A Martian Tweak of the Martian Golden Age
Image from Arik
A Martian tweak from the First Golden Age of Mars, during the Federation era. The low gravity on this world allows this clade to attain an average height of 2.75 metres. These tweaks are tolerant of high levels of greenhouse gases, such as carbon dioxide and halocarbons.
A Martian Tweak of the Current Era
Image from Phil B
A Martian tweak from the Current Era, adapted to the atmospheric conditions that exist on Blue Mars. Additional nostrils at the top of the nose allow the tweak to breathe in and out in a cyclic fashion, absorbing extra oxygen from the 0.7 bar atmosphere.
Interplanetary Age Martian Tweak
Image from Steve Bowers
An early Martian tweak of the Pre-Technocalypse Era, adapted to very low pressure environments. These tweaks did not remain on the planet once the atmosphere of Mars passed 100 millibars, since the thick atmosphere was uncomfortable for them. Most members of this clade have migrated to various locations in the Terragen Sphere since this time, particularly New Mars".
Source : http://www.orionsarm.com/eg-article/4eea9e2f31f63