Arthur delayed making any decision on the Captaincy until the end of January, to be given the time to assess the leadership qualities of each candidate.
"Jarryd and Timmy, while very different individuals, both bring their own unique qualities to the Captaincy role," Arthur said.
"I believe with these 2 individuals we have great leaders both on and off the field and that is important for our Members and fans.
"The Coach informed the entire squad of his decision at a team meeting this morning and emphasised how impressed he was by the leadership qualities throughout the group.
"What is really promising is that amongst this group we have a number of players with leadership qualities," Arthur explained.
"Men who have been at the club for a long time, those who haven't, young players and experienced ones, it's a great sign."
Closest of mates, Hayne and Mannah are both local juniors who have played their entire careers in Blue and Gold.
Hayne debuted in the NRL as an 18-year old in 2006 and has gone on to represent both his State and Country - and is one of just three Dally M winners at the club, taking out the prestigious honour in 2009. The fullback will this year help launch a new initiative for the club helping troubled youth from Western Sydney go down the right path.
Mannah started his NRL career in 2009 and showed leadership qualities from an young age. On the field the durable prop has only ever missed a game due to representative duties. Away from football Tim is an ambassador for Ronald McDonald House and this year started his own charity organisation, the Mannah Foundation. Most recently he was awarded Parramatta's Citizen of the Year.