have a better idea of relative numbers.

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