Timeline of mosasaur research

This timeline of mosasaur research is a chronologically ordered list of important fossil discoveries, controversies of interpretation, and taxonomic revisions of mosasaurs, a group of giant marine lizards that lived during the Late Cretaceous Epoch. Although mosasaurs went extinct millions of years before humans evolved, humans have coexisted with mosasaur fossils for millennia. Before the development of paleontology as a formal science, these remains would have been interpreted through a mythological lens. Myths about warfare between serpentine water monsters and aerial thunderbirds told by the Native Americans of the modern western United States may have been influenced by observations of mosasaur fossils and their co-occurrence with creatures like "Pteranodon" and "Hesperornis".
The scientific study of mosasaurs began in the late 18th century with the serendipitous discovery of a large fossilized skeleton in a limestone mine near Maastricht in the Netherlands. The fossils were studied by local scholar Adriaan Gilles Camper, who noted a resemblance to modern monitor lizards in correspondence with renowned French anatomist Georges Cuvier. Nevertheless, the animal was not scientifically described until the English Reverend William Daniel Conybeare named it "Mosasaurus", after the river Meuse located near the site of its discovery.
By this time the first mosasaur fossils from the United States were discovered by the Lewis and Clark expedition, and the first remains in the country to be scientifically described were reported slightly later from New Jersey. This was followed by an avalanche of discoveries by the feuding Bone War paleontologists Edward Drinker Cope and Othniel Charles Marsh in the Smoky Hill Chalk of Kansas. By the end of the century a specimen of "Tylosaurus" would be found that preserved its scaley skin. Later Samuel Wendell Williston mistook fossilized tracheal rings for the remains of a fringe of skin running down the animal's back, which subsequently became a common inaccuracy in artistic restorations.
The 20th century soon saw the discovery in Alabama of a strange mosasaur called "Globidens", with rounded teeth suited to crushing shells. Mosasaur remains were also discovered in Africa and California. In 1967 Dale Russell published a scientific monograph dedicated to mosasaurs. Embryonic remains in the 1990s confirmed that mosasaurs gave live birth like in ichthyosaurs. The 1990s also saw a revival and escalation of a debate regarding whether or not some supposed mosasaur toothmarks in ammonoid shells were actually made by limpets. By the end of the century, the evolutionary relationship between mosasaurs and snakes as well as the possible involvement of mosasaurs in the extinction of the aforementioned ichthyosaurs became hot button controversies.
The debates regarding snakes, toothmarks, and ichthyosaurs spilled over into the early 21st century. These discussions were also accompanied by the discovery of many new taxa, including new species of "Globidens", "Mosasaurus", and "Tylosaurus" as well as entirely new genera like "Yaguarasaurus" and "Tethysaurus". In 2013, Lindgren, Kaddumi, and Polcyn reported the discovery of a "Prognathodon" specimen from Jordan that preserved the soft tissues of its scaley skin, flippers and tail. Significantly, the tail resembled those of modern carcharinid sharks, although the bottom lobe of the tail fin was longest in the mosasaur whereas shark tails have longer upper lobes.
Prescientific.
The Cheyenne believe that there were many different kinds of water monsters that lived not only in lakes, rivers, and springs but also high bluffs and hills. The locations given as water monster habitat are similar to the locations where local marine fossils can be found as fossils often erode out of hillsides or stream banks. The Cheyennes feared the water monsters, because they could be dangerous predators or capsize their canoes. Even in modern times, tradition-minded Cheyenne sometimes take pains to avoid sleeping too close to springs due to fears of water monsters.
18th century.
1760s.
1764
1766
1770s.
1772
1780s.
1784
1790s.
1795
1798
1799
19th century.
1800s.
1804
"September 10th"
1810s.
1818
1820s.
1820
1822
1829
1830s.
1830
1839
1840s.
1845
1850s.
1850
1853
1860s.
1868
1869
1870s.
1870
"November"
1871
1872
1874
1878
1880s.
1885
1889
1890s.
1891
1892
1894
1895
1897
1898
Williston also discussed mosasaur life appearance and behavior. He compared mosasaur scales to those of monitor lizards and misinterpreted some fossilized cartilage as evidence for a fringe of soft tissue down mosasaurs' backs. He hypothesized that mosasaurs left the safety of the water to lay eggs on land. The paleobiology of individual mosasaur taxa also received Williston's attention. He thought the genus "Clidastes" as an inhabitant of near-surface waters. In contrast, Williston interpreted "Platecarpus" as a "deep diver" and thought "Tylosaurus" fed primarily on other marine reptiles.
He also elaborated on his earlier research into mosasaur biostratigraphy. He observed that "Tylosaurus" ranged throughout the Smoky Hill Chalk but went extinct around the time the Fort Pierre Shale was deposited. "Platecarpus" was also only known from the Niobrara Formation. "Clidastes" was only known from the upper Niobrara.
1899
20th century.
1900s.
1902
1904
1905
1907
1910s.
1911
1912
1914
1917
1918
1920s.
1920
1922
1930s.
1930
1935
1937
1939
1940s.
1942
1945
1950s.
1951
1960s.
1960
1963
1967
Dale Russell published a monograph on American mosasaurs. This monograph contained significant taxonomic revisions for the family. Among these were his conclusion that "Platecarpus coryphaeus" and "Platecarpus ictericus" were likely junior synonyms of "P. tympaniticus" while "P. planfirons" was too poorly preserved to be classified confidently at all. Russell also dismissed the species "Tylosaurus dyspelor" described by Cope as a dubious probable-synonym of "Tylosaurus proriger".
Russell also published additional information and speculation on mosasaur biostratigraphy. He reported the presence of mosasaur vertebrae up to 90 million years old among the Turonian fossils curated by the University of Kansas Museum of Natural History. Another of this work's significant contributions to mosasaur biostratigraphy concerned the mosasaurs of the Smoky Hill Chalk. Russell devised two biostratigraphic zones based on the Chalk's mosasaur fossils. The lower zone was characterized by "Clidastes liodontus", "Platecarpus coryphaeus", and "Tylosaurus nepaeolicus". The upper was home to "Clidastes", "Platecarpus ictericus", and "Tylosaurus proriger". He regarded "Platecarpus" and "Tylosaurus" as deep water animals but concluded that the biostratigraphic evidence from the Smoky Hill mosasaurs suggested that the Chalk's depositional environment was becoming shallower and nearer to the ancient coastline over time. Russell also argued that by the end of the Late Cretaceous, mosasaurs were converging on the body plan that characterized the first ichthyosaurs during the Triassic period and gradually replacing these older marine reptiles.
1969
1970s.
1970
1972
1975
1977
1980s.
1980
1982
1985
1986
1987
1988
1989
1990s.
1990
1991
1992
1993
1994
"January"
1995
1996
"September"
1997
1998
"August 8th"
1999
21st century.
2000s.
2000
2001
2002
"September"
2003
2004
"May"
2005
2007
2008
2009
2010s.
2011
2012
2013
2015
2016
2017
2018
2019