出典:Wikipedia
出典:『Wikipedia』 (2011/03/11 13:32 UTC 版)
Decapodiformes is a superorder of Cephalopoda, which includes all species with ten limbs; the name derives from the Greek word meaning ten feet. The ten limbs are divided into 8 short arms and 2 long tentacles. It is presumed that an ancestral coleoid had five identical pairs of limbs, and that one branch evolved a modified arm pair IV and became the Decapodiformes species. Another branch evolved and then eventually lost its arm pair II, becoming the Octopodiformes.