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Onychophora

life science Maturity 11-13 Next article →

Velvet worms are amazing, soft-bodied animals. Their name, Onychophora, means "to carry claws."

Velvet worm
Velvet worm

They feel velvety to the touch. Many people think they look like worms with legs or caterpillars.

Peripatoides 226306189
Peripatoides 226306189

These animals are very special because they live entirely on land. They are closely related to arthropods and tardigrades. Scientists call this group Panarthropoda. They are helpful for studying how early animals lived.

Onychophora global distribution map
Onychophora global distribution map

Velvet worms have a very cool way of hunting. They use a sticky, white slime to catch prey.

Peripatopsis overbergiensis 45218773
Peripatopsis overbergiensis 45218773

On each side of their head, they have two openings called oral papillae. These openings contain large slime glands. The worm squirts the slime out in two fast streams. The streams cross in the air to make a net. This net entangles other small animals. The worm can even shoot slime up to ten centimeters away.

Ooperipatellus viridimaculatus 34495501
Ooperipatellus viridimaculatus 34495501

Making this slime is a big job for the worm. It can take 24 days to make a new supply.

Peripatopsis capensis internal anatomy IMG 0781a
Peripatopsis capensis internal anatomy IMG 0781a

Because it takes so long, velvet worms actually eat their dried slime. The slime is mostly water, but it also contains proteins. These proteins make the slime very strong and stretchy. The slime also has a special substance called nonylphenol. This is the only time we see this substance in nature. It might help the slime reach its target without sticking to the worm.

We can learn a lot from velvet worm fossils. Scientists have found two types of fossils that are definitely velvet worms. One is named Antennipatus from the Late Carboniferous period.

Helenodora
Helenodora

The other is named Cretoperipatus from the Late Cretaceous period. These fossils help us see how ancient ancestors might have looked. Velvet worms have many different body shapes and sizes. The smallest is called Ooperipatellus nanus. The largest is Mongeperipatus solorzanoi. They can have between 13 and 43 pairs of legs.

Euperipatoides claw pair
Euperipatoides claw pair

Their bodies are made of many segments. You can see these segments by looking at the legs and skin pores.

Dissected Euperipatoides
Dissected Euperipatoides

Each leg is a stubby part called a lobopod. These legs do not have joints like our arms or legs. Instead, they stay stiff using fluid pressure inside. They have tiny, hard claws on the end of each leg. These claws are made of a tough material called chitin. The claws are built like nesting dolls with three layers. This helps them stay strong as they grow.

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🖼️ Images & Media (22)
File:Peripatoides novaezealandiae 272115998.jpg
Peripatoides novaezealandiae 272115998.jpg
File:Ooperipatellus viridimaculatus 34495501.jpg
Ooperipatellus viridimaculatus 34495501.jpg
File:Peripatopsis overbergiensis 45218773.gif
Peripatopsis overbergiensis 45218773.gif
Euperipatoides claw pair.tif
File:Peripatopsis capensis internal anatomy IMG 0781a.JPG
Peripatopsis capensis internal anatomy...
File:Dissected Euperipatoides.jpg
Dissected Euperipatoides.jpg
File:Onychophora_global_distribution_map.jpg
Onychophora_global_distribution_map.jpg
File:Peripatoides 226306189.gif
Peripatoides 226306189.gif
File:New Zealand peripatus, Wellington, NZ imported from iNaturalist photo 601149090.jpg
New Zealand peripatus, Wellington, NZ...
File:Eoperipatus_totoro.jpg
Eoperipatus_totoro.jpg
File:Velvet worm.png
Velvet worm.png
File:SEM image of Milnesium tardigradum in active state - journal.pone.0045682.g001-2 (white background).png
SEM image of Milnesium tardigradum in...

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