From Star Trek Online Geekipedia
The Pahkwa-thanh were a species of space-faring reptiles which were in contact with the United Federation of Planets in the 24th century. While some members of the species are known to possess empathic abilities, most members of the species have no measurable empathic talent.
Humans were known to be rather uncomfortable around members of the species due to their passing resemblance to the dinosaurs of prehistoric Earth. Because of this around only about 100 members of the species, including Doctor Shenti Yisec Eres Ree, were the only Pahkwa-thanh to be serving in Starfleet in the 2370s.