Lecture—8 October 2003

Cast of characters

Trilobites—one of the few major groups to be extinct

Major episodes of catastrophism

Chelicerata

Xiphosurans---horseshoe crabs Limulus polyphemus

Arachnid

Regular spiders

Phalangid—daddy long legs

Scorpions

Pseudoscorpions

Ticks and mites

Sea spiders—all marine groups, eat hydroid polyps

Mandibulates

Insecta –Hexpoda-

Myriapods

Centipedes

Millipedes

Onychophora—Peripatus—velvet worm proposed as the connecting link between annelid s and arthropods

Lophotrochozoa

Lophophore---crown of tentacles

Phornida—marine benthic worms

Bryozoa—colonial

Brachiopods

Annelids—

Trochophore

Mollusks

Shell

Mantle

Foot

Gills

Radula