Mumbai, Dec. 16 -- The Indian rupee extends slide against the dollar in opening trades on Tuesday amid muted equities and sustained foreign fund outflows. Uncertainty over an India-US trade deal is also seen pressurizing the counter. INR opened at fresh record low of Rs 90.87 per dollar but recovered slightly to a high of 90.78 so far during the day. Yesterday, rupee slumped sharply to hit fresh lifetime low levels of 90.80 before settling at a fresh all-time low of 90.74 (provisional) against the US dollar, registering a loss of 25 paise over its previous close. Besides, prevailing risk-averse market sentiment, compounded by strong US dollar demand from importers, further dented investor sentiment. The benchmark S&P/BSE Sensex ended down...