Phylum Arthropoda Subphylum Chelicerata Characteristics of Chelicerata Body

Phylum: Arthropoda Subphylum: Chelicerata

Characteristics of Chelicerata: Body divided into a cephalothorax (fused head and thorax) Six pairs of appendages Chelicerae Pedipalps Four pairs walking legs Usually segmented abdomen with no appendages

Class: Merostomata Cephalothorax is covered by carapace Abdomen is ALSO covered by shield Has 6 pairs of appendages (5 for walking) Has ADDITIONAL 6 pairs on abdomen Last 5 are bookgills for respiration

Example: Horseshoe Crab Fun Facts: A living fossil Valuable for testing bacterial contaminants in human blood They have 10 eyes--on top, on bottom, and on its tail.

Class: Arachnida Most abundant of chelicerates Scorpions Spiders Ticks Mites

Class: Arachnida Order: Scorpiones Pedipalps are pincers Tip of tail has stinger with poison (mostly for defense) 2 main body segmentscephalothorax and abdomen Abdomen is segmented Have book lungs for respiration Spiracles are on abdomen

Example: Fun Facts: Emperor Scorpion Smallest scorpion is most lethal (called buthil) Can freeze solid, thaw out and walk away! Glow when exposed to certain UV light

Class: Arachnida Order: Araneae Have two parts to body— cephalothorax and abdomen Abdomen is unsegmented Abdomen and cephalothorax join at narrow waist called pedicel Digestive juices break down inside of prey before going into digestive tract Sometimes happens in mouth cavity

Class: Arachnida Order: Araneae All spiders make silk Glands produce silk which is make of protein Spinnerets shape the silk Young spiders use silk to ‘balloon’ to other areas Have book lungs

Fun Facts: Claws at end of each leg 2 types of poison: neurotoxic and necrotic Sheep and rabbits are immune to black widow venom