1. Chelicerae:
- Chelicerates possess specialized appendages called chelicerae, which are modified into fangs, claws, or pincers. Chelicerae serve various functions, including capturing prey, injecting venom, masticating food, and defense.
2. Two Main Body Segments:
- Chelicerates have a body divided into two main tagmata (sections): the prosoma (cephalothorax) and the opisthosoma (abdomen).
3. Jointed Appendages:
- Like other arthropods, chelicerates have jointed appendages that provide support, locomotion, and sensory functions.
4. Lack of Antennae:
- Unlike other major arthropod groups, chelicerates lack antennae.
5. Open Circulatory System:
- Chelicerates have an open circulatory system, where the blood flows freely through body cavities and tissues.
6. Respiration:
- Chelicerates use various respiratory structures depending on the species. Some have book lungs (modified gills), while others have tracheae (air tubes) or aquatic respiratory systems.
7. Simple Eyes or No Eyes:
- Chelicerates typically have simple eyes, such as ocelli or lateral eyes, and some species may lack eyes altogether.
8. Predation and Feeding:
- Most chelicerates are carnivorous predators, capturing and consuming arthropods, insects, small animals, or fluids like blood (e.g., ticks).
9. Diverse Habitats:
- Chelicerates occupy a wide range of habitats, including terrestrial, freshwater, and marine environments.
10. Examples of Chelicerates:
- Chelicerates include diverse groups such as spiders, scorpions, ticks, mites, horseshoe crabs, and sea spiders.
11. Venomous Species:
- Many chelicerates are venomous, utilizing their venom for capturing prey or defense against predators. Notable examples are spiders and scorpions.
Studying chelicerates provides insights into the evolution, diversity, and ecological significance of this fascinating group of arthropods. Chelicerates offer valuable opportunities to understand arthropod biology and their roles in ecosystems.