A team of RIKEN researchers has finally solved the riddle of
how the turtle shell originated. By observing the development of different
animal species and confirming their results with fossil analysis and genomic
data, researchers from the RIKEN Center for Developmental Biology show that the
shell on the turtle's back derives only from its ancestors’ ribcage and not
from a combination of internal and external bone structures as is often
thought. Their study is published today in the journal Nature Communications.