Produced by the Population Genetics and Evolution class, Furman University

The Carboniferous: Casineria
Casineria was a tetrapod that lived during the Mississippian portion of the Carboniferous Period (Wikipedia 2009). The first specimen was found on the shores of Cheese Bay, Scotland in 1992 and was formally presented in Nature magazine in 1999 (Wikipedia 2009). This small reptilomorph was about 15 centimeters, and along with other similar species, was the first vertebrate to live and reproduce on land (Wikipedia 2009). This ability was made possible by having a stiff backbone, five digits on each hand, more advanced leg bones that could support its slender body while walking on land, and the ability to lay eggs outside of water - thereby skipping the aquatic larval stage of amphibians (Monastersky 1999). These 'amniotic' eggs had multiple embryonic membranes that surrounded, protected, and nourished the growing fetus. However; the outer shell was not hard like present day reptiles (Fossil Wiki 2010). These multiple membranes allowed for gases, nutrients, and waste to pass through with out loosing water, and are not present in the simpler eggs of fish and amphibians (Monastersky 1999). Since the multiple membranes kept the egg moist and prevented it from drying out, primitive amniotes like Casineria were able to spread out and colonize land (Wikipedia 2010). From Casineria and its terrestrial adapted, egg-laying descendents, present day reptiles, birds, and mammals evolved (Fossil Wiki 2010).

Page by Chapin Hardy

Casineria. Photo Credit: Wikipedia

Fossil Wiki. 2010. Amniote. Accessed March 3, 2010.

Monasterky R. 1999. Out of the Swamp. Science News Online. Accessed March 3, 2010.

Wikipedia.2010. Amniote. Accessed March 3, 2010.

Wikipedia.2010. Casineria. Accessed March 3, 2010