- Our first "di" today is a small flying creature called Dimorphodon, a member of the extinct group of reptiles called pterosaurs. The name "Dimorphodon" comes from three roots, "di," "morph," and "don." "Di," of course, means "two." In this context, the root word "morph" means "form." In mythology and fantasty, a being that can take more than one form is often said to be able to morph their appearance. Finally, the root word "don" is one of my favorites (and is used a whole lot in giving animals their scientific names): it means "tooth." Altogether now: two-form tooth. This name refers to the fact that Dimorphodon actually has two different types of teeth in its jaw. For mammals, that's nothing special, but amongst reptiles, that is pretty rare!
- Dimetrodon-another animal with two kinds of teeth! "Di" and "don" still mean the same thing as they did in Dimorphodon (above), but there is a new root in between: "metro." For this root, think of the term "metric." The name "Dimetrodon" actually means "two measures of teeth!" Dimetrodon's two types of teeth would, in the groups that it is ancestral to, one day evolve to become the varied types of teeth that we see in the mouths of mammals! Dimetrodon is more closely related to mammals than it is to any group of living reptile, and all of us mammals did evolve from a Dimetrodon-like ancestor! So remember, if anyone ever tells you that Dimetrodon is a dinosaur, tell them that Dimetrodon actually lived around 40 million years before the first dinosaur ever walked the Earth! That'll show them.
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| Dimetrodon (left) attacks the primitive amphibian Eryops. Much like in the skull of Dimorphodon, you can clearly see the much larger teeth in the front of the skull and the smaller teeth in the back of the skull of Dimetrodon. |
- Let's travel forward to the Late Cretaceous Period, time of Tyrannosaurus and Triceratops, to meet Didelphodon, a primitive mammal about the size of the living Virginia opossum! As a matter of fact, it is from the opossum that Didelphodon gets its name: "Didelphodon" translates to "opossum tooth," as Didelphis is the genus name for the Virginia opossum and several related species of opossum! In turn, "Didelphis" means "double womb," which presumably refers to the fact that the opossum, like all marsupials, has its internal reproductive tracts where the baby will develop for a bit, and its external pouch, where the baby will develop until full term.
- A fourth animal with "two" and "tooth" in its name is Diprotodon! The middle root, "pro," in this name means "forward," like the word "proceed." So the name "Diprotodon" actually means "two forward teeth." A quick examination of the skull of this massive mammal quickly reveals why! Although it looks like it might be some sort of ungodly large rodent, Diprotodon is actually a hippopotamus-sized wombat, the largest marsupial known to have walked the Earth!
- Diceratops is a genus of ceratopsian dinosaur that is often considered to actually be a Triceratops. The name, which means "two-horned face," was later discovered to already belong to a type of insect, and changed to the name Nedoceratops. Some other paleontologists believe that Nedoceratops is really the same animal as Triceratops, but I don't really know enough about Nedoceratops to have an informed opinion on the matter. However, paleontologist Jack Horner believes that Nedoceratops is an intermediate growth form between Triceratops and Torosaurus, and since I don't agree with his ideas of Triceratops ontogeny and that I think Triceratops and Torosaurus are definitely distinct dinosaurs, that leads me to suspect that Nedoceratops is more likely distinct, and certainly doesn't bridge the gap between Triceratops and Torosaurus.
- The name of Diplodocus, which means "double beam" originates from the two rows of chevron that are on the underside of the animal. This was originally thought to be a feature unique to Diplodocus, a defining characteristic that would set it apart from other closely related sauropods. Since Diplodocus was named by paleontologist Othniel Charles Marsh in the late 1800s, this feature has since been discovered on a number of other sauropods, including Barosaurus, also from the Morrison Formation, like Diplodocus.
- Dilophosaurus, one of the stars of the original Jurassic Park movie, gets its name from the two crests on its head. Last time, we met Monolophosaurus, which means "single-crested lizard." Therefore, Dilophosaurus means "two-crested lizard!"
While it is the Greek cardinal root for "two" that is used most frequently in binomial nomenclature, it is the Latin root that is most often used for multiples (i.e. once, twice, thrice, etc.), the root "bi." You can probably think of several words right off the top of your head that use this root! In fact, the word "biped," used to describe creatures that walk on two feet (as opposed to, say, a quadruped), comes from the two roots "bi" and "ped," with "ped" meaning "foot" in Latin. So literally, "biped" means "two feet!" Let's look at a few more!
- Marshosaurus bicentesmus - A theropod dinosaur from the Morrison Formation (one who has received "Full-Post Status," as you can see by clicking HERE). The exact relationships of Marshosaurus to other theropods isn't exactly clear, but some people think it might even be some sort of primitive coelurosaur, while others think it is more closely related to Megalosaurus and kin. Regardless of its phylogenetic relationships, the name of Marshosaurus is quite exciting! The genus name "Marshosaurus" honors the famous paleontologist Othniel Charles Marsh, who did a lot of work in the Morrison Formation. The species name "bicentesmus" refers to the fact that the species was described in 1976, the bicentennial of the United States. The bicentennial is, of course, a 200 year anniversary, and the "bi" in the name distinguishes a 200 year anniversary from a 100 year anniversary, or a centennial.
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| Here are two shots of a specimen of Marshosaurus that were on display in the lab at the Denver Museum of Nature and Science last year. This first picture is the right maxilla, which would have made up part of the front section of the animals snout. |
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| Here we have more of the same specimen, on display at the same time and the same place. You can see several vertebrae and ribs in this shot. |
- Baeolophus bicolor - This is the scientific name of the tufted titmouse, a small woodland bird native to much of the eastern half of the United States. These little birds live in holes in trees that have been abandoned by woodpeckers, and are closely related to chickadees and, of course, the other titmice. I couldn't figure out what the genus name "Baeolophus" means, but it is pretty apparent that the species name "bicolor" refers to the fact that this little bird is gray on its back, and white on its underside. Some of the other species in the genus, such as the juniper titmouse (Baeolophus ridgwayi), are simply all gray.
- Diceros bicornis - Here we have the scientific name of the black rhinoceros, a "Critically Endangered" species of African rhino. According to some sources, the black rhino often prefers to eat Acacia leaves, presumably employing its prehensile upper lip to avoid the plants thorns. The black rhino has pretty poor vision, with much better auditory and olfactory sensing capabilities. Humans are easily the most dangerous threat to the black rhinoceros, with lions and the spotted hyena occasionally taking young black rhinos as prey, and even more rarely attacking adults. The scientific name of the black rhinoceros literally means "two-horn two-horn." As we have already established, both "di" and "bi" are roots that mean two. Both "ceros" and "corn" are roots that refer to horns: think "Triceratops" for ceros (three-horned face), and "unicorn" for corn (one-horn).
