Mississippian	Pennsylvanian
320-360 Ma	286-320 Ma

Mississippian

Abundant fossils include:

crinoids blastoids (Pentremites) bryozoans (Archimedes) fusulinid foraminifera

Early Mississippian crinoid, Edwardsville Formation, Indiana Denver Museum of Natural History

Pennsylvanian

Diorama of Pennsylvanian coal swamp Denver Museum of Natural History

Marine Life

1. Beginning a recovery after the Late Devonian extinction of tabulate-stromatoporoid reefs, extinctions of many fish, floating and swimming animals, and many freshwater forms.

2. Ammonoids rediversified quickly. Predators. Good index fossils in Late Paleozoic.

3. Sharks and ray-finned fishes persisted as a diverse group of predators.

4. Heavily armored fish were replaced by more mobile forms. Ability to swim more rapidly became a necessity as predators became more efficient.

5. Reefs remained poorly developed after the demise of the tabulate-stromatoporoid reefs near the end of the Devonian. Frame-building organisms were scarce.

6. Brachiopods continued to thrive.

7. Bryozoans were prominent.

8. Crinoids and blastoids were common in the sea.

9. Large foraminifera (fusulinids) appeared. First occur in Upper Mississippian; most abundant in Pennsylvanian and Permian.

Life on the Land

Plant Life

More plant fossils in Carboniferous strata than in any other geologic interval.

Coal deposits formed from plant remains in lowland swamps. Coal represents an enormous biomass of plants.

Common coal swamp plant genera:

1. Lycopod trees or club mosses
   • Lepidodendron
   • Sigillaria
   
   Lepidodendron
   Note leaf scars on the trunk.
   (Trees grew to 30 m tall; 90 ft).
   Lycopods are spore-bearing plants, and were confined to swamps. Some grew to about 100 ft tall and were 3 feet across at the base.

2. Ferns and fern-like plants were also common, including spore-bearing ferns and seed ferns like Glossopteris.
   
   Smithsonian Institution, Museum of Natural History
   
   Seed fern
   Denver Museum of Natural History

3. Sphenopsids (like Calamites) were spore-bearing and similar to living horsetails or scouring rushes.
   They are often interpreted as living in moist areas, even perhaps standing water (paleoenvironmental information courtesy of Dr. Richard L. Leary, Curator of Geology (Paleobotany), Illinois State Museum).
   
   Calamites leaves
   Smithsonian Institution, Museum of Natural History
   
   Calamites trunk
   Fernbank Museum of Natural History
   Atlanta. GA
4. Cordaites were tall trees (up to 100 ft). Seed plants. A type of gymnosperm.

5. Note: few lycopods or sphenopsids exist after the Permian. Cordaites became extinct by the end of the Permian. (In the Permian, conifers took over the terrestrial environments.)

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Freshwater and Terrestrial Animals

Aquatic habitats

Ray-finned fishes diversity.
Freshwater sharks.
Molluscs became common - such as clam shells associated with coal deposits.

Terrestrial habitats

1. Insects had important ecological roles
   • Food for other animals
   • Consume and decompose plants and animals

   Insects first appeared in Devonian - wingless.
   Wings appeared by the Late Carboniferous.

   Types of wings:

   • Fixed wings (ex.: dragonflies, damselflies, mayflies)
   • Folding wings - many specializations develop

   
   Dragonfly reconstruction,
   Pennsylvanian coal swamp
   Denver Museum of Natural History

2. Vertebrates
   1. Amphibians
      • First appeared Late Devonian
      • Aquatic or semi-aquatic
      • Eggs and young in water
      • Broad spectrum of shapes, sizes, and modes of life.
      • Were up to 20 feet in length (but most living amphibians are small).

   2. Reptiles
      • First appeared in the Pennsylvanian
      • First found in Nova Scotia inside hollow trees filled with sediment

      The key feature in the origin of reptiles is the development of the amniotic egg.
      • Durable outer shell protects embryo from drying
      • Egg can be laid on land
      • Yolky part of egg provides nutrition; sac contains embryo and another sac collects waste products.
      • Eliminated need to lay eggs in water, allowing vertebrates to live and reproduce on dry land for the first time.
      • Amniotic egg probably evolved in Carboniferous.
      • First fossil eggs are early Permian

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   Similar adaptations occurred in plants and then in animals allowing reproduction on dry land:
   

   1. Plant reproductive structure is seed (Devonian).
   2. Animal reproductive structure is amniotic egg (Carboniferous).

   General trends show a necessity to build the food chain.
   1. Plants first:
      1. Onto land but reproduced by spores, and tied to water
      2. Seed allows tie to water to be severed; plants can colonize dry land

   2. Animals follow plants:
      1. Insects eat plants and are in turn food for other things (like amphibians)
      2. Vertebrates eat plants, insects, and other vertebrates
         1. Fish diversified in freshwater environments (drought stimulus?)
         2. Lungfish and lobe-finned fishes are transitional to amphibians (which eat insects) which are tied to water for reproduction.
         3. Amniotic egg allows tie to water to be severed; animals can colonize dry land.

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   This page created by Pamela J. W. Gore
   DeKalb College, Clarkston, GA
   October 30, 1995
   Last modified November 19, 1997