PHYLUM PHYLUM CNIDARIANCNIDARIAN

OutlineOutline

• ClassificationClassification

• CharacteristicsCharacteristics

• ReproductionReproduction

• Description of the 4 classesDescription of the 4 classes

• Current experimentationCurrent experimentation

• DistributionDistribution

• Fossil recordsFossil records

ClassificationClassification

Alternate phylum name is Coelenterate Alternate phylum name is Coelenterate (Gr. (Gr. KoilosKoilos, hollow, + , hollow, + enteronenteron, gut, + L. , gut, + L. ataata [pl. suffix] [pl. suffix]

Consist of more than 9000 speciesConsist of more than 9000 species

4 classes 4 classes

Cnidarian - (Gr. Cnidarian - (Gr. KnideKnide, nettle, + L. , nettle, + L. aria aria [pl. suffix] like or connected with)[pl. suffix] like or connected with)

Characteristics of cnidariansCharacteristics of cnidarians

• Aquatic (marine, some Aquatic (marine, some fresh water)fresh water)

• Body structure (radial Body structure (radial or biradial symmetry)or biradial symmetry)

• Gastro vascular cavityGastro vascular cavity

• Two layers (epidermis Two layers (epidermis and gastrodermis)and gastrodermis)

• Nematocysts Nematocysts

Two forms of Two forms of cnidarianscnidarians

1.1. Polyp (attached)Polyp (attached)– live in colonies live in colonies

2.2. Medusa Medusa (jellyfish)(jellyfish)– Free-Free-

swimmingswimming

REPRODUCTIONREPRODUCTION

Class ScyphozoanClass Scyphozoan(Gr. (Gr. Skyphos, cup)Skyphos, cup)

“The true jellyfish,” can be characterized by a “The true jellyfish,” can be characterized by a thick, jelly like bell made up of mesoglea and thick, jelly like bell made up of mesoglea and

95% to 96% water. Their entire body is 95% to 96% water. Their entire body is covered with nematocysts, which packs a covered with nematocysts, which packs a painful sting. Oral arms are their primary painful sting. Oral arms are their primary

source for feeding and ingestion. source for feeding and ingestion. Reproduction is sexual.Reproduction is sexual.

Class HydrozoaClass Hydrozoa(Gr. (Gr. HydraHydra, water serpent, + zoon, animal), water serpent, + zoon, animal)

MainlyMainly marine and live colonial. Consist of an marine and live colonial. Consist of an epidermis, gastrodermis, and mesoglea. epidermis, gastrodermis, and mesoglea.

Hydras use a basal disc for movement and Hydras use a basal disc for movement and secrete mucous for assistance. The hydra secrete mucous for assistance. The hydra

relies on tentacles for feeding and digestion. relies on tentacles for feeding and digestion. They reproduce asexually (budding) and They reproduce asexually (budding) and

sexually, usually in Autumn.sexually, usually in Autumn.

Class AnthazoanClass Anthazoan(Gr. (Gr. Anthos, Anthos, flower, + flower, + zoon, zoon, animal).animal).

Only exist in the polyp form.Only exist in the polyp form. Can live Can live solitary as anemones or in colonies, such as solitary as anemones or in colonies, such as

corals. Possess a gastro vascular cavity corals. Possess a gastro vascular cavity subdivided by septa bearing nematocysts. subdivided by septa bearing nematocysts.

Reproduction through separate sexes or Reproduction through separate sexes or asexually by budding, but commonly pedal asexually by budding, but commonly pedal

lacerationlaceration

Class CubozoaClass Cubozoa(Gr.(Gr. Kybos Kybos, a cube + , a cube + zoonzoon, animal)., animal).

Size range up to 25 cm tall, but are usually 2 to 3 cm. Size range up to 25 cm tall, but are usually 2 to 3 cm. The transverse of the bell appears square in these The transverse of the bell appears square in these

animals. On the corners of the bell are tentacles these animals. On the corners of the bell are tentacles these help in moving and feeding. Reproduce by asexual help in moving and feeding. Reproduce by asexual

budding.budding.

Current experimentationCurrent experimentationBioluminescenceBioluminescence

Aequorin, composed Aequorin, composed of Calcium+of Calcium++activated +activated photoprotein emits photoprotein emits a blue-green light. a blue-green light. This light is used This light is used by scientists to by scientists to highlight genes for highlight genes for quicker studies.quicker studies.

DistributionDistributionFungiid Coral from IndonesiaFungiid Coral from Indonesia

DistributionDistribution

• Cnidarians generally occupy two Cnidarians generally occupy two major niches major niches

• Some use their cnidocysts to trap Some use their cnidocysts to trap prey. Other cnidarians, such as prey. Other cnidarians, such as anthozoans depend on depend on zooxanthellae. zooxanthellae. These are, These are, symbiotic symbiotic dinoflagellates within their within their tissues. This is how they survive.tissues. This is how they survive.

DistributionDistribution

• These single-celled protists carry out These single-celled protists carry out photosynthesis within the animal's photosynthesis within the animal's tissues, and pass on the carbon tissues, and pass on the carbon compounds they fix to their hosts; compounds they fix to their hosts; corals, therefore, are photosynthetic corals, therefore, are photosynthetic animals in a sense animals in a sense

DistributionDistribution

• While not all corals are dependent on While not all corals are dependent on symbionts — some live at great depths symbionts — some live at great depths where there is never light where there is never light

• colonial, reef-forming corals depend on colonial, reef-forming corals depend on these symbionts; therefore, reefs can only these symbionts; therefore, reefs can only exist in shallow water. The white areas on exist in shallow water. The white areas on the coral reef on the next slide show the the coral reef on the next slide show the reefs exposed at low tide. This loss of reefs exposed at low tide. This loss of symbionts, called bleaching, is deadly to symbionts, called bleaching, is deadly to coral reefs. coral reefs.

Fossil RecordsFossil Records

• Cnidarian fossils date back to the Cnidarian fossils date back to the time when animals first appear in the time when animals first appear in the fossil record, the Vendian. Since fossil record, the Vendian. Since then, the fossil record of cnidarians then, the fossil record of cnidarians without mineralized skeletons is without mineralized skeletons is quite sparse, and restricted to quite sparse, and restricted to unusual sites with excellent fossil unusual sites with excellent fossil preservation.preservation.

Fossil RecordsFossil Records

• Cnidarians which possessed hard skeletons, the Cnidarians which possessed hard skeletons, the corals, have left a significant legacy of their corals, have left a significant legacy of their existence. While a few mineralized coral-like existence. While a few mineralized coral-like fossils have turned up in the Cambrian Period, fossils have turned up in the Cambrian Period, identifiable corals began an evolutionary identifiable corals began an evolutionary radiation in the Early Ordovician. These Paleozoic radiation in the Early Ordovician. These Paleozoic corals included taxa known as tabulate corals, corals included taxa known as tabulate corals, rugose corals, and heliolitid corals. All these rugose corals, and heliolitid corals. All these forms were wiped out at the end of the Permian forms were wiped out at the end of the Permian Period, in a mass extinction event that claimed Period, in a mass extinction event that claimed something like 95% of all marine invertebrate something like 95% of all marine invertebrate species (Foster, 1979)species (Foster, 1979)

Fossil RecordsFossil Records

• Scleractinian corals first appear in the Middle Scleractinian corals first appear in the Middle Triassic, about 15 milion years after the Triassic, about 15 milion years after the Permian extinction. They rapidly expanded Permian extinction. They rapidly expanded into ecological niches once dominated by into ecological niches once dominated by tabulate and rugose corals, and became the tabulate and rugose corals, and became the dominant dominant hermatypichermatypic (reef-building) (reef-building) organisms in shallow tropical marine organisms in shallow tropical marine habitats. Because corals are sensitive to habitats. Because corals are sensitive to changes in light, temperature, water quality, changes in light, temperature, water quality, and salinity, their fossils provide information and salinity, their fossils provide information that can be used to interpret climate and that can be used to interpret climate and geography of past environments.geography of past environments.

ScyphozoaScyphozoa

• All scyphozoa are marine, though a All scyphozoa are marine, though a few fresh water forms have few fresh water forms have occasionally been reported.occasionally been reported.

• While many species live solitary While many species live solitary lives, some like lives, some like AureliaAurelia may travel in may travel in shoals of hundreds to thousands of shoals of hundreds to thousands of individuals stretching for dozens of individuals stretching for dozens of kilometers.kilometers.

HydrozoansHydrozoans

• Hydrozoans may date back to the Vendian Hydrozoans may date back to the Vendian (late Precambrian), but the fossil record of (late Precambrian), but the fossil record of hydrozoans is scanty before the Cenozoic, hydrozoans is scanty before the Cenozoic, starting about 65 million years ago. The starting about 65 million years ago. The oldest fossil milleporines and stylasterines oldest fossil milleporines and stylasterines — the "fire corals," so called from their — the "fire corals," so called from their stony growths that resemble those of true stony growths that resemble those of true true corals — appeared in the Late true corals — appeared in the Late Cretaceous and are moderately common as Cretaceous and are moderately common as fossils in the Cenozoic fossils in the Cenozoic

• A rare fossil hydroid, A rare fossil hydroid, MississippidendriumMississippidendrium from the from the Cretaceous of northeast Mississippi Cretaceous of northeast Mississippi

AnthozoansAnthozoans

• Anthozoans are exclusively marine, Anthozoans are exclusively marine, polypoid cnidarians. They occur from the polypoid cnidarians. They occur from the intertidal zone to the depths of the trenches intertidal zone to the depths of the trenches (to 6000 m). In excess of 6000 species (to 6000 m). In excess of 6000 species currently exist (Hyman 1940), comprising currently exist (Hyman 1940), comprising about two-thirds of extant cnidarian species about two-thirds of extant cnidarian species (Dunn 1982); some anthozoans, such as the (Dunn 1982); some anthozoans, such as the scleractinian corals, have a rich fossil scleractinian corals, have a rich fossil history (Wells and Hill 1956).history (Wells and Hill 1956).

CubozoansCubozoans

• A few probable cubozoans are known A few probable cubozoans are known as fossils from the famous Mazon as fossils from the famous Mazon Creek locality (Pennsylvanian age) Creek locality (Pennsylvanian age) near Chicago, Illinois near Chicago, Illinois

• Other fossils that may be cubozoans Other fossils that may be cubozoans have been found in the Jurassic have been found in the Jurassic Solnhofen Limestone of Bavaria, Solnhofen Limestone of Bavaria, Germany Germany

DispersalDispersal

• Cnidarians live in aquatic environments and inhabit all Cnidarians live in aquatic environments and inhabit all depths, from the sandy substrate up to the surface. depths, from the sandy substrate up to the surface. They can be found from the Great Barrier Reef rising They can be found from the Great Barrier Reef rising off the coast of northeastern Australia to the off the coast of northeastern Australia to the continental shelves of bone-chilling arctic oceans, and continental shelves of bone-chilling arctic oceans, and just about every saltwater marine habitat in between. just about every saltwater marine habitat in between. (national zoo, 2008)(national zoo, 2008)

• Some jellyfish are even found in freshwater lakes, Some jellyfish are even found in freshwater lakes, such as the freshwater jellyfish (such as the freshwater jellyfish (Craspedacusta Craspedacusta sowerbyisowerbyi), which haunts several lakes in New ), which haunts several lakes in New Zealand. Not to worry though, these jellyfish are Zealand. Not to worry though, these jellyfish are harmless to humans and feed mainly on zooplankton harmless to humans and feed mainly on zooplankton (national zoo, 2008) (national zoo, 2008)

Figure 1a. Distribution map of 60 species of Chilean sea anemones according to the literature. The two Figure 1a. Distribution map of 60 species of Chilean sea anemones according to the literature. The two species with doubtful classification and the species without location are not shown in the distribution species with doubtful classification and the species without location are not shown in the distribution map. p: type localities; D: type locality of synonymous species; : other collection sites; collection sites map. p: type localities; D: type locality of synonymous species; : other collection sites; collection sites are connected by lines for greater clarity. NPZ: North Patagonian Zone, CPZ: Central Patagonian Zone, are connected by lines for greater clarity. NPZ: North Patagonian Zone, CPZ: Central Patagonian Zone,

SPZ: South Patagonian Zone.SPZ: South Patagonian Zone.

Dispersal PatternsDispersal Patterns

Works CitedWorks Cited

• Conway Morris, S., 1993: The fossil record and early evolution of the Metazoa. --Nature, vol. 361, 21 January, pp. Conway Morris, S., 1993: The fossil record and early evolution of the Metazoa. --Nature, vol. 361, 21 January, pp. 219-225 219-225

• Daly, M, DG Fautin & VA Cappola (2003), Systematics of the Hexacorallia (Cnidaria: Anthozoa). Zool. J. Linn. Soc. Daly, M, DG Fautin & VA Cappola (2003), Systematics of the Hexacorallia (Cnidaria: Anthozoa). Zool. J. Linn. Soc. 139: 419–437139: 419–437

• Fautin, Daphne G. and Romano, Sandra L. 1997. Cnidaria. Sea anemones, corals, jellyfish, sea pens, hydra. Version Fautin, Daphne G. and Romano, Sandra L. 1997. Cnidaria. Sea anemones, corals, jellyfish, sea pens, hydra. Version 24 April 1997. http://tolweb.org/Cnidaria/2461/1997.04.24 24 April 1997. http://tolweb.org/Cnidaria/2461/1997.04.24 inin The Tree of Life Web Project, http://tolweb.org/ The Tree of Life Web Project, http://tolweb.org/

• Fautin, Daphne G. and Romano, Sandra L. 2000. Anthozoa. Sea Anemones, Corals, Sea Pens. Version 03 October Fautin, Daphne G. and Romano, Sandra L. 2000. Anthozoa. Sea Anemones, Corals, Sea Pens. Version 03 October 2000. http://tolweb.org/Anthozoa/17634/2000.10.03 2000. http://tolweb.org/Anthozoa/17634/2000.10.03 inin The Tree of Life Web Project, http://tolweb.org/ The Tree of Life Web Project, http://tolweb.org/

• Fautin, D. G. and R. N. Mariscal. 1991. Cnidaria: Anthozoa. Pp. 267-358 in F. W. Harrison and J. A. Westfall (eds.), Fautin, D. G. and R. N. Mariscal. 1991. Cnidaria: Anthozoa. Pp. 267-358 in F. W. Harrison and J. A. Westfall (eds.), Microscopic Anatomy of Invertebrates, volume 2: Placozoa, Porifera, Cnidaria, and Ctenophora. Wiley-Liss, Inc., New Microscopic Anatomy of Invertebrates, volume 2: Placozoa, Porifera, Cnidaria, and Ctenophora. Wiley-Liss, Inc., New York and other cities.York and other cities.

• Fautin, D. G., Romano, S. L. & Oliver, W. A. Jr., 1999: Zoantharia - Sea Anemones and corals. The Tree of Life Fautin, D. G., Romano, S. L. & Oliver, W. A. Jr., 1999: Zoantharia - Sea Anemones and corals. The Tree of Life

• Fedonkin, Misha A. and Waggoner, Benjamin M. 1997. The Late Precambrian fossil Kimberella is a mollusc-like Fedonkin, Misha A. and Waggoner, Benjamin M. 1997. The Late Precambrian fossil Kimberella is a mollusc-like bilaterian organism. Nature 388(6645): 868-871 bilaterian organism. Nature 388(6645): 868-871

• Foster, Merrill W. 1979. Soft-bodied coelenterates in the Pennsylvanian of Illinois. pp. 191-267 In: Foster, Merrill W. 1979. Soft-bodied coelenterates in the Pennsylvanian of Illinois. pp. 191-267 In: Mazon Creek Mazon Creek fossilsfossils. edited by Nitecki, Matthew H. Academic Press, New York, NY. . edited by Nitecki, Matthew H. Academic Press, New York, NY.

Works citedWorks cited

• Fundación Huinay, Departamento de Biología Marina, Universidad Austral de Chile Casilla 567, Fundación Huinay, Departamento de Biología Marina, Universidad Austral de Chile Casilla 567, Valdivia, Chile Valdivia, Chile

• http://nationalzoo.si.edu/Animals/Invertebrates/Facts/cnidarians/http://nationalzoo.si.edu/Animals/Invertebrates/Facts/cnidarians/

• Parker, S. P. (ed.), 1982: Synopsis and classification of living organisms. Vols. 1 & 2 --McGrew-Hill Parker, S. P. (ed.), 1982: Synopsis and classification of living organisms. Vols. 1 & 2 --McGrew-Hill Book CompanyBook Company

• Image: http://en.wikipedia.org/wiki/JellyfishImage: http://en.wikipedia.org/wiki/Jellyfish

• Image: Image: www.aloha.comwww.aloha.com