We are independent & ad-supported. We may earn a commission for purchases made through our links.

Advertiser Disclosure

Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.

How We Make Money

We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently from our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What does Incertae Sedis Mean?

Michael Anissimov
Updated May 21, 2024
Our promise to you
All The Science is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At All The Science, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

In biology, "incertae sedis" (Latin: of uncertain position (seat)) signifies a taxonomic group difficult to place in the larger taxonomic scheme. This may be because the group is newly discovered, taxonomically challenging, or a fossil animal only known from fragments. Thanks to molecular phylogeny, most animals can be taxonomically categorized quite easily as long as there is sufficient funding and a tissue sample. However, because there are millions of animal species, many have not yet been definitely classified using molecular techniques.

Since molecular phylogeny became widely available in the 1970s, more animals have been classified as incertae sedis, because taxonomists are less willing to guess about a taxon's place unless it is obvious. For instance, in the Colubridae family of snakes, there are more than a dozen genera listed as incertae sedis. In taxonomy, there is also a growing trend to put a basal (primitive) taxa in the clade that contains its ancestors, but refrain from giving it a more specific classification. For instance, a basal reptile might be considered part of class Sauropsida with other reptiles, but not given a family or genera designation. These sorts of animals are relatively rare, and most are fossils.

Some of the most fascinating organisms classified as incertae sedis are fossils from the Ediacaran period known as the Ediacaran fauna. Many of these fossils are said to have "uncertain affinity" (a term related to incertae sedis) because they are so cryptic. The Ediacaran fauna consists of a number of bag, carpet, circular, and cone-shaped forms, often with a distinct quilted pattern on their surface. Some scientists have described the Ediacaran fauna as "a failed experiment in life." Distinctive Ediacaran fossils like Dickinsonia costata are some of the earliest examples of bilateral animals, and grew as large as 1.4 m (4.6 ft) in length, almost the size of an average human.

One iconic example of an incertae sedis fossil from the Cambrian period is Wiwaxia, an oval-shaped animal covered in spikes. It has been alternatively been classified as a mollusk and an annelid (segmented worm). The debate over Wiwaxia's true affinity is ongoing.

All The Science is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Michael Anissimov
By Michael Anissimov , Writer
Michael Anissimov is a dedicated All The Science contributor and brings his expertise in paleontology, physics, biology, astronomy, chemistry, and futurism to his articles. An avid blogger, Michael is deeply passionate about stem cell research, regenerative medicine, and life extension therapies. His professional experience includes work with the Methuselah Foundation, Singularity Institute for Artificial Intelligence, and Lifeboat Foundation, further showcasing his commitment to scientific advancement.

Discussion Comments

Michael Anissimov

Michael Anissimov


Michael Anissimov is a dedicated All The Science contributor and brings his expertise in paleontology, physics, biology...
Learn more
All The Science, in your inbox

Our latest articles, guides, and more, delivered daily.

All The Science, in your inbox

Our latest articles, guides, and more, delivered daily.