Cnidaria 1 Animal innovations Gap (Septate) junctions Loss of the choanocytes Porifera Placozoa 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 Gap (septate) junctions (Connexon) 3 Animal innovations True tissues with all components Internal digestive epithelium Oral-aboral axis and symmetry Porifera Placozoa Cnidaria Ctenophora Platyhelminthes Gastrotricha Gnathostomulida Cycliophora Rotifera Annelida Mollusca Sipuncula Nemertea Brachiopoda Phoronida Bryozoa Arthropoda Tardigrada Onychophora Nematomorpha Nematoda Priapulida Kinorhyncha Loricifera Echinodermata Hemichordata Chordata Symmetry types Radial Biradial Bilateral Cnidaria Cnidocytes Polyp body plan Epitheliomusculature Planula larva Porifera Placozoa Cnidaria Ctenophora Platyhelminthes Gastrotricha Gnathostomulida Cycliophora Rotifera Annelida Mollusca Sipuncula Nemertea Brachiopoda Phoronida Bryozoa Arthropoda Tardigrada Onychophora Nematomorpha Nematoda Priapulida Kinorhyncha Loricifera Echinodermata Hemichordata Chordata Page 1
7 8 9 10 Extant Animalia ~1,300,000 species Parazoa (1.2%) Radiata (0.9%) Protostomia (3.9%) Platyzoa (2.2%) Platyhelminthes (1.9%) Others (0.3%) Lophotrochozoa (9.8%) Mollusca (8.5%) Annelida (0.9%) Others (0.5%) Ecdysozoa (82.0%) Crustecea (3.1%) Chelicerata (7.6%) Atelocerata(70.3%) Others (1.1%) Deuterostomia (4.0%) Chordata (3.5%) Others (0.4%) Cnidarian characters Cnidocytes - nematocyst Cnidocil Operculum Nematocyst capsule 12 Page 2
Polyp body wall Body wall Gastrodermis Gastrodermis 13 14 Hydrostatic skeleton (Polyp) Body wall Cnidocyte Epitheliomuscular cells (longitudinal) Nutritive muscular cells (Circular) Epidermal nerve cell Epitheliomuscular cell Gland cell Nutritive muscular cell 15 16 Cnidarian characters Planula larva Epitheliomuscular cells Sensory cell Nerve cell Myoneme 17 18 Page 3
Anthozoa Biradial symmetry a variation on radial Modified radial caused by paired structures on a radial body plan Anthozoan innovations (autapomorphies) Biradial symmetry Siphonoglyphs Muscular septa Gonads in gastrodermis 19 20 Anthozoa Biradial symmetry a variation on radial Anthozoa Anemone anatomy Tentacles Pharynx Septum 21 22 Anthozoan body wall Anthozoan septal wall Incomplete septum Complete septum Retractor muscle Siphonoglyphs Pharynx 23 Retractor muscles Gonadal band Ciliated band Cnidoglandular lobe 24 Page 4
Anthozoa: Corals Cnidarian innovations 25 Dimorphic life cycle Medusa by strobilization Opercular nematocysts Tetraradial symmetry 26 Dimorphic life cycle Strobilization Gastrodermis Polyp Medusa 27 28 Scyphozoa Aurelia Life cycle Medusa Ephyra Planula Scyphozoan innovations Rhopalia on medusa bell margin Strobila Scyphistoma 29 30 Page 5
Scyphozoa Aurelia medusa Tentacles Gonad Gastric pouch Canal system Rhopalium Scyphozoa Aurelia gastrovascular system Gastric filament Eggs Oral arm 31 32 Rhopalia - Cnidarian sensory system (on margin of medusa) Hood Pigment spot Pigment cup Statocysts Cnidarian innovations Medusa produces a single medusa 33 34 Cubozoa Cubozoan innovations Polyps undergo metamorphosis into medusa Unique eye Pedalia 35 Gonad Rhopalium (not on the margin of the medusa) Tentacle Pedalium 36 Page 6
Cubozoan rhopalium Statocyst Eyes Hydrozoan innovations Medusa from lateral buds Dimorphic life cycle Medusa with a velum 37 38 Hydrozoa Obelia colony Hydrozoa Obelia Gonozooid Medusa Gonozooid Gastrozooid Fertilized egg Planula Gastrozooid (hydranth) 39 Young Colony Settled planula 40 Hydrozoa Hydra Encapsulated embryo Ovaries Spermaries Budding Sexual cycle Asexual cycle 41 Page 7