* Q4 net loss widens on higher R&D, sales, marketing costs
* Q4 revenue rises 95 pct to $36.3 mln
* On schedule to deliver Model S in mid-2012 (Adds CEO comments from analyst conference call, adds byline)
By Nichola Groom
LOS ANGELES, Feb 15 Electric car maker Tesla Motors Inc (TSLA.O) on Tuesday reported a wider quarterly net loss as higher expenses for research, development, sales and marketing offset a 95 percent surge in revenue.
The company's net loss was $51.4 million, or 54 cents per share, for the fourth quarter ended Dec. 31, compared with a net loss of $24.2 million, or $3.43 per share, in the same quarter a year earlier.
Last year's figures were based on a smaller number of shares outstanding. Tesla, based in Palo Alto, California, went public in June.
Excluding one-time items, the company reported a loss of 47 cents per share. Analysts had been expecting a loss of 50 cents a share, according to Thomson Reuters I/B/E/S.
Revenue for the quarter rose 95 percent to $36.3 million from $18.6 million a year ago. Wall Street analysts had been expecting revenue of $34.32 million.
Gross margin rose to 31 percent from 30 percent in the previous quarter.
During the quarter, Tesla logged higher costs for research and development and for expanding its sales and marketing activities.
Tesla said it was on schedule to deliver its Model S passenger sedan in the middle of 2012.
Tesla has not produced a profit, and doing so hinges on the success of vehicles like the Model S, which the company has said will cost about $57,000 before government electric vehicle incentives are applied.
The company has received more than 3,700 Model S reservations to date, Tesla said. It has also delivered 1,500 Roadster electric sports cars.
In a conference call with analysts, Tesla Chief Executive Elon Musk said that alpha prototypes of the Model S have been tested since late last year and the next phase of development, beta prototype testing, will begin later this year. The alpha tests are ongoing in cold weather, he said.
An electric crossover vehicle called the Model X based on the Model S platform is in development, said Musk, who said Tesla will unveil a design prototype for this vehicle by the end of the year.
Musk said the Model X will give Tesla "potentially twice as much volume" as it competes in the premium luxury market.
Pricing for the Model X will be "comparable to the Model S," Musk said.
Tesla plans to sell its cars in what it says is an innovative type of auto dealership. Musk offered few details but said a Tesla store will soon open in San Jose, California.
Tesla shares rose 1.6 percent after hours to $23.20 after closing at $22.84 on the Nasdaq.
(Additional reporting by Bernie Woodall in Detroit; Editing by Bernard Orr)