From his name, it would be easy to assume a Latin origin for the east Hull-born forward. Indeed, Italy coach Paul Broadbent went so far as to put his name down in a provisional World Cup squad for the Azzurri.
But Mariano’s roots can be traced to Portugal’s Cape Verde Islands, through his father. His international eligibility does not stop there, however.
“My dad’s from the Cape Verde Islands, on the west coast of Africa,” the 26-year-old told Love Rugby League.
“My old assistant coach, Paul Broadbent, who was the Italy assistant coach, just put my name down for them. He didn’t even ask me!
“I had an option at the World Cup to represent the United States, because my grandad’s American. My grandmother is Scottish too.
“But it never occurred to me to get into contact with anyone about it.”
Should Scotland have an international tournament this year, though, Mariano would be eager to pull on the dark blue jersey of his grandmother’s nation.
“Of course I would,” he insisted.
“The experience side of things would make me want to do it, the experience of playing alongside great players. It’s an experience you can never achieve anywhere else.
“I’d be happy to play. The Americans came calling this year but I couldn’t find my grandad’s records at the time, so I didn’t play.
“To be honest, I enjoyed the time off. It was nice to spend time with my family. It was the first time for years I didn’t have an operation to recover from.”
Mariano is looking forward to his time at Castleford, after moving from local rivals Wakefield Trinity Wildcats, where he played 46 games.
He is grateful for the chance that the Wildcats offered to him to revitalise his career, though, after leaving Hull Kingston Rovers in 2010.
“I was sad to leave Hull KR, with it being my hometown club,” he said.
“But when I did, I worked with John Kear at Wakefield. His exact words were, ‘I’ll throw you in the deep end, and we’ll see what you’ve got’.
“I ended up playing every game but two that year. That’s what I needed to kickstart my career, really.”