Christmas Bells

Christmas Bells
Christmas Bells - Blandfordia nobilis

Monday, July 14, 2008

Soft-bodied Creatures

This is something of a follow-up to a posting "Red" by Junior Lepid over at "Lepidoptera Diary"

Soft-bodied creatures, with an excess of legs have been puzzling me for some time. I do not even know how to begin to classify this tiny creature. The term "insects" does not fit, for a mere 6 legs would appear to be boring, to these little guys. On my counting, this creature has 10 pairs of legs, plus two large "palps" (or similar feeding devices) on its front end. This is the best I can do with this image, before pixellation causes distortion. (Click to enlarge to maximum size.) The little creature was quite active, as you can see from how it changed angles, over a few seconds.

I went to the Australian Faunal Directory, and looked for creatures with 20 legs, but was no closer to an answer after hours of scouring through Webpages. Part of my problem is I do not know if this creature is a "larval stage" of something else which might be more familiar if I saw it in its adult stage. I am thinking here of how Ladybird (beetles) look nothing like their larval stages, or indeed caterpillars and moths.

Here is the creature in situ, on the bark of a "Scribbly Gum", to give a sense of scale, to any Aussie Nature lovers. It is about real size on my screen, when not 'blown up" to higher resolution.
I added the title "Larva" for want of any better name.
I am not even sure if this creature meets the definition of an "arthropod" for it ought have a "hard exoskeleton (doubtful), a body divided into segments (yes) and jointed legs (doubtful - certainly flexible, but "jointed" - not sure.)"

Now that I have been linking up with other Nature Bloggers in Australia, I am hoping for some words of wisdom from more experienced naturalists or even some taxonomists. Perhaps Christopher Taylor might be able to help, or Mosura, who seems to know his way around a microscope, or Junior Lepid, or any of my other new-found friends and colleagues. I would be happy to get to within a "Class" or "Order" - but this Berkeley University website on the Tree of Life tells me that even in that aspiration I am trying to apply out-of-date science.



Christopher Taylor said...

Going by the arrangement of the legs, I would guess that what you have there is a very young scutigerid - what is commonly called a house centipede. I couldn't tell you what species or anything, though I wouldn't be surprised if such precision wouldn't be possible with a specimen as young as this one would appear to be. Centipedes hatch out with less legs than they will have as adults and add legs as they mature.

The "very active" description fits well with a centipede as well. All centipedes are very fast moving and almost impossible to catch unless you are very quick off the mark. Scuties (as most people I work with refer to scutigerids) are about the most impressive in this regard, as the large number of long legs gives them an incredible ability (difficult to explain if you haven't seen it) to appear to be ambling along with no great haste until you try to catch them, at which point you realise they are actually travelling very fast indeed.

Mosura said...

For now I've narrowed it down to the kingdom Animalia and I've also ruled out the trilobites. This may be as far as I get :-)

Gouldiae said...

G'day Denis,
Haven't got a clue, sorry. Never seen anything like it before. Fascinating.
I'll be keeping an eye out here to see what transpires.
Regards, Gouldiae

Duncan said...

Denis, I think you'll find that it's a mealy bug. The "legs" are waxy threads.

Junior Lepid said...

Gee Denis, now you're testing me! I think I'd agree it might be the larvae of something like a Ladybird. I've had a bit of a look but found nothing significant. This one needs an actual entomologist's opinion, I think! :-)

Denis Wilson said...

Well, Thanks everybody for the range of comments.
I think Christopher is most likely on the money, especially with the comments about these creatures adding legs as they age. No wonder they are a puzzle to most of us.
The active bit makes sense, for I have seen an adult "House Centipede" once. Very weird creature (to my eyes). I probably look weird to it.
Mosura - a man with a sense of humour appropriate to the task! Glad you ruled out the Tribolite!
Too active for any Mealy Bug I have seen, Duncan, but thanks for the suggestion.
Wonderful to have a group of people prepared to offer suggestions.
Thanks to you all.

Mosura said...

Interesting. I discounted the idea of a young scutigeromorph early on as I was unaware that they started out with less than a full compliment of legs. I'm still wondering where the antennae are -- are those short appendages near the front end coming of the head?

Denis Wilson said...

Hi Mosura
I cannot explain any more than one can see in those photos. Certainly there look to be two heavy things which I took to be "palps" (or legs acting to bring food to the mouth) clearly visible in first, second and fourth frames. I do not see "antennae", but I am not sure if they are a pre-requisite for immature insects.
Two dark spots on top of head are prominent eyes. I cannot even get a consistent count on the number of legs, as they seem to pair up, and then separate.
Are Antennae critical to an identification?

Duncan said...

Denis, I photographed a very similar creature a year or two ago, but for the life of me I can't find the picture in the many thousands on three hard drives. At the time it was identified as a mealy bug, but I wasn't all that happy with the id. I'll be looking with interest to see if you get a positive id.

Mosura said...

No I'm not suggesting antennae are critical to an identification? I'm just trying to get my head around it myself. Photographs I've seen of young scutigeromorphs did have antennae but maybe your one is even younger. I just don't know. My questions are simply questions :-)

Denis Wilson said...

Hi Duncan
I sympathise. The hard thing is knowing how to file these odd creatures. I shall create an "unknown critters" file. It will probably fill up very shortly.
If you do ever come across the photos, I would be interested to see them.
I understand why Mealy Bug seems a likely choice, but I am not convinced.
The Bugsguide clearly shows them in the order of Insects/true bugs/ so they have 6 legs, and body appendages which are waxy leg-like things, but not real legs. That is what I think, anyway. See this link:
My creature definitely was walking with all those legs.
Still puzzling onwards.