The
Romulans are a
Humanoid race from the planet
Romulus in the
Beta Quadrant. The Romulans are biological cousins of
Vulcans, as they are descended from those who rejected
Surak's reforms during the
Time of Awakening. The
Romulan Star Empire is the Romulan state and one of the major powers in known space.
http://www.memory-alpha.org/en/wiki/Romulan
Physiology
Like Vulcans, Romulans have pointed ears, eyebrows that are arched and upswept, and
copper-based
blood that is green when
oxygenated in the arteries, or copper or rust-colored when deoxygenated in the veins. (
Star Trek Generations) Most Romulans have two brow ridges above the bridge of their nose, forming a V-shape on the forehead. However, a minority of Romulans lack these ridges, making them outwardly indistinguishable from Vulcans.
These "browless" Romulans appear to be confined to the 23rd century, from Mark Lenard's Romulan Commander in 2266 ("Balance of Terror") through Ambassador Nanclus in 2293 (Star Trek VI: The Undiscovered Country). Despite their common ancestry there are also many subtle internal physiological differences between Vulcans and Romulans. This is evidenced in Dr.
Beverly Crusher's failed attempt to treat a Romulan,
Patahk, who had suffered advanced synaptic breakdown, with the methods used to treat Vulcans. (
TNG: "
The Enemy")
Romulans lack the rigorous mental disciplines developed by the followers of Surak. They are a passionate people, easily moved to extreme emotions. (
TOS: "
The Enterprise Incident")
This lack of mental discipline would seem to explain why Romulans lack the telepathic abilities that Vulcans possess. There have been numerous instances of Romulans successfully mating with other species, as evidenced in
Sela (Human/Romulan),
Ba'el (Klingon/Romulan), and the grandfather of
Simon Tarses (Human/Romulan). General
Korrd indicates in a conversation with
Caithlin Dar that Romulan women may have a unique anatomical makeup, although such comments are never substantiated.
Star Trek V: The Final Frontier
A reference to Saavik being half-Romulan and half-Vulcan was cut from the final edit of Star Trek II: The Wrath of Khan. It was, however, mentioned in the novelization of Star Trek III: The Search for Spock. While Vulcans possess much greater physical strength than most humanoids, Romulans are roughly equal to
Humans in their strength. (
Star Trek Nemesis)
The
Terothka virus is a
disease unique to Romulan physiology. Romulans are also susceptible to
Tuvan Syndrome. (
VOY: "
Message in a Bottle";
DS9: "
Inter Arma Enim Silent Leges")
Valdore, a Romulan male (2154)
A male Romulan (2266)
A female Romulan (2268)
Vreenak, a Romulan male (2374)