Here we go. We have seen or heard of the following "T-Races", "T-Planets" or at least "T-Regions" after which some animal, illness or food is named:
|Tarvokians||TNG: "The Game", "Liaisons"||Considering that Tarvokian desserts are almost as famed as Ktarian pudding, it probably refers to a planet.|
|Talosians||"The Cage", TOS: "Menagerie"||Civilization that lost their physical skills and has gained the power to create illusions instead|
|Tallonians||DS9: "Hippocratic Oath"||"Tallonian crystals" may refer to a city or region as well, but fits in well here.|
|Tholians||TOS: "The Tholian Web", ENT: "Future Tense", "In a Mirror, Darkly"||The Tholians are a non-humanoid xenophobic race.|
|Troyians||TOS: "Elan of Troyius"||The teal-skinned race in this episode|
|Tavnians||DS9: "The Muse"||Civilization with strict separation of sexes|
|Thalians||TNG: "The Dauphin"||The "Thalian chocolate mousse" originates on Thalos VII.|
|Thasians||TOS: "Charlie X"||Non-corporeal entities|
|Tarsians||TNG: "The Hunted"||This may be a civilization the Angosians once fought against in the Tarsian War, or it preferably refers merely to a region on the planet.|
|Taresians||VOY: "Favorite Son"||The population of Taresia consists almost entirely of attractive woman.|
|Tanugans||TNG: "A Matter of Perspective"||The Tanugans from Tanuga IV are probably members of the Federation, although they have their own law system (when they accuse Will of killing Dr. Apgar).|
|Trabalians||VOY: "Threshold"||Neelix served on a Trabalian freighter for two years, so this must be a spacefaring race.|
|Tartarans||DS9: "Q-Less", "If Wishes Were Horses"||Vash decides to explore the ruins on Tartaras V. This is probably the planet where Quark's Tartaran paintings come from, and this would indicate that there may be a present-day Tartaran civilization too.|
|Tandarans||ENT: "Detained"||Civilization that maintains detainment camps for Suliban|
|Taguans||TNG: "Qpid"||Inhabitants of Tagus III|
|Tabrans||VOY: "The Swarm"||"Tabran monks" may refer to a city or region as well, but fits in well here.|
|Tagrans||DS9: "Q-Less"||Inhabitants of Tagra IV|
|Trakians||TNG: "Lower Decks"||"Trakian ale" may refer to a city or region as well, but fits in well here.|
|Takret||ENT: "The Catwalk"||They are apparently immune to certain forms of harmful radiation.|
|Tarkans||VOY: "Darkling"||A race in Voyager's flight path that should be better avoided|
|Tarchannens||TNG: "Identity Crisis"||The creature Geordi almost mutated to is from Tarchannen III, therefore they should be most likely called "Tarchannens".|
|Tarkannens||VOY: "Innocence"||A humanoid civilization Chakotay made first contact with, so it can't be the same as the above Tarchannens.|
|Tarcanians||VOY: "Imperfection"||Tarcanian wildflowers are a variety of flowers native to the Delta Quadrant. The actual spelling could be the same as in "Tarkanian".|
|Tarkanians||TNG: "The Drumhead", VOY: "The Haunting of Deck Twelve"||A Tarkanian diplomat is mentioned in "The Drumhead". In "The Haunting of Deck Twelve" Paris refers to a "Tarkanian Desert" which may be a city or region as well, but more likely refers to the planet of the Tarkanians.|
|Tarkassians||TNG: "Rascals", "Imaginary Friend"||Guinan's first pet was a Tarkassian razorbeast. It is not sure if there is an intelligent species named "Tarkassians", though.|
|Tarkalians||DS9: "Starship Down"||The "Tarkalian sheep herders" may refer to a city or region as well, but fits in well here.|
|Tarkaleans||DS9: "Past Prologue", "Nor the Battle to the Strong", "The Begotten", VOY: "Body and Soul", ENT: "Regeneration"||After references like "Tarkalean tea", "Tarkalean hawk", "Tarkalean condor" and "Tarkalean flu" the Tarkaleans finally appear in ENT: "Regeneration". They could be identical to "Tarkalian".|
|Takarans||VOY: "Suspicions"||Jo'Bril's race that is capable of entering a death-like stasis|
|Takarians (I)||VOY: "The Cloud", DS9: "The Visitor"||Civilization on a planet probably named Takar in the Alpha or Beta Quadrant. Maybe this refers to the same planet as "Takarans".|
|Takarians (II)||VOY: "False Profits"||Civilization in the Delta Quadrant, visited by the Holy Sages aka Ferengi. Takar is most likely just a city, though.|
|Ta(r)karians||VOY: "Tsunkatse"||Her opponent compares Seven with a "Tarkanian field mouse". This may refer to a city or region as well, but fits in well here. It is very unlikely that it refers to the underdevolped planet Takar that appeared three seasons earlier.|
|Talaxians||VOY (all)||Neelix' race, with a strange affection to having an "X" in every name, just like Trek authors love the "T"|
|Talavians||DS9: "Things Past", "The Darkness and the Light"||A Romulan spy posed as a Talavian smuggler, so this is most likely a civilization.|
|Tamarians||TNG: "Darmok", "Hero Worship"||First contact was made in 2367, and in the following year a Tamarian beverage was served in Ten Forward.|
|Talarians||TNG: "Heart of Glory", "Suddenly Human", "Realm of Fear", DS9: "Improbable Cause"||A warrior race with an appearance close to humans, although a DS9 episode suggests otherwise|
|Tarellians||TNG: "Haven"||Civilization from the planet Tarella, now nearly extinct|
|Terellians (I)||TNG: "Liaisons", "Genesis"||The Terellians were mentioned to have four arms in "Liaisons".|
|Terellians (II)||VOY: "Drive"||The spelling of these folks is not clear, but they live in the Delta Quadrant and therefore must be still another race, aside from the various other T(e,a,y)r(r)ellians. Startrek.com spells them "Terrellians" in the entry for Irina (it was not mentioned in the episode that she was Ter(r)ellian, but that makes sense in the course of the race), but then has a link to a generic page about the various Alpha Quadrant "Terellians" who are not distinguished from one another. In other words, they are at a complete loss.|
|Terrellians||TNG: "All Good Things", DS9: "Life Support", VOY: "Infinite Regress", "Gravity", "The Fight", ENT: "Singularity"||This nice spelling variant showed up in the form of the Terrellian plague, and in the DS9 episode it became clear that Terrellians are supposed to be just another race (with two arms, I suppose). In "Gravity", young Tuvok was said to have had a Terrellian girl-friend. Chakotay's opponent in "The Fight" (definitely with two arms) was another Terrellian, according to the closed captioning. I am tempted to say that the plague in the Enterprise episode is meant to be the same illness as on TNG, but spelt differently.|
|Terrelians||Enterprise Announcement||Yes! Lt. Mayweather has a Terrelian girl-friend. That was just the missing spelling, although it may be just misspelled. Most likely these are the same as the "Terrellians".|
|Tyrellians||TNG: "Starship Mine"||Inhabited Federation planet, with no atmosphere at all, and also without a magnetic pole. Well, maybe there are inured indigenous Tyrellians.|
|Telerians?||DS9: "Q-Less"||Inhabitants of the Teleris star cluster which may be actually uninhabited, though|
|Trelonians||DS9: "Profit and Loss"||An alleged traitor to the Trelonian (planetary?) government was executed.|
|Teros(i)ans?||DS9: "Second Sight"||"Terosia Prime" is mentioned in the episode, and this points at this planet being the home to a civilization.|
|Tilonians?||TNG: "Frame of Mind"||The inhabitants of Tilonus must be named something like that.|
|Tellarites||TOS: "Journey to Babel", "Whom Gods Destroy", ENT (various mentions)||Federation members with pig-like noses|
|Teldarians||TNG: "The Mind's Eye"||"Teldarian cruiser" almost definitely refers to a spacefaring race.|
|Teluridians||VOY: "Ex Post Facto"||That's what the inhabitants of Teluridian IV would be called, but it is possible that this planet, site of a skirmish between Starfleet and the Maquis, is uninhabited.|
|Telluridians||TNG: "Legacy"||Name of a beverage. It need not refer to a planet but fits in here perfectly.|
|Telurians||TNG: "A Matter of Time", ENT: "Cold Station 12"||Name of a plague. It need not refer to a planet but fits in here perfectly.|
|Tellurians||TNG: "The Most Toys", DS9: "The Assignment"||Another place or planet of delicious food, not necessarily a race|
|Tellunians||TOS: "Elaan of Troyius"||That's what the Elasians and Troyians would be called if they had to choose a common name, because they are both in the Tellun system. But probably they didn't only want to distinguish them from each other but also from the countless other T-Races. ;-)|
|Thelusians||TNG: "Unnatural Selection"||"Thelusian flu" is a rather harmless iliness. It may refer to a may refer to a city or region, though.|
|Thesians?||TNG: "The Outrageous Okona"||The "Jewel of Thesia" refers most likely to a city or region, and is included just for the sake of completenesss.|
|Tesnians||ENT: "Shuttlepod One"||Enterprise picked up some Tesnians in this episode.|
|Tyrineans||TNG: "In Theory"||"Tyrinean carvings" may refer to a city or region likewise, but fits in well here.|
|Tenebians||ENT: "Fortunate Son"||One child aboard the Fortunate has a "Tenebian skunk" as a pet, which may refer to a city or region likewise, but fits in well here.|
|Tenarans?||VOY: "Basics"||Inhabitants of the Tenarus star cluster which may be actually uninhabited, though|
|Trellans||VOY: "Tuvix"||"Trellan crepes" may refer to a city or region likewise, but fits in well here.|
|Terrans||All||Inhabitants of Sol III. Mostly harmless.|
Note The list only includes races beginning with "T" which sound very close to each other, as opposed to a few distinct names like "Trills" or "Tosk". In addition, there are many names beginning with other letters that would fit into the above scheme like "Ktarians - Takarians", "Retellians - Terellians", or "Circassian - Tarkassian - Cardassian", to name only a few.
There is no conclusive explanation why the designations of so many alien races and planets were created following the "T****ians" pattern. We may suppose that most if not all of these names are the human versions, which would be a lot easier to pronounce than strange indigenous names, just like many countries, cities or other places on Earth have English names that, if at all, only imitate the original pronunciation. The same may apply to names of alien individuals. If, however, humans came up with their own names for aliens, why are they all so similar, more than any names of unrelated places on Earth resemble each other? Wouldn't they be subject to a lot of confusion?
The T-names themselves are not really a matter of exobiology or of geography. Nevertheless, the question arises if and how many of them may refer to the same planet or species, which could alleviate the matter at least a little bit. Perhaps some of them don't denote a planet or race at all. It is obvious that several of the above listed names do not necessarily refer to a planet of race, although it may have been the original intention. As soon as we count in cities, provinces or individuals, it becomes much more plausible that their names may coincide. I'm thinking of the search term "Darmok", for instance, which yielded dozens of results from different cultures in the TNG episode of the same name.
Some of the phonetically identical names may denote the same race like one or two of the four "Ta(r)kar(i)ans", one or two of the four "Ter(r)el(l)ians" or some of the "Tel(l)ur(id)ians". The apparent differences between them may be simple misspellings. But in some cases it is just necessary that there are different races with the same name like the Alpha-Takarians and the Delta-Takarians, the Alpha-Ter(r)ellians and the Delta-Terellians, or the humanoid Tarkannens as opposed to the Tarchannen creatures. The galaxy is a big place, but the fact that such a large number of considerably different species or even species in opposite quadrants have the same name, remains a mystery.
As for the real-world reason, I'm at a total loss explaining the bizarre frequency, to put it mildly, of names that all sound the same. Misspellings could have easily occurred when authors vaguely remembered names mentioned before in Star Trek and just didn't get them quite right. "Tarkalians" and "Tarkaleans", for instance, may have been supposed to be the same race. That's no big deal. But why should different individuals frequently come up with very similar or even phonetically identical names, where the script logic unconditionally calls for something or someone never seen or heard of before? Considering how seldom stories were harked back to in the time from TNG to Voyager, it is an eccentric habit to frequently re-use names of minor aliens for casual mentions regardless whether it makes sense or not.
On many occasions the writers obviously ignored the Star Trek Encyclopedia in which they could have easily looked up what they may re-use and what not. Even worse, they may have thought they could do attentive fans a "favor" by a completely arbitrary re-use of names they found in this book. But actually they often created anti-continuity with this misunderstood fan service. There is no excuse for a two-armed boxer in VOY: "The Fight" being called a Ter(r)ellian, for we know from TNG: "Liaisons" that Terellians have four arms. But this was obviously still not enough. The absurdity culminates in a race called "Terellians" (sp?) even in the Delta Quadrant (VOY: "Drive"), in addition to the abundance of "T*rel(l)ians" in the Alpha Quadrant. I can't help but calling this T-mania a collective obsession that goes along with inappropriate carelessness.
Create more and better T-Races in a minute than Brannon Braga could in all his life! If you always wanted to become a Trek author, you can't go without this little tool.
Hit the button several times! The names are genuinely random-generated and they should have sufficed for the next 47 seasons of Enterprise.
© Ex Astris Scientia 2001
Thanks to Shawn Havery for information about the closed captioning.