BASILOSAURUS CORONODON AETIOCETUS BASILOSAURUS ISIS WHEN About 37 million years ago WHERE Modern Egypt Jordan and Morocco LENGTH 59 to 65 1 2 feet 18 to 20 meters LOOK FOR An incredibly long tail compared to the rest of its body PREHISTORIC PROFILE You definitely wouldn’t want to encounter a Basilosaurus in the ancient ocean Scientists think Basilosaurus was likely a predator and its jaws and teeth had a very powerful bite Evidence shows that they fed on fish and sharks and Basilosaurus bite marks on fossil Dorudon atrox skulls suggest that Dorudon may also have been prey to Basilosaurus These massive animals may have been some of the first fully aquatic mammals There are two different species of Basilosaurus and numerous fossils found across northern Africa suggest that it likely lived during the late Eocene period CORONODON HAVENSTEINI AETIOCETUS WELTONI WHEN 28 to 24 million years ago WHERE Ancient eastern North Pacific Ocean LENGTH Up to 11 feet 3 5 meters LOOK FOR Wide triangular flat snout with both baleen and teeth present PREHISTORIC PROFILE Although today we divide whales up based on whether they have teeth or baleen Aetiocetus weltoni may have had both With a jaw structure that may have allowed this ancient cetacean to expand its jaw sideways like modern baleen whales Aetiocetus most likely fed on fish by trapping them in their mouth and then pushing the additional water back out Although scientists aren’t sure if the presence of early baleen made this cetacean a true filter feeder the baleen might have helped hold on to slippery fish WHEN About 30 million years ago WHERE Modern Charleston South Carolina LENGTH 16 feet 5 meters LOOK FOR Large whalelike creature with a wide nose and teeth with fanlike edges PREHISTORIC PROFILE Coronodon havensteini used its teeth for both catching prey and filtering food out of the water making it one of the first filter feeding whales First discovered in 2017 Coronodon provides a link between ancient whales and modern baleen whales and is part of a prehistoric group of cetaceans known as archaeocetes Have you ever run your finger along your back teeth You’ll probably feel bumps on the surface Coronodon had bumps all around its teeth which it used to filter its food out of the water Coronodon likely took in a big mouthful of prey and seawater and then forced the water back out of its mouth catching its prey in the fanlike edges of its teeth 12
WAHAROA SWORD SNOUTED WAHAROA RUWHENUA DOLPHIN WHEN 27 3 to 25 2 million years ago WHERE Modern South Island of New Zealand LENGTH 16 1 2 to 19 1 2 feet 5 to 6 meters LOOK FOR Long thin mouth that opens past the eyes with teeth at the end of each jaw PREHISTORIC PROFILE Hey Waharoa ruwhenua why the long face Scientists think that these early cetaceans probably weren’t lunging predators but rather filtered their food out of the water making them one of the early relatives of modern baleen whales Because their jaws were very long and thin they were also delicate and there is evidence that their jaws did not get incredibly long until adulthood as scientists have found multiple fossils for this species at all different ages Because of their incredibly large jaw they were given the Maõri name waharoa which both means gateway and is the name of the horse mussel a mussel with a long thin wedge shaped shell that looks similar to Waharoa’s jaw EURHINODELPHIS LONGIROSTRIS WHEN About 23 to 5 million years ago WHERE Modern Belgium France and Maryland LENGTH 6 1 2 feet 2 meters LOOK FOR A long thin snout PREHISTORIC PROFILE Think about a swordfish with its long pointed snout The sword snouted dolphin had a very similar and sharp nose that it probably used to hunt prey Fossils of this prehistoric cetacean have been found in Europe and the United States and these sword snouted dolphins lived during the Miocene period They had complex ear bones that scientists believe may have been used for a form of echolocation 13
PHOBERODON PHOBERODON ARCTIROSTRIS WHEN 23 to 15 97 million years ago WHERE Modern Patagonia Argentina LENGTH 10 1 4 feet 3 meters LOOK FOR Sharklike teeth and a small dorsal fin PREHISTORIC PROFILE Look out a shark Or well shark toothed dolphin Unlike modern day dolphins with their conical teeth Phoberodon arctirostris had ridged teeth similar to modern sharks and were part of a family of ancient cetaceans called Squalodontidae First discovered in 1840 Phoberodon was not largely studied until more than 100 years later Although most modern dolphins are not directly related to Phoberodon they provide an important link to help scientists better understand how different cetaceans evolved to adapt to their environment GIANT TOOTHED SPERM WHALE LIVYATAN MELVILLEI WHEN About 13 to 12 million years ago WHERE Modern Peru LENGTH Estimated 42 1 2 to 52 1 2 feet 13 to 16 meters LOOK FOR An incredibly long skull with large piercing teeth PREHISTORIC PROFILE When this species was first discovered scientists wanted to name it Leviathan because the ancient whale had a massive skull and jaw but that name was already taken by a species of mastodon Instead they named it Livyatan This ancient sperm whale likely lived during the Miocene era and fossils found in Peru suggest it lived in the Pacific Ocean Much like modern sperm whales see page 64 Livyatan had a large bulge on its skull that was likely a spermaceti organ The second part of this whale’s name melvillei is actually a reference to the writer Herman Melville who created the famous sperm whale Moby Dick Livyatan teeth are truly massive and they measure about 14 inches 35 1 2 centimeters long and 4 or 5 inches 10 to 13 centimeters wide with sharp tips For comparison Tyrannosaurus rex teeth were about 6 to 12 inches 15 to 30 centimeters long 14
WHALERUS SKIMMING PORPOISE ODOBENOCETOPS LEPTODON SEMIROSTRUM CERUTTII WHEN About 7 to 5 million years ago WHERE Modern Peru and Chile AVERAGE TUSK SIZE 3 feet 1 meter on the right side and 10 inches 25 centimeters on the left LOOK FOR A wide head similar to modern day walruses with one long tusk PREHISTORIC PROFILE What do you get when you cross a whale and a walrus A whalerus This extinct form of a toothed whale had a face similar in shape to a walrus and large tusklike teeth Because this whale had a walrus like head and tusks it was nicknamed the whalerus or walrus whale Their two tusks were not the same size which makes them different from any modern marine mammals although they are somewhat similar to modern narwhals WHEN About 5 to 1 6 million years ago WHERE Modern California JAW LENGTH About 2 3 4 foot 85-centimeter jaw LOOK FOR A long lower jaw with a comparatively short triangular upper jaw PREHISTORIC PROFILE Imagine what it would feel like if your bottom jaw was twice as long as your upper jaw The skimming porpoise a prehistoric porpoise that may be related to modern porpoises had a very interesting mouth with a lower jaw that extended out far beyond the upper jaw Scientists think they may have used this jaw to help them skim food from the seafloor 15
