Anatomy and Physical Appearance of Bipedal Lizards

I will now describe the anatomy and physical appearance of these unknown large bipedal lizards. I will first describe the anatomy and diversity of lizards in general.

Introduction To Lizards

Lizards are a group of reptiles belonging to the suborder Lacertilia in the order Squamata. Their closest living relatives are the snakes, which are also members of the order Squamata, and the tuataras, which belong in the closely-related order Rhynchocephalia. Squamates are the second-most speciose order of vertebrates on Earth, second only to the Perciformes, and they live on every continent other than Antarctica. Lizards are a very diverse and incredibly successful group of animals that have managed to evolve and adapt to numerous habitats and ecosystems all across the world.

Within the lizards, there is great diversity in body size and shape, as well as behavior and lifestyles. For example, monitor lizards are large terrestrial apex predators, while iguanas are arboreal and mostly herbivorous. In the past, there existed even greater diversity than this. One example is the mosasaurs. These were gigantic, carnivorous lizards that were adapted to a marine lifestyle. They were among the top predators in the Cretaceous seas, and they are thought to have fed on fish, shellfish, plesiosaurs, and possibly even other mosasaurs. 

Therefore, it is clear that the lizards are a very adaptable and remarkably succesful group of organisms.

Leg Anatomy

Like all other living reptiles, most lizards walk predominately on four legs, with their legs sprawling out to the sides of their bodies. This is different from mammals, birds, and dinosaurs, who all have legs which are directly underneath their bodies. However, some species, such as the larger monitors, are capable of walking with their legs held in a semi-erect fashion beneath their bodies.

This is because, generally, lizards' legs have a tendency to become more erect the longer they are, and the larger the animal is. Therefore, large lizards with long legs can have limbs that appear and function just like the more erect limbs of mammals and birds.

In my last post, I wrote about how sightings of small carnivorous 'dinosaurs' in North and South America probably represent an unknown species of giant, predatory iguanid lizard that frequently walks on two legs. These animals appear to be capable of both quadrupedal and bipedal locomotion. However, as their front limbs appear to be much shorter than their hind legs, it appears to me that they are mostly bipedal, and occasionally drop down on all fours. This would make them more bipedal than any other lizards known to science. 

In addition, these creatures also appear to have much longer hind limbs than any other lizards known to science. This would presumably enable them to run quickly in pursuit of prey. And, indeed, this is what numerous sighting reports seem to indicate.

Teeth And Claws

These animals appear to be omnivores which eat both plants and meat. They use their sharp teeth and claws to  capture and kill their prey. Some sighting reports have indicated that they have especially long and sharp claws on their feet, like the extinct 'raptor' dinosaurs, or dromaeosaurs. I would presume that they would probably use these claws as weapons, possibly for predation. It is also possible that they could be used for self-defense, or for fights between males (male lizards, especially iguanas, tend to fight with each other a lot). 

It is unclear what purpose, if any, the relatively short forearms could be used for. It's possible that they could use their arms to grasp small prey items, but this is just speculation. We do know that they also have long, sharp claws on their hands, albeit not as long as the claws on the feet. 

They are also armed with powerful jaws full of long, sharp teeth. The teeth have large, bump-like serrations. Teeth that are serrated in this way are useful for both chomping on plants and slicing through flesh. Once again, this is presumably indicative of these animals' omnivorous diet. 

Skin And Coloration 

These animals are covered with scaly skin, like all other reptiles. Some eyewitnesses have reported seeing hair- or feather-like structures on the skin, especially on the back. I think that these are probably  just scales that resemble hair or feathers. Many iguana species have spikes on their backs, and it is possible that a confused witness could mistake them for fur or feathers. 

The color of the skin varies considerably according to the reports. However, most of the time, these animals are described as being either green, brown, or orange. Their bodies are covered with brown or black stripe-like markings, or splotches.

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In conclusion, these giant bipedal iguanid lizards are about 9 to 10 feet long, and 4 to 5 feet tall when standing erect on 2 legs. They have long, erect hind limbs, and short arms. They have scaly skin with fur-like scales on the back, and they are adorned with stripe-like markings on their skin. They have sharp teeth with large, bumpy serrations, and very sharp and dangerous claws on the feet.

In my next few posts, I will discuss the behavior and habits of these animals, as observed from the sighting reports. I will try to identify what animals they prey on, what habitats they live in, and possibly also what methods cryptozoologists should use to try to search for them. 

Until then, cheers!

Giant Bipedal Lizards in North America

Since the American civil war, large bipedal reptiles which closely resemble theropod dinosaurs have been sighted in the United States. Most of these sightings have happened in the western states, such as Wyoming, Colorado, and northern New Mexico.
Witnesses describe an animal that is always on its hind legs, is around 10 feet long from head to tail, and stands about 5 feet tall. It has a long, pointed snout filled with sharp teeth, and sharp claws on its hands and feet. It has large eyes. Sometimes, witnesses also report that these creatures have spines on their backs, like iguanas. Usually, they run away from humans. However, a few encounters do appear to show agression towards humans.

Although they have been sighted all over the southwest, there is one town in southern Colorado which has gained significant publicity in recent years due to sightings of these creatures. That town is Pagosa Springs, Colorado. The animals have been seen here since at least the 1930s. From 1995 to 2002, another rash of sightings occurred in Pagosa Springs. Several people described seeing creatures exactly like the ones that were previously seen in that area many decades earlier.
On 2 August 2002, an article in a Colorado newspaper discussed these sightings, and a local reptile expert was quoted as saying that the descriptions of the creatures did not appear to match those of any known reptile.

Convergent evolution

Researchers who have been studying the sightings have come up with several theories about what the strange animals are. Obviously, the animal that first comes to your mind when you hear the description is a small theropod dinosaur, such as a Velociraptor or a Troodon. Therefore, it is no wonder that many researchers believe that these animals are surviving theropod dinosaurs.
However, I have a hard time accepting this theory. You see, there is a trend in cryptozoology which me and many others as well have noticed. Darren Naish calls it the 'Prehistoric Survivor Paradigm' (PSP). The prehistoric survivor paradigm is the belief among some cryptozoologists that, if a cryptid looks just like a certain prehistoric animal, then it must be a surviving descendant of that prehistoric animal. Personally, I disagree with this assumption.
There exists a phenomenon which is familiar to most biologists known as convergent evolution.
Convergent evolution is when two or more unrelated organisms look or act very similar to each other, even though they are completely unrelated to each other. This often happens if both of the organisms live in similar habitats, or occupy a similar ecological niche. Convergent evolution is the reason why bats, birds, and bees all have wings. It is the reason why a rhinoceros somewhat resembles a Triceratops. It is also the reason why birds and mammals are both warm-blooded. There are lots and lots of other examples of convergent evolution out there, as well.

One of the most striking examples of convergent evolution is the resemblance of the recently-extinct Thylacine (Thylacinus cynocephalus) to the common Grey Wolf (Canis lupus). However, despite the obvious physical resemblence of these two predatory mammals, they are completely unrelated to each other. The wolf is a placental mammal, like cats, elephants, and humans, while the thylacine is a marsupial, like kangaroos and opossums.

Therefore, what I think is that a species of lizard has evolved to look like a small theropod dinosaur, due to convergent evolution. It has evolved erect limbs and bipedalism (more on this later). The type of lizard cannot be conclusively determined from the reports; however, I think it is probably an iguanian lizard.

In conclusion, I think that most of the sighting reports of "Velociraptors" in the U.S.A. are really just large bipedal lizards. I will be writing much more about these large bipedal North American lizards soon in other posts, including detailed analysis of some of the more notable sightings. I will also examine lizard anatomy and physiology much more closely, in order to clear up any confusion.

See you later!