Sea Spider
Anoplodactylus erectus

photo credit Jayson Gillespie

Sea spiders are classified in the phylum Arthropoda and the class Pycnogonida. Pycnogonids are spider-like in their appearance and hence the name "sea spider". They are quite common in the marine environment but you need a keen and careful eye to spot them. Most sea spiders are 1 to 10 mm in length but some deepwater species in Antarctica can have a leg span up to 90cm! Sea spiders are found throughout the worlds oceans, in a variety of habitats, ranging from the intertidal to the subtidal. You can find some sea spiders on rocks and dock pilings around hydroids and bryozoans. Many sea spiders are carnivores and feed on hydroids, soft corals, anemones, bryozoans, small polychaetes, and sponges, but some species will also eat algae.

Questions and Answers about Marine Arthropods

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