Prof disagrees with assigned textbook regarding an exam question This actually happened to my wife, but for the sake of simplicity I'll talk about it as if it happened to me.

I wrote a final exam for a university course last week, and a couple days ago I got my marks and the correct answers back. I disagreed with one of the questions I answered wrong, so I pulled out the textbook that was assigned to this course and found that it supports my answer. I sent an email to my prof with the page number and the exact quote from the textbook that supports my answer. His reply was (with slightly changed wording):


  In class I said that correct exam answer... This is an issue with any text and shows why class is so vital: Texts rapidly go out of date or (such as the broad text used for this course)  demonstrate a lack of depth. Lectures are usually much more up to date.


Keep in mind that this is an Archaeology class, which in my unprofessional opinion really doesn't "go out of date" all that quickly. The textbook is the assigned textbook for this course by the university. The online lecture notes posted by the prof make no mention of the disagreement. I was not present at the lecture.

Do professors have an obligation to recognize the assigned textbook as an authority in the context of the course? In my experience, when confronted with such a problem they typically go "Ok, fair enough, I'll give you the mark", but are they just being nice or are they supposed to do this? He's not a senior prof (not even PhD yet), so do you think going to his superior would help?

If I get this one extra mark it will bump me up 0.4 GPA for the course because I'm right at the cut-off. 

Edit:
Since several people asked, the question was something like "Which Aztec god is the god of war and is associated with water". The book said one god, Huitzilopochtli, was the god of war, while Tlaloc was the god of fertility and rain. When studying for the exam, Huitzilopochtli stuck in my head as the god of war, so I picked him. The prof said that in class he mentioned that Tlaloc also had militaristic aspects.
Note that I'm not saying the prof is wrong objectively, only that our book makes no mention of Tlaloc being war-like and instead makes emphasis on fertility and life, being a beneficial god, which seemed totally opposite to war. When I sent my email I explained that I picked Huitzilopochtli because the book lists only him as the war god, but that I recognize my answer is only half-right due to the water reference, and that I feel that Tlaloc is also only half-right since he's not a war god.  Also, the prof agreed with me that the book was misleading, but said that I should've come to the lecture. Hence my question here focusing on whether the book should have any authority without getting into the details of the question itself.
Do professors have an obligation to recognize the assigned textbook as an authority in the context of the course?


No, there is no such obligation.  It's a bad educational practice to choose a textbook that's seriously unreliable, but even good textbooks slowly go out of date, and they sometimes have a lack of detail or even outright errors as well.  It's important for professors to try to be clear about any deficiencies the textbook has, for example by highlighting them in class.  I provide a written list of any typos or other issues I am aware of (although I note that of course there may be others as well).  However, there is no obligation to accept the textbook's version as a correct answer, and there are no specific rules about how things must be brought to the students' attention.  It's entirely up to the lecturer's discretion.

I would expect that many professors would be more flexible or accommodating than what happened in this instance, but not all of them.  At least in the sort of universities I'm familiar with (in the U.S.), there's no way an administrator will change the grade under these circumstances if the faculty member who assigned it is unwilling to do so.  

On the other hand, it's not clear to me from what you say whether this person is a regular faculty member (due to the lack of a Ph.D.).  If you are dealing with a teaching assistant, it could be worth asking the professor in charge of the whole course.  This will probably upset the TA, but it might work (since the professor will want to maintain common policies among all the TAs assigning grades).  Other than that, I don't see any recourse.

Added in light of Pete Clark's answer: I'm assuming your answer is definitely wrong.  I.e., either the textbook had an error in it or it's out of date regarding a clear scholarly consensus.  On the other hand, if you can make a case that your answer is actually correct or accepted by serious researchers (not just that the textbook says it, but that authoritative and up to date scholarly sources agree), then you've got more of a basis for disputing the grade.