im not ruling out that it may be a female, but the pictures can be deceptive...if it's a young individual, there is the possibility it has not fully developed yet. also, if a fresh import, sometimes the malnourishment can deflate the package. i bought a real nice male last year that was in pretty bad shape, and it probably could have been confused with a female. also going on the pattern idea, i have to agree with andrew that i have only seen males with the bark striping pattern.
but i still wouldnt give a definitive answer until a length is offered.