The Inaccuracy of Common Names

The vast majority of keepers who own exotic and common animals know their animals by their common name, a simplified description of an animal’s species. For example, people who keep Python regius recognize the species as Royal Python or Ball Python. As you can see, there are two common names that describe the same species and many might not know both common names. This is part of the reason why common names can be inaccurate and misleading.

This post will go over the basics of common names versus binomial nomenclatures and why it is better to use and learn the binomial nomenclatures of the species you keep. Basically, an introduction to nomenclature!

Binomial Nomenclature

 “The system of nomenclature, the devising of names for things, in which two terms are used to denote a species of living organism, the first one indicating the genus and the second the specific epithet.”

To start, I will briefly cover the taxonomic hierarchy, so we have a better understanding of where the binomial nomenclature comes from. The taxonomic hierarchy is a structured framework used to classify and organize all living organisms on Earth. It is a nested sequence of eight categories, often referred to as “taxa”. The order is as follows: Domain →  Kingdom → Phylum →  Class →  Order → Family → Genus → Species. For example, the common household cat is described as the following: Eukarya → Animalia → Chordata → Mammalia → Carnivora → Felidae → Felis → catus. Thus, the binomial nomenclature for the domestic cat is Felis catus. We continue the discussion of the specifics of binomial nomenclature below.

Each species ever discovered and officially described has a completely unique binomial nomenclature, which separates them out from all other species. These binomials typically consist of a genus name, which is a larger group classification that similar species belong to, and a species name, which is usually a form of descriptor of the species, location where the species is found, or a name of the person who discovered the species. Compared to common names, these binomial nomenclatures are very specific and unique to every species. The exception to the two word rule is if there is a need to further classify and describe a species, such as in the cases of subspecies. For example, the Gray Wolf is Canis lupus, but the domestic dog is Canis lupus familiaris. 

To give an example of why binomial nomenclature is important, there are no other species in the entire world that have the same binomial of Aphonopelma chalcodes. Aphonopelma chalcodes describes a specific species of a specific genus and was originally described in 1940 by Ralph Vary Chamberlin.  However, the common name ‘Desert Blonde Tarantula’ can refer to two different species; Aphonopelma chalcodes and Aphonopelma iodius. Both species are relatively similar, but they are not the same and both have unique taxonomic differences. These tarantulas also have different ranges of the United States, so their habitats are different as well. It is also important to understand if these species are being bred, as they should never be bred together, which would create a hybrid or infertile eggs.

Understanding and knowing the binomial nomenclature of the species a keeper keeps also makes finding images, doing research, and sourcing other information much easier on the internet. It is also useful when talking to professionals, who may know a lot about a specific species within a genus, but may not be overly familiar with the whole genus. Remember, every binomial is unique, so only one species or type of animal will have that name whereas common names may be shared between species, be inaccurate descriptors, or be too vague of a name to come back with the specific species you are looking for.

A quick additional tid-bits about binomial nomenclature. You will notice that when I write a species name, such as Felis cactus, I use italics on the species name and only capitalize the genus of which the species belongs. This is proper formatting when writing binomial nomenclature. If a person is describing a new species or wants to further specify the species they are talking about, they may also include the year of when the species was described and who described the species. For example, using Aphonopelma chalcodes again, writing it this way would be →  Aphonopelma chalcodes (Chamberlin, 1940). Note that the format using the taxonomist and year of the description is not typically used when speaking/typing informally, such as on a blog post. This format is typically used in taxonomic catalogs and scholarly publications.

Why Common Names Are Inaccurate or Confusing

As mentioned previously, different species may have multiple common names or a common name may describe multiple species. I briefly mentioned Royal Pythons earlier in this page. However, if I were to call them by this common name in the United States of America, the vast majority of keepers would not know what species I am referring to despite their overwhelming popularity as pets. This is because they have two common names and the latter is much more popular, however less accurate to the binomial nomenclature. Keepers often know them as Ball Pythons rather than Royal Pythons despite the fact that their binomial nomenclature, Python regius, literally translates as ‘python royal’. They were given their common name of Royal Python because of the African cultural practices that ancient kings would wear these snakes around their necks. The species name P. regius is also based upon this ancient cultural practice, where ‘regius’ means ‘royal’. Looking at this example, it can be confusing to many when one common name is used over the other. The more popular common name, at least in the United States, is Ball Python which is less accurate to the binomial nomenclature and would be misleading if they were not as popular as they are.

Another example of why not to use common names and why they are confusing is because a single common name can refer to many different species or even different genera. This is commonly seen in many different exotic animal hobbies, but I will use a tarantula example for this. Multiple genera and many species have the common name ‘Birdeater’ attached to it. Amongst these genera are Lasiodora, Pamphobeteus, Phormictopus, Theraphosa, and Xenesthis. There are more genera involved with this common name, but I’ve chosen a couple of popular genera for this example. Theraphosa are the most iconic for the species with the ‘Birdeater’ common name because they are the largest known terrestrial species of Theraphosidae and all three of the species in the genus have this common name with just ever so slight variation to the name. 

Theraphosa apophysis →  Pinkfoot Goliath Birdeater

Theraphosa blondi →  Goliath Birdeater

Theraphosa stirmi →  Burgundy Goliath Birdeater

As you can see, the difference between each common name is very slim and all three in the genus can be referred to as ‘Goliath Birdeaters’ despite this name representing three different species. They are also very similar species, which can lead to further confusion and the possible hybridization of species if a breeder were to mistake the identity of a specimen because they were using the common names or received a spider that was listed under its common name.

Changing Binomial Nomenclatures And Memorizing Binomials

With the new advancements in our understanding of our natural world and the many species that inhabit our world, binomial nomenclatures change quite regularly. It is common, especially in the more niche exotic species like Theraphosidae (tarantulas). Many of the binomial nomenclatures of invertebrates change as we regularly discover new species and properly describe others in taxonomy.

While it is likely that the binomial nomenclatures of the species you keep will change at one point, it is actually pretty easy to stay on top of. If you do not follow taxonomy pages on social media, it's easy to find out if a binomial has changed by simply google searching the current binomial you have for your species. Typically, Wikipedia is pretty good about keeping up to date with the binomial nomenclatures of every species with a page. However, if you want the most up-to-date information and taxonomy, please check out World Spider Catalog. WSC is a great and useful tool to always keep up with taxonomic reclassifications and the classification of new species of all sorts of arachnids.

When it comes to memorizing binomials, it is easiest to simply label each enclosure a keeper has with each unique binomial (or repeating if you have multiple of the same species) and then say it every time feeding/maintenance for the animal is required. Do not be afraid of mispronunciation! The important part is knowing what species you have and how to spell it out. While I recommend that the label on the enclosure should be the full binomial nomenclature, these species names can abbreviate the binomials when talking with other keepers. For example, Tliltocatl albopilosus can be abbreviated to T. albopilosus.

Common Exotic Species and Their Binomial Nomenclatures

Python regius - Royal/Ball Python

Boa imperator - Common/Red Tail Boa

Boa constrictor - Red Tail Boa

Heterodon nasicus - Plains/Western Hognose

Ranoidea caerulea - White’s/Australian Green Tree Frog

Anaxyrus americanus - American Toad

Ambystoma tigrinum - Tiger Salamander

Ambystoma mexicanum - Axolotl

Correlophus ciliatus - Crested Gecko

Eublepharis macularis - Leopard Gecko

Hemitheconyx caudicinctus - African Fat Tail Gecko

Pogona vitticeps - Central/Inland Bearded Dragon

Chrysemys picta - Painted Turtle

Sternotherus odoratus - Common Musk/Stinkpot Turtle

Chelydra serpentina - Common Snapping Turtle

Testudo hermanni - Hermann’s Tortoise

Tliltocatl albopilosus - Curly Hair Tarantula

Aphonopelma chalcodes - Arizona Blonde/Desert Tarantula

Chromatopelma cyaneopubescens - Green Bottle Blue Tarantula

Acanthoscurria geniculata - Brazilian Whiteknee Tarantula

Phiddipus regius - Regal Jumping Spider