Board Thread:Wiki Discussion/@comment-32744161-20180614142011/@comment-47205-20180614160245

It's important to remember what the purpose of the taxonomy project is. It compares different creatures made by different people. How can so many alien organisms be compared? Well, there are common themes that many people follow when they create creatures, so the taxonomy project describes what these themes are and which creatures follow them.

When we say that we should focus on morphological features rather than using in-fiction information, this isn't to be taken as some axiomatic dogma. The point is that a lot of in-fiction information - evolutionary relationships, biochemistries, etc. - is generally going to be specific to each individual's fiction, and is often entirely absent, so it can't be used to relate different people's creations to each other.

One thing that is shared by lots of people's creations is that they bear some resemblance to Earth fauna, often deliberately. Sometimes they'll be inspired by individual species, at other times they'll only be intended to approximate a certain class, being e.g. "reptilian" or "avian" or "insectoid". Because this is a common theme that many (possibly most) people follow, whether by intent or otherwise, it is something that the taxonomy project can legitimately use as a criterion for classification.

In this sense, Dinosauria is as morphological as it needs to be: it means that the creatures within it should have features of real dinosaurs or fictional dinosaur depictions.