The turtle's shell is divided into two sections&colon; carapace and plastron. They have an inflexible trunk encased in a horny carapace above and a plastron below. The species is identified on the basis of the structure of the carapace and plastron. The plastral scutes join along a central seam down the middle of the plastron. The wood turtle's plastron (ventral shell) is yellowish in color and has dark patches. The plastron, or lower shell, is yellow with dark blotches symmetrically arranged. The ventral surface is called the "plastron". Males have concave plastra in contrast to the flat plastron of females. The lower shell that encases the belly is called the plastron. In many species, dimorphisms include elongated foreclaws or a concave plastron in the male. The male also has a more concave plastron, believed to be another adaptation for mating. The male plastron is curved inwards to aid reproduction. Raphael is a bright, handsome turtle despite the cracks on his plastron. The actual suture between the bridge and the plastron is called the anterior bridge strut. Concerns have also arisen over the use of turtle plastron and seahorses.