@ThylacineAlive - I have NEVER met anyone who would refer to, lets say a Sumatran tiger as
Panthera tigris sondaica or an okapi as
Okapia johnstoni in either a natural or formal conversation, and I doubt I ever will. I would also, tentatively, say I doubt you've ever said that, or any other scientific name besides
Orca, although I have obviously never spoken to or met you. Outside of the less than 1% of the population who thoroughly understand scientific names, most people would, believe it or not, think common names make more sense and facilitate conversation easier.
And I'm sorry, but what a completely bizarre and random example to give. Is that the best example you could come up with? That's more of a random bit of trivia than anything else.
On an somewhat unrelated note, it seems to be accepted that there are very few pure bred tigers, for example. What happens to the scientific names then? Do we just make up new ones? I have wondered about it for a while and it seems like a good time to ask.
As I said in my post, yes common names are often much easier to use when speaking informally. However, I have met several people who do refer to a lot of species by their scientific names, and do you really think the zoo world sticks to common names behind the scenes and in their records? The argument of saying scientific names change so they're useless compared to common names is beyond invalid as, like I said, even old and unused scientific names still refer to the one taxa, whereas common names can refer to any number of taxa or make one species seem like several (as the list
@TinoPup posted proves).
Panthera uncia,
Uncia uncia,
Felis uncia,
Uncia irbis, and
Felis irbis can all very easily be traced back to the Snow Leopard, but if I asked you to tell me what cat species 'Ounce' was, could you do it? Additionally, common names change wildly and without reason all the time. When a scientific name gets changed, most if not all of the time there needs to be an official report published explaining the reasoning why. Common names? I've seen zoo PR departments just make up brand new common names for well-known species for seemingly no reason. Example: What's a Patagonian Tapir? Oh, it's
Tapirus terrestris, more commonly known as the Brazilian Tapir, South American Tapir, Lowland Tapir, Anta, and Flachlandtapir among others. I guess those were all be listed separately if this were an ungulates in the US thread? And don't say it's unfair to put the common names used in other languages because that is exactly the point, especially when those do not translate back into the other common names I used. But you know what is the exact same name in every scenario and in every language? That's right, the scientific name! And besides, sometimes common names change when the scientific name does because the old common name no longer fits, such as when
Starnoenas cyanocephala was discovered to be more like Australian pigeons than New World quail-doves, and as such the common name was changed from Blue-Headed Quail-Dove to Blue-Headed Partridge-Dove. Not a huge change, no, but it'd certainly strike many people as two completely different species should they have just seen the names and not known anything about them.
I do not fully understand scientific names, or do I use them in general conversation all that often, but if someone told me their local zoo just received 'Negros Water Monitors', I would need the scientific name to know they were referring to
Varanus nuchalis.
Also there are a lot more species whose common name
is their scientific name, you just probably don't realize it. Every Dinosaur for example, as well as
Boa constrictor (often referred to Common Boa, and several others depending on subspecies/population), and
Lynx,
Planigale,
Liocichla, etc. If common names are easier than you should know exactly what those animals are as they're the same as the scientific name.
How is that a completely bizarre and random example to give? Are Malawi cichlids not important enough to be spoken about with clarity? How about Lake Victoria cichlids, many of which are on the brink of extinction? Zoos use the common name 'Lake Victoria Cichlid' when exhibiting these species, though collectively they're referring to at least a dozen species kept and bred. If you want a more "relevant" example, tell me what zoos mean when they say they keep 'Blue-Crowned Motmot' because that common name refers to seven species.
Subspecies hybrid tigers are just
Panthera tigris. As Kakapo pointed out, a tigerXLion hybrid would be
P. tigrisXleo or
P. leoXtigris depending on whether the father was a tiger or a Lion. Speaking of tigers and the Sumatran animals, though, this is a perfect example of why your taxonomy changing argument holds no water. The vast majority of the time nowadays, a taxonomy change occurs when one species is split into more species. However, this doesn't cause as much confusion as you seem to think as it doesn't really change that much. Traditionally the tigers of Sumatra have long been considered
Panthera tigris sumatrae. If one follows the thinking that the island tigers are actually a separate species, then these become either
P. sumatrae or
P. sondaica sumatrae. If one follows the new subspecies revision, then these become
P. tigris sondaica. Whichever way you write it, most of us still know you mean the tigers of Sumatra. Yes more people will understand what you mean when if you call them 'Sumatran Tigers', but under this new taxonomic revision that's not technically the correct common name for them anyway. So if I'm talking to you about 'Sunda Tigers', would know what I meant? Would you be able to tell if I were talking about the animals from Sumatra, Java, or Bali? Even if you have to do a quick Google for the scientific name, Googling any one of the scientific names I provided to bring you to the Sumatran cat, whereas Googling 'Sunda Tiger' would not. This fact extends to every other example I've provided.
~Thylo
I always have to choose a taxonomy school for the thousands of changing taxa. Usually I choose the most classical used and tend more to lump than split (but I analize case by case). For example, the lizard that TinoPup mentioned maybe the skink Lygosoma fernandi/Mochlus fernandi/Riopa fernandi. I choosed the first one for my files and use 
