The national coach has also included the eight Scotland men selected for the British & Irish Lions’ tour of South Africa.
Among the dozen uncapped players is Dylan Richardson, the South African-born Sharks forward who can play at flanker or hooker.
Scotland kick off the series with a match against Tonga on October 30, then face Australia, South Africa and Japan. All the games are at BT Murrayfield
Four uncapped players who were named in last week’s training squad have dropped out; Edinburgh’s Matt Currie, Jack Blain and Charlie Savala, and Glasgow Warriors full-back Cole Forbes.
The extended group welcomes back Lions Stuart Hogg, Ali Price, Finn Russell, Chris Harris, Duhan van de Merwe, Hamish Watson, Zander Fagerson and Rory Sutherland following their involvement in the South African series.
A total of 11 new players have been added to the squad from the training group, including the English-based Ewan Ashman, Josh Bayliss, Matt Scott, Huw Jones and Adam Hastings.
In the pack, the uncapped players are Ashman, Bayliss, Richardson, Rory Darge, Luke Crosbie, Jamie Hodgson, Marshall Sykes and Pierre Schoeman.
Glasgow Warriors provide all the uncapped backs in Rufus McLean, Jamie Dobie, Ross Thompson and Sione Tuipulotu.
Townsend said: “It’s exciting to bring together a blend of highly experienced and uncapped players for our first week of the Autumn Nations Series campaign.
“There have been some notable performances from both our home-based players and those at clubs outside of Scotland, which has enabled us as coaches to select a group which are playing well and will be motivated across the four games.
“We also feel that this the right time to bring in some younger players given their early season form. They have created opportunities for themselves to represent their country and we believe that they will thrive in the Test match environment.
“We face four tough matches in four weeks and Tonga, Australia, South Africa and Japan each present a different challenge and an opportunity to perform in front of our people at BT Murrayfield. It’s great to hear that we will now play Australia in front of a capacity crowd at BT Murrayfield, and it means a huge amount to the players to have this level of support.”
Scotland squad for Autumn Nations Series
Ewan Ashman – Sale Sharks - uncapped
Josh Bayliss – Bath Rugby - uncapped
Jamie Bhatti – Glasgow Warriors – 18 caps
Fraser Brown – Glasgow Warriors – 54 caps
Luke Crosbie – Edinburgh Rugby – uncapped
Rory Darge – Glasgow Warriors – uncapped
Matt Fagerson – Glasgow Warriors – 13 caps
Zander Fagerson – Glasgow Warriors – 38 caps
Grant Gilchrist – Edinburgh Rugby – 45 caps
Nick Haining – Edinburgh Rugby – 8 caps
Rob Harley – Glasgow Warriors – 22 caps
Jamie Hodgson – Edinburgh Rugby – uncapped
Oli Kebble – Glasgow Warriors – 8 caps
Murray McCallum – Glasgow Warriors – 3 caps
Stuart McInally – Edinburgh Rugby – 40 caps
Dylan Richardson – Cell C Sharks – uncapped
Jamie Ritchie – Edinburgh Rugby – 27 caps
Sam Skinner – Exeter Chiefs – 12 caps
Pierre Schoeman – Edinburgh Rugby – uncapped
Rory Sutherland – Worcester Warriors – 16 caps
Marshall Sykes – Edinburgh Rugby – uncapped
George Turner – Glasgow Warriors – 17 caps
Hamish Watson – Edinburgh Rugby – 41 caps
Mark Bennett – Edinburgh Rugby – 22 caps
Darcy Graham – Edinburgh Rugby – 19 caps
Jamie Dobie – Glasgow Warriors – uncapped
Chris Harris – Gloucester Rugby – 28 caps
Adam Hastings – Gloucester Rugby – 23 caps
Stuart Hogg – Exeter Chiefs – 85 caps
George Horne – Glasgow Warriors – 14 caps
Damien Hoyland – Edinburgh Rugby – 4 caps
Sam Johnson – Glasgow Warriors – 18 caps
Huw Jones – Harlequins – 31 caps
Blair Kinghorn – Edinburgh Rugby – 25 caps
Duhan van de Merwe – Worcester Warriors – 10 caps
Rufus McLean – Glasgow Warriors – uncapped
Ali Price – Glasgow Warriors – 42 caps
Finn Russell – Racing 92 – 55 caps
Matt Scott – Leicester Tigers – 39 caps
Kyle Steyn – Glasgow Warriors – 1 cap
Ross Thompson – Glasgow Warriors – uncapped
Sione Tuipulotu – Glasgow Warriors – uncapped