• Chelicerates are the group of spiders, scorpions, ticks, mites, and their relatives.
• All chelicerates have a body plan of two main segments.
• The first segment carries the senses and limbs, while the second has the main organs.
• The eyes are simple (like human eyes), not compound like insect eyes.
• They have no antennae, but pedipalps, which grow from the sides of the mouth.
• Pedipalps can have a variety of functions, they can act as sensory organs (as in spiders), for communication, or as a weapon (like in scorpions).
• All chelicerates have chelicerae, which are hollow fangs like vampires.
• Chelicerae are used to pierce the prey, inject gastric juices, and then suck the resulting melted fluid.
• Chelicerae can also be used to suck blood as ticks do.
• Some chelicerates breathe using tracheae (like big pores) and some with lungs made of layers, called book lungs.

Tick; photo by Dr_relling cc-by	Jumper Spider; photo by Thomas Shahan cc-by	Whip Scorpion; photo by Istolethetv cc-by

Sources:

-The Tree of Life - www.tolweb.org:
-The Variety of Life, Colin Tudge, 2000

Citation: García, A.I. 2015. The Tree Of Nature (Online) at http://thetreeofnature.com

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