CenozoiC: neogene: MioCene and PlioCenelaCey Kasten / aPril 2012

Continental Movement: Miocenenorth america:• Sierra Nevada & Cascade mountain ranges are formed.• The Panama isthmus begins to form a connection between North and South America.

Eurasia:• The Tethys Sea connection between the Mediterranean and Indian Ocean is severed• The Paratethys barrier is periodically disrupted allowing migration

Africa:• Rifting occurred in East Africa• The African-Arabian plate united with Eurasia

antarctica:• Became isolated from the other continents leading to the formation of a circumpolar ocean circulation

South America:• The Andes mountains rise due to plate tectonics.

Climate Changes: Miocenenorth america:• Non-seasonal and drier mid-continent climate occurred due to mountain range development• The increasing occurrences of drought and an overall decrease in absolute rainfall promoted drier climates.• Grasslands began to spread, radiating large herbivores and carnivores into extinction.

Australia:• An overall increase aridity occurred as it continued to drift northwards• The continent went through many wet and dry periods, decreasing rainforests.

Eurasia:• Severing of the Tethys Sea caused the increase in aridity in Southern Europe.

Africa:• The union of the continents of Africa and Eurasia caused interruption and contraction of the Tethys Sea, thereby depleting the primary source of atmospheric moisture in that area.

antarctica:• The antarctic polar ice cap was allowed to develop. This accelerated the development of global seasonality, aridity, and enhanced global cooling.

Life Forms: Miocene• A major shift occurred when kelp forests and grasslands became more diversified.

• Open vegetation systems (deserts, tundra, and grasslands) became more common than closed vegetation systems (such as forests).

• This led to a rediversification of temperate ecosystems and many morphological changes in animals.

• Mammals and birds in particular developed new forms, whether as fast-running herbivores, large predatory mammals and birds, or small quick birds and rodents.

• By the end of the Miocene 95% of modern seed plant families existed.

• Kelp forests appeared for the first time, as did sea otters and other critters unique to those environments.

Miocene Life Form: Megapiranha

Name: Megapiranha (Big piranha).

Species: M. paranensis (type).

Diet: Uncertain, probably carnivorous, but teeth could have been used for a herbivorous diet.

Size: Estimated up to 1 meter long.

Known locations: Argentina.

Time period: Tortonian of the Miocene.

Fossil representation: Premaxillae teeth.

Continental Movement: Pliocenenorth america:• The joining of North and South America officially happened at the Isthmus of Panama• The Cascades, Rockies, Appalachians, and the Colorado plateaus were uplifted• The Sierra Nevada was elevated and tilted to the west

Eurasia:• The Indian and Asia plates interacted, forming the Himalayas

antarctica:• Large polar ice caps began to develop and the continent became frozen

Climate Changes: Pliocene

• Climate cooling was significant in the Pliocene epoch.

• The beginning of the epoch saw numerous fluctuations in temperature, which gave way to the general cooling trend towards the end of the Pliocene.

• This long term cooling, actually started in the Eocene and continued up to the ice ages of the next epoch.

• Generally, the climate was warmer than modern day temperatures, although significant cooling was occurring on a global scale.

Life Forms: Pliocene• Grasslands continued to develop as well as the grazers that lived off of them.

• On land, the creation of a land bridge between North and South America enabled species to migrate

between the two continents.

• This led to a migration of armadillo, ground sloth, opossum, and porcupines from South to north america

References --“Megapiranha.” Prehistoric Wildlife. Web. 09 Apr. 2012. <http://www.prehistoric-wildlife.com/species/m/megapiranha.html>.“The Miocene Epoch.” UCMP. Web. 09 Apr. 2012. <http://www.ucmp.berkeley.edu/tertiary/miocene.php>.“PIRANHA PICTURES: Yard-long “Megapiranha” Fossil Found.” National Geographic. National Geographic Society. Web. 09 Apr. 2012. <http://news.nationalgeographic.com/news/2009/06/photo-galleries/giant-piranha-pictures-evolution/index.html>.“The Pliocene Epoch.” UCMP. Web. 09 Apr. 2012. <http://www.ucmp.berkeley.edu/tertiary/pliocene.php>.