Sheridan just made its fifth announced acquisition of the year, buying Premier Emergency Medical Specialists, a 49-physician group in Phoenix, Arizona. Sheridan is the Physician Services division of AmSurg Corp. (NASDAQ: AMSG), the ambulatory surgery giant, which last year paid $2.35 billion for Sheridan, then a portfolio company of Hellman & Friedman. The purchase marks Sheridan’s entry into the emergency medicine market in Phoenix, and boosts AmSurg’s presence there. It also marks the 71st transaction for a doc practice in 2015, and the second announced in December.