The Evolution of Reptiles

About 20 million years after Pappochelys, we began to see a more similar looking ancestor to the turtle, the Odontochelys semitestacea. O.semitestacea was roaming the planet in the Late Triassic era in modern day China. Odontochelys differed a lot from modern turtles. Modern day turtles possess a horned like beak without any teeth present in their mouth, while Odontochelys fossils showed that teeth were found embedded in their upper and lower jaws. One of the most interesting features of turtles, both modern and prehistoric, are their shells that formed an armored protective casing over its body. Odontochelys only possessed the plastron (the bottom portion of a turtle's armor) and it had yet to develop a solid carapace. Instead of a carapace,

Adaptive radiation of different organisms have occurred throughout geological time through the filling of ecological niches. Organisms different from one another are capable of radiating greatly, as they evolve traits that allow them to thrive better in their environment. The Anolis lizards of the Caribbean islands are a great example of a single genus to have radiated not once, but multiple times through very similar mechanisms. Different populations of the Anolis phenotypically vary in their morphological traits to facilitate adaptation to particular niches. These phenotypic variations have evolved in convergence in more than one occasion, as recently discovered fossil specimens show similar patterns in morphology to modern Anolis.

Scientists say reptiles evolved from amphibians 340 million years ago. The first reptile was an insect eater. Reptiles were more adaptable and able to

Subclass – Archeorinthes –*Fossil birds (Jurassic birds of Mesozoic Age). *Flight feathers present. *Long tail without a pygostyle. *Carpals and metacarpals free. *Abdominal ribs present. *Hand reduced to three digits.

Staurikosaurus is a dinosaur within the therapod group. Its name is Greek for “Southern Cross Lizard,” named after a small cross constellation visible in the southern hemisphere. It was named by Edwin H. Colbert and its species name is “pricei,” named after Colbert’s colleague, Llewellyn Ivor Price. Price discovered the dinosaur in 1936 in Southern Brazil, but it was described by Colbert in 1970. Staurikosaurus lived in the late Triassic period, roughly 225 million years ago, making it one of the earlier dinosaurs. It was relatively small, standing only 2.25 meters tall, but stretching to a long 7.5 meters from head to tail. It also only weighed about 66 pounds. While the fossil record of the Staurikosaurus is relatively incomplete, scientists

First, the author notes that since modern reptiles are cold-blood and have very low metabolism, ancient reptiles such Pterosaurs could not provide enough energy for powered flight due to their low body metabolism. The professor refutes this statement by referring to the fact that fossil remaining of Pterosaurs proved that, similar to warm-blood animals like birds, these animals had

The Bunostegos have knobbly growths on their skull and are the largest recognizable reptiles ever seen in the Pareiasaur group, which are plant eating creatures. The Bunostegos traveled a remote desert approximately 260 million years ago. The unusual reptile belongs to the Pareiasaur group, they thrived during the Permian period. The cow sized creature has been named Bunostegos, which means “Knobby roof”. Researchers supports the idea that there was a remote desert in the middle of Pangea with unusual animals. It is possible that the bony knobs on the skull of Pareiasaurs did not serve as a protective function, but were purely ornamental. The knobbly growths remarkably vary in size and shape between different species. The long period of isolation

Physiological diversity among prosimians contributes to a variety of locomotion patterns observed by different species. Walker suggests that prosimian locomotion can be classified into three groups, vertical clinging and leaping, active quadrupedalism and slow climbing quadrupedalism (355). Prosimians that utilize vertical clinging and leaping use the two hind limbs together to propel themselves forward. During this arboreal and terrestrial type of bipedal locomotion, prosimians hold the trunk of their body upright. Active quadrupedalism is characterized by the use of all four limbs when climbing, walking, and leaping. Similarly, slow climbing quadrupedalism involves all four limbs. However, leaping is not observed by prosimians utilizing this form of locomotion. Rather, three limbs are in contact with the branch or ground at all times (Walker, 1974).

     The early tetrapods were the first vertebrates to actually walk the solid earth. They began their conquest of land in the Paleozoic era around 360 million years ago. The question many paleontologists have been asking for a long period of time is whether the anatomy for locomotion on land was developed in water for swimming purposes, or if it was adapted after the creatures became terrestrial. Recent findings of fossils indicate that the transformations of the aquatic creatures happened underwater in order to help them survive in the changing world. When looking for answers, they had to examine forearm, hip, wrist, finger, and other bones, as well as the lungs or gills of the early tetrapod fossils.

     A long long time ago, in a galaxy not too far away, was a little blue

Paleontological evidence was compiled to differentiate between extant species to generalize the lineage of testudinid turtles. Lamb and Lydeard (1994) describes the study of molecular phylogeny within the testudinoidea lineage by obtaining blood and muscles samples to isolate genomic DNA and compare mtDNA sequence variation. The above mentioned scientists examined distinct assemblages of the four extant gopher tortoise species: Bolson tortoise (Gopherus flavomarginatus), gopher tortoise (Gopherus polyphemus), desert tortoise (Gopherus agassizii), and the Texas tortoise (Gopherus

Matrotrophy is the alternative reproductive method to laying shelled eggs in reptiles. With this maternal strategy, females can supply their unborn offspring nutrients from their own bodies via a placenta for their entire gestation period rather than relying on egg nutrient stores and external incubation (Itonaga et al. 2012). Squamates are known to contain several species that give birth to live young, contrary to the usual shelled-egg method of most other reptilian taxa such as the Crocodilians and Tuataras. Matrotrophy in Squamates likely has many origins and probably did not evolve as a result of one environmental element alone (Albergotti and Guillette 2011). The amount of maternal provisioning is vastly different between viviparous and

The way snakes give birth is either through live birth, viviparity, or by laying eggs, oviparity. Snakes are located within, Reptilia, the same class many dinosaurs were located in. Reptiles are the descendants of creatures in the Paleozoic period called, Labrynthodonts. One of the earliest reptiles that resembles the snake is the, Eophis, an eight inch long snake that lived in England (Guillette Jr. 1993). The Eophis was very different compared to modern snakes, Eophis had four legs and is believed to have been living near water. The limbs are what enabled Eophis to move rapidly in water (Guillette Jr., 1993). Around 100 million years ago the limbs in Eophis were loss and limbless snakes evolved (Guillette Jr., 1993). The fossil record of early snakes is very rare due to snakes consisting of many small and very fragile bones making them easily destroyed. Most of the species classified within Reptilia are oviparous. (Guillette Jr., 1993). Snakes are no

Reptiles are first group of vertebrates which became fully adapted for terrestrial mode of life. Reptiles consist mainly of snakes, tortoises, crocodiles. They are not considered economically useful as many of them like snakes and crocodiles are harmful. Still they have some economic importance such as – As food –*Reptiles are important source of protein for human populations. *The

This lab report compares Amphibia, Reptilia, and Mammalia in order to outline the similarities and differences between the many vertebrate classes. By comparing and contrasting theses classes, a further understanding and knowledge of Vertebrates can be gained.