An ellipsis (plural ellipses) is a series of three periods, as you can see in the icon to the right.
As with most punctuation marks, there is some contention about its usage. The main point of contention is whether or not there should be a space between the periods (. . .) or not (…). MLA, APA, and Chicago, the most common style guides for students, support having spaces between the periods. Others you may encounter, such as in journalism, may not.
Quotes
Like the brackets we just learned about, you will primarily see ellipses used in quotes. They indicate a missing portion in a quote. Look at the following quote for an example:
Sauropod dinosaurs are the biggest animals to have ever walked on land. They are instantly recognized by their long, sweeping necks and whiplashed tails, and nearly always portrayed moving in herds, being stalked by hungry predators.
In recent years, a huge amount of taxonomic effort from scientists has vastly increased the number of known species of sauropod. What we now know is that in many areas we had two or more species co-existing alongside each other.
A question that arises from this, is how did we have animals that seem so similar, and with such high energy and dietary requirements, living alongside one another? Was there some sort of spinach-like super plant that gave them all Popeye-like physical boosts, or something more subtle?
It’s a lengthy quote, and it contains more information than you want to include. Here’s how to cut it down:
Sauropod dinosaurs are the biggest animals to have ever walked on land. They are instantly recognized by their long, sweeping necks and whiplashed tails. . . .
In recent years . . . [research has shown] that in many areas we had two or more species co-existing alongside each other.
A question that arises from this, is how did we have animals that seem so similar, and with such high energy and dietary requirements, living alongside one another?
In the block quote above, you can see that the first ellipsis appears to have four dots. (“They are instantly recognized by their long, sweeping necks and whiplashed tails. . . .”) However, this is just a period followed by an ellipsis. This is because ellipses do not remove punctuation marks when the original punctuation still is in use; they are instead used in conjunction with original punctuation. This is true for all punctuation marks, including periods, commas, semicolons, question marks, and exclamation points.
By looking at two sympatric species (those that lived together) from the fossil graveyards of the Late Jurassic of North America . . . , [David Button] tried to work out what the major dietary differences were between sauropod dinosaurs, based on their anatomy.
One of the best ways to check yourself is to take out the ellipsis. If the sentence or paragraph is still correctly punctuated, you’ve used the ellipsis correctly. (Just remember to put it back in!)
Practice
Portions of the following passage have been bolded. Re-type the passage with these portions removed. Be sure to use ellipses correctly!
Camarasaurus, with its more mechanically efficient skull, was capable of generating much stronger bite forces than Diplodocus. This suggests that Camarasaurus was capable of chomping through tougher plant material than Diplodocus, and was perhaps even capable of a greater degree of oral processing before digestion. This actually ties in nicely with previous hypotheses of different diets for each, which were based on apparent feeding heights and inferences made from wear marks on their fossilized teeth.
Diplodocus seems to have been well-adapted, despite its weaker skull, to a form of feeding known as branch stripping, where leaves are plucked from branches as the teeth are dragged along them. The increased flexibility of the neck of Diplodocus compared to other sauropods seems to support this too.
In terms of their morphological disparity (differences in mechanically-significant aspects of their anatomy), Camarasaurus and Diplodocus appear to vary more than almost any other sauropod taxa, representing extremes within a spectrum of biomechanical variation related to feeding style.
Pauses
There is one additional use of the ellipsis: this punctuation mark also indicates . . . a pause. However, this use is informal, and should only be used in casual correspondence (e.g., emails to friends, posts on social media, texting) or in creative writing.