Rio 2016: Hawkins brothers to run marathon
Derek Hawkins will join younger brother Callum in the marathon at this summer's Rio Olympics.
Derek, 26, will also go to Brazil after posting a personal best time of two hours, 12 minutes 57 seconds, inside the 2:14:00 qualifying mark.
English duo Ally Dixon and Sonia Samuels will run in the women's event.
Derek Hawkins, who had a nervous wait to find out if he would be a selectors' pick, told BBC Scotland: "I was in my bed when I got a phone call early this morning; I was elated.
"When I crossed the line, I was the third Brit and just out of the automatic selections, but I ran a PB and you feel that you have justified your selection.
"But it is a matter for the selectors, so it out of your control and you are sitting there thinking for a couple of days."
Callum Hawkins, 23, finished eighth in the London Marathon in a new personal best of 2:10:52 and hailed it as a great achievement for their father, Robert, who is also their coach.
"Before Sunday, he was a bag of nerves and probably more nervous than us," he said. "To get us both in is huge.
"To have your training partner and brother in the same race at the Olympic Games is going to be unbelievable."
Asked what his target would be in Rio, the younger Hawkins said: "In a perfect world, top 20, but it is going to be really tough and conditions are going to be pretty tough - something I've never experienced before in a marathon."
Tewelde, a Glasgow-based Eritrean who claimed asylum in Britain in 2008, ran 2:12:23 to finish 12th in what was his first marathon.
It caps a remarkable story for the 25-year-old, who still bears the scars on his forehead from a landmine that exploded next to him when he was eight, killing his friend.
"It's massive for me," said Tewelde. "It's exciting to be part of the British team and I'm very happy."
Along with the marathon runners, 50km race walker Dominic King has been selected to represent Great Britain after competing in the same event four years ago at London 2012.