Andrew D. Basiago:
There are three principal typologies of humanoid beings on Mars.
The first typology, which I call Homo maris terris, are our genetic relatives from the time before the solar system catastrophe of 9,500 BC, when Earth and Mars were in contact. They resemble bald, homely Earthlings. This is the type that my father and I met at Curtiss-Wright in 1970. They are human beings, like human beings from Earth. It was clear that by 1970 they both had a more advanced space-faring capability than we did on Earth and were working with the United States government.
The second typology, which I call Homo maris, are the indigenous Martian humanoids. They have narrower heads, pointier ears, longer fingers, and smaller bodies than Earthlings. They resemble the creature in the vintage film, Nosferatu. We were advised that if hungry enough, they would sometimes kill and eat human visitors from Earth, so we should be wary of them. This is the type that I encountered when walking through the dilapidated brick city to deliver the data disk to the communications center there. They gave rise to the notion of "Martian" in folklore and popular culture on Earth.
The third typology, which I call Homo maris extraterrestrialis, resemble the Grey ETs of the UFO contact literature. This is the type that Courtney M. Hunt and William B. Stillings and I of the CIA’s jump room program encountered after I saw one that was sitting on the roof of the jump room facility called The Corkscrew when we arrived on Mars one time in 1981-82. As I exited The Corkscrew ahead of my fellow chrononauts, I called out to them, “Court, Brett! A Grey. On the roof. Observing us!” They are probably the result of a branch of the Greys that was left back on Mars at some time in Martian history. It was this type of Martian that is depicted in my historic image, “The Humanoid Being on Tsiolkovski Ridge,” which I published in 2008 in my landmark paper "The Discovery of Life on Mars," which is the first image of a humanoid being on another planet ever published on Earth.
There is a fourth typology of humanoid beings on Mars, the tiny ones that Dave Beamer has detected being crushed under the wheels of NASA’s Mars Exploration rovers. I don't include this type of Martian humanoid in this taxonomy because they are far smaller than the three other typologies of Martians and us.