Ronnie Ortiz-Magro from 'Jersey Shore' was allegedly dragged by a car driven by his baby mama, Jen Harley ... and she's been arrested for domestic battery.
Jen was busted late Sunday in Vegas after she and Ronnie got into a fight while driving home from a BBQ. Sources close to the exes tell us Jen hit Ronnie in the face during the argument, and he demanded she pull over and let him out of the car.
We're told Ronnie got caught in his seatbelt, but Jen took off anyway ... dragging Ronnie. Worst of all ... we're told their 2-month-old daughter, Ariana, was in the car at the time.
Harley was booked for domestic violence at Clark County Detention Center
We're told Ronnie's face was bloodied and bruised and, as you'd expect, he's got a nasty road rash. Also, none of this was for cameras ... "Jersey Shore" was not shooting Sunday.
As we previously reported ... Harley allegedly spit on him and punched him in the head earlier this month. They also got into an explosive fight caught on video back in April.