The panel chaired by Trevor Hohns could find no room for Glenn Maxwell - chosen as a standby batsman as recently as the Gabba Test against England in November - and also left out the Adelaide Test 12th man Chadd Sayers.
At the age of 21, Richardson has played only five first-class matches, but took 17 wickets in four Sheffield Shield games for Western Australia prior to the start of the Big Bash League. Richardson has stated he takes inspiration from South Africa's Dale Steyn.
Those four appearances included some slippery spells against a full-strength New South Wales team at Hurstville Oval, where he impressed Australia's captan Steven Smith with his pace and movement. "He has impressed very much so early days of this Sheffield Shield season," Hohns said of Richardson. "He's bowled very well, he's got good pace, pretty good control we think. He's certainly a player of the future. He offers a pretty good package too; he's a good fielder and he's pretty handy with the bat. We do see a good future for him particularly that he just seems to have that extra pace which may well be required in South Africa.
"There's no doubt about that [Sayers is unlucky]. Chadd is performing well as he always does, but with Jackson Bird there he has the jump on Chadd at the moment, there's no doubt about that. We have him, Josh Hazlewood is a well-renowned seam bowler then we have the good pace of [Mitchell] Starc, [Pat] Cummins and Jhye Richardson."
Australia's desire to have a high-speed reserve option in South Africa is long-standing. They rushed James Pattinson back from injury in 2014, and he played a substantial role in the pivotal third Test of the series in Cape Town, alongside Mitchell Johnson and Ryan Harris. Pattinson may well have come into consideration this time as well, alongside Nathan Coulter-Nile, but both men are injured.
"I haven't really expected to play for Australia, just having the amount of experience I've had in Shield cricket," Richardson said. "I've only played five games under my belt. But having said that, I'm going in with full confidence. I'm learning so quickly, especially being around these guys, seeing how they go about their business and I'm certainly developing as a person and a player extremely quickly.
"I had a relatively good domestic one-day competition. And, as I said, I'm really confident with how I'm bowling. Body is feeling good. Technique is coming along really nicely, being able to swing the ball at the top of the order is always nice. The message was just to go about the business as you do and just be myself around the group.
"I'm only 70-odd kilos and 178cm tall so I'm not the biggest unit around, but it's always something in your head, you always want to prove people wrong and I think that's been my attitude from the start, If someone is going to beat me down, why not prove them wrong. There's going to be a lot of people that put me down for not having the experience at this sort of level but if I can go in being as confident as I am right now I think I'll be able to get the job done."
Bancroft's technique was gradually dismantled by England over the course of five Tests, but his presence in the team was strongly endorsed by both Smith and the coach Darren Lehmann, who had pointed to his success in building partnerships with David Warner even though he did not always look comfortable. Handscomb's retention as reserve batsman - having been dropped for Mitchell Marsh after the second Ashes match in Adelaide - is likewise a vote of confidence. The decision to retain the pair was simplified by a badly-timed injury to Joe Burns, while the Big Bash League has deprived Matt Renshaw of opportunities to press for a recall.
"It's a absolutely a vote of confidence in Cameron Bancroft," Hohns said. "He's the type of player we love having there at the moment. He's the type of player that seems he could excel in Test cricket. We do have other options for openers if something needs to happen in that area. We've got the spare batsman, currently it's Peter Handscomb.
"We feel adequately covered anywhere in the batting line-up with the personnel we have available. There is no doubt Mitch has made the most of the renewed opportunity, that has to be said. I suppose at the moment Peter is the spare batsman and it's up to the others to perform as they have out here."
Rather than choosing Ashton Agar as a possible second spin bowler, the role he filled in Bangladesh last year, the selectors also recalled 30-year old Jon Holland as injury cover for Nathan Lyon and also as a net-bowling approximation of South Africa's Keshav Maharaj. Hohns said that the unlikelihood of needing to play two spinners meant Holland was preferred as Lyon's back-up.
"[Agar] is definitely still in the developmental stage of his spin-bowling career," Hohns said. "He's a different type of package. He offers us the all-round type of package when the need is there to play two spinners in the one team, probably like in the subcontinent when we've played two or three as well. But, in this instance going to South Africa, we don't envisage the pitches that we will encounter will necessitate playing two spinners in the one side.
"What we thought we needed there was actually a specialist spinner as back-up to Nathan Lyon if anything were to happen to him and he couldn't play and take his place in the side on any given day. [Holland] is a wicket-taker, simple as that. You have a look at his record, it speaks for itself over the past couple of seasons. He fits that specialist role very well."
Of the Test squad, only David Warner will take part in the Twenty20 tri-series against England and New Zealand that begins on February 7. He has been chosen as stand-in captain to allow Smith a break after the current ODI series and also the chance to have a full preparation for the South Africa series, which begins on March 5 and takes place across four Tests in Durban, Port Elizabeth, Cape Town and Johannesburg.
"Steve has had a very big summer and will benefit from a short break both physically and mentally, before he leaves for South Africa," Hohns said. "David is a very capable leader and has captained in Steve's absence before and done a fine job. We wanted to ensure the T20 side had key leadership throughout this Series and we know the team is in good hands with him at the helm."
D'Arcy Short, the indigenous left-handed batsman, earned his place in the T20 squad through a series of outstanding BBL displays, while the left-arm swing bowling of the Sydney Sixers' Ben Dwarshuis has also been recognised. Chris Lynn, who withdrew from the ODI squad due to a calf injury, was recalled, with a chance to prove his fitness by playing for the Brisbane Heat beforehand. The most curious omission was that of Fawad Ahmed, the leading Australian spinner in the BBL but deemed to be behind Adam Zampa in the selectors' order of preference.