Sea spiders are marine arthropods of the order Pantopoda (lit. ‘all feet’), belonging to the class Pycnogonida, hence they are also called pycnogonids (named after Pycnogonum, the type genus; with the suffix -id). They are cosmopolitan, found in oceans around the world. There are over 1,300 known species, with legs 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.

Pantopoda. Retrieved May, 08 2021, from en.wikipedia.org/wiki/Sea_spider.