The Whovian Science Blog: Rethinking Triceratops: Part 1

It is one of the world's favorite prehistoric animals and its mineralized bones can be seen in nearly any paleontological exhibit in a natural history museum, these days. Living near the end of the Cretaceous in the U.S and southern Canada, Triceratops is probably the most popular dinosaurian reptile among both the public and professional dinosaur-hunting paleontologists, after Tyrannosaurus rex.

The exact longevity of Triceratops is 68 million to a little more than 66 million years ago, almost 10 times as long as the period between now and the very first hominid we can call a true human (Homo sapiens sapiens). Dinosaur fossils found in the Hell Creek formation of Montana, Wyoming, South Dakota, and North Dakota reveal that Triceratops, was in fact, the most common herbivorous dinosaur at the time, near the Cretaceous-Paleogene Mass Extinction. Triceratops was so common in fact, that its bones fill museum collections and it is even possibly to buy your own 67-million-year-old, authentic Triceratops fossil tooth (link below).
TRICERATOPS AUTHENTIC TEETH FOR SALE
I even have one of my own, with the original enamel patterns still preserved.

So where did Triceratops come from in the first place? An important bit of paleontological knowledge is that Triceratops is from a group of dinosaurs called the ceratopsians, which were one of the longest-lived dinosaur groups, aside from sauropods. The three main features of this group are short to long bony frills, facial horns, and large beaks. Triceratops's closest cousins in the group "chasmosaurine" are Eotriceratops and Torosaurus. Other members of "chasmosaurine," but more distantly related include Chasmosaurus and Pentaceratops.

Pentaceratops, a very closley related cousin of Triceratops

One of the other main groups of the ceratopsians was the centrosaurine, which includes such dinosaurs such as Centrosaurus, Pachyrhinosaurus, Styracosaurus, and Xenoceratops. Both these groups are part of the ceratopsids, a clade which are quite advanced compared to some of the earlier and more primitive ceratopsians.

Centrosaurus, a closely related cousin of Triceratops

Earlier forms of ceratopsians include Protoceratops and Turanoceratops which had shorter, but still long frills compared to their body size. These ceratopsians were quadrupedal, but the earliest forms were actually bipedal and had very short frills or even none at all. These include Leptoceratops, Psittacosaurus, and Archaeoceratops. You probably can see where this is going now. The whole suborder of ceratopsia is very, very large and very, very complicated in terms of branches of evolution. The ceratopsids (chasmosaurine and centrosaurine), the dinosaurs we usually think of ceratopsians, made up only a fraction of all ceratopsians. Most ceratopsians in fact, resembled Psittacosaurus and probably were bipedal.

Pssitacosaurus, a bipedal ceratopsian

The earliest and most primitive ceratopsian known is probably Yinglong ("hidden dragon") which lived 158 million years ago (Middle Jurassic), in what is now China. It lacked a bony frill of any kind and instead had a bony shelf on the back of its skull, as well as a thick muscular tail. Yinlong was only about 3.9 feet long and a small rostral bone on its skull identifies it as a definite ceratopsian. Yinglong, although the earliest known ceratopsian, is actually not the most primitive. That seat belongs to Micropachycephalosaurus, which lived during the Early Cretaceous, and was first thought to be a genus of pachycephalosaurid.

Yinglong, the earliest known genus of ceratopsian

Micropahcycephalosaurus, the most primitive ceratopsian known to science

It was originally though that ceratopsians including Triceratops evolved from ornithopod dinosaurs, the same group which includes Iguanodon from the Early Cretaceous. However, it is more likely that ceratopsians descended from a much more basal creature like the species Pisanosaurus. Although the earliest ceratopsians come from the Middle Jurassic, their earliest members probably go back much farther in the Mesozoic, possibly in the Triassic.

So moving on! What did Triceratops look like? Well, when it was first identified as a dinosaur, it was portrayed usually as green-colored, scaly, and with a large robust "fat" body. It was also drawn with knobby spiny skin and long sharp horns, like a chameleon. However this notion has been long proven incorrect.

A very outdated reconstruction of what Triceratops may have looked like

During the so-called dinosaur revolution in the 1960's and 70's, when paleontologists were rethinking long-held theories about dinosaurs, Triceratops was still depicted as before, with some differences. Ceratopsians like Triceratops were drawn as more livley agile animals and movies like Jurassic Park solidified that. Again, before this time, nearly all dinosaurs were depicted as slow and sluggish, and putting something like say...feathers on them, was considered preposterous among the scientific community.

Many paleontologists still doubt Triceratops had feathers

However starting in the 1980's to 2000's, paleontologists began digging up fossils of small meat-eating eating dinosaurs, from Cretaceous rocks in China, such as Microraptor and Sinosauropterx. These dinosaurs had died around prehistoric freshwater lake beds, and the soft deposition of sediment, preserved nearly every detail of their corpses, including...FEATHERS!

At first, it was thought that these small, carnivorous, bird-like theropods were a very small majority. Some paleontologists even stick with the assumption today in the scientific community. However, when larger dinosaurs such as the tyrannosaur, Yutyrannus huali were discovered as having feathers, this belief began to mostly change. Today is it safe to say that any raptors or tyrannosaurs including Tyrannosaurus rex, DEFINITELY had feathers or soft fuzz of some kind or another.

Yutyrannus huali, the first known feathered "t-rex."

So what do all this "dinosaurs with feathers" have to do with Triceratops anyway? More than you might think. Recently fossils of primtive ceratopsians such as Pssitacosaurus and ornithopods such as Tianyulong have been found with bristle-like structures, similar to feathers. Some such as Tianyulong even had these bristles, covering their entire bodies, possibly to protect themselves from possible anual cold weather or to attract potential mates.

Tianyulong was probably COVERED in feathers

As to date, it seems that nearly all dinosaurs, including the giant sauropods had some kind of fur, fuzz, or feahters of some kind. Some, such as Sinosauropteryx were probably covered in feathers, while others such as Tyrannosaurus rex, probably had a moderate ammount. The large sauropods probably had fuzz or bristles on their backs, and certatopsians such as Triceratops proabably were coated in a thin layer of fur.