Pycnogonida (Sea Spiders)
Order: Pantopoda
Family: Ascorhynchidae
| Scientific Name | Author/s | Common Name | Last Record | Distribution | Status | Taxon Profile |
| Ascorhynchus hippos | Turpaeva, 1994 | (rediscovered) | Kuril-Kamchatka Trench | Rediscovered | Access |
Family: Nymphonidae
| Scientific Name | Author/s | Common Name | Last Record | Distribution | Status | Taxon Profile |
| Nymphon gerlachei | Giltay, 1935 | (rediscovered) | Antarctic | Rediscovered | Access |