You're approaching this from the wrong direction. It'a a matter of linguistic consistency, dammit! How can you have a solid setting with vermisilitude and gravitas when the naming conventions are all over the place.
The Macetail Behemoth is just fine. Ankylosaurs, pshaw! Dog latin, overly scientific and technical, non-descriptive. 4e had the right idea - it just didn't go far enough!
In 5e, I look forward to seeing the Stripefur Bigcat replace the so-called 'tiger', the ugly quasi-Greek portmanteau of 'minotaur' succeeded by the Bullhead Mazegiant, ridiculous outdated Gygaxianisms like 'aboleth' smoothed into 'Skinslime Slaverfish', and deliberately obscure, exclusionary and pretentious literary references such as 'Demogorgon' made understandable and accessable with the intuitive and elegant use of 'Twoarguingbaboonhead Rottouchtentaclearmssortaaquaticdemonguy'
You know it makes sense.
Edit: and sorry if this seems overly snarky or edition-war-ish, not my intention. I just find the whole compound name thing irresistably funny...