PERIPATUS – a ‘missing link’ unchanged
for 500million years
The New Zealand peripatus are secretive,
caterpillar-like animals, with soft, unsegmented body, velvety in
appearance. They are 2.0-8.0 cm in length, slow-moving, with 13-16 pairs
of soft stumpy legs.
Peripatus are usually coloured in dull
shades of blue, green, grey or brown. Several New Zealand species are
more brightly coloured, for example, Peripatoides indigo from the Nelson
region is indigo-blue. The head bears a pair of large antennae and a
pair of small oral papillae. Two tiny dark beady eyes are located near
the bases of antennae. The name “peripatus” originates from Greek
“peripatein” – “to walk around”, as these animals do with determination
on their many stumpy legs.
Peripatus are voracious predators and feed
on soil and litter arthropods (beetle larvae, crickets, spiders,
termites, isopods, etc.), even on animals larger than themselves.
Peripatus hunts by stalking the prey and immobilizing it with the
transparent glue-like substance, which is squirted from the openings
beside the mouth. This glue is extremely sticky, and soon entangles the
prey. Peripatus then approaches and bites the prey, injecting it with
digestive saliva; it can then suck out the liquified body tissues.
Velvet worms themselves can be preyed upon by birds, lizards, large
arthropods, and possibly rodents, although few observations of predation
Similar to insects, peripatus breathe
atmospheric air, which enters the body through spiracles – tiny openings
in the body cuticle. Unlike insects, however, velvet worms cannot open
or close the spiracles at will – the spiracles are always open, making
these animals extremely vulnerable to dessication. The inability to
control water loss restricts peripatus to damp, humid habitats.