What makes reptiles distinctive?

What are some examples of similarities between mammals and reptiles?

For example, students see that even the extinct T-Rex has striking similarities to the reptiles of today. Students can compare modern skulls (such as the black rhino and bearded dragon) and see that the same observations made from modern mammals and reptiles can be made of those that lived long ago (such as the T-Rex and colobus monkey).

What should a reptile skull look like?

For example, a reptile should have the cone shaped teeth and may even have the extra cavities seen in the 3D fossil skulls. Students should be able to communicate to their class why they designed their fossilized skull the way that they did.

What kind of skull does a snake have?

Skull and dentition. All reptiles of the super order Lepidosauria (lizards, snakes, and tuatara) have kinetic skulls, but they differ from the dinosaurs in that the joint on the floor of the skull occurs at the juncture of basisphenoid and pterygoid bones in lepidosaurians.

What is the most primitive type of reptile skull?

This is the most primitive type of skull of reptiles that occurred in primitive labyrinthodont amphibians and then in primitive reptiles likeSeymoria. The anapsids were the first reptiles to appear in the Carboniferous Period (345 to 280 million years ago). “Anapsid” means “without arch”, meaning that they have no fenestrae in their skulls.

What is the most primitive reptile skull?

ANAPSID SKULL (found in Cotylosauria and Chelonia) This is the most primitive type of skull of reptiles that occurred in primitive labyrinthodont amphibians and then in primitive reptiles like Seymoria. The anapsids were the first reptiles to appear in the Carboniferous Period (345 to 280 million years ago).

Why are birds sometimes thought of as special types of reptiles?

Birds are sometimes thought of as a special type of reptile because they share a common ancestor with the _______, crocodiles, and alligators. Both birds and crocodiles possess a _______ heart.

Why is the temporomandibular joint only found in mammals?

The answer is that the quadrate and articular bones, once they were no longer part of the jaw hinge, evolved dramatically. They became reduced in size and eventually turned into the incus and malleus, two of the middle ear bones of mammals. The temporomandibular joint is only found in mammals.

Does the temporal bone articulate with the mandible?

In reptiles and other vertebrates, the mandible does not directly articulate with the temporal bone. Note on the mammalian temporal bone: The temporal bone of mammals is formed by the fusion of several bones, including the squamosal.

How powerful is a reptile’s jaw compared to a human jaw?

By comparison, the human jaw exhibits a paltry 500 Newtons of force by comparison. But while the muscles generating the downward force are immensely powerful, this is at the cost of the muscles which open the mouth, a fact exploited by animal handlers able to hold the reptiles’ jaws closed with their hands.

Which is more rigid bird or reptile skeleton?

Many bones in the bird skeleton are fused, making them more rigid than a reptile skeleton. 5. Feathers are made of chitin. Birds are sometimes thought of as a special type of reptile because they share a common ancestor with the _______, crocodiles, and alligators.

Why are marsupials important for the development of jaw articulation?

This change in size represents a change in function from a major support of the jaw to an ear-drum tensing role within the middle ear. Marsupials therefore provide a great resource for following the transition from primary to novel jaw articulation.

How were the ear and jaw formed in early mammals?

In such transitional fossils it is clear that the first step in the process of formation of a mammalian-like ear and jaw was the development of a double jaw joint, that is, two side by side joints, one between the articular and the quadrate and the other between the dentary and the squamosal.

Is the temporal bone the same as the squamosal bone?

Note on the mammalian temporal bone: The temporal bone of mammals is formed by the fusion of several bones, including the squamosal. For the purposes of this lab, we can say that the part of the temporal bone we’re looking at is the same as the squamosal bone in reptiles or amphibians.

Is the lower jaw a vertebrate or invertebrate?

In lizards and other reptiles, the lower jaw (mandible) is formed from several bones joined together. This multi-part mandible is the original vertebrate style, as found in fish and amphibians.

What is the strongest jaws of mammals?

The strongest jaws of mammals – BFQ No Animal BFQ 1 Tasmanian devil 181 2 Spotted-tailed quoll 179 3 Least weasel 164 4 Northern olingo 162 29 more rows

What is TMJ (temporomandibular joint)?

The temporomandibular joint (TMJ) is a bilateral synovial articulation between the ends of the mandible (lower jaw) and temporal bone, part of the skull. Both mastication and facial muscles are attached to the lower jaw.

What happened to the quadrate and articular bones of the jaw?

The answer is that the quadrate and articular bones, once they were no longer part of the jaw hinge, evolved dramatically. They became reduced in size and eventually turned into the incus and malleus, two of the middle ear bones of mammals.

How many bones are in a mammal’s lower jaw?

All mammals, living or fossil, have a single bone, the dentary, on each side of the lower jaw, and all mammals, living or fossil, have three auditory ossicles or ear bones, the malleus, incus and stapes. In some fossil reptiles the number and size of the lower jaw bones are reduced compared to living reptiles.

Is a mammal stronger than a reptile in fight?

In most cases mammal is stronger than reptile kg on kg. There are too much examples: wolverine vs monitor, even marten or polecat. Otter is stronger than crocodile in fight and whakes are much stronger. . Even rat maybe stronger than monitor kg on kg.

How did the three-ossicle ear evolve in mammals?

The evolution of the three-ossicle ear in mammals is thus intricately connected with the evolution of a novel jaw joint, the two structures evolving together to create the distinctive mammalian skull. Keywords: evolution mammals, jaw joint, middle ear

What is the articulation of the jaw?

The jaw articulation in mammals is composed of an articulation between the temporal portion of the squamosal bone (temporal) and the condylar process of the dentary of the lower jaw (mandibular), hence the name temporomandibular joint (TMJ).

Is the reptile jaw related to the middle ear bones of mammals?

The idea that the bones that form the reptile jaw are related to the middle ear bones of mammals was first proposed way back in 1837 by the German anatomist Karl Reichert, long before the field of genetics even came into existence. 12 This theory however, is not consistent with what we now know from genetics and developmental biology.

What is the origin of the middle ear in mammals?

Even the mammalian middle ear (MME) had more than one origin: The middle ear of the triconodont Yanoconodon (Luo et al. 2007), classified as a true mammal, surprisingly shows the ‘pre-mammalian’ condition where the middle ear bones were still connected to the mandible.

What is the evolution of the reptile jaw?

The evolution appears to be directed. Complex changes to the lower jaw and associated soft body parts (muscles, internal ear organisation) and concomitant changes in the post-cranial skeleton and tissues appear to be orchestrated towards a pre-determined end. Not all reptiles evolved in this direction.