Difference Between Diapsid vs Synapsid
Diapsid and Synapsid are not common terms or references that being used in the usual language, but those bear some considerable significance. The significance of being aware about these types of animals is that humans and other mammals are included in one. Before understanding the differences between Diapsid and Synapsid, it would be proper to be aware of the characteristics of these two types of animals, and this article provides such information in a summarized form and finally performs a comparison for a better clarification.
What is Diapsid?
A diapsid is any vertebrate with two major holes known as temporal fenestrae in their skull. The earliest known diapsid lived on the Earth about 300 million years ago. Most of the reptiles and birds belong to the group of diapsids, as they have two temporal holes in their skull. There are more than 14,600 extant species of birds and reptiles included in the type of diapsids. That means they are an extremely diversified group of animals including crocodiles, lizards, snakes, tuatara, and birds. However, lizards and snakes have only one temporal hole in the skull, but their ancestors had two. In addition, birds have a heavily restructured and modernized skull, but both those birds along with snakes and lizards are still categorized as diapsids, as their ancestors had two temporal fenestrae. These all-important holes are located at the both sides of the skull above and below the eye, which counts up to four as two from each side. The importance of this bone arrangement is that it allows for a firm and strong muscle attachment. Therefore, the jaw muscles can provide a super powerful bite from a widely opened mouth. Crocodiles would be the best example to explain the diapsid arrangement of the skull bones and its success for a predatory life. Apart from the present day existing animals, the extinct animals such as dinosaurs, pterosaurs, plesiosaurs, and many more reptiles were diapsids. According to the ancestral skulls of the diapsids, the lower arm bone was longer than the upper arm bone of the holes.
What is Synapsid?
Literally, the term synapsid means the fused arch, and the synapsids are a group of animals (vertebrates) including all the mammals and few other mammal-like reptiles. The distinguishing feature of the synapsids is the presence of only one hole in each side of their skull around the temporal bone, which accounts two holes in total. Synapsids have special types of teeth known as incisors, canines, and molars. The presence of different types of teeth has allowed the animals to be more versatile in feeding behaviours. Therefore, the ecological influences in feeding have been diversified across synapsids. The metabolism, presence of hair on the skin, and many other mammalian characteristics are also present among present-day synapsids. However, the synapsids have originated among reptiles, and with time, it became more mammalian and less reptilian.
What is the difference between Diapsid and Synapsid?
• Synapsids have only one opening in the skull behind each eye, whereas diapsids have two temporal holes in each side of the skull.
• Most of the reptiles and all the birds are diapsids while most of the mammals are synapsids.
• Diapsids can open their mouth wider and could give a stronger bite compared to the synapsids.
• Diapsids have only canines while synapsids have more teeth types including incisors, canines, and molars.
• Synapsids have more feeding niches than diapsids.
• The taxonomic diversity is higher among diapsids than the synapsids.
• Synapsids have evolved more than the diapsids have.