Marine Vertebrates Marine Biology Dr. Ouida Meier

Representative Marine Phyla: Phylum Porifera Phylum Cnidaria Phylum Bryozoa Phylum Mollusca Phylum Annelida Phylum Arthropoda Phylum Echinodermata Phylum Chordata

Subphylum Urochordata –Class Ascidiacea (tunicates) –Class Thaliacea (salps, gelatinous thaliaceans) Subphylum Vertebrata – this week. All chordates possess at some time during development a notochord (made of cartilage) along midline of body, below a hollow dorsal nerve cord, as well as a postanal tail and pharyngeal pouches.

Subhylum Vertebrata Class Agnatha (jawless fish) Class Chondrichthyes (cartilaginous fish) Class Osteichthyes (bony fish) Class Reptilia (reptiles) Class Aves (birds) Class Mammalia (mammals)

Subphylum Vertebrata Class Agnatha (jawless fish) Class Chondrichthyes (cartilaginous fish) Class Osteichthyes (bony fish) Class Reptilia (reptiles) Class Aves (birds) Class Mammalia (mammals)

Features of Vertebrates Postanal tail, pharyngeal pouches (chordate) Vertebral column (develops from notochord; segmented) Specialized sensory organs Brain at anterior end of nerve cord Closed-loop circulatory system (heart, arteries, capillaries, veins) Myomeres (muscle segments)

Marine Fish Agnatha – hagfish (most primitive), lampreys –[body fluids isotonic to seawater; 30-50% in other vertebrates] Chondrichthyes – sharks, skates, rays –[large: 15m] Osteichthyes – bony fishes: tarpon, eels salmon, sardines, lanternfish, toadfish, flying fish, seahorses, pipefishes, scorpionfishes, sculpins, basses, groupers, snappers, barracudas, wrasses, tunas, triggerfishes, molas, pufferfish, etc. –[bone stronger and lighter than cartilage; small size, diverse adaptations and habitats]

Body shape specialization: High maneuverability (e.g., butterflyfish) Rapid acceleration (e.g., barracuda) Efficient cruising (e.g., tuna) Eating methods: –Ramming (e.g., sharks) –Biting (e.g., triggerfish) –Sucking (e.g., butterflyfish)

Marine Reptiles Snakes (61 species of true sea snakes, most of them highly venomous) Turtles (7 species of sea turtles) Iguanas (1 species of marine iguana, Galapagos Islands) Estuarine environments: additional snakes, caymens, alligators, crocodiles)

Marine Birds Feathers and front appendages adapted for flight Species: range of dependence on marine environment –Ducks, geese, coots –Shorebirds: herons, stilts, sandpipers –Albatrosses, petrels, gannets, pelicans, gulls, terns, murres –Penguins Birds and Mammals are true homeotherms

Marine Mammals Order Carnivora –Pinnipeds: Seals, sea lions, walruses, sea otters –Polar bears Order Cetacea –Whales, dolphins, porpoises Order Sirenia –Manatees, dugongs

Characteristics of mammals Viviparous Body hair Milk-secreting mammary glands Specialized teeth Separate reproductive / digestive tract openings [other vertebrate groups oviparous or ovoviparous, and have a cloaca]

Modern cetaceans Suborder Mysticeti – [baleen whales] lack teeth; have rows of baleen projecting from upper jaw to filter-feed Suborder Odontoceti – [toothed whales] smaller; specialized teeth help capture slippery fish, squid, other prey

Links Basic background on marine mammals Pinniped photo gallery Cetacean photo gallery National Marine Mammal Lab, Cetacean Assessment ProgramNational Marine Mammal Lab, Cetacean Assessment Program Sea Otter Evolution and Adaptations