Class Arachnida consists of several orders, each containing species with distinct characteristics. Some of the main orders include:
1. Araneae (Spiders)
Key Features: Produce silk, have spinnerets, venomous chelicerae, narrow connection between cephalothorax and abdomen (pedicel).
Ecological Role: Predators that help control insect populations.
2. Scorpiones (Scorpions)
Key Features: Elongated bodies with a segmented tail ending in a venomous stinger, large pedipalps (claws) for grasping prey.
Ecological Role: Predators of insects and other small animals.
3. Acari (Ticks and Mites)
Key Features: Small size, sometimes microscopic, diverse feeding habits (parasitic, predatory, detritivorous).
Ecological Role: Ticks are well-known vectors of diseases, while mites play various roles in ecosystems, from soil health to pest control.
4. Opiliones (Harvestmen or Daddy Longlegs)
Key Features: Rounded bodies, long legs, lack of silk production, no venom glands.
Ecological Role: Scavengers and predators of small invertebrates
5. Pseudoscorpiones (False Scorpions)
Key Features: Small size, pincers similar to those of true scorpions, no tail or stinger, venomous pedipalps.
Ecological Role: Predators of small arthropods, aiding in pest control.
6. Solifugae (Camel Spiders or Wind Scorpions)
Key Features: Large chelicerae, elongated bodies, fast runners, lack of venom glands.
Ecological Role: Predators that primarily feed on insects and small animals.
7. Thelyphonida (Whip Scorpions or Vinegaroons)
Key Features: Long, whip-like tail, ability to spray acetic acid (vinegar-like substance) as a defense mechanism.
Ecological Role: Predators of insects and other small invertebrates.