Reconstruction of the Permian Period Climate
Date Issued
September 2004
Author(s)
Abstract
Early Permian was the only geological period during which creatures with large spiny back-sails had evolved. These
creatures included the reptiles Dimetrodon and Edaphosaurus as well as the amphibian Platyhystrix. An even earlier
form of reptile, Ianthasaurus, existed which evolved a sail.
This paper examines the body temperature variation of Dimetrodon during the different seasons of the year. The
effect of the sail of Dimetrodon on its body temperature is also evaluated by means of a computer program written
for this purpose and validated from experiments with a model animal. Many suggestions were proposed as to the
function of the sail in a debate that lasted for a century. Among the first suggestions was the utilisation of the sail for
camouflage, waiting for prey while among reeds, or for using the sail literally as a sail on a boat. Today the most
widely accepted view is that the sail was used as a solar collector allowing Dimetrodon to absorb heat from the sun
when it was cold in the morning. By warming up as fast as possible during the day, being a cold blooded animal
Dimetrodon would have a distinct advantage over its prey and its rivals.
The fact that at least two different types of spine bearing reptiles (Dimetrodon and Edaphosaurus) appeared and
disappeared at approximately the same geological period suggested strongly that environmental factors may have
given the spines significant survival value. In this study it is assumed that the sail was an important thermoregularity
element of the animal. Therefore, instead of assuming weather conditions for the Permian period, those of Cyprus,
which exhibit great diurnal and seasonal variations, are used in order to reconstruct the climate condition of the
Permian period.
It is shown that the sail of pelycosaurs provided an advantage to the reptile by warming it up quicker in the morning
in cold environments. This would be a benefit, allowing Dimetrodon to prey on large reptiles, above 55 kg, in the
early morning while they were sluggish. From the results presented a climate similar to that of March for Cyprus
could be representative of that of the Permian period. When the climate became warmer the presence of the sail
became unnecessary, increasing the body temperature above the lethal point. This may resulted in the extinction of
these reptiles.
creatures included the reptiles Dimetrodon and Edaphosaurus as well as the amphibian Platyhystrix. An even earlier
form of reptile, Ianthasaurus, existed which evolved a sail.
This paper examines the body temperature variation of Dimetrodon during the different seasons of the year. The
effect of the sail of Dimetrodon on its body temperature is also evaluated by means of a computer program written
for this purpose and validated from experiments with a model animal. Many suggestions were proposed as to the
function of the sail in a debate that lasted for a century. Among the first suggestions was the utilisation of the sail for
camouflage, waiting for prey while among reeds, or for using the sail literally as a sail on a boat. Today the most
widely accepted view is that the sail was used as a solar collector allowing Dimetrodon to absorb heat from the sun
when it was cold in the morning. By warming up as fast as possible during the day, being a cold blooded animal
Dimetrodon would have a distinct advantage over its prey and its rivals.
The fact that at least two different types of spine bearing reptiles (Dimetrodon and Edaphosaurus) appeared and
disappeared at approximately the same geological period suggested strongly that environmental factors may have
given the spines significant survival value. In this study it is assumed that the sail was an important thermoregularity
element of the animal. Therefore, instead of assuming weather conditions for the Permian period, those of Cyprus,
which exhibit great diurnal and seasonal variations, are used in order to reconstruct the climate condition of the
Permian period.
It is shown that the sail of pelycosaurs provided an advantage to the reptile by warming it up quicker in the morning
in cold environments. This would be a benefit, allowing Dimetrodon to prey on large reptiles, above 55 kg, in the
early morning while they were sluggish. From the results presented a climate similar to that of March for Cyprus
could be representative of that of the Permian period. When the climate became warmer the presence of the sail
became unnecessary, increasing the body temperature above the lethal point. This may resulted in the extinction of
these reptiles.
Subjects