Crassigyrinus, the "thick tadpole,"
was the rebellious teenager of 
life's transition to land. This two-
meter-long creature was one of the 
first tetrapods, or animals with 
four legs. You might not have 
noticed, though, because of its tiny 
limbs! Crassigyrinus' limbs were 
likely vestigial because it had 
readapted to a fully aquatic life-
style. This left it with a slender,
eel-like profile that was perfect
for prowling the early Carboniferous
waters it called home. Following the
teenage trend of ungainly propor-
tions, its head and jaws were gigan-
tic in order to accommodate massive
eyes and two rows of teeth. These
adaptations made Crassigyrinus an 
effective predator. Its streamlined 
body helped it move swiftly through 
the water, while its hefty head tore 
into its prey of choice: small 
vertebrates, like fish.

This wee beastie swam in the swamps
and lakes of what is now Scotland. 
Its large eyes were perfectly adept
at peering through the murky water
that it lived in, and may have also
provided nocturnal vision for when
it snuck out past curfew and tried 
to go party at the pub. Other 
frequenters of the Scottish swamps
included Crassigyrinus' the small 
fish that it feasted upon, anthra-
cosaurs like Proterogyrinus, 
terrestrial temnospondyls, and an 
assortment of arthropods.