I generally go by this standard: If I'm reading something, and I realize that my eyes are moving but I'm no longer understanding, then what I'm "reading" should be phrased better. Rarely is something incomprehensible simply because that's the reality of it. It happens a lot when reading journals especially. It's like there's a conspiracy to waste my time. (I'm perfectly capable of that on my own.) On wikipedia I can do something about it. 

 * The taxonomy and evolution section is difficult to read. Part of me says that there are too many links in it, but another part says that that's all of the words that your average person would wish to be defined. So perhaps what is missing is the space between the technical/linked words. So you could use simpler, 'filler', text there or break it into paragraphs (or both). 
 * The description section doesn't leave me with a visualization of what it actually looks like. There may not be a good way to describe it, which is probably why field guides normally have color drawings/photos. 
 * Put an appropriate image in the description section. 
 * Break up the description section into further sections/paragraphs. or: 
 * It also seemed like much of the description info would be better placed as paragraphs in appropriate later sections. (Egg desc in Eggs section; Larvae desc in Larvae section; etc) 
 * I think the "Life cycle" and "Ecology, behaviour and life history" sections are good, however I think the section titles could be more clear as to what each section is; and why they aren't the same thing. 
 * The subspecies section is good, but I wonder if the "Phenotypes" and "Biogeography and genetics" lists would be better combined, or at least listed in the same order to help someone compare the two lists. 
 * Something else: I suspect that there is a good reason that you've studied this salamander and put such work into it's article page. What is it? You might want to add that (new section?) towards the beginning so people care enough to read the rest of the article. Currently there isn't anything significant distinguishing it from just about every other salamander in existence.