Arsenio Rodríguez initially developed son montuno from son. He added instrumental solos called montunos. He also added guaguanco influence, increased the importance of the trumpets and tres, and added new instruments such as the congas and piano. Beny Moré (known as the "Barbarian of Rhythm") further evolved the genre, adding guaracha, bolero and mambo influences, helping make him extraordinarily popular and is now cited as perhaps the greatest sonero.
Later, mambo was derived from son montuno and danzón by making the montuno sections the focus of songs.
Son's characteristics vary widely today, with the defining characteristic a bass pulse that comes before the downbeat, giving son and its derivatives (including salsa) its distinctive rhythm; this is known as the anticipated bass.
The sonclave has both a reverse and forward clave, which dever because a forward clave has a three note bar (tresillo), followed by a two note bar, while the reverse is the opposite.
In the 1970s and onwards, sonmontuno was combined with other Latin musical forms, such as the mambo and the rumba, to form contemporary salsa music, currently immensely popular throughout Latin America and the Hispanic world.