Thread:UltimateTitan6/@comment-995426-20160727080041/@comment-995426-20160728073800

I was still studying the subject. When I read a lot more extensively on the matter (for research on cladistics in particular), I read about various "amphibian-like fish" and "reptile-like amphibians" and so forth in the fossil record. Among the things that were clarified: When I realized the clarity of these distinctions (there were no pre-amphibian tetrapods, there were no pre-reptilian amniotes), the distinctions collapsed and became artificial, and the simpler wisdom is to use the more familiar terms for categories rather than the hyper-technical terms I'd been using before. In fact, one of the only real category doublets we still use are Category:Vertebrates vs. Category:Fish, as Vertebrates are a more quick-access category directly containing groups like fish, amphibians, reptiles, birds, mammals and humans, while Fish contains only more direct fish entries and Category:Amphibians as a direct child entry. And while it is cladistically correct that all reptiles are amphibians, all reptile entries should be limited to its category or subcategories, and not placed directly in the amphibian category. In fact, for the most part, categories only contain entries that cannot be placed into subcategories, which is usually a species that has only been used for one character. All this helps keep the category trees relatively neat, convenient and uncluttered.
 * All tetrapods are amphibians and vice versa, and "amphibian" refers to both prehistoric tetrapods and to modern living ns. "Amphibian" arose more as a descriptive term before the understanding of modern taxonomy.  But while "tetrapod" may be a more taxonomically technical term (vertebrates with four legs), "amphibian" is the more familiar term, and usually the only term likely to be encounter in a lay person's usage.
 * Similarly, all amniotes are reptiles and vice versa, and the distinction has the same issues as tetrapod vs. amphibian. An "amniote" is any vertebrate that lays eggs (or gestate) whose fetus is surrounded by an amniotic membrane.  But technically, the first amniote coincides with the first true reptile, though there were "reptile-like amphibians" earlier in the fossil record which were already beginning to exhibit reptile-like features.  And again, "reptile" is going to be the familiar term, and "amniote" more technical.

Does that make sense?