14 December 2007

An immaculate symphylan

symphylan1

While looking for snails in the backyard this afternoon, I noticed this multi-legged, whitish creature crawling around on the underside of one of the rocks I had turned over. I grabbed the camera and took some pictured of it.

I turned out to be a symphylan, an arthropod in the class Symphyla, distant relatives of insects. This page has a discussion of the position of symphylans in the evolutionary scheme of arthropods.

symphylan2

This particular individual was ~4.5 mm long from the front of its head to the tips of the appendages (cerci) at the rear end. It may very well be Scutigerella immaculata, apparently a common species, but don't take my word for it; I don't know much about these creatures.

1 comment:

Christopher Taylor said...

Unfortunately, the page you linked to has a fairly dated interpretation of arthropod phylogeny. I think the majority view now sees myriapods as a monophyletic group, that may not be very closely related to hexapods (crustaceans may be closer to insects).

Those are some pretty impressive symphylan pictures, though. I've come across symphylans while digging in the garden, but only as minute white crawlers.