Sea spider
Sea spiders are marine arthropods of the order Pantopoda (lit. ‘all feet’), belonging to the class Pycnogonida, hence they are also called pycnogonids (/pɪkˈnɒɡənədz/; named after Pycnogonum, the type genus; with the suffix -id). They are cosmopolitan, found in oceans around the world. The over 1,300 known species have leg spans ranging from 1 mm (0.04 in) to over 70 cm (2.3 ft). Most are toward the smaller end of this range in relatively shallow depths; however, they can grow to be quite large in Antarctic and deep waters.
| Sea spiders Temporal range: | |
|---|---|
| Left to right, top to bottom: Austrodecus bamberi (Austrodecidae), Colossendeis sp. (Colossendeidae), Pycnogonum stearnsi (Pycnogonidae), Ammothea hilgendorfi (Ammotheidae), Endeis flaccida (Endeinae), Nymphon signatum (Nymphonidae) | |
| Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Chelicerata |
| Class: | Pycnogonida Latreille, 1810 |
| Order: | Pantopoda Gerstaecker, 1863 |
| Type genus | |
| Pycnogonum Brünnich, 1764 | |
| Families | |
|
See text. | |
| Synonyms | |
|
Arachnopoda Dana, 1853 | |
Although "sea spiders" are not true spiders, nor even arachnids, their traditional classification as chelicerates would place them closer to true spiders than to other well-known arthropod groups, such as insects or crustaceans, if correct. This is disputed, however, as genetic evidence suggests they may be a sister group to all other living arthropods.