Velvet Worm

Phylum Onychophora — the velvet worms, also called peripatus — contains about 200 species worldwide and is one of the most ancient surviving animal lineages on Earth. Velvet worms are NEITHER worms (not phylum Annelida) NOR arthropods (not phylum Arthropoda) — they are their own separate phylum, sister group to Arthropoda, sharing a common ancestor with all spiders, insects, crustaceans, and centipedes approximately 540 million years ago in the Cambrian Explosion. The body plan is essentially unchanged since the Cambrian: a soft, segmented, velvety-textured body (15-150 mm long depending on species) with 14-43 pairs of stubby unjointed legs (lobopods) tipped with tiny claws. Velvet worms are nocturnal predators of small invertebrates (crickets, woodlice, termites, occasional small lizards). The hunting strategy is unique among all known animals: paired slime glands beside the head fire dual jets of fast-setting adhesive slime up to 4 cm. The slime is fired through tiny adjustable nozzles and oscillates back and forth as it ejects, producing zigzag deposition patterns that maximize prey contact. The slime is liquid in flight but solidifies into rubbery sticky strands within 1-2 seconds of contact, trapping prey larger than the velvet worm herself. Once the prey is immobilized, the velvet worm walks over, bites with sharp jaws, injects digestive saliva, and consumes the partially-digested liquid tissue (and the slime — slime production is metabolically expensive, so the worm reabsorbs and recycles it). Velvet worms are also one of the few terrestrial invertebrates that practice maternal care: most species are viviparous (live-birth) and the female protects and feeds the young for weeks after birth. The species occur in temperate and tropical forest leaf litter and rotting log habitat, primarily in the Southern Hemisphere (especially South America, southern Africa, and Australia/New Zealand) — a Gondwanan distribution dating to the original Pangaean lineage.