Scattered mythological and archaeological evidence lends credibility to the theories of an ancient reptilian race. Possibly extra terrestrial in origin and possibly of Earthly origin that may have pre-dated or even coexisted with the Human Race. The Ubaid Lizardmen are an example of Reptilian People. These artifacts however, lack an extant civilization or mythos to help explain them.
In Judeo-Christian lore, the Bible does not mention reptilians per se, but does mention serpents such as the one that got Adam and Eve evicted from the Garden of Eden.
The serpent of Eden was actually not a snake as we would recognize one and was only somewhat serpentine.
The Hebrew word for Serpent, as used in the Book of Genesis is 'Nahash' sometimes rendered as Nachash. According to many ancient Hebrew texts, the serpent walked upright as men did. Such an interpretation of an erect - two legged serpent is actually in agreement with the book of Genesis and other ancient resources.
Genesis 3:14 'So the Lord God said to the serpent, 'Because you have done this,' Cursed are you above all livestock and all wild animals! You will crawl on your belly and you will eat dust all the days of your life." which implies that prior to his transgression he had legs and walked as opposed to crawled.
Legends of the Jews by Louis Ginzberg states that the serpent in Genesis could speak and walk upright on two legs. He also chased Adam and Eve through the garden.
"Among the animals the serpent was notable. Of all of them he had the most excellent qualities, in some of which he resembled man. Like man he stood upright upon two feet, and in height he was equal to the camel." .. In Gods punishment of the serpent God is cited as stating ... "I created thee to be king over all animals, cattle and the beasts of the field alike; but thou wast not satisfied. Therefore thou shalt be cursed above all cattle and above every beast of the field. I created thee of upright posture; but thou wast not satisfied..."
So therefore as per Hebrew legend , the serpent of Eden was not originally a snake as we know them today, but a reptilian creature that did not crawl and slither about. He was not cursed to crawl on his belly till after the transgression with Eve of Eden. The 'Serpent' of eden was not a Snake but a reptilian creature unknown to Modern man.
Other cultures have myths of serpent people as well. Cecrops I, first King of Athens was half man, half snake. The Chinese have legends of Dragon Kings sometimes depicted as reptilian humanoids.
In ancient Egyptian the reptilian legends generally refer to Sobek who is depicted as a human with a crocodile head.
Further south from Egypt, to the land from which humanity sprang - Africa. Some African folklore tells about a race of reptilian People that controlled the earth eons ago. Chitauri, the reptilian race as per legend employed native Africans to mine gold for them.
The Hopi Indians refer to a reptilian race they call the Sheti, translated as "Snake-Brothers", who live underground. Other Amerindian Groups have similar legends.
In India - the Naga are the reptilian people of legend and myth.
Kappa, the Japanese reptilian alien has been mentioned and talked about in many Japanese texts and tales from the ancient times. The Japanese Kappa has some qualities reminiscent of the teenage mutant ninja turtles, but he is in line with other reptilian myths.
Carl Sagan in The Dragons Of Eden speculated that if non-avian dinosaurs hadn't become extinct, would they have evolved into man like intelligent creatures ? His speculation inspired a number of other writers including Paleontologist Dale Russell.
Russell theorizes that had the dinosaurs not been exterminated by the ancient meteorite[s] that wreaked havoc on the Earth 65 Million years ago, two legged bipedal predators that were extant at that time, would have eventually evolved into intelligent beings somewhat similar in staure to Humans.
Russell even went so far as to create a hypothetical being known as the "Dinosauroid"with large eyes , three fingers per hand and similar reptilian characteristics. Russell's Dinosauroid bears a resemblance to the Ubaid lizardmen.
And last but certainly not least, David Icke in his book Human Race Get Off Your Knees , draws on ancient legend when he describes the Chitauri  as shape shifting reptilians.
David Icke popularized the conspiracy theory of shape-shifting reptilians that control the Earth by taking on humanoid forms to manipulate human societies. Icke and his followers claim that many of the world leaders are shape shifting reptilians or are controlled and / or possessed by them. In 2013 poll in the US indicated that roughly 4% of registered voters believed in Ickes reptilian conspiracy theory.
The word Chitauri draws on ancient Zulu legend of a reptilian race that came to Earth in prehistory. See: Secret History Of Creation according to Zulu Secret Society