Introduction to Sea Spiders
Sea spider is also known as Pantopoda or Pycnogonida. The scientific name of Sea spider is Callipallene brevirostris. It is a common and widespread species found in the Mediterranean and Caribbean seas as well as the Artic and Antarctic Oceans. The size ranges from 1 to 10 millimeters to over 90 centimeters. There are around 1300 known species of sea spiders. They have long legs in contrast to the size of the body. The number of walking legs is four pairs, but spiders with five pairs and six pairs exist. They are a member of Phylum Arthropoda. Sexes are separate and males and females cling together for the process of reproduction. The average life span is around one year.
Information about its biology, habitat and types of Sea Spider
Biology They have a small and slender body. They have no respiratory and excretory system. They release gases by diffusion. Food is externally digested in most species. Sea spider has two, three or four simple eyes on the top of its head. They have three pairs of appendages known as chelicerae, which are utilized for grasping food.
Metabolic wastes are lost through the digestive tract while other wastes are stored in the cuticle and released during moult. Sea spiders have a circulatory system and a nervous system. The branches of reproductive and digestive systems reach up to legs. Classification of this group depends on the presence or absence of anterior appendages. They look like under fed spiders .Their body is reduced and only a small place is left for the legs to be attached.
Abdomen is smaller than cephalothoraxes or proboscis. The shape and size of proboscis is variable between species. Females lay eggs on the egg-carrying legs of the male. They carry the eggs until they hatch.
They are found in different parts of the world. They are common in shallow waters, but can be found as deep as 7, 000 meters and live in both marine and estuarine habitats. They migrate to sub littoral zones during winter season. They walk along the floor with their stilt-like legs or swim by pulsing them in motion. Most are carnivores and feed on Cnidarians, sponges, polychaetes and bryozoans. The sea spider also feeds on marine worms, sea anemone.
They are generally predators or scavengers. Pycnogonids are predators that feed by sucking the bodily fluids from other marine animals. They are common in tide pools, but these intertidal species are typically small and hard to see, whereas deep sea pycnogonids can grow up to 50 cm. They spend most of their time on seafloor. They are completely unrelated to the terrestrial spiders but superficially resemble them. This species are found on the underneath stones and sea weeds. It is able to swim and also lives in shallow water.
Sea Giant Spider
The scientific name of deep sea giant spider is Colossendies. It is found in the East Pacific region at about 2.5 km depth. They feed on corals, sessile organisms, sucking up their contents through their enormous proboscis. Males take care of the eggs and young ones.