Adapted from Lesser Known Protostome Phyla. SICB 2001. J.R. Garey. Porifera Cnidaria Ctenophora Platyhelminthes Gastrotricha Gnathostomulida Cycliophora Rotifera Annelida Mollusca Sipuncula Nemertea Bryozoa Brachiopoda Phoronida Arthropoda Onychophora Tardigrada Nematomorpha Nematoda Priapulida Kinorhyncha Loricifera Echinodermata Hemichordata Chordata Tardigrada http://www.solutionassoc.com/Fun/Fun.html Tardigrada: “water bears” • • • • • • First discovered in 1773 800 spp 0.1-0.5mm in length Widespread Live in semi aquatic habitats, water film Cryptobiotic, some are cyclomorphic – Temp range from +149C to -272C, withstand high vacuum, high UV, long periods without O2 – Dessication for > 120 years: back to life in hours Tardigrada • Metameric body plan • Toes on each leg with intrinsic musculature (cf onychophoryans) • Walk with muscles, not with hydrostatic skeleton • Oral stylets pierce plant cell walls – Diets specialized for predation, herbivory, detritivory • Internal fertilization, shed cuticle with eggs Adapted from Lesser Known Protostome Phyla. SICB 2001. J.R. Garey. Porifera Cnidaria Ctenophora Platyhelminthes Gastrotricha Gnathostomulida Cycliophora Rotifera Annelida Mollusca Sipuncula Nemertea Bryozoa Brachiopoda Phoronida Arthropoda Onychophora Tardigrada Nematomorpha Nematoda Priapulida Kinorhyncha Loricifera Echinodermata Hemichordata Chordata Onychophorans: velvet worms Onychophorans • Discovered in 1826 • 110 spp, 5mm-15 cm • Extant spp all terrestrial – Humid habitats only – Cuticle thin (no Ca), permeable • 13-43 pairs of sac-like legs • Metameric – little tagmatization – little cephalization • Annelid/arthropod link – Head ~ polychaete Oral “slime” papillae • Predaceous • Spray adhesive goo from slime glands (modified nephridia) to entangle prey • Gas exchange by trachea, spiracles – Not homologous to arthropod trachea • Reproduction: – Ovoparity, viviparity, ovoviviparity Arthropoda Mollusca Chordata Platyhelminthes Nematoda Annelida Porifera Echinodermata Other Sarcomastigophora Apicomplex Ciliophora Phylum Arthropoda • Arthro = joint, poda = feet – Refers to hard, chitinous exoskeleton • “Terrestrialized” annelid body plan • Metameric • Tagmatized: – head, thorax, abdomen – cephalothorax, abdomen – prosoma, opisthosoma • Cephalized – Compound eyes, antennae (mechano- & chemosensory) P. Arthropoda Modern crustacea Trilobita Cenozoic (65-present) Mesozoic (251-65 mya) Paleozoic (542-251 mya) Crustaceamorph stem line Precambrian (>542 mya) Phylum Arthropoda • Subphylum Trilobita • SubPhylum Chelicerata – Class Merostomata – horseshoe crabs – Class Arachnida – spiders, ticks – Class Pycnogonida – sea spiders • Subphylum Hexapoda – Class Entognatha – Class Insecta …!! • SubPhylum Crustacea – 6 subclasses Phylum Arthropoda Subphylum Trilobita • Common 500 mya (4000 spp) but extinct by 225 mya • Each body segment had a biramous appendage (inner for walking) • 3 body tagma • Compound eyes with ommatidia Subphylum Chelicerata • Include spiders and mites and daddy LL, scorpions, horseshoe crabs • Lack antennae • 1st pair of appendages on the prosoma = the chelicerae (adapted for feeding) Class Merostomata • 4 spp, all marine • Not true crabs (i.e., not crustaceans) • head + thorax = prosoma or cephalothorax • appendages of opisthosoma flattened to become “book gills” for gas exchange Telson
