Answer: he presence of neotenic populations near those with large larvae has made it difficult to identify mole salamander species. The tiger salamander complex was previously considered a single species ranging from Canada to Mexico, falling under the name A. tigrinum. Despite differences in coloration and larvae, tiger salamanders were found throughout their unbroken range, which made it difficult to delineate subspecies, let alone elevate any populations to species status. In morphological terms, tiger salamanders are all very similar, with large heads, small eyes, and thick bodies. This is probably because tiger salamanders have the primitive morphology of mole salamanders. They are also the largest of the mole salamanders and have very large larvae. All populations have similar lifestyles, and their lifecycles are identical. However, when one looks at tiger salamander populations distant from each other, different species within this complex become apparent. The ranges of these potential species overlap, and hybridization occurs, blurring the lines between species.
Step-by-step explanation: