This is Darren Till's stance
This is Lyoto Machida's stance, he's a well known Karate fighter
This is a traditional Muay Thai stance, as shown by Thai stadium champions Nong-O and Singdam
This is a Muay Thai stance adapted for MMA. Shevchenko is a world champ in Muay Thai and a title contender in 2 UFC divisions.
Darren Till's stance is fairly close to Machida's, and if you watch his footwork it's also closer to Machida's than Shevchenko's. There's a lot of emphasis on blitzing straight in with an attack, watch the way he skip steps and lunges in on his opponents, that is not MT footwork. Till has competed in MT in the past but he doesn't fight in a MT style, he looks like someone with a Karate background who went into kickboxing and MMA.