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Taxonomic Term Confusion

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Taxonomy, the classification of living things, is really complicated. For example, anyone who's worked in a record store and had to fit every band into one neat little category or other has an idea as to why: Many organisms defy traditional or obvious categories in the absence of genetic studies. This is why there is such a wide variety of terms for organizing living things (and theoreticians regularly come up with new ones).


Writers of fiction tend to tidy things up a bit. They regularly come up with creative ways of employing normal classification terms in ways that are incredibly inappropriate. Primarily, what seems to be at fault is a failure to recognize that the terms for taxonomic categories have specific meanings, and are not just interchangeable synonyms for "a big group of similar things". Sometimes they do know better; it's just that they couldn't resist the Beast Fable pun of having an Animal Kingdom. You know, where the lion is the King.

For the record, any group of related organisms, regardless of the degree of relatedness, is called a taxon. The major recognized taxonomic ranks are:

  • Domain
  • Kingdom
  • Phylum (division in botany; the division goes directly beneath the class in zoology)
  • Class
  • Order
  • Family
  • Genus
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  • Species

(If you're having trouble remembering, remember this simple mnemonic: "Danny Kaye, Please Come Over For Good Strawberries" or, if you prefer, "Dear King Phillip Came Over For Good Soup". A commonly-used one is "Dumb Kids Playing Catch On Freeways Get Squashed". Before "Domain" was added to the top of the list, mnemonics were "Kings Play Cards Only For Gold and Silver," "Kings Play Chess on Fine Glass Surfaces," and "King Philip Came Over From Greece Swimming."note )

Every species past and present is part of all of these, in a nested pattern. So a given kingdom will contain one or more phyla, which each contain one or more classes, etc. Although some phenomena (like horizontal gene transfer and hybridization) muddy this a bit, in general there is no overlap. In a way, as huge and diverse as life is, it can be easier to classify than records. (A band can create a hard-to-sort genre like "folktronica", but fish and birds can't have babies or otherwise be combined to make a new taxon — yet.) The demarcations just aren't as obvious, in part thanks to the granularity (as if every band was accompanied by hundreds of extremely similar bands, and the music itself was the only source material for data).


Compound variations on these terms such as "subspecies" and "superfamily" are in common use. Some taxonomists also make use of the term "tribe" for a rank intermediate between subfamily and genus. This is not just limited to fiction; in a strictly factual sense birds are technically reptiles, and the whole animal/plant/fungus distinction is being rewritten of late so more often than not, it's hard to know the correct terminology because it's always changing. It doesn't help matters that the current system was invented before evolution was understood, and that the ranks are pretty arbitrary. One "genus" might be older and more diverse than another "family." Some scientists even want to abolish taxonomic ranks.

Another important distinction is whether a named group is monophyletic ("one tree") or not. A monophyletic group is exactly all descendants of some ancestor species. One way to think of phylogenetics and cladistics is they are the determination of which groups are monophyletic. All groups with a taxonomic rank (e.g. a genus) should be monophyleticnote , but commonly used group names may not be — e.g. "monkey" is not monophyletic unless you consider humans and other apes to also be monkeys, as Old World monkeys are more closely related to apes than New World monkeys are. How to deal with this is debatable, and indeed debated in the examples on this very page. Some would argue that "monkey" must include humans, others that "monkeys" are not a legitimate group, others that "monkey" is useful and legitimate, but you just need to be aware it is not monophyletic.

The scientific Latin name for a species consists of the genus name (capitalized), followed by the species name (in all lower case), both italicised. Tyrannosaurus rex is genus Tyrannosaurus, species rex; Homo sapiens is genus Homo, species sapiens. If the species is well known, or has already been mentioned earlier in the same work, the genus name will frequently be abbreviated to a single letter, e.g. T. rex or H. sapiens. If more hairsplitting is needed, the subspecies or variety name can be appended as a third word, e.g. Homo sapiens sapiens.

Frankly, it's not surprising that writers are sometimes ignorant or confused. Though this can also turn into a case of Fan Wank as many of these words also have different less precise meanings in regular English as in family and class are both used to refer to groups of similar things, a class of ships, the t-series family of trucks so a lot of these errors are just people using the words with their regular meanings. But there's really no excuse for such errors when they're committed by scientists who work in zoology and other fields that explicitly require them to be well-versed in how the nomenclature works.

Of course, things are also more complicated than even this. Cladistics, dendrograms, phylogenetics… We'll just leave it at this lest Your Head Asplode.


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    Comic Books 
  • Archie Comics' Sonic the Hedgehog: The Funny Animal characters are considered one species called "Mobian" despite being Uplifted Animal versions of various animals, ranging from hedgehogs to crocodiles.
  • Subverted in a Marvel Star Wars comic in which Jaxxon, a rabbit character, says "I ain't no rodent!" He's an alien Beast Man, so he's hardly a rabbit either.
  • X-Men:
    • The mutants are referred to as a species separate from humans, called Homo superior, even though they can produce fertile offspring with humans. It would be more accurate to call them a new subspecies ("subspecies" being a fairly arbitrary and flexible term). This is partially solved in later comics where Magneto, and several others, refer to Mutants as "Homo sapiens superior" (compared to Homo sapiens sapiens). Although some writers forget this, Homo sapiens superior specifically refers to a human subspecies with a single, quantifiable characteristic that Homo sapiens sapiens lacks — the emission of a certain type of brainwave (this is how Cerebro distinguishes mutants from baseline humans). Superhuman powers or anatomical quirks are very common among mutants, but they are not a requirement.
    • Every human, nay, every individual of any species born is almost certainly a mutant, several times over, by the actual definition of the term. A typical human may have dozens of alleles (that is, genetic variations) not present in either of its parents. These are all mutations. So using the term "mutant" isn't all that scientifically useful, either.

  • In the Discworld continuum, zoology generally follows the same Linolean nomenclature as on Roundworld with its eight disparate Kingdoms. However, in A.A. Pessimal's Whyand Were, it is revealed (in the context of a biology lesson at the Assassins' Guild School) that there are at least two additional Kingdoms: the silicarae covers all silicon-based life (trolls, gargoyles and others) and there is also the Sanguinae Mysterii (Bloody Strange) which covers all creatures of magic and living myth. Elves, Orcs, Goblins and Dwarfs are viewed as branches of the human family.
    • An extra complication is presented when Doctor Johanna Smith-Rhodes finds herself on Earth, teaching zoology at Caltech, Pasadena, California. She has to tailor her standard lecture to students on the Discworld to local conditions on a new planet. This means censoring out all references to silicon-based life, as Trolls do not exist on the Roundworld, and omitting all mention of things like basilisks, unicorns, Pegasi, and werecreatures. She gets to talk about Trolls, but in the context of a thought-experiment in which her students are invited to speculate on what silicon-based life might look like and how it could thrive.

    Films — Animated 
  • Finding Nemo: "Let's name the species of the open seaaaaaaaaaaaaaa!!!" The "species" mentioned in Mr. Ray's song are actually phyla.
  • In Disney's The Sword in the Stone, for Merlin and Mad Madame Mim's Wizard Duel, the two spellcasters are only allowed to turn into animals, and not vegetables, minerals, or "nonexistent creatures like pink dragons and such." However, when the duel is over, Mim breaks one of her own rules by turning into a dragon (specifically a purple dragon), and Merlin defeats her by turning into a germ, which is not even an animal at all!
  • At a few points in Zootopia, characters refer to the "predator family." Even going by the in-universe definition of "predator" (that is, a sapient mammal species that eats other sapient mammals), that's still wildly biologically inaccurate (one could say that they were thinking of Carnivora, but that's an order, it contains several types of animals that don't eat mammals (and some don't even normally eat animals, period), and there are mammals outside of Carnivora that eat other mammals).

    Films — Live-Action 
  • Batman Forever:
    Dr. Chase Meridian: Well, let's just say that I could write a hell of a paper on a grown man who dresses like a flying rodent.
    Batman: Bats aren't rodents, Dr. Meridian.
  • The Faculty contains this line: "We discovered a new phylum in biology class today; maybe even a new species." This makes no sense, because something in a new phylum would have to be in a new species. Probably the actor accidentally switched "species" and "phylum" around from the scripted line, and nobody caught the mistake.
  • In Godzilla: King of the Monsters, Titans are all classified under the genus Titanus. Besides the fact that this name is already used for a beetle (and hence cannot be reused), Titans represent everything from Godzilla (a reptile) to King Kong (a mammal) to Mothra (an insect).
  • In Guardians of the Galaxy, calling Rocket a "rodent" is one of his Berserk Buttons. He's a raccoon, order Carnivora; rodents are order Rodentia.
  • In The Horror of Party Beach, a doctor explains that the monster is actually a dead human whose organs were invaded by aquatic plants before they had the chance to decompose, and calls the result "a giant protozoa." Protozoa are single-celled lifeforms, being neither plants nor animals. "Protozoan" is the word for describing one in the singular.
  • In Jurassic Park, Alan Grant says that humans and dinosaurs are "two species separated by 65 million years." Granted, that line probably sounded great in the trailers, but you'd think a paleontologist would know better than to call dinosaurs a species.
    • More generally, the Jurassic Park series—and many other works, for that matter—often uses "species" when they mean "genus", such as in the first film when Grant is handling a newborn baby dinosaur and asks what species it is, to which Wu answers with Velociraptor, it's genus name.
  • Only three of the members of Kill Bill's Deadly Viper Assassination Squad are actually named for vipers.

  • The Book Of College Pranks: In relating a story about how a cow was elected Homecoming Queen because all the human entrants were disqualified, it says that the cow "was in the wrong phylum, but at least had not cheated." In fact, cows and humans are in the same phylum (Chordata) and the same class (Mammalia).
  • Bored of the Rings has an appearance by "six different phyla of giant insects". Insects, whatever their size, are a single CLASS of phylum Arthropoda.
  • The Childcraft book About Animals identifies arthropods as a "class" of animals, when it really is a phylum. It could be argued that phylum is too advanced a word for a book aimed at 6-year-olds, but that could also be argued of arthropod, and that didn't stop the publishers. (Probably they figured that anything was better than risking spiders getting classed as "insects".) Even more egregious as there are more arthropods in existence than every other phylum of animals combined.
  • Discworld: In-Universe example of taxonomic confusion, Played for Laughs, of course: In Hogfather, Ponder Stibbons states that:
    "Although, funnily enough banana is not actually a fruit, sir. [...] Botanically, it’s a type of fish, sir. According to my theory it’s cladistically associated with the Krullian pipefish, sir, which of course is also yellow and goes around in bunches or shoals.
  • In Cachalot, a marine biologist refers to a newly-discovered undersea race as "the first intelligent invertebrates we've ever encountered". Granted, this wouldn't be an issue in some scifi series ... but Cachalot is one of the Humanx Commonwealth novels, where humans and thranx have been virtually joined at the hip for centuries. Did Alan Dean Foster forget that his insect-based thranx also lack an internal skeleton?
    • Perhaps they meant the first such species encountered in an aquatic environment?
    • He also repeatedly refers to shrews as "rodents" in his Spellsinger series.
  • Melville spends a chapter of Moby-Dick committing an extended crime against taxonomy. He starts by classifying whales as "spouting fish" and proceeds from there.
    • Moby-Dick was written in first person perspective from the POV of a not especially well educated man in the early 19th century, when it's likely that someone actually would think that a whale was a fish.
      • There was a court case in 1818 in New York City in which a businessman tried to argue that his whale oil was not subject to government inspection because the law specified "fish oil" needed to be checked for adulteration and whales were not fish. He brought in several scientists to testify to that effect. He lost. The law was changed shortly after, however, to exempt whale oil.
    • Actually, Herman Melville had pretty much shown his work, enumerating physiological differences between whales and "other fish", and even referring to the Systema Naturae by Carl Linnaeus, and Ishmael'snote  subsequent "classification" can be read more as Take That! from a more down-to-earth (or rather down-to-sea) point of view of working class protagonists of the novel, using word "fish" in a looser sense of "any exclusively marine vertebrate" rather than as "a strictly defined taxon".
      "I submitted all this to my friends Simeon Macey and Charley Coffin, of Nantucket, both messmates of mine in a certain voyage, and they united in the opinion that the reasons set forth were altogether insufficient. Charley profanely hinted they were humbug."
    • And the actual Ishmael's taxonomic "system" consists of simply grouping of cetaceans roughly according to their respective sizes (and thus their economic value), with terminology based upon book sizes - i.e. Folio, Octavo and Duodecimo. The best acceptable explanation for all this is just regarding chapter 32 "Cetology" as a prolonged Stealth Parody of both the common whalers' sea-lore and then-current scientific cetological classification.

    Live-Action TV 

In General:

  • Occasionally a host of a Food Network show will try to emulate Alton Brown's use of scientific terminology, and wind up sounding like a Know-Nothing Know-It-All. The host of Food Feuds, for one, has openly referred to clams as crustaceans, apparently on the assumption that all seafood without fins is in the same taxon.
    • Adam Growe made a similar mistake on the Canadian edition of Cash Cab.


  • Doctor Who has a species of reptilian humanoids, the Silurians, that are referred to sometimes as Homo reptilia. The Homo genus is mammalian. Furthermore, reptiles hadn't even evolved by the Silurian era, making that part of the name rather baffling as well. (The Doctor once suggested that they should have been called "Eocenes" after another geological period they didn't come from.)
  • In the Elementary episode "Dead Clade Walking", Holmes incorrectly says a "clade" is any group of organisms that have survived a major extinction event, which is actually part of the definition of the "dead clade walking" paleontological concept. (A clade is simply any named group consisting of an ancestral species and it descendents. As it happens the question of whether taxonomy should be "cladistic" is one of the core wrenches in the field.) To be fair, he's exhausted after late hours talking to a geologist, and the extinction part is what's important to him.
  • An episode of Fringe features what looks like a cucumber-sized slug that crawls out of its victim's mouth, which the cast later identifies as an enlarged single-cell cold virus (which don't have cells, even a single one).
  • In-universe example: Mr/s. Kipling the water monitor of Jessie was called a dinosaur (namely a Velociraptor) as an insult. Another episode goes with the "koala bear" term (although Ravi notes that koalas are marsupials).
  • The narrator on Monsterquest seems to have confused "species" with individuals, inverting the usual pattern where higher-than-species clades are mixed up. The voiceover claims that "millions of species" of fishes are found off the coast of Florida, which is a couple of orders of magnitude more than the actual number of fish species on the planet (~32 thousand).
  • Star Trek likewise seems to have repurposed "Homo" to mean "intelligent humanoid": Vulcans were Homo vulcan, etc.
    • In Star Trek: Discovery, Burnham once refers to the tardigrade "species" as if there's only one. Tardigrada is actually a phylum with over 1,150 species. As a scientist, she should really know better.
  • The female scientist near the beginning of the series Surface described the creature she'd seen as "An entirely new phylum of mammal!" This is especially mind-boggling when we later learn that the creatures are created from the DNA of liopleurodons(a prehistoric sea reptile)... which she describes as "A type of prehistoric eel"... You know, just stop trying. If they just wanted to incorrectly refer to something as a "prehistoric eel", they could have at least used a mosasaur, which are far more eel-like in shape than pliosaurs such as Liopleurodon, which were generally shaped more like sea turtles with crocodile heads.

    Tabletop Games 
  • In an aversion, Shadowrun seems to get the race/species thing right. The book mentions that Metahumanity (Humans, Dwarves, Elves, Orks, and Trolls) are all different races within the same species. They can even interbreed (at least, they can this early on in the Sixth World), though they don't create Half-Human Hybrids when they do. If, for example, an elf and a human mate, the child will most likely be either an elf or a human. Or maybe a dwarf. Things are weird in the Sixth World.
  • Meta example: The Wizards of the Coast forums for Dungeons & Dragons 3.5 had a lot of fun early on trying to determine the exact taxonomic classification of dragons, due to a mention in the Draconimicon that despite their reptilian appearance, dragons are actually endothermic mammals.

    Video Games 
  • Zig-zagged in Mass Effect, in which the names of the various alien species are very carefully non-capitalised, thus avoiding the common assumption that an alien planet is just another country but a bit further away, and aliens are referred to as "mammal-analogues" or the like when it's needed, rather than making the mistake of simply calling them "mammals," but they still refer to aliens as animals and plants and bacteria and insects without the "-analogue" modifier.
  • Averted in StarCraft II. Whereas the previous game (and early Expanded Universe materials) capitalized species name as is often done in science fiction (erroneously), StarCraft II promotional materials and the new books all spell "protoss" and "zerg" with non-capitals. The fandom hasn't quite caught on yet.
  • Hidden object casual games regularly succumb to this trope, as when clicking on a "seahorse" isn't registered as finding a "fish".
  • Averted in the Warcraft franchise, where across all media species names are almost always left uncapitalized. However, many, many fans do so anyway.
  • In the Mii Plaza game Flower Town/StreetPass Garden, the plants are classified as being different "breeds"; pollination methods aside, different varieties of a given plant species are referred to as cultivars, and cross-species hybrids are called... er, hybrids.
  • According to Discworld Noir, cladistics on the Discworld was formalised by Linoleum, who came up with a system not a million miles away from that proposed on Earth by Carl Linneaus. However, Linoleum's sense of humour was unfortunate: he named werewolves as Bonuus Canii (good doggies), trolls as Stultus Sternum (stupid rocks), vampires as Nosferatu Sanguinae (bloody undead) and dwarfs as Hortus Decorensii (Garden Ornaments). The Watch called his subsequent death "suicide".

    Web Original 
  • The Nostalgia Critic admitted in his third "F*** Up" countdown that in his earlier review of Dunston Checks In where he repeatedly called the eponymous orangutan (and other films staring ape actors) monkeys, he didn't know there was a difference between apes and monkeys until he was corrected by his watchers.
  • An extremely stupid example: There was a video by a certain "Angry MGTOW" (now gone, but you can watch an, err, review by TL DR here) where he claims that women suck and even cockroaches are better. At one point he claims "animals tend to be more compassionate than the female species of our group!
  • RWBY: Little Bit Beastly characters called "Faunus" are implied to be one species separate from humans. This includes reptile Faunus, fish Faunus, and mammalian Faunus.

    Western Animation 
  • Looney Tunes
  • An episode of The Angry Beavers does this, as well. Rabbits are lagomorphs, not rodents, though Rodentia and Lagomorpha are sister orders in the clade Glires. However, in the Elmer Fudd case at least, the mistake is perhaps forgivable. Indeed, taxon Lagomorpha was placed within Rodentia until at least early 1900's, making then-Rodentia equivalent to now-Glires, and Fudd was already depicted as a middle-aged man in 1940.
  • Family Guy's Meg Griffin calling a raccoon a rodent. They're actually members of the order Carnivora, close relatives of BEARS. Rodents and carnivores are both boreoeutherian placental mammals, but that's about as far as their taxonomic relationship extends. It's like saying we humans (which are primates) are related to horses (which are perissodactyls). Life After People: The Series did the same thing.
  • Futurama:
    • In one episode, Darwinius massilae is presented as a transitional form between apes and humans, when in fact it is a lemur-like form that has little to do with humans. Also, a transitional form between apes and Darwinius is referred to as Homo farnsworth, but it would be far too primitive to be Homo if it went that far back.
    • Done in-universe in Bender's Game. When a character refers to an enormous spider he was riding as a "giant bug", the Professor angrily corrects him by calling it a "giant arachnid".
    • "Moebius Dick" makes a running gag out of Leela calling people out on the "whales are fish" thing. Though it's a rather arbitrary line to draw insisting that a fourth-dimensional, vacuum-inhaling, fractal-exhaling Space Whale was a mammal/whale, instead of an Animalistic Abomination.
  • Jackie Chan Adventures had a weird one in which Jackie and a crime boss refer to an octopus as a fish and respectively are corrected by Captain Black and a random mook by saying it is a "multipod". What makes this a headscratcher is that the correction is more incorrect then the original statement because there is no taxon called multipod nor has one ever existed.
  • Done in-universe in Ed, Edd n Eddy where they make a bet by taking on the others personality quirks and behaviors, with Eddy trying to unsuccessfully imitate Edd's Sesquipedalian Loquaciousness by claiming chickens to be mammals.
  • Done in-universe in one episode of The Legend of Tarzan where after capturing a magical white gorilla with Healing Hands, the villain goes on an rant on his mooks because they repeatedly refer to it as a monkey.
  • Dinosaur Train uses "species" when "genus" would be more appropriate.
  • Phineas and Ferb
    • Subverted and also done in-universe in the episode "The Return of the Rogue Rabbit", where characters would object to rabbits being called rodents and correct that they are lagomorphs.
    • An early episode "Toy to the World" had a platypus referred to as a marsupial. Later episodes corrected this and have platypodes properly identified as monotremes.
    • "What a Croc!" refers to crocodiles as lizards. Crocodilians are more closely related to dinosaurs and thus birds, and they are actually far away from lizards on the evolutionary branch.
  • Dinosaucers, even if it's a show about intelligent dinosaurs, includes in the cast an ichthyosaur, a plesiosaur, a dimetrodon, and a pterosaur. None of the four are actually dinosaurs.
  • Spongebob Squarepants treats "plankton" as if it were a species the character named Plankton belong to. The term "plankton" is not actually taxonomic at all, it refers to any oceanic organism that floats but cannot swim against the current. Given the show often shows its work about marine biology, and that Plankton is actually a copepod (a rather obscure species), this was probably done for simplicity's sake.


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