Alaska's North Slope dinosaurs are ofinternational scientific importance. They lived in places once thought impossible for Known Dinosaur Sites dinosaurs to survive. Already the numbers ofdifferent e Colville River area dinosaursfound on the North S lope and the amounts offossils 8 Western North Slope recovered surpass all other 8 Talkeetna Mountains dinosaur sites in the rest ofthe world's polar regions. 8 Aniakchak National Park & Preserve 0 Black Lake Area Mesozoic Era "Age of Dinosaurs" (245-65 mya=million years ago) Triassic Period (245-208 mya) dinosaurs of this time as yet unknown from Alaska Jurassic Period (208-146 mya) dinosaurs of this time known from Alaska Peninsula Cover photo: Cliffs along Cretaceous Period (146-65 mya) rivers on the North Slope dinosaurs of this time found on sometimes reveal signs that Alaska Peninsula, North Slope, and dinosaurs lived here long ago. in the Talkeetna Mountains. Twelve known dinosaur types Family #2: Troodontids had relatively large brains. have beenfound on the North Their large eyes possibly were better Slope, while evidencefor a 13th adapted for hunting during twilight or is under review. All are about at high latitudes. One type known: 68-73 million years old and are from the Late Cretaceous Period. Troodon small, lightly built, six feet high, eight feet long, weighed several hundred pounds; most common Theropod Meat-Eaters according to abundance of teeth found. Found in Alaska: teeth and skull Theropods were fast- running, meat­ fragments. eating dinosaurs ofvarious sizes with sharp serrated teeth. They are thought Family #3: to have hunted in packs or social groups. Dromaeosaurids were possibly the They walked on two legs. Theropods fastest, fiercest predators of any kind. found so far are grouped into four families: Two types known: Family #1: Tyrannosaurids had massive heads and Dromaeosaurus very reduced arms. Two types known: small, lightly built, around four feet tall, six feet long, 100 pounds; a "cousin" to the scary Velociraptor made famous in the movie Jurassic Park; Found in Alaska: isolated teeth and a single tail vertebra. Saurornitholestes very similar to Dromaeosaurus, four feet tall, six feet long, 100 pounds; Albertosaurus Found in Alaska: isolated teeth and up to 10 feet tall, 15-1 7 feet long, a vertebrae. smaller "cousin" of the famous T. rex; Found in Alaska: isolated teeth and rare Family #4: bones of a smaller adult or juvenile. Ornithomimids were relatively small, ostrich-like meat- and plant-eating dinosaurs that walked on two legs; had small, light heads, relatively big brains, large eyes, and long narrow toothless beaks. One type known: Tyrannosaurus Ornithomimid under 15 feet tall, 10-15 feet long, species genus uncertain; up to 11-19 feet long, not known; specimen probably an earlier over 200 pounds; "cousin" of T.rex, same genus; Found in Alaska: single foot bone Found in Alaska: a single tooth. (metatarsal). Plant-Eaters Hadrosaurs were large, plant-eating, duck-billed dinosaurs that walked on two legs. Three types known: Edmontosaurus 10 feet tall, more than 40 feet long, weighing up to three or more tons, non-crested, most common type known; Found in Alaska: teeth and more than 60 percent ofits bones; juveniles and young adults dominate recovered remains. Kritosaurus around 10 feet tall, up to so feet long, Paleontologists excavate Late Cretaceous weighing about three tons, non­ dinosaur bones in the vertical banks ofthe crested; Colville River on Alaska's North Slope. Ceratopsians were large, plant­ Found in Alaska: teeth. eating, horned dinosaurs that walked Pachycephalosaurids were relatively on four legs. small, plant-eating dinosaurs that Two types walked on two legs; notable for known: having thick-domed skulls suggesting Lambeosaurid that some may have used them for (Identity under review with its presence in How to speak dinosaur Alaska uncertain) head-butting, or some other ritual crested but genus uncertain; can be combat. Recent studies indicate AIbertosaurus AL-BERT-to-SORE-us more than 10 feet tall, up to 50 feet jDachyrhinosaurus domes may be an adaption for heat Anchiceratops AN-ki-ser-ra-tops long, weighing more than three tons; seven feet high, 18 feet long, dissipation or loss. Ceratopsian SERRA-tops-ee-n Found in Alaska: teeth and upper jaw. weighing up to four tons; One type known: Dromaeosaurus DROH-may-oh-SORE-us Found in Alaska: partial upper skull Edmontosaurus Ed-MON-toh-SORE-us Edmontonia Ed-mon-TOE-ne-ah Hypsilophodontids were small, frill, horn core and shoulder blade. Hadrosaur HAD-roh-sore swift-running, plant-eating dinosaurs Hypsilophodontid Hip-sih-LOE-foe-don- tid that walked on two legs. One type Kritosaurus KRITE-oh-SORE-us known: Lambeosaurid LAMB-ee-oh-sore-id Ornithomimid Or-NITH-o-MIM-id Ornithopod Or-NITH-o-pod Pachycephalosaurus PAK-ee-sef-a-Ioe-SORE-us Anchiceratops-like form jDachycephalosaurus-type Pachyrhinosaurus PAK-ee-RINE-oh-SORE-us Thescelosaurus up to seven feet high, 16-20 feet long, up to 6 feet tall, 03-15 feet long, 0300 Saurornitholestes Sore-OR-nith-oh-LES-teez weighing up to four tons; pounds; genus uncertain; Thescelosaurus Thes-kel-oh-SORE-us less than five feet high, 11 feet long, Theropod THER-oh-pod 200 pounds; Found in Alaska: part of rear end of Found in Alaska: egg-sized skull Tyrannosaurus Tie-RAN-oh-SORE-us Found in Alaska: teeth and toe bone. skull. fragment. Troodon TROH-oh-don volcanism or changing vegetation Dinosaurs on Alaska's unfavorable to some dinosaurs. North Slope Current thinking is that the dinosaurs died off from a combination ofcauses. Dinosaur discoveries Were North Slope dinosaurs "warm­ In the 1980s, the first dinosaur bones blooded" or "cold-blooded"? discovered on the Alaska North Slope belonged to the duck-billed In the past, paleontologists assumed Edmontosaurus. Fully grown, these all dinosaurs were cold-blooded. Only plant-eaters could reach 10 feet tall, in the 1960s, did scientists begin 40 feet long and weigh three tons. entertaining the possibility that These dinosaurs are thought to have dinosaurs could be warm-blooded. lived in social groups or herds. The bone cross-sections ofwarm­ How did they survive so far north? blooded mammals have more blood Did they slow their metabolism or channels while the bones ofcold­ hibernate? Did they migrate blooded reptiles have fewer channels. southward for food and warmer Some dinosaur bones show a climates? combination of both patterns, with more blood channels as juveniles, and No one knows the exact answers to fewer channels in adults. North Slope these questions, but new discoveries dinosaurs so far exhibit a juvenile on the Colville River throw doubt on pattern. The debate isn't settled. It the migration theory. Several new may be these dinosaurs had unique dinosaurs, including small meat-eaters metabolisms unlike animals today. such as the Troodon and Dromaeosaurus probably couldn't physically migrate DNA studies and North Slope the round-trip distance of5,000 miles. Instead, North Slope dinosaurs may dinosaur bones have survived year-round on ancient So far, no DNA has been found in river systems which supported lush dinosaur bones of the North Slope. summer vegetation. Enough seasonal vegetation may have grown during The highly mineralized bones ofthese the 24-hour sunlit summers to last dinosaurs haven't yielded any bone during the cool-to-cold dark days of tissue from which DNA could be winter. retrieved. Dinosaur extinction Although not proven, the best candidates for containing recoverable Did a meteorite strike the earth, throw biomolecular material and maybe even up dust to block the sun, and possibly DNA are dinosaur bones with lots of cause the extinction of dinosaurs 65 silica mineralization. There is the million years ago? Maybe, but then possibility that the silica could have why did certain reptiles, including encapsulated and helped protect some crocodiles, turtles, and snakes, survive? original cell matter. Whether such A few paleontologists suggest that ancient material exists, or whether it disease may have been a factor. could be viable or extractable, is also Others point to the possibility of unknown. climatic changes caused by increased Western North Slope ~ dinosaur finds ~ Kuk, Kokolik, and Avingak Rivers area: 1980s discoveries at various locations of isolated tracks and skin impressions as reported by field Central-Western Talkeetna geologists. 2001 discovery ofpartial Mountains: 1994 discovery of a 90­ hadrosaur lower leg (tibia) bones million-year-old hadrosaur (genus found with amber. Volcanic ash beds uncertain). This discovery includes being analyzed to determine the most bones from a single dinosaur "absolute" age for deposits containing yet found, but the skull is missing. bones. These are the first dinosaur It is the oldest hadrosaur known in body fossils found on the North Slope Alaska and one ofthe oldest in North west of Umiat. America. The specimen probably was a juvenile or young adult, five-to-six feet tall, nine feet long, and 300-400 Other dinosaur fossils found pounds. elsewhere in Alaska Aniakchak National Park & Preserve: 2001-2002 discovery of Black Lake area on Alaska two tracks ofa s-tocd 65-75-million­ Peninsula: 1975 discovery of 14 year-old Ornithopod (Hadrosaur?) dinosaur footprints ofJurassic age on a river estuary beach, about 420 (more than 146 million years old), miles southwest ofAnchorage. This which makes them the first of this extends the known range ofthis type age found in Alaska; tracks probably of dinosaur and is the first evidence represent two different meat-eaters of Late Cretaceous age dinosaurs but specific types are uncertain. from this part of Alaska. Other dinosaur (non-bone) fossils found on the North Slope North Slope, various locations: 1970s and later, mostly limited Western Talkeetna Mountains: the discoveries ofdinosaur skin imprints 1990 discovery of a skull found in a and footprints in different areas.