What other Arthropoda are related to the spider?

Answer 1

Arthropoda is phylum which includes the subphyla:

• Subphylum Trilobitomorpha (trilobites - which are extinct)
• Subphylum Chelicerata (this is the one Spiders belong to)
• Subphylum Myriapoda (centipedes, millipedes and the like)
• Subphylum Crustacea (crustaceans like shrimp, crabs, lobsters, barnacles, etc.)
• Subphylum Hexapoda (insects and 3 other classes of 6 legged bugs)

Within the subphylum chelicerta you have the related classes:

• Arachnida - spiders, scorpions, etc.
• Xiphosura - horseshoe crabs, etc.
• Pycnogonida - sea spiders
• Eurypterida - sea scorpions (extinct)

Within the class Arachnida you have the related orders

• Acarina (mites and ticks)
• Amblypygi (weird looking flat critters called whip spiders and tailless whip scorpions)
• Araneae (Spiders)
• Haptopoda (an extinct order that resembled the Amblypygi order)
• Opiliones (common names for these arthropods include "daddy longlegs" and "granddaddy longlegs" - note that they are NOT spiders)
• Palpigradi (microwhip scorpion - looks like a tiny 8 legged termite with a long harry tail)
• Phalangiotarbida (another extinct order)
• Pseudoscorpionida (false scorpion or book scorpion - tiny arachnids with a flat, pear-shaped body and pincers that resemble those of scorpions - but no scorpion tail)
• Ricinulei (hooded tickspiders)
• Schizomida (shorttailed whipscorpion - relatively small, soft-bodied arachnids, somewhat similar in appearance to whip scorpions - although they don't have any "whip" like the whipscorpion)
• Scorpiones (Scorpions)
• Solifugae (camel spiders, wind scorpions and sun spiders or solifuges - urban legends tend to exaggerate the size of camel spiders and definitely exaggerate their danger)
• Thelyphonida (vinegaroons or whipscorpions - look kind of the Schizomida but they have a long, thin whip-like "tail")
• Trigonotarbida (Extinct - Trigonotarbids can be envisaged as spider-like arachnids, but without silk-producing spinnerets. They ranged in size from a few millimetres to a few centimetres in body length)