The 22-year-old openside flanker, who can also play hooker, was born in Pinetown, 16km west of Durban, but qualifies for Scotland through his father, who is from Edinburgh.
Richardson, of Cell C Sharks, is the only man in the training squad who does not play for Edinburgh or Glasgow Warriors.
A former South Africa Under-20 international, he featured in both matches when the Sharks played the British & Irish Lions in July. He also played against Glasgow Warriors earlier this month in the United Rugby Championship, finishing up on the losing side at Scotstoun and also having to endure a stint in the sin-bin.
Townsend has been tracking Richardson for some time, according to reports in South Africa. The Scotland coach had a spell in Super Rugby with the Sharks in 2004 where he was a team-mate of Eduard Coetzee, the former prop who is now chief executive of the Sharks. It is understood that Townsend’s relationship with Coetzee helped open the door for Richardson to join the Scotland fold.
Other new boys in the squad include the Edinburgh quartet of Pierre Schoeman, Marshall Sykes, Charlie Savala and Matt Currie. But there is no place for Ben Vellacott, the scrum-half who has made such an outstanding start to the season with the capital club.
In total, there are 14 uncapped players, nine of whom were also picked by Scotland in the summer for matches against England A, Romania and Georgia which were all cancelled due to Covid-19.
The squad will gather at the Oriam on Sunday and train on Monday and is likely to form the basis of the side which plays Tonga in the opening match of Scotland’s Autumn Nations Series at BT Murrayfield on October 30.
The game falls outside the recognised Test window which means Townsend is unlikely to have access to his English-based players or Finn Russell of Racing 92. There is a full programme of league fixtures in both the Gallagher Premiership and French Top14 over the weekend of the Tonga match.
Townsend will name an updated squad next Wednesday which is expected to include the exiles. The autumn Tests continue next month with matches at Murrayfield against Australia (November 7), South Africa (November 13) and Japan (November 20).
Richardson is not the only new South African addition to the squad. Schoeman, the 27-year-old Edinburgh loosehead prop, is called up for the first time after qualifying for Scotland in the summer via the three-year residency rule.
He is joined by team-mate Sykes, the lock forward from Suffolk who is a Scotland Under-20 international and has started two of Edinburgh’s three URC games this season alongside Grant Gilchrist. Sykes qualifies through his Dundee-born grandmother.
The inclusion of Sydney-born Savala is something of a surprise. The former rugby league player has had limited game-time as a stand-off with Edinburgh. His father is from Ayr and Savala, 21, attended the prestigious Scots College in Sydney where he played rugby union before switching codes to join Sydney Roosters.
Currie, the Edinburgh-born centre, has not played competitively for the capital club this season but got his break at the tail end of the last campaign when he featured in three matches. A shoulder injury then curbed his involvement but the 20-year-old impressed for Watsonians in Super6 at the weekend and was player of the match in their win over Ayrshire Bulls. He trained with Scotland during the Six Nations.
The other uncapped players all featured in the summer squad and include on-form back-row player Rory Darge and his Glasgow Warriors team-mates Ross Thompson, Cole Forbes, Rufus McLean, Jamie Dobie and Sione Tuipulotu. There are also places for Edinburgh’s Luke Crosbie, Jamie Hodgson and Jack Blain.
Ali Price, Hamish Watson and Zander Fagerson, who were all part of the Lions tour to South Africa and haven’t played since, are named in the squad. There are also returns for experienced hookers Stuart McInally and Fraser Brown who both missed the Six Nations with neck injuries. Their inclusion sees Dave Cherry drop out, tough luck on the Edinburgh man who had a solid Six Nations after making his international debut off the bench in the historic win over England at Twickenham.
Edinburgh centre Mark Bennett, who was last capped in the defeat by the United States in Houston in 2018, is back after a fine start to the season and there is also a recall for Murray McCallum, the thrice capped prop who moved to Glasgow from Edinburgh in the summer.
Notable omissions include Jaco van der Walt, the Edinburgh stand-off who was man of the match in their draw with the Stormers on Saturday, experienced Glasgow No 10 Duncan Weir and tightheads WP Nel and Simon Berghan.
Townsend said: “It has been great to see both Edinburgh Rugby and Glasgow Warriors make positive starts to their URC campaigns driven by some standout performances from both young and established players.
“With four tough Test matches ahead of us in this year’s Autumn Nations Series it is important we bring players together early, connect with them as coaches and enable them to grow as a group before the campaign gets underway against Tonga at BT Murrayfield. We’ll then move on to the challenge of facing in-form Australia, world champions South Africa and a very dangerous Japan team.
“We are pleased with the depth we are able to call upon to make up this training squad and it provides a genuine opportunity for players to put their hand up for selection to the full Autumn Nations Series squad.”
Autumn Nations Training Squad
Matt Fagerson – Glasgow Warriors – 13 caps
Nick Haining – Edinburgh Rugby – 8 caps
Hamish Watson – Edinburgh Rugby – 41 caps
Rory Darge – Glasgow Warriors – uncapped
Dylan Richardson – Cell C Sharks – uncapped
Jamie Ritchie – Edinburgh Rugby – 27 caps
Luke Crosbie – Edinburgh Rugby – uncapped
Grant Gilchrist – Edinburgh Rugby – 45 caps
Jamie Hodgson – Edinburgh Rugby - uncapped
Rob Harley – Glasgow Warriors – 22 caps
Marshall Sykes – Edinburgh Rugby – uncapped
Zander Fagerson – Glasgow Warriors – 38 caps
Oli Kebble – Glasgow Warriors – 8 caps
Murray McCallum – Glasgow Warriors – 3 caps
George Turner – Glasgow Warriors – 17 caps
Fraser Brown – Glasgow Warriors – 54 caps
Stuart McInally – Edinburgh Rugby – 40 caps
Pierre Schoeman – Edinburgh Rugby – uncapped
Jamie Bhatti – Glasgow Warriors – 18 caps
Rufus McLean – Glasgow Warriors – uncapped
Damien Hoyland – Edinburgh Rugby – 4 caps
Darcy Graham – Edinburgh Rugby – 19 caps
Cole Forbes – Glasgow Warriors – uncapped
Sione Tuipulotu – Glasgow Warriors – uncapped
Mark Bennett – Edinburgh Rugby – 22 caps
Matt Currie – Edinburgh Rugby – uncapped
Sam Johnson – Glasgow Warriors – 18 caps
James Lang – Edinburgh Rugby – 6 caps
Kyle Steyn – Glasgow Warriors – 1 cap
Jack Blain – Edinburgh Rugby – uncapped
Blair Kinghorn – Edinburgh Rugby – 25 caps
Ross Thompson – Glasgow Warriors – uncapped
Charlie Savala – Edinburgh Rugby – uncapped
Ali Price – Glasgow Warriors – 42 caps
George Horne – Glasgow Warriors – 14 caps
Jamie Dobie - Glasgow Warriors - uncapped