(spiders, harvestmen, scorpions, mites, etc.)
Arachnida: Taxonomy | Info | Species on this site
The phylogenetic order, Arachnida, is a group of arthropods that includes spiders, scorpions, ticks, harvestmen, etc.
- Kingdom: Metazoa ((=Animalia) multicellular animals)
- Phylum: Arthropoda (arthropods)
- Class: Arachnida (spiders, harvestmen, scorpions, mites, etc.)
Arachnids have two tagmata (body segments), each with various appendages:
- Prosoma: The arachnid prosoma is its cephalothorax (fused head and thorax). The attached appendages include a single pair of pre-oral chelicerae, a single pair of post-oral pedipalps, and four pairs of legs.
- Opisthosoma: The arachnid opisthosoma is its abdomen and contains 12 segments. The single to four pairs of spinnerets of a spider are specialized appendages used to create silk threads and are attached to the spider's opisthosoma.
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