Pectinodon

PectinodonComb Tooth
Classification
Domain	Eukaryota
Kingdom	Animalia
Phylum	Chordata
Subphylum	Vertebrata
Superclass	Tetrapoda
Clade	Sauropsida
Class	Reptilia
Clade	Archosauria Avemetatarsalia Ornithodira Dinosauria Saurischia Theropoda Neotheropoda Averostra Tetanurae Orionides Avetheropoda Coelurosauria Maniraptora Paraves
Family	Troodontidae
Species	Pectinodon bakkeri
Presence
Location	Hell Creek Formation, Montana - South Dakota, USA Lance Formation, Wyoming, USA
Temporal Range	67 - 66 million years ago, Maastrichtian Stage, Late Cretaceous Period
Episodes	North America (Segments 1 and 3)
Characteristics
Height	80 centimeters (2 feet, 8 inches)
Length	2.4 meters (8 feet)
Diet	Carnivorous
Tooth Length of 6.2 millimeters (0.24 inches) Teeth have comb-like serrations on the rear edges

“ A family of Pectinodon. They're feathered, but flightless. And they're lead by their father. ”

― David Attenborough, North America

Pectinodon (Comb Tooth) is a genus of troodontid theropod dinosaur that lived in western North America 67 - 66 million years ago, during the Maastrichtian stage of the Late Cretaceous Period.

Just shortly before the animal's actual appearance in the third segment of North America, a small pack of similar-looking troodontids can be seen in the first segment of the same episode, and are also discussed here for convenience. However, there is currently no confirmation that these troodontids are also Pectinodon, as they were never implied to be one and the same.

Paleobiology

Pectinodon is a small troodontid around 2.4 meters (8 feet) long. It earned its name, "comb tooth", due to the shape of the serrations on the rear edges of their teeth. It is mostly believed that the only discovered traces of Pectinodon are four teeth, with one 6.2-millimeter (0.24-inch) tooth belonging to a mature individual and three teeth that belong to juveniles. However, Dr. Darren Naish, Prehistoric Planet's lead consultant, revealed that the show's depiction did not have these teeth in mind. Instead the animal's portrayal is based on an unpublished find that is referred to the taxon, a complete specimen in private hands.

On Prehistoric Planet, Pectinodon are portrayed as being mostly covered in brown integument, with the feathers lining their arms being a darker shade of brown. The males are shown to have white stripes running from their top and bottom jaws, over their shoulders, down to their white undersides. What may be females or younger males are also shown with no white stripes running from their jaws, an underside with the same shade of brown as the rest of their bodies, and small, white feathers lining the dark brown ones on their arms. The juveniles are depicted with a white coat speckled with black markings, their snouts bare, revealing the black scales beneath.

Paleoecology

Paleoenvironment

Main: Hell Creek and Lance Formations

Main: Hell Creek and Lance Formations

A selection of non-avian dinosaurs that lived in the Hell Creek, Lance, and Scollard Formations (Pectinodon on the right side, in thatch)

“ These coastal seas are full of life. Yet on land, and only a few hundred miles away, there is desolation. Here, powerful movements deep in the Earth's crust are beginning to raise the Rocky Mountains. ”

― David Attenborough, North America

Pectinodon lived 67 - 66 million years ago in Laramidia, an island continent that would one day become western North America, which, by that time, was split in half by an inland sea. Remains have been excavated from the Hell Creek Formation in Montana and South Dakota, and the Lance Formation in Wyoming. These two formations show that the sort of world that Pectinodon lived in was one dominated by rivers, forests, and coastal plains, regions kept constantly humid by ample rainfall and a subtropical climate warmer than those areas are today (hence, there was no cold season in those areas back then).

A soda lake in the Denver Formation

“ The immense changes in the landscape have cut off this lake from nearby rivers. Its waters evaporate in the strong winds and intense summer sun, and the minerals that have dissolved in it are beginning to reach toxic levels. For most, this water is simply too poisonous to drink. Even so, every year, this place is visited by all kinds of animals. ”

― David Attenborough, North America

Prehistoric Planet depicts Pectinodon as visiting a lake hundreds of miles from the sea, slowly evaporating and degrading into toxicity due to the same tectonic movements raising the Rocky Mountains. This soda lake is depicted as being in the Denver Formation of Colorado. Little is known about the area, and Pectinodon fossils have yet to actually be found there. However, deposits indicate that there were floodplains, marshes, and rivers that formed by the foot of the growing Rocky Mountains during that time, and the existence of Pectinodon in other areas of the US outside of the Hell Creek and Lance Formations is somewhat plausible.

Also featured in the first segment of North America (set in the Javelina Formation) is a trio of similar troodontids. It was never confirmed if these were Pectinodon, and given how they were simply referred to as "troodontids" in the narration, it is possible that they were indeed meant to be a different species, as Pectinodon itself is not known from the Javelina Formation. However, it is possible for related animals to have similar coats (as the troodontids of the Javelina Formation are shown to have a similar color scheme with only a few differences), though it is also likely that the model of Pectinodon was simply recycled for this sequence to save on costs. The Javelina Formation does have remains classified as "Troodon sp.", though currently, Troodon is considered a potentially dubious genus due to its remains being considered undiagnostic, with most fossils once referred to it being reclassified as Stenonychosaurus, Latenivenatrix (which may or may not be a junior synonym of Stenonychosaurus), or Pectinodon. With the identity of the Javelina Formation troodontid still undetermined, the existence of Pectinodon itself in Texas (and, by extension, other areas in the US) is also possible.

As one of the last non-avian dinosaurs, Pectinodon, along with most of the animals it coexisted with, would have bore witness to the Cretaceous-Paleogene Extinction Event 66.043 million years ago, a catastrophe that ultimately wiped out three-quarters of all life on Earth, including all non-avian dinosaurs.

Feeding Preferences and Parental Habits

A Pectinodon with his offspring

“ Pectinodon are particularly intelligent dinosaurs. It doesn't take them long to work out the best way to collect flies. ”

― David Attenborough, North America

Pectinodon are shown to be opportunistic hunters like any other predator, with a trio of them (or closely-related troodontids) closing in on the smell of an Alamosaurus carcass, and one briefly risking its life to grab a piece of meat from the carcass while a Tyrannosaurus is feeding on it before running off. This opportunistic behavior is seen again when a family of Pectinodon visit an evaporating toxic lake. As troodontids, Pectinodon are shown to be particularly intelligent dinosaurs. The juveniles feed on flies living around the lake, eventually working out that the best way to eat as many as they can is to rush at the flies with their jaws fully agape.

“ Pectinodon are not only intelligent, they're also very skillful hunters. ”

― David Attenborough, North America

While the juveniles go after flies, their father, staying low and hidden behind the rock and mineral pillars surrounding the lake, ambushes and grabs one of the "Styginetta" that also came to feed on the flies. As with Prehistoric Planet's depiction of T. rex, juvenile Pectinodon are only lead and cared for by their father.

Appearances

North America, Segment I

	North America, Segment I
	Setting Javelina Formation, Texas, USA Filming Location Wharariki Beach, Cape Farewell, South Island, New Zealand

North America, Segment I

Setting
Javelina Formation, Texas, USA

Filming Location
Wharariki Beach, Cape Farewell, South Island, New Zealand

“ Dawn. And these troodontids have picked up a scent. They're quick to investigate anything new, especially if it might be worth eating. But biting through a three inch-thick hide is beyond their power. Very frustrating. ”

― David Attenborough, North America

In the first segment of North America, as a herd of Alamosaurus travel along a beach, one of them, a 70 year-old male, collapses due to his great age and passes away. The next day, a trio of troodontids (which may or may not be Pectinodon) discover the corpse, but frustratingly find themselves unable to bite through the titanosaur's hide, which is three inches thick. The troodontids are then scared away by a male Tyrannosaurus, which is easily able to feed on the carcass with his six-inch teeth and bone-crushing bite. One troodontid manages to take one strip of meat as the T. rex feeds before being forced away again.

North America, Segment III

	North America, Segment III
	Setting Denver Formation, Colorado, USA Filming Location Mono Lake, Mono County, California

North America, Segment III

Setting
Denver Formation, Colorado, USA

Filming Location
Mono Lake, Mono County, California

In the third segment of North America, many animals are shown visiting an evaporating toxic lake for feeding opportunities. Among them, "Styginetta", a primitive relative of ducks, and a family of non-avian dinosaurs. Six juvenile Pectinodon poke out from the rocks, lead to the toxic lake by their father.

“ These dinosaurs and the Styginetta are both drawn here by a strange seasonal bonanza. Flies. The larvae of these insects are able to filter out the lake's toxic salts, and, as a consequence, they thrive in immense numbers. Now, they're hatching into adults in their millions. They are a rich and abundant source of protein for all the lake's visitors. ”

― David Attenborough, North America

Watching millions of flies and emerging from the lake, the juvenile Pectinodon jump up and snap at the flies, but they soon eventually figure out that the best way to scoop up as many flies as possible is by rushing at them, stirring the flies like dirt from the ground, with their jaws gaping open to collect them in mouthfuls. A flock of "Styginetta" watch as the juveniles run around gulping flies, which eventually ends up with two of the juveniles crossing each other's paths while rushing, causing them to collide and get knocked to the ground. While all this is happening, however, the father of the Pectinodon chicks closes in on one "Styginetta" flock from behind, slowly approaching the birds while staying low, obscured by the rock and mineral pillars around the lake. By the time the birds realize he is there, the flock taking to the air, the Pectinodon leaps up and catches one by the throat in midair, swinging and slamming his prey twice to the ground before finishing off the bird with another bite.

“ Success. A rather more substantial meal for the family, and just as well. The flies will only be here for so long, and the dinosaur family will be forced to find food elsewhere. ”

― David Attenborough, North America

As the "Styginetta" fly off, with many other flocks of them still ankle-deep in the lake, looking for flies to eat, the Pectinodon father brings his catch to his six chicks, the family settling down to eat as flocks of "Styginetta" fly overhead.