cambrian. anomalocaris marella hallucigenea

Cambrian

Anomalocaris

Marella

Hallucigenea

Jellyfish?

Shrimp?

Sponge?

       Parts of Anomalocaris were at first thought to be three separate animals.

Anomalocaris

Wiwaxia corrugataWiwaxia corrugata

Wiwaxia corrugata

Marrella splendens

HallucigeniaHallucigenia

GLB in the Paleozoic EraGLB in the Paleozoic Era

Central North America experienced Central North America experienced repeated transgressions and regressions of repeated transgressions and regressions of shallow, tropical seas during Paleozoicshallow, tropical seas during Paleozoic

Midwest is below equatorMidwest is below equator

Large areas of tropical coral reefsLarge areas of tropical coral reefs

Seas deposited layers of materials that became Seas deposited layers of materials that became sedimentary rockssedimentary rocks Limestone, shales, sandstone, gypsumLimestone, shales, sandstone, gypsum Thornton Quarry, Sagawau Canyon limestoneThornton Quarry, Sagawau Canyon limestone

Ordovician PeriodOrdovician Period 490 - 443 Million Years Ago Shallow, shifting seas covered most of North

America Biodiversity increasing rapidly

Corals, bryozoans, crinoids, cephalopods, a great variety of new brachiopods, trilobites

First fish appear in fossil record Squid-like cephalopods were the largest creatures in

Ordovician seas. Cone-shaped shells sometimes reached a length of 5 meters

(about 16 ft.).

Ordovician PeriodOrdovician Period

Sea floor covered by calcium carbonate mud produced by the breakdown of "stony" algae and animal remains.

Bryozoans and algae trapped the sediment to form small mounds. Mounds protected animals, such as brachiopods,

corals, crinoids, starfish, mollusks, and trilobites.

Receptaculitids are common in the rocks from this area.

Ordovician Ordovician FossilsFossils

Ordovician PeriodOrdovician Period

Algae with Skeletons• Receptaculites appeared

around 488 million years ago in the Lower Ordovician and disappeared 250 million years ago in the Lower Triassic.

• Their modern-day cousins, the Dasycladaceae, are algae that also form calcareous skeletons.

BrachiopodsBrachiopods

Onniella meeki

Illinois

Rhynchotrema dentatum

Illinois

BrachiopodsBrachiopods300 living species 300 living species

of brachiopodsof brachiopods

Brachiopods-Brachiopods-LampshellsLampshells

CrinoidCrinoid

Pycnocrinus dyeri

Cincinnati, Ohio

Nautiloid CephalopodNautiloid Cephalopod

Plectoderas undatus

Illinois

CoralsCorals

tabulate coral Favistella alveolata

Illinois

rugose coral Grewingkia canadensis

Cincinnati, Ohio

Coral ReconstructionsCoral Reconstructions

Rugose coral

Tabulate Coral

Tentaculites -Tentaculites - mollusc mollusc

Tentaculites incurvus

Cape Girardeau, Missouri

Tentaculites oswegoensisTentaculites oswegoensis Waubonsee Creek in Oswego, IL

Rock called Brainerd Formation

Shale and thin dolomite

Upper Ordovician and Silurian

Tentaculites oswegoensisTentaculites oswegoensis

Fossils found only known in Fossils found only known in Illinois Illinois

Animal ranged from Oswego, Animal ranged from Oswego, IL (Kendall County) to possibly IL (Kendall County) to possibly Kankakee River State Park in Kankakee River State Park in Will County.Will County.

TrilobiteTrilobite

Isotelus iowensis

Missouri

Graptolites ‘‘Graptolite' means 'writing in rock‘Graptolite' means 'writing in rock‘ Hemichordate – related to echinoderms & chordatesHemichordate – related to echinoderms & chordates Most graptolites are thought to have been Most graptolites are thought to have been

planktonic, floating or slowly sinking through the planktonic, floating or slowly sinking through the water. water. The spiral shape of some was probably an adaptation to The spiral shape of some was probably an adaptation to

slow sinking. slow sinking. Other graptolites may have been connected to gas-filled Other graptolites may have been connected to gas-filled

sacs, keeping them buoyant. sacs, keeping them buoyant. Lived in water with low oxygen levelsLived in water with low oxygen levels

Fed on planktonFed on plankton

GraptolitesGraptolitesHemichordatesHemichordates

Phyllograptus archaios Phyllograptus archaios

SpirograptusSpirograptus

Graptolite ReconstructionsGraptolite Reconstructions

Silurian PeriodSilurian Period 443 - 417 Million Years Ago — Silurian Period443 - 417 Million Years Ago — Silurian Period Shallow, tropical sea covered Illinois (then south of the Shallow, tropical sea covered Illinois (then south of the

equator) equator) Reefs, corals, crinoids, and shelled invertebrates flourished Reefs, corals, crinoids, and shelled invertebrates flourished Delicate corals, bryozoans, and crinoids were in protected Delicate corals, bryozoans, and crinoids were in protected

pockets and along the sides of the reefs. pockets and along the sides of the reefs. Brachiopods, snails, clams, and trilobites were hidden in the Brachiopods, snails, clams, and trilobites were hidden in the

tangle of the complex branches of these animalstangle of the complex branches of these animals These shelled animals were eaten by predatory, squid-like These shelled animals were eaten by predatory, squid-like

cephalopods. cephalopods. Largest animals of the time were 2-meter-long (6.5 ft.) sea Largest animals of the time were 2-meter-long (6.5 ft.) sea

scorpions called eurypteridsscorpions called eurypterids

Eurypterids

A group of eurypterids (sea scorpions) from group of eurypterids (sea scorpions) from Upper Silurian rocks of the Niagara Peninsula.Upper Silurian rocks of the Niagara Peninsula.

Silurian PeriodSilurian Period

Ocean reefs occurred in a band 30 degrees to Ocean reefs occurred in a band 30 degrees to the north and south of the equator. the north and south of the equator.

Most widespread distribution of reefs in the Most widespread distribution of reefs in the history of North America during Silurianhistory of North America during Silurian

Reefs ranged fromReefs ranged from less than a meter (3.3 ft.) to several kilometers in less than a meter (3.3 ft.) to several kilometers in

diameter anddiameter and

less than 3 meters (about 10 ft.) to nearly 304 meters less than 3 meters (about 10 ft.) to nearly 304 meters (about 1000 ft.) high. (about 1000 ft.) high.

Silurian PeriodSilurian Period

Rich fossil deposits in Illinois and lower Rich fossil deposits in Illinois and lower Midwest from this periodMidwest from this period Many fossils from ancient Silurian reefsMany fossils from ancient Silurian reefs

e.g. Trilobites, Ammonites, Eurypterids, Corals, e.g. Trilobites, Ammonites, Eurypterids, Corals, Crinoids, Brachiopods, Jawless Fish, Primitive Sharks Crinoids, Brachiopods, Jawless Fish, Primitive Sharks

Be sure to visit the online Silurian Reef exhibit from Be sure to visit the online Silurian Reef exhibit from the Milwaukee Public Museum!the Milwaukee Public Museum!

Plants and wingless insects arosePlants and wingless insects arose But GLB fossils of these are rare since entire region But GLB fossils of these are rare since entire region

was under water was under water

Silurian PeriodSilurian Period

Silurian rocks are exposedSilurian rocks are exposed

Along the Kennedy Expressway at Addison Along the Kennedy Expressway at Addison (southbound lanes) (southbound lanes)

In the Thornton Quarry at Homewood In the Thornton Quarry at Homewood

In the Sag Bridge abandoned quarries (Cook County In the Sag Bridge abandoned quarries (Cook County Forest Preserves) Forest Preserves)

Along Rock Creek in the Kankakee River State Park Along Rock Creek in the Kankakee River State Park

Along the Illinois River Along the Illinois River

Near the towns of Lemont, Romeoville and Joliet. Near the towns of Lemont, Romeoville and Joliet.

Silurian Seat at Navy PierSilurian Seat at Navy Pier

Thornton Quarry: Then and Thornton Quarry: Then and NowNow

Chicago is built upon a vast Chicago is built upon a vast Silurian Reef.Silurian Reef.

Silurian Reef Diorama at the Field Silurian Reef Diorama at the Field Museum of Natural History in ChicagoMuseum of Natural History in Chicago

Fossil Crinoids, Brachiopods, Trilobites, Fossil Crinoids, Brachiopods, Trilobites, Ammonoids, Gastropods and Corals are found Ammonoids, Gastropods and Corals are found in Thornton Quarry rock. in Thornton Quarry rock.

Modern reef environments are found in warm, Modern reef environments are found in warm, shallow oceans. shallow oceans. The water is usually clear of silt and wind-blown The water is usually clear of silt and wind-blown

sediments. sediments. Many of the reef inhabitants are filter feeders and Many of the reef inhabitants are filter feeders and

sediment prevents feeding.sediment prevents feeding.

Scene from a Silurian seaScene from a Silurian sea

Silurian FossilsSilurian Fossils

BryozoanBryozoan

Fenestrellina elegans

Chicago

CrinoidsCrinoids

Eucalyptocrimus crassus

Indiana

Scyphocrinites sp

Diorama of a Silurian Reef

Living CrinoidsLiving Crinoids

CephalopodsCephalopods

Nautaloid Cephalopod

Michelinoceras

Illinois

Ammonoid

Living Chambered Living Chambered NautilusNautilus

Silurian TrilobitesSilurian Trilobites

Calymene celebra

Milwaukee

Slab of Upper Ordovician Tyndall Limestone at the quarry in Garson, north of Winnipeg showing a large Receptaculites (calcareous algae) and mottles produced by Thalassinoides burrows.

SpongesSponges

Astylospongia praemosa

Modern SpongesModern Sponges

Sponge Fossils

Corals Corals

tabulate coral Cladopora reticulata

Louisville, Kentucky

Tabulate Coral

Living Corals

Living Coral Polyps

TrilobitesTrilobites

Dicranurus monstrosus Dicranurus monstrosus

Note: defensive spinesNote: defensive spines

In the late Silurian, the first-known land In the late Silurian, the first-known land plants (plants (CooksoniaCooksonia) and air-breathing ) and air-breathing animals (millipedes, centipedes and animals (millipedes, centipedes and scorpions) appeared. scorpions) appeared.

Cooksonia

Psilotum

Arthropleura Pleurojulus steuri Myriopoda millipede

Pleurojulus steuri