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Unformatted text preview: 4 pairs of legs (5 in horseshoe crabs) No antennae Feed by sucking liquid on prey-pycnogonida sea spiders 300 species-body is small, legs make up for most of size-merostomata horseshoe crabs 5 species use to be very diverse, many extinct-400+ million years old, fossil record shows body plan-book gills-arachnida spiders, scorpions, mites 100000 species -light limbs, muscle in thorax fast movement -complex nervous system, distinct brain-ticks and mites are parasitic Picture of phylogeny on lecture 17 page 5 Spiders have 8 eyes Chiton on body as hairs Synapomorphies not important...
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- Fall '08