SURGE is an acronym of Sudden Unexplained Recessive Genetic Expression. It occurred in the 2060s with the return of Halley's Comet (SR4A, p. 32 & p. 54).
In 2061, a massive mana pulse affected revelers bathing in the holy waters of the Ganges. The traits expressed by some were unusual skin tones and a pair of extra arms. They are called the Nartaki (Dancers) in deference to Shiva, who the people were celebrating at the time. The Nartaki are considered a distinct type, showing no shared metagenetic markers with other types (RC p.49).
Another SURGE metatype are the hobgoblins, an orc derivation. They have less bodymass than the ork. Greenish skin, sharp teeth and prominent ears are characteristics of the hobgoblins. Most hobgoblins are of Central Asian or Arabic descent (RC p. 49).
Other ork meta-variants include satyrs, oni, ogres in addition to the hobgoblins (RC p.50-51)
The Runner's Companion details meta-variants for elves, dwarves and trolls as well.
SR4A: Shadowrun Core Rulebook 4th Edition
RC: Runner's Companion which covers alternate rules and additional qualities and meta-types for player characters.