Zoology: Species to know Cnidaria and Ctenophora Fall 2014 Classification • Remember that organisms are grouped into subgroups (taxa) based on characteristics shared by members of that group. These characteristics may include morphology (shape and structures within the body), DNA, behavior, geographic range and other considerations. Taxa: Kingdom Phylum Class Order Family Genus species The Genus species name is a unique name for each individual species. It is italicized. The genus is capitalized, but the species name is not. Phylum Cnidaria Evolution of Cnidaria Characteristics of Cnidaria • 4 classes: Hydrozoa, Scyphozoa, Cubozoa, Anthozoa • Over 9000 species • Aquatic, mostly marine • 2 tissue layers (diploblastic): epidermis, gastrodermis • External radial symmetry, internal bilateral symmetries or asymmetries • Single opening = mouth and anus surrounded by tentacles with nematocysts • Defining characteristic: nematocysts Anatomy of a Nematocyst Body Plan of Cnidaria Reproductive Cycle of Cnidarians Class Hydrozoa Characteristics of Hydrozoa • Small • Mostly marine, some freshwater • Three distinguishing characteristics: 1. Nematocysts only in the epidermis 2. Gametes are epidermal and released to the outside rather than into the gastrovascular cavity 3. Mesoglea never contains amoeboid mesenchyme cells Genus Obelia Characteristics of Obelia • Zooplankton: small, 2.5-6mm • Exists in both medusa and polyp stages of life • Flat • Four quadrants • Worldwide distribution Genus Polyorchis, Red-eye Jelly Polyorchis characteristics • Bell is as high as it is wide • 50-60 mm bell diameter, as adults • Ocelli (eyespots) around the bell margin, at the base of the tentacles, are ringed with red which can be clearly seen. • 4 unbranched radial canals which have many (15-25 pairs of) lateral diverticula • Occur in nearshore waters off the coast of North America Aequorea victoria, Water Jelly Aequorea victoria characteristics • Bioluminescent via GFP (green flourescent protein, now used in many cellular and genetic investigations) • Almost entirely transparent and colorless • 5 to 10 cm in size • Highly contractile mouth and manubrium at the center of up to 100 radial canals that extend to the bell margin. • The bell margin is surrounded by uneven tentacles, up to 150 of them in fully-grown specimens • The bell margin is ringed with the muscular velum, which is typical of hydromedusae, and aids in locomotion through muscular contraction of the bell. • Occurs off the west coast of North America from the Bering Straits to Baja California Velella velella Velella: By-the-wind sailor • Hydroid colony (more than one animal) • Under 7 cm long • Carnivorous • Habitat: all oceans • Locomotion: currents and wind, can get stranded on beaches, particularly on the west coast of North America during the spring, beginning in the north and moving south over a few weeks’ time Class Scyphozoa • All marine species • Majority of life spent in medusa stage = true jellies • Lack a velum • Mesoglea contains amoeboid mesenchyme cells • Nematocysts in gastrodermis as well as epidermis Aurelia aurita, Moon Jelly Aurelia aurita Characteristics • Translucent • 25-40 cm in diameter • 4 Semi-circle shapes in bell = gonads • Capable of limited motion (uses currents) • Has ocelli; negative phototaxis (meaning that it avoids light and comes to the surface at twilight) • Plankton feeder Chrysaora fuscescens: Pacific Sea Nettle Chrysaora fuscescens: Pacific Sea Nettle Characteristics • Size: 0.5-1m in diameter • Golden-brown bell with reddish tint • White oral arms, up to 24 reddish tentacles • Move via drifting • Feed on zooplankton, crusaceans, pelagic snails and small fish, and other jellyfish • Sting is annoying or painful to humans but not dangerous • Occurs from Gulf of Alaska south to Baja California and sometimes west to Japan, common along California and Oregon coasts Class Cubozoa: Box Jellyfish Cubozoa Characteristics • Cube shaped bell • Tentacles hang from each corner of their velarium • Well-developed eyes • Toxic poison associated with their sting • Extremely agile and strong swimming ability Chironex fleckeri Chironex fleckeri Characteristics Also known as the Sea Wasp • Bell up to 30 cm • Tentacles up to 3 m • Transparent • Very strong venom: depending on the size of the sting area, stings can be lethal in as little as 3 minutes • Feeds on prawns and small fish • Eaten by turtles Chironex fleckeri Distribution Class Anthozoa Class Anthozoa Characteristics • Class Anthozoa includes the anemones and corals. • May be colonial or solitary • All marine • Found at all depths • Differs from Hydrozoa in three ways: 1. Mouth leads to pharynx, a region prior to the gastrovascular cavity 2. Gastrovascular cavity divided into sections by mesenteries (membranes) 3. Mesoglea contains amoeboid mesenchyme cells Metridium farcimen, plumose anemones Metridium farcimen Characteristics • White, feathery tentacles • Size: 50 cm to 1 m • Carnivore: feeds on small invertebrates and zooplankton • Occurs on the west coast of North America • Has been known to live to 100 years in an aquarium; the cause of death was equipment failure, not a natural death Ptilosarcus gurneyi, The Sea Pen Ptilosarcus gurneyi Characteristics The Sea Pen • Description: A sea pen with a fleshy lower part of stalk buried in the sediment. • Upper part of central stalk (rachis) has a hard central support. • Branches are thick and fleshy with small polyps along the edges. • Usually yellow or orange, often large (up to 1/2 meter). • Geographical Range: Gulf of Alaska to southern California • Depth Range: Shallow subtidal to 70 m • Habitat: Sand and mud bottoms • Biology/Natural History: The entire central part (rachis) is said to be one large polyp. Smaller, inconspicuous polyps open into it and pump water in an out as needed for expansion or contraction. Produces a strong greenish luminescence when disturbed. Preyed upon by several nudibranchs, including Hermissenda crassicornis, Armina californica, and Tritonia festiva, and of the seastars Dermasterias imbricata, Pycnopodia helianthoides, Mediaster aequalis, and Crossaster papposus. The sea pens may rapidly burrow into the sediment when contacted by a predator. Although they do not appear to burrow when exposed only to seawater which contained a predatory seastar, they were more likely to burrow after contacting a predatory seastar if they had already been exposed to its smell. This species responds to different predators differently. (Walla Walla.edu) Video: https://www.youtube.com/watch?v=_NuafQVAcaQ Urticina crassicornis Urticina crassicornis Characteristics Painted Anemone, Christmas Tree Anemone • Tentacles can be cross-banded in color • Column can be variable in color • Diameter: up to 20 cm • Height: up to 30 cm • Geographic distribution: Alaska to Southern California • Depth Range: Low intertidal to 30 m. • Habitat: Often below or hanging from the underside of boulders. • Biology/Natural History: Feeds on crabs, urchins, mussels, gastropods, chitons, barnacles, and fish. May feed on stranded jellyfish. • May live 60-80 years. Anthropleura elegantissima Anthropleura elegantissima Characteristics Aggregating Anemone • Clonal • Hosts endosymbiotic zooxanthellae (which photosynthesize) • Diameter: up to 8 cm • Range: Pacific Coast of North America • Reproduction: Sexual and asexual. New individuals colonizing a rock can undergo binary fission; colonies of polyps are genetically identical Anthropleura xanthagrammica Haystack Rock, Cannon Beach, Oregon August 12, 2014 Taken by the Haystack Rock Awareness Program Includes a camouflaged cabezon fish. Anthropleura xanthagrammica Characteristics Giant Green Sea Anemone • Animal Wire video of Anthropleura eating a juvenile cormorant: https://www.youtube.com/watch?v=oQaMF1mmJ38 • Diameter: up to 17.5 cm • Height: up to 30 cm • Bright green underwater in bright sunlight, appears brown when exposed at low tide • Occurs in low to mid intertidal zones from Alaska to Southern California • Tend to be solitary and can actually move on their basal disks, but tend to be solitary Phylum Ctenophora Ctenophora Characteristics • Distinguishing feature: Colloblasts, structures on the tentacales that capture prey by squirting glue on them. • Two cell layer with mesoglea in the middle (diploblastic). • Mesoglea contains muscle-like cells • Size: 1 mm to 1.5 m • Non-colonial • Largest non-colonial animals to use cilia for locomotion • Most species have eight strips, called comb rows, that run the length of their bodies and bear comb-like bands of cilia, called "ctenes," stacked along the comb rows so that when the cilia beat, those of each comb touch the comb below. • Nervous system contained in a nerve net (no central nervous system) • Sense of orientation: can tell up from down • Carnivorous Ctenophora body plan Credits • http://bioelevenncuevas.wordpress.com/phylum-porifera/ • "Porifera body structures 01" by Philcha - Own work. Licensed under Creative Commons Attribution-Share Alike 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Porifera_body_structures_01.png#mediaviewer/File:Porifera_body_structures_01.png • https://www.portol.org/thesaurus/images/reticulate%20skeleton.JPG • http://upload.wikimedia.org/wikipedia/commons/8/84/Velellavelella.JPG • http://www.funpicweb.com/wp-content/uploads/2011/03/MoonJelly.jpg • http://upload.wikimedia.org/wikipedia/commons/a/a9/Anthopleura_xanthogrammica_1.jpg • http://www.photomacrography.net/forum/userpix/2226_Hydra_5X_1.jpg • http://upload.wikimedia.org/wikipedia/commons/2/2e/Coral_Outcrop_Flynn_Reef.jpg