#3533 - Occiperipatoides gilesii
Look at those peets, Lookit them.
As it happens, less than an hour before I took these photos, somebody at the Bioblitz asked me where they could find Velvet Worms, and I had to tell 'somewhere less dry than Julimar', which I felt was good advice - even with the rain that weekend, nearly every inch of ground was bare gravel, with the exception of the small piles of bark litter around the bases of the Wandoo eucalypts. Hardly good habitat for a Phylum that can dry out easily.
And then @purrdence was poking around one of those bark piles and found this.
Occiperipatoides gilesii also comes in blue-black, is found on the Swan Coastal Plain and adjacents areas on the Darling Escarpment, and is one of four species of velvet worm found in this corner of the country. Three of those used be considered one species - Occiperipatoides occidentalis - but are now considered their own genus, Kumbadjena. Kumbadjena is derived from Noongar (or Nyungar) words referring to the southwest region of Western Australia where these are found. Occiperipatoides means 'Western-Peripatus-like'. Peripatus itself is the quitessential velvet worm, and means 'walking about'. Which they do. On adorable peets.
Like other Velvet Worms, Occiperipatoides is a predator, hunting down other invertebrates with its sensory tentacles, and immobilising them with glue sprayed from nozzles in their face. The glue glands are large, running half the length of the body, but it can still take several weeks to refill them. The prey is then devoured with curved jaws deep in oral cavity. Some velvet worm species are social, and hunt as a pack, with dominant females getting to feed first.
Reproductive anatomy and behaviour is complex. Some have bladed structures - on the face, again - that they appear to use to place sperm packets in the female's genital slit she she holds him in place, and others deposit semen on her skin. Immune cells in her blood then gather underneath the sperm packet, and dissolve the skin and spermatophore integument between them and the sperm cells, whereupon the sperm swims into her body and starts looking for the eggs. Some velvet worms give birth to live young (a few even have a placenta!), and some are known to stand gaurd over their offspring.
Predators of velvet worms include other invertebrate predators, birds, and Hemprich's coral snake Micrurus hemprichii of South America, which apparently has velvet worms as a major part of its diet.
Being soft-bodied, velvet worms rarely fossilised well, but it seems they are descendents of the marine Lobopods, such as Aysheaia and the famous Hallucigenia of the Cambrian-age Burgess Shale. It's unclear when they moved onto the land, but it was most likely during the Ordovician or Silurian.
Julimar State Forest, WA.
