New Zealand, looking to finish this series as 3-1 winners after their dramatic one-wicket victory off the last ball at The Oval on Wedenesday, made a slow start.
But they added 96 runs in the final 10 overs with Styris and Grant Elliott (23 not out) putting on an unbroken 65 for the sixth wicket.
The 32-year-old Styris, appearing in his 152nd one-day international, faced just 91 balls with three sixes and five fours.
Together with big-hitting fellow all-rounder Jacob Oram he upped the tempo with a run-a-ball fifth wicket stand of 77.
That followed Styris and Daniel Flynn's fourth-wicket partnership of 53.
Styris, dropped on 13 off a difficult chance, also survived a tight stumping call on 39.
He was content to play second fiddle while Oram broke the shackles with 52 off 40 balls, including three sixes and two fours.
The tall left-hander eventually holed out to off-spinner Graeme Swann who finished with an impressive two wickets for 33 runs in 10 overs.
Styris, whose fifty came with a six off James Anderson, carved the fast bowler's final ball for six and then did the same to left-armer Ryan Sidebottom with a cleanly struck hit over mid-wicket.
Both Sidebottom and Stuart Broad conceded 50 runs apiece after initially impressive starts with Sidebottom's last two overs going for 28
Kevin Pietersen, in his first match as England captain, with regular skipper Paul Collingwood starting a four-game ban imposed following the team's slow over-rate at The Oval, saw his decision to field first after winning the toss backed up by accurate pace bowling.
Even the normally aggressive Brendon McCullum, hampered by a stomach bug according to a team spokesman, found runs hard to come by.
But it was first change Broad who made the breakthrough after taking some punishment from Jamie How.
The opener, carelessly dropped by Tim Ambrose on four, was out when he sliced Broad's sixth ball to Ravi Bopara at backward point.
Ross Taylor never looked comfortable against Broad and was caught behind for four. And when McCullum, whose 23 runs took an unusually slow 57 balls with just one boundary, nicked Anderson to Swann at slip, New Zealand were 71 for three in the 19th over.
England then dropped two difficult chances, both off Swann.
Styris's slice was put down by a scrambling Bopara at backward point before a diving Ian Bell couldn't cling on to Flynn's hard-hit drive at short cover.
Flynn though was beaten in the flight by Swann and bowled for 35.
Tall left-hander Oram showed his strength and timing by driving medium-pacer Luke Wright for six over Sidebottom at long-off.
Styris, on 39, survived a tight stumping chance after English TV umpire Richard Kettleborough ruled in favour of the batsman and, with 10 overs left, New Zealand were 170 for four.
Oram though hoisted Owais Shah for two huge sixes, the first over mid-wicket and the second over long-on, to go to fifty. Occasional off-spinner Shah's three overs cost an expensive 30 runs.
But, attempting another big shot, Oram lofted Swann to Broad at long-off.