image: This is the morphological homology of forelimb. A comparison of forelimb morphology in tetrapods. Green shows the scapula, red shows the humerus, pink shows the radius and ulna, and yellow shows the phalanx, metacarpals and carpals. Note, between the animals there are minor morphological changes and variations in numbers. Connectivity's between the elements are not changed, which is called morphological homology. In the case of turtle morphology, the scapula is actually situated ventral to the ribs; however morphological homology, including the muscle plate, is conserved. This image relates to an article that appeared in the July 10, 2009, issue of Science, published by AAAS. The study, by Dr. Hiroshi Nagashima of RIKEN Center for Developmental Biology and colleagues was titled, "Evolution of the Turtle Body Plan by the Folding and Creation of New Muscle Connections." view more
Credit: [Image courtesy of Shigeru Kuratani and Hiroshi Nagashima]