Timeline of plesiosaur research

This timeline of plesiosaur research is a chronologically ordered list of important fossil discoveries, controversies of interpretation, taxonomic revisions, and cultural portrayals of plesiosaurs, an order of marine reptiles that flourished during the Mesozoic Era. The first scientifically documented plesiosaur fossils were discovered during the early 19th century by Mary Anning.[1] Plesiosaurs were actually discovered and described before dinosaurs.[2] They were also among the first animals to be featured in artistic reconstructions of the ancient world, and therefore among the earliest prehistoric creatures to attract the attention of the lay public.[3] Plesiosaurs were originally thought to be a kind of primitive transitional form between marine life and terrestrial reptiles. However, now plesiosaurs are recognized as highly derived marine reptiles descended from terrestrial ancestors.[4]

Letter concerning the discovery of the 1823 Plesiosaurus, from Mary Anning.

Early researchers thought that plesiosaurs laid eggs like most reptiles. They commonly imagined plesiosaurs crawling up beaches and burying eggs like turtles. However, later opinion shifted towards the idea that plesiosaurs gave live birth and never went on dry land.[5] Plesiosaur locomotion has been a source of continuous controversy among paleontologists.[6] The earliest speculations on the subject during the 19th century saw plesiosaur swimming as analogous to the paddling of modern sea turtles. During the 1920s opinion shifted to the idea that plesiosaurs swam with a rowing motion.[7] However, a paper published in 1975 that once more found support for sea turtle-like swimming in plesiosaurs.[8] This conclusion reignited the controversy regarding plesiosaur locomotion through the late 20th century.[9] In 2011, F. Robin O'Keefe and Luis M. Chiappe concluded the debate on plesiosaur reproduction, reporting the discovery of a gravid female plesiosaur with a single large embryo preserved inside her.[10]

PrescientificEdit

Associated remains of plesiosaurs and animals like the diving bird Hesperornis or the pterosaur Pteranodon may have inspired legends about conflict between Thunder Birds and Water Monsters told by the Native Americans of Kansas and Nebraska.[11]

18th centuryEdit

1719

19th centuryEdit

 
1824 skeletal reconstruction of Plesiosaurus by Henry De la Beche
 
Duria Antiquior, the first artistic restoration of a Mesozoic ecosystem, features a Plesiosaurus being preyed upon by an Ichthyosaurus

1810sEdit

1811

1820sEdit

1821

1822

  • Parkinson coined the name Plesiosaurus priscus for some of the remains used by de la Beche and Conybeare as the basis for Plesiosaurus. This species is currently regarded as of dubious taxonomic value.[14]

1823

December

  • Mary Anning discovered a nearly complete Plesiosaurus skeleton near Lyme Regis. This specimen would later be catalogued as BMNH 22656.[15]

c. December

  • Around the same time as the discovery of BMNH 22656, another Plesiosaurus specimen was discovered at the same site. The specimen was donated to the Oxford University museum and is probably the specimen known today as OXFUM J.10304.[16]

1824

  • Conybeare described the new species name Plesiosaurus dolichodeirus for the Plesiosaurus discovered by Anning. As the first species name given to a distinctive and well preserved Plesiosaurus skeleton it has come to be regarded as both the type specimen of Plesiosaurus dolichodeirus specifically and of the genus Plesiosaurus as a whole.[15][17]

1829

  • Mary Anning collected the Plesiosaurus dolichodeirus specimen now known as BMNH R.1313.[18]

1830sEdit

1837

  • Buckland in Conybeare described the new species Plesiosaurus macrocephalus.[19]

1839

1840sEdit

 
Cast of the flipper of Pliosaurus brachydeirus. The species was named by Owen in 1841.
 
Skeleton of the "Barrow Kipper" Atychodracon megacephalus specimen

1840

1841

1842

1846

1848

  • The trustees of the British Museum of Natural History bought the type specimen of Plesiosaurus from the estate of the first duke of Buckingham, Richard Glenville. The museum catalogued the specimen as BMNH 22656.[16]

1860sEdit

 
Skeleton of Rhomaleosaurus cramptoni. R. cramptoni was described by Carte and Baily in 1863.

1863

  • Carte and Bailey described the species now known as Rhomaleosaurus cramptoni.[19]

1864

1865

 
Edward Drinker Cope's head-on-the-wrong-end skeletal reconstruction of Elasmosaurus platyurus.

1867

  • An army surgeon named Dr. Theophilus Turner discovered the fossils of a large animal in the Pierre Shale of Kansas, USA. The remains represented the first nearly complete plesiosaur specimen from North America. Turner gave some of its vertebrae to a member of the Union Pacific Railroad's survey named John LeConte. LeConte sent the vertebrae to Edward Drinker Cope for study. Cope recognized the find as a significant plesiosaur discovery and wrote to Turner asking him to excavate and ship the fossils to him.[24]

March, mid

 
An 1869 life restoration of Elasmosaurus (with the head still on the wrong end) confronting the theropod dinosaur Laelaps (now Dryptosaurus) platyurus.
  • Cope erected the new genus and species Elasmosaurus platyurus for the fossils sent by Turner in a rushed descriptive manuscript written within two weeks of obtaining them.[25]

March 24

  • Cope presented his findings regarding Elasmosaurus to a meeting of the Academy of Natural Sciences in Philadelphia, Pennsylvania.[26]

1868

  • Cope described the new species Elasmosaurus platyurus.[19]
  • Cope's description of Elasmosaurus was formally published.[26]

September

  • William E. Webb and others collected and shipped a plesiosaur specimen to Cope.[27]
 
Flipper of Polycotylus latipinnis. P. latipinnis was described by Cope in 1869.

1869

August

  • Cope prepared a preprint for the Transactions of the American Philosophical Society of his Elasmosaurus description, including reconstruction of the animal with a short neck and very long tail. The manuscript was then distributed to other scholars.[26]

1870sEdit

 
Modern life restoration of Elasmosaurus with an anachronistic scuba diver to scale

1870

March 8

  • Cope's mentor Joseph Leidy gave a presentation reporting his recent discovery that Cope's reconstruction of Elasmosaurus positioned the skull at the end of the tail rather than the end of the neck.[26]
  • Leidy's discovery embarrassed Cope, who began spreading notice of an unspecified error in his Elasmosaurus description with an offer to replace it with a corrected version and its second volume.[28]

November

  • O. C. Marsh collected a better an additional specimen of Polycotylus in Kansas that was better preserved than the type described by Cope. The specimen is now catalogued as YPM 1125.[29]
 
Skull of Cryptoclidus. C. eurymerus was originally described by Phillips in 1871.

1871

1872

  • Cope imagined elasmosaurs feeding by craning their necks above the water and striking downward at fish long distances from their bodies.[30]
  • B. F. Mudge discovered ten articulated vertebrae in the Fairport Chalk of Kansas that he mistook for ichthyosaur remains. These fossils are now catalogued as KUVP 1325.[31]
 
Life restoration of Liopleurodon, described by Sauvage in 1873

1873

  • Sauvage described the new species Liopleurodon ferox.[19]
  • Joseph Savage discovered a second, better preserved Trinacromerum "anonymum" in Kansas.[31]
 
Life restoration of Mauisaurus haasti, described by Hector in 1874

1874

  • Hector described the new species Mauisaurus haasti.[19]
  • Seeley described the new species Muraenosaurus leedsi.[19]
  • B. F. Mudge discovered fragments of a large elasmosaur skeleton in the Fort Hays Limestone of Kansas.[32]
  • Mudge and Williston excavated the remains another large Kansan plesiosaur, this one from the Smoky Hill Chalk.[32] The specimen may be a Styxosaurus snowii and is currently catalogued as YPM 1644. It was the first plesiosaur Mudge had ever found with gastroliths and the first plesiosaur encountered by Williston in general.[33]
  • Hector reported the presence of elasmosaur remains in New Zealand.[34]
  • Seeley published a paper intended to help improve the state of science's understanding of plesiosaur shoulder girdle anatomy, which had been muddled by the poor preservation of the fossils many early paleontologists had to rely on for their observations.[35]

1875

  • Cope once more portrayed elasmosaurs as feeding by fishing from a distance with heads held above the waterline.[36]

1876

1877

  • Lydekker described the species now known as Simolestes indicus.[19]
  • Mudge discussed the gastroliths of YPM 1644 in a scientific publication.[33] He concluded that plesiosaur exploited gastroliths to assist in breaking down food the way many modern birds and reptiles do.[37]

1879

1880sEdit

1880

  • Oxford acquired the Misses Philpot collection, which included the type specimen of Plesiosaurus macromus. The museum catalogued this specimen as OXFUM J.28587.[38]

1881

1882

  • The British Museum of Natural History purchased the Edgerton collection, which included the complete Plesiosaurus dolichodeirus jaw now known as BMNH R.255.[18]
 
Skeletal mount of Trinacromerum bentonianum. T. bentonianum was described by Cragin in 1888.

1884

Spring

  • The Smithsonian bought a partial plesiosaur skeleton from Charles Sternberg. The specimen is now catalogued as USNM 4989 and would later serve as the type specimen of the new genus and species Brachauchenius lucasi.[39]

1888

1890sEdit

 
Skull and neck of Styxosaurus snowii. S. snowii was described by Williston in 1890.

1890

  • In an article published in the New York Herald, Marsh brought up Cope's anatomic reversal of Elasmosaurus.[28]
  • E. P. West excavated a skull and partial neck belonging to the elasmosaur that would come to be named Styxosaurus snowii. The specimen is now catalogued as KUVP 1301.[42]
  • Williston described the species now known as Styxosaurus snowii.[19]

1892

  • Seeley described the species now known as Muraenosaurus beloclis.[19]
 
Life restoration of Seeleysaurus, described by Dames in 1895

1893

  • Marsh described the new species Pantosaurus striatus.[21]
  • Charles H. Sternberg obtained two large elasmosaur vertebrae that would later serve as the type specimen of Elasmosaurus sternbergi. The specimen is now catalogued as KUVP 1312.[43]
  • F. W. Cragin discovered a partial plesiosaur skeleton and associated gastroliths in what is now recognized as the Kiowa Shale. This specimen is now catalogued as KUVP 1305 and would later be named Plesiosaurus mudgei.[44]
  • Williston argued that plesiosaurs ingested gastroliths only accidentally or to relieve "food craving[s]".[37] However, he also observed that the rocks used as gastroliths were more similar to rocks 400–500 miles away in Iowa or the Black Hills of South Dakota than those of the local geology.[45]

1894

  • Cragin described the new species Plesiosaurus mudgei for KUVP 1305.[44]
 
1897 life restoration of Elasmosaurus by Charles R. Knight

1895

  • Dames described the species now known as Seeleysaurus guilelmiimperatoris.[19]

1897

1898

  • Knight described the new species Megalneusaurus rex.[19]

1899

20th centuryEdit

 
Plesiosaur gastroliths
 
Jaws of Tricleidus

1900sEdit

1900

  • Knight described the species now known as Tatenectes laramiensis.[21]
  • George F. Sternberg discovered the plesiosaur specimen now known as KUVP 1300 that would later serve as the type specimen of Dolichorhynchops osborni.[48]

1902

  • Williston described the new species Dolichorhynchops osborni.[19]

1903

  • Williston made several changes to plesiosaur taxonomy. One of these was the description of the new genus and species Brachauchenius lucasi, whose type specimen was a partial skeleton discovered in Kansas. This specimen is now catalogued as USNM 4989.[39] He also described the new species Trinacromerum anonymum based on the vertebral series discovered by Mudge in 1872. This specimen is now known as KUVP 1325.[31] Lastly, Williston regarded Plesiosaurus mudgei as a junior synonym of the species Plesiosaurus gouldii.[44] He also commented on the ongoing debate regarding plesiosaur gastroliths, acknowledging the possibility that they were used for ballast while also maintaining openness to his 1893 suggestion that the stones were ingested accidentally.[49]

1904

  • Barnum Brown hypothesized that plesiosaurs used their gastroliths in a gizzard-like organ to grind up their invertebrate prey since they had no grinding or crushing teeth to do that job for them.[49]
  • Harvard paleontologist Charles R. Eastman, "offended" by Brown's claim that plesiosaurs had a gizzard, criticized the idea in print.[49]
  • Williston responded to Eastman, reasserting the evidence for plesiosaur gastroliths by noting that by this time at least 30 specimens containing them had been found.[50]

1906

  • Williston described several new taxa and specimens. One of these was the new species Elasmosaurus nobilis.[32] Williston also described the new Elasmosaurus species E. sternbergi based on the vertebrae discovered by Charles H. Sternberg in 1893. He remarked that these fossils were the largest elasmosaur vertebrae that he had ever seen.[43] Lastly, Williston described Marsh's Polycotylus, YPM 1125.[29]

1907

  • Williston reported the discovery of another Brachauchenius specimen, although this one was discovered in Texas.[51]
  • Williston argued that Brachauchenius lucasi was closely related to Liopleurodon ferox.[52]

1909

1910sEdit

 
Skeleton of Rhomaleosaurus (now Meyerasaurus) victor

1910

1911

1913

 
Skull of Brancasaurus

1914

  • Williston criticized portrayals of long-necked plesiosaurs as having unnaturally flexible necks.[46]
  • Wegner described the new species Brancasaurus brancai.[19]
  • Williston observed that the semicircular canals inside a plesiosaur's ear were well developed, giving them a good sense of balance and coordination.[53]

1919

  • The Smithsonian obtained the Tylosaurus specimen with preserved polycotylid stomach contents from Charles Sternberg.[54] The Tylosaurus is catalogued as USNM 8898 and its last supper as USNM 9468.[55]

1920sEdit

1922

  • Andrews described the new species Leptocleidus superstes.[19]
  • Sternberg observed that being contained in the stomach of a mosasaur might have helped ensure the preservation of the polycotylid now known as USNM 9468 by protecting it from scavenging sharks.[55]

1923

1924

1926

  • George F. Sternberg discovered a third specimen of Dolichorhynchops osborni in Kansas.[48]

1929

  • More Kronosaurus fossils were discovered in central Queensland near the site of the type specimen's discovery.[47]

1930sEdit

 
Life restoration of Macroplata

1930

  • Swinton described the new species Macroplata tenuiceps.[19]

1931

  • George F. Sternberg and M. V. Walker discovered a well-preserved large elasmosaur specimen.[56]

1931-1932

  • Harvard University dispatched a fossil hunting expedition to Queensland, Australia. In Army Downs they discovered a nearly complete specimen of Kronosaurus.[57]

1934

c. 1935

  • The University of Nebraska State Museum bought the elasmosaur specimen discovered by Sternberg and Walker in 1931. The specimen is now catalogued as UNSM 1195.[56]

1935

  • Russell described the new species Trinacromerum kirki.[19]

1936

  • A specimen of Trinacromerum was discovered in a roadside exposure of the Greenhorn Formation in Kansas. The specimen is now catalogued as KUVP 5070.[31]

1938

  • A large pliosaur skeleton was found on the banks of Russia's Volga River. However, the specimen was damaged during the excavation and only the skull and chest region were successfully extracted.[59]

1940sEdit

 
Cast of the "Plesiosaurus" now Attenborosaurus conybearei type specimen that was destroyed by Nazi bombers
 
Life restoration of Aristonectes
 
Life restoration of Thalassomedon
 
Life restoration of Libonectes morgani

1940

  • A complete specimen of Plesiosaurus conybeari, including preserved soft tissues, was destroyed in a bombing raid against Bristol. Fortunately, a cast of the specimen survived in the British Museum.[60]
  • White described the new species Seeleyosaurus holzmadensis.[61]

1941

1942

1943

1944

1948

1949

1950sEdit

 
Kronosaurus mount at Harvard

1950s

  • Alfred Sherwood Romer helped mount the Kronosaurus discovered in Queensland by the 1930s Harvard expedition for the University's Museum of Comparative Zoology. The poorly preserved bones required a significant amount of plaster for the restoration, earning the specimen the mocking nickname "Plasterosaurus".[57] The final mount was 42 feet long, probably due to Romer overestimating the number of vertebrae in its spine; a more likely length is about 35 feet.[63]

1950

  • Fossil hunters Robert and Frank Jennrich serendipitously discovered a partial Brachauchenius skeleton when looking for sharks teeth.[52]
  • Shuler, like Williston in 1914, found elasmosaurs to have relatively inflexible necks.[36] He also found elasmosaurs to have stereoscopic vision, which would have been useful for hunting small prey.[53]

October

  • George Sternberg excavated the Brachauchenius discovered by the Jennriches. This specimen, now known as FHSM VP-321, was both larger and better preserved than the Brachauchenius type specimen. Although it was put on display soon after discovery, it would not be described for the scientific literature for nearly 50 years.[52]

1952

  • Welles argued that the "Elasmosaurus sternbergi" type specimen was actually pliosaur vertebrae.[43]

1954

  • A private landowner in Kansas donated some Elasmosaurus vertebrae to the Sternberg Museum. These fossils are now catalogued as FHSM VP-398.[64]

1960sEdit

 
The Addyman plesiosaur

1960

1962

  • Welles described the species now known as Callawayasaurus colombiensis.[21]
  • Welles reported the presence of elasmosaur remains in South America.[34]
  • Chatterjee and Zinsmeister reported the presence of elasmosaur remains in Antarctica.[34]

1967

1970sEdit

1971

  • Beverly Halstead reclassified the Volga pliosaur, Pliosaurus rossicus, to the genus Liopleurodon.[59]
  • Paul Johnston discovered plesiosaur fossils in a roadside exposure of the Greenhorn Formation in Kansas.[67] During the excavation the dig site was scouted by two suspicious men. After a break from digging the Johnston team returned to find all of the fossils crudely extracted from the rock except for a flipper that the team had reburied. Based on the flipper, the stolen plesiosaur could be identified as Trinacromerum bentonianum.[68]
 
Styxosaurus in subaqueous "flight"

1975

1976

1977

  • Robinson publishes follow up research to her previous publication on plesiosaur locomotion.[9] This second paper notably concluded that plesiosaurs were incapable of leaving the water.[69]

1980sEdit

 
Life restoration of Bishanopliosaurus

1980

1981

  • Michael Alan Taylor published a paper concluding that plesiosaurs would have been capable of moving on land after all because their spinal column was too arched for their lungs to collapse.[70]
  • Brown described the new species Kimmerosaurus langhami.[19]
  • Brown emended the species Plesiosaurus guilelmiiperatoris originally described by Dames in 1895.[15]
  • Taylor argued that plesiosaurs used their gastroliths to adjust buoyancy or to help stay level and balanced while swimming.[37]

1982

  • Samuel F. Tarsitano and Jürgen Riess published a paper harshly critical of Robinson's previous work on plesiosaur locomotion. However, while criticizing Robinson's work they were reluctant to make any positive claims of their own, concluding that the details of plesiosaur locomotion were "unknown".[9]
  • Richard A. Thulborn published the results of his recent re-examination of the purported plesiosaur embryos discovered by Harry Govier Seeley. Thulborn concluded that Seeley's supposed embryos were actually nodules of mudstone and shale derived from sediments that once filled in a crustacean burrow system and were not even animal body fossils.[40]
  • Delair described the new species Bathyspondylus swindoniensis.[21]

1984

1985

1986

  • A South Australian opal miner named Joe Vida discovered the skeleton of a juvenile plesiosaur whose remains had converted to opal. Its preparator, Paul Willis nicknamed it Eric. An entrepreneur named Sid Londish bought the specimen and funded its preparation, but went bankrupt. When the specimen was put up for auction fear spread that a potential buyer might break the specimen down for its gemstone value. A television drive was arranged on behalf of the Australian Museum. The Museum succeeded in raising 340,000 dollars to buy the specimen, whose gemstone value was about $300,000. Eric was later identified as a specimen of Leptocleidus.[22]
 
Liopleurodon teeth share traits with those of killer whales (skeleton pictured)
  • Wiffen and Moisley described the new species Tuarangisaurus keysei.[21]

1987

  • Judith Massare published an analysis of plesiosaur feeding habits. She concluded that the long-necked plesiosauroids ate soft prey. Liopleurodon and its relatives, on the other hand, had teeth resembling those of killer whales and probably ate larger, bonier prey.[51]
  • Orville Bonner discovered a specimen of Dolichorhynchops osborni that was later seen to preserve developing young inside it.[71]

1988

  • Judy Massare analyzed Mesozoic marine reptile swimming abilities and found that long-necked plesiosaurs would have been significantly slower than pliosaurs due to excess drag incurred from the length of the neck.[72]
  • The Los Angeles County Museum of Natural History acquired the Dolichorhynchops osborni specimen discovered by Bonner and catalogued it as LACMNH 129639.[44]

1989

  • Beverly Halstead published a paper suggesting that plesiosaurs swam using all four flippers paired with an undulatory motion of the body comparable to a sea lion's.[73]
  • Nakaya reported the presence of elasmosaur remains in Japan.[34]

1990sEdit

1990

May

  • J. D. Stewart, accompanied by Everhart, discovered a nearly complete Dolichorhynchops rear flipper in the lower Smoky Hill Chalk. Unfortunately it was too late to correct the erroneous statements in his aforementioned paper regarding the supposed rarity of plesiosaurs in the lower Smoky Hill Chalk. The flipper is now catalogued as LACMNH 148920.[77]
 
Location of Lawrence in the U.S. state of Kansas

October

  • Stewart's paper, complete with his now-erroneous statements, was published in the Niobrara Chalk Excursion Guidebook in honor of the society's 50th anniversary meeting in Lawrence that year.[75]

1991

  • Ralph E. Molnar published suspicion that the "Kronosaurus queenslandicus" specimen discovered by the Harvard expedition might actually be a distinct species.[47]
  • Several Elasmosaurus vertebrae and gastroliths were found near the site where the type specimen of the genus itself was excavated.[64]
  • Cruikshank and others hypothesized that plesiosaurs could smell and taste water that "passively" flowed through its nasal passages while they swam.[53]

1992

  • Hampe described the new species Kronosaurus boyacensis.[19]
  • Everhart discovered some fragmentary plesiosaur fossils in the lower Smoky Hill Chalk of Kansas. Some of the fossils seemed to have been partially digested. The remains were later catalogued as FHSM VP-13966.[75]
  • Everhart showed the partially digested fossils to J. D. Stewart, who recognized them as pieces of a plesiosaur skull. The fossils are now catalogued as[clarification needed][77]
  • Everhart and his wife helped excavated a Styxosaurus snowii specimen in Kansas. During the dig Mrs. Everhart discovered an additional partial plesiosaur skeleton.[78]

1993

  • Robert T. Bakker nicknamed the long-necked plesiosaurs "swan lizards".[72]
  • Robert T. Bakker argued that plesiosaurs suffered several major extinction events throughout the Mesozoic rather than continuously diversifying until the end-Cretaceous mass extinction.[79]
  • Robert T. Bakker argued that Dolichorhynchops and its relatives became the most common kind of short-necked plesiosaur in the Cretaceous Western Interior Seaway after the ichthyosaurs became extinct. Further, they convergently evolved many traits similar to those of ichthyosaurs like long snouts and large eyes.[80]
  • Tony Thulborn and Susan Turner examined the crushed skull of the long-necked plesiosaur Woolungasaurus and found the presence of tooth marks left by some giant predator. They hypothesized that a Kronosaurus was the culprit.[81]
  • Storrs, like Williston and Shuler before him, argued that long-necked plesiosaurs had relatively inflexible necks.[36]
  • Rothschild and Martin reported the presence of the remains of a fossilized fetus preserved in the abdomen of a Dolichorhynchops osborni.[82]

1994

  • Glenn W. Storrs formally described the world's smallest plesiosaur for the scientific literature.[74]
  • South Dakota School of Mines paleontologist James Martin excavated and described a very young pliosaur specimen.[74] The specimen was located in what would have been the middle of the Cretaceous Western Interior Seaway. It is more plausible to think that this young individual was born in the seaway itself rather than surviving the extremely long swim from shore. So, the specimen provided circumstantial evidence for live birth and possibly even parental care by pliosaurs in the Cretaceous Western Interior Seaway.[83] However, since there were no adult fossils present this interpretation is speculative. Further, the fossil site had been heavily vandalized before discovery by scientists. A large hole was located near the baby pliosaur that could have once held the bones of its mother or other pod members.[84]
 
Trinacromerum bentonianum from the Late Cretaceous of Kansas

1996

  • Carpenter published a review of the Cretaceous short-necked plesiosaurs known from western North America. In this paper he both revised these plesiosaurs' taxonomy as well as offering observations on their biostratigraphy and evolution.[87] Carpenter described the new genus and species Plesiopleurodon wellesi.[21] He also argued against the prevailing trend to treat Dolichorhynchops Trinacromerum as taxonomic synonyms by observing that they could be distinguished based on their skull anatomy.[88] However he did conclude that the Trinacromerum species T. anonymum and T. willistoni were junior synonyms of T. bentonianum.[31]

In his remarks on short-necked plesiosaur evolution, Carpenter argued that polycotylids were more closely related to long-necked plesiosaurs than pliosaurs.[89] He observed that Trinacromerum bentonianum seems to have existed from the late Cenomanian to the Turonian. This represents a span of time approximating 3.3 million years. He found Dolichorhynchops osborni to have had an even longer lifespan, from the middle Turonian to the early Campanian., or roughly 4 million years. His research also suggested that there was a span of time during the life of the Western Interior Seaway in which it was not inhabited by polycotylids.[29]

He also reported that the Dolichorhynchops specimen KUVP 40001 from the Pierre Shale of South Dakota may have achieved the extraordinary length of 23 feet.[34] The large size of the Pierre Shale Dolichorhynchops compared to those of the earlier Smoky Hill Chalk suggested to Carpenter that these plesiosaurs were evolving larger body sizes over time. In fact the Pierre Shale specimens of Dolichorhynchops were nearly as large as Brachauchenius lucasi.[78] Carpenter described a particularly large specimen of that latter taxon in this paper as well, specifically FHSM VP-321.[52] His study of Brachauchenius led him to concur with Williston that it was closely related to Liopleurodon ferox.[52]

 
Location of Hokkaido Prefecture in Japan.

1997

1998

  • Tamaki Sato and Kazushige Tanabe reported that a partial long necked plesiosaur skeleton had been discovered on the banks of Hokkaido's Obirashibe River. Although they could not identify its exact species, the specimen was significant because its stomach contents provided clues to long-necked plesiosaur diets. This individual's gut preserved the beaks of thirty small ammonites.[91]
  • John A. Long bemoaned the fact that the putative "Kronosaurus queenslandicus" uncovered by a Harvard team during the early 1930s had still not been formally described for the scientific literature.[47]
  • Michael Everhart and Glenn Storrs excavated additional Elasmosaurus ribs, vertebrae and gastroliths at the site of the 1991 discovery.[64]
  • Long reported the presence of elasmosaur remains in Australia.[34]

1999

  • Carpenter published a summary of the elasmosaur fossils discovered in the Smoky Hill Chalk.[42]
  • Storrs published a revision of Elasmosaurus taxonomy.[92] He reinterpreted the Elasmosaurus nobilis type specimen as indeterminate elasmosaurid remains.[32] He also reinterpreted the "Elasmosaurus" sternbergi type specimen as two cervical and one dorsal vertebrae rather than two dorsal vertebrae as Williston had reported in his original description. However, Storrs did agree that it was an elasmosaur specimen rather than a pliosaur as argued by Welles in 1952.[43]

21st centuryEdit

2000sEdit

 
Life restoration of Leptocleidus capensis.
 
Life restoration of Leptocleidus capensis.
 
Life restoration of Enchodus .
 
Speculative life restoration of the Aramberri pliosaur.

2000

  • Theagarten Lingham-Soliar published further criticism of Robinson's interpretation of the biomechanics of plesiosaur locomotion.[93]
  • O'Keefe described the new species Hauffiosaurus zanoni.[21]
  • Michael Everhart re-examined UNSM 1195.[56]
  • Lingham-Soliar argued that plesiosaur hind-flippers weren't mobile or muscular enough to help propel them through the water.[94]
  • Everhart published a study of the gastroliths associated with the elasmosaur specimen KUVP 129744 from Kansas. The specimen was associated with roughly 13.1 kg of gastroliths. The largest of these was 17 cm long and 1.4 kg in weight. Everhart would later compare its size to that of a softball and observe that not only was it one of the largest known plesiosaur gastroliths, but also one of the largest gastroliths from any animal.[37]

November

  • The Advertiser, a newspaper based in Adelaide, Australia bought the Addyman opalized plesiosaur specimen for $25,000 and donated it to the South Australian Museum. A paleontologist at the museum named Ben Kear identified it as a member of the genus Leptocleidus. The two foot long specimen was the smallest specimen of the genus ever found and probably a baby.[66]

2001

  • David J. Cicimiurri and Michael J. Everhart published a study of the Styxosaurus snowii specimen NJSM 15435, which preserved both stomach contents and gastroliths.[37] Among the stomach contents were remains of the bony fish Enchodus.[53] By this point in time at least fifteen different plesiosaur specimens were known with preserved stomach contents.[95] The researchers observed that the Enchodus remains preserved in NJSM 15435 were an example of shifting dietary preferences in plesiosaurs, who fed primarily on cephalopods for most of their evolutionary history, before coming to rely more heavily on fishes during the Late Cretaceous.[53]

They also noted that some of NJSM 15435's gastroliths were scarred by rounded chips and arc-shaped marks. These were likely inflicted by contact with other gastroliths during the churning of the animal's stomach, and constituted physical evidence that plesiosaurs used their gastroliths to help break down their food during digestion.[96] Cicimurri and Everhart disputed the hypothesis that plesiosaurs used their gastroliths for ballast on the grounds that swallowing and vomiting such stones would be relatively difficult for the long-necked forms and their feeding grounds may have been hundreds of miles from sources of stones.[97]

  • Everhart resumed the study of the partially digested plesiosaur skull bones, FHSM VP-13966. He sought the expertise of Ken Carpenter due to his relevant 1996 paper on short-necked plesiosaurs. Carpenter identified the bones as probable Dolichorhynchops remains.[31]
  • Noe published another study of Pachycostasaurus. He changed his mind regarding its diet. Where previously he believed it to feed on soft-bodied animals, the robust and "heavily ornamented" build of its teeth suggested it fed on harder, bonier prey.[86]
 
Life restoration of Leptocleidus capensis.

September

September 11

  • Everhart was forced to cancel plans to examined the Tylosaurus specimen USNM 8898 and its polycotylid dinner USNM 9468 due to the September 11th terrorist attacks.[55]

November

  • Everhart was finally able to examine the tylosaur specimen with the polycotylid stomach contents.[55]
 
Life restoration of Kaiwhekea.
 
Life restoration of Edgarosaurus

20012002

  • Robin O'Keefe publishes a series of papers examining the aspect ratios of plesiosaur flippers and comparing them to the wings of birds, bats, and aircraft. O'Keefe concluded that long-necked plesiosaurs were long distance swimmers, while pliosaurs were more maneuverable.[99]

2002

  • Cruickshank and Fordyce described the new species Kaiwhekea katiki.[21]
  • Druckenmiller described the new species Edgarosaurus muddi.[21]
  • Michael Everhart examined FHSM VP-398 and found Sternberg's original note revealing that these fossils had been collected at the same site as the 1991 Elasmosaurus discovery. Everhart realized that the remains discovered there collectively represented most of the bones that had been missing from the Elasmosaurus type specimen. He inferred that they may represent fragments that fell off of the decomposing type carcass while it was adrift, before its final burial and fossilization.[64]
  • An elasmosaur specimen with over 600 associated gastroliths was discovered in the Pierre Shale of Nebraska. The specimen is now catalogued as UNSM 1111-002.[37]

December 30

  • The BBC began making sensational claims about the Aramberri pliosaur, claiming that the unidentified pliosaur was a Liopleurodon, that it was 65 feet long, that its teeth were the size of machetes, and its jaws powerful enough to crush granite.[100]

2003

  • The University of Nebraska led the excavation of a long-necked plesiosaur skeleton on local Santee Sioux land.[101] The Santee people requested that the skeleton be mounted and displayed with a plaque acknowledging them as the source of the fossils and as having given permission for the museum to display the remains. However, the museum claims it could not honor the request as it did not have the funding to mount the skeleton for display, and it further claimed that the land the fossils were recovered from was of "disputed" ownership.[102]
  • Mulder and others reported the presence of elasmosaur remains in Europe.[34]
 
Life restoration of Thililua
  • Sato described the new genus and species Terminonatator ponteixensis. In his study of the animal's skeleton, he found that the vertebral discs in the neck were flat on both sides and packed tightly together. He estimated that there would have been only about 0.5 cm of cartilaginous padding between these discs. These observations provided additional evidence for a lack of flexibility in plesiosaur necks.[36]
  • Everhart argued contrary to Carpenter's 1996 paper that polycotylids were present throughout the life of the Western Interior Seaway.[48]
  • Everhart finally described the partially digested partial plesiosaur skull he discovered in 1992. These were among the earliest known plesiosaur fossils in the Smoky Hill Chalk. He has since concluded that the animal that partially digested the remains was probably a shark, which would go on to vomit them up before they were buried and preserved.[77]
  • Bardet and others described the new species Thililua longicollis.[21]

2004

  • Michael Everhart found Charles H. Sternberg's account of the discovery of the Elasmosaurus sternbergi type specimen in his 1932 book. This allowed Everhart to verify the specimen's geographic and stratigraphic provenance.[103]
  • Everhart argued that the greater abundance of arc shaped marks and rounded divots in plesiosaur gastroliths compared to rocks deposited by ancient rivers and sea shores was evidence for their use in the breakdown of plesiosaurs' food.[96]
  • Everhart redescribed the Tylosaurus specimen USNM 8898 and its polycotylid dinner USNM 9468. Contrary to Sternberg's original assessment of the stomach contents as representing a "huge plesiosaur" Everhart found it to be a young polycotylid only about 2-2.5 m long.[55]
  • Noe et al. described the new species Pliosaurus portentificus.[19]
 
Life restoration of Umoonasaurus, described by Kear in 2006

2005

 
Skull of Futabasaurus suzukii. F. suzukii was described by Sato and others in 2006.

2006

2007

2008

2009

2010sEdit

 
Restoration of a Polycotylus giving birth.

2010

2011

 
Albertonectes with a human to scale.

2012

 
Jaws of Cryonectes.
  • Knutsen, Druckenmiller and Hurum described the new species Pliosaurus funkei[118]
  • Knutsen, Druckenmiller and Hurum described the new genus Spitrasaurus and two species, S. wensaasi, and S. larseni.[119]

2013

 
Life restoration of Atychodracon.

2014

2015

2016

2017

2018

2019

2020

See alsoEdit

FootnotesEdit

  1. ^ a b Ellis (2003); "Introduction: Isn't That the Loch Ness Monster?", page 3.
  2. ^ Ellis (2003); "The Marine Reptiles: An Overview", page 20.
  3. ^ a b Ellis (2003); "The Marine Reptiles: An Overview", page 21.
  4. ^ Ellis (2003); "The Plesiosaurs", page 118.
  5. ^ Ellis (2003); "The Plesiosaurs", page 119.
  6. ^ Ellis (2003); "The Plesiosaurs", page 136.
  7. ^ Ellis (2003); "The Plesiosaurs", page 137.
  8. ^ a b Ellis (2003); "The Plesiosaurs", page 138.
  9. ^ a b c Ellis (2003); "The Plesiosaurs", page 139.
  10. ^ a b O'Keefe and Chiappe (2011); "Abstract", page 870.
  11. ^ For the mythical creatures as Thunder Birds and Water Monsters, see Mayor (2005); "The Stone Medicine Bone, Pawnee Territory", page 178. For plesiosaurs as a specific source of these legends, see "Cheyenne Fossil Knowledge", page 211.
  12. ^ Stukeley (1719); in passim.
  13. ^ Ellis (2003); "The Plesiosaurs", page 123.
  14. ^ Storrs (1997); "Remarks:", pages 150-151.
  15. ^ a b c Storrs (1997); "Introduction", page 146.
  16. ^ a b Storrs (1997); "Remarks:", page 151.
  17. ^ For the original publication, see Conybeare (1824).
  18. ^ a b Storrs (1997); "Referred specimens:", page 150.
  19. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak al am an ao ap aq ar as at au av aw ax ay az ba bb bc bd be Smith (2007); "Appendix 1", page 257.
  20. ^ Ellis (2003); "The Marine Reptiles: An Overview", page 37.
  21. ^ a b c d e f g h i j k l m n o p q r s t u v w x y Smith (2007); "Appendix 1", page 258.
  22. ^ a b Ellis (2003); "The Pliosaurs", page 166.
  23. ^ Ellis (2003); "The Marine Reptiles: An Overview", pages 21-22.
  24. ^ Everhart (2005); "Where the Elasmosaurs Roamed", page 121.
  25. ^ Everhart (2005); "Where the Elasmosaurs Roamed", pages 121–122.
  26. ^ a b c d Everhart (2005); "Where the Elasmosaurs Roamed", page 122.
  27. ^ a b c Everhart (2005); "Pliosaurs and Polycotylids", pages 146–147.
  28. ^ a b Everhart (2005); "Where the Elasmosaurs Roamed", page 123.
  29. ^ a b c Everhart (2005); "Pliosaurs and Polycotylids", page 147.
  30. ^ Everhart (2005); "Where the Elasmosaurs Roamed", pages 130-132.
  31. ^ a b c d e f g Everhart (2005); "Pliosaurs and Polycotylids", page 150.
  32. ^ a b c d Everhart (2005); "Where the Elasmosaurs Roamed", page 128.
  33. ^ a b Everhart (2005); "Where the Elasmosaurs Roamed", pages 128-129.
  34. ^ a b c d e f g Everhart (2005); "Where the Elasmosaurs Roamed", page 129.
  35. ^ Storrs (1997); "Forelimb", page 171.
  36. ^ a b c d e Everhart (2005); "Where the Elasmosaurs Roamed", page 132.
  37. ^ a b c d e f Everhart (2005); "Where the Elasmosaurs Roamed", page 137.
  38. ^ Storrs (1997); "Discussion", page 180.
  39. ^ a b Everhart (2005); "Pliosaurs and Polycotylids", pages 151–152.
  40. ^ a b Ellis (2003); "The Plesiosaurs", page 149.
  41. ^ Ellis (2003); "The Pliosaurs", pages 188–189.
  42. ^ a b Everhart (2005); "Where the Elasmosaurs Roamed", page 125.
  43. ^ a b c d Everhart (2005); "Where the Elasmosaurs Roamed", page 126.
  44. ^ a b c d Everhart (2005); "Pliosaurs and Polycotylids", page 154.
  45. ^ Everhart (2005); "Where the Elasmosaurs Roamed", page 138.
  46. ^ a b Ellis (2003); "The Plesiosaurs", page 153.
  47. ^ a b c d e Ellis (2003); "The Pliosaurs", page 176.
  48. ^ a b c Everhart (2005); "Pliosaurs and Polycotylids", page 148.
  49. ^ a b c Ellis (2003); "The Plesiosaurs", page 156.
  50. ^ Ellis (2003); "The Plesiosaurs", pages 156–157.
  51. ^ a b Ellis (2003); "The Pliosaurs", page 184.
  52. ^ a b c d e Everhart (2005); "Pliosaurs and Polycotylids", page 152.
  53. ^ a b c d e Everhart (2005); "Where the Elasmosaurs Roamed", page 134.
  54. ^ Everhart (2005); "Pliosaurs and Polycotylids", pages 144–145.
  55. ^ a b c d e Everhart (2005); "Pliosaurs and Polycotylids", page 145.
  56. ^ a b c Everhart (2005); "Where the Elasmosaurs Roamed", page 127.
  57. ^ a b Ellis (2003); "The Pliosaurs", page 175.
  58. ^ Ellis (2003); "The Plesiosaurs", page 121.
  59. ^ a b c d Ellis (2003); "The Pliosaurs", page 181.
  60. ^ Ellis (2003); "The Plesiosaurs", page 161.
  61. ^ Storrs (1997); "Discussion", page 179.
  62. ^ Ellis (2003); "The Pliosaurs", page 188.
  63. ^ Ellis (2003); "The Pliosaurs", pages 175–176.
  64. ^ a b c d Everhart (2005); "Where the Elasmosaurs Roamed", page 124.
  65. ^ Ellis (2003); "The Plesiosaurs", page 154.
  66. ^ a b Ellis (2003); "The Pliosaurs", page 174.
  67. ^ Everhart (2005); "Pliosaurs and Polycotylids", pages 150–151.
  68. ^ Everhart (2005); "Pliosaurs and Polycotylids", page 151.
  69. ^ Ellis (2003); "The Plesiosaurs", pages 139–140.
  70. ^ Ellis (2003); "The Plesiosaurs", page 142.
  71. ^ Everhart (2005); "Pliosaurs and Polycotylids", pages 153–154.
  72. ^ a b Ellis (2003); "The Plesiosaurs", page 152.
  73. ^ Ellis (2003); "The Plesiosaurs", page 143.
  74. ^ a b c Ellis (2003); "The Plesiosaurs", page 150.
  75. ^ a b c Everhart (2005); "Pliosaurs and Polycotylids", pages 149–150.
  76. ^ "Exploring in Herschel, Saskatchewan « Royal Saskatchewan Museum". royalsaskmuseum.ca. Retrieved 2019-01-28.
  77. ^ a b c Everhart (2005); "Pliosaurs and Polycotylids", page 149.
  78. ^ a b c d Everhart (2005); "Pliosaurs and Polycotylids", page 153.
  79. ^ Ellis (2003); "The Plesiosaurs", page 163.
  80. ^ Ellis (2003); "The Pliosaurs", pages 189–191.
  81. ^ Ellis (2003); "The Pliosaurs", page 176. For the original paper, see Thulborn and Turner (1993).
  82. ^ Everhart (2005); "Where the Elasmosaurs Roamed", pages 139–140.
  83. ^ Ellis (2003); "The Plesiosaurs", pages 150–151.
  84. ^ Ellis (2003); "The Plesiosaurs", page 151.
  85. ^ Ellis (2003); "The Pliosaurs", page 169.
  86. ^ a b c Ellis (2003); "The Pliosaurs", page 191.
  87. ^ Carpenter (1996); in passim.
  88. ^ Ellis (2003); "The Pliosaurs", page 189.
  89. ^ Everhart (2005); "Pliosaurs and Polycotylids", page 144.
  90. ^ "History Of Ancient Echoes". www.ancientechoes.ca. Retrieved 2019-01-28.
  91. ^ Ellis (2003); "The Plesiosaurs", pages 155–156.
  92. ^ Storrs (1999); in passim.
  93. ^ Ellis (2003); "The Plesiosaurs", page 141.
  94. ^ Everhart (2005); "Where the Elasmosaurs Roamed", page 135.
  95. ^ Ellis (2003); "The Plesiosaurs", page 155.
  96. ^ a b Everhart (2005); "Where the Elasmosaurs Roamed", page 139.
  97. ^ Ellis (2003); "The Plesiosaurs", page 159.
  98. ^ Ellis (2003); "The Pliosaurs", pages 181–182.
  99. ^ Ellis (2003); "The Plesiosaurs", pages 142–143.
  100. ^ Ellis (2003); "The Pliosaurs", page 182.
  101. ^ Mayor (2005); "Cultural and Historical Conflicts", page 303.
  102. ^ Mayor (2005); "Cultural and Historical Conflicts", pages 303–304.
  103. ^ Everhart (2005); "Where the Elasmosaurs Roamed", page 126–127.
  104. ^ Sato, Tamaki (2005). "A New Polycotylid Plesiosaur (Reptilia: Sauropterygia) from the Upper Cretaceous Bearpaw Formation in Saskatchewan, Canada". Journal of Paleontology. 79 (5): 969–980. doi:10.1666/0022-3360(2005)079[0969:ANPPRS]2.0.CO;2. JSTOR 4095068.
  105. ^ Sennikov and Arkhangelsky (2010); in passim.
  106. ^ Smith and Vincent (2010); in passim.
  107. ^ Berezin (2011); in passim.
  108. ^ Benson and others (2011); in passim.
  109. ^ Ketchum and Benson (2011); in passim.
  110. ^ Schwermann and Sander (2011); in passim.
  111. ^ Vincent et al. (2011); in passim.
  112. ^ Kubo, Mitchell and Henderson (2012); in passim.
  113. ^ Vincent and Benson (2012); in passim.
  114. ^ Benson, Evans and Druckenmiller (2012); in passim.
  115. ^ Knutsen, Druckenmiller and Hurum (2012b); in passim.
  116. ^ McKean (2012); in passim.
  117. ^ Smith, Araújo and Mateus (2012); in passim.
  118. ^ Knutsen, Druckenmiller and Hurum (2012a); in passim.
  119. ^ Knutsen, Druckenmiller and Hurum (2012c); in passim.
  120. ^ Benson et al. (2013b); in passim.
  121. ^ Vincent, Bardet, and Mattioli (2013); in passim.
  122. ^ Hampe (2013); in passim.
  123. ^ Schumacher, Carpenter and Everhart (2013); in passim.
  124. ^ Benson et al. (2013a); in passim.
  125. ^ Otero et al. (2014); in passim.
  126. ^ Gasparini and O’Gorman (2014); in passim.
  127. ^ Cau and Fanti (2015); in passim.
  128. ^ Smith (2015); in passim.
  129. ^ Araujo et al. (2015); in passim.
  130. ^ O’Gorman et al. (2015); in passim.
  131. ^ Judyth Sassoon; Davide Foffa; Ryan Marek (2015). "Dental ontogeny and replacement in Pliosauridae". Royal Society Open Science. 2 (11): 150384. Bibcode:2015RSOS....250384S. doi:10.1098/rsos.150384. PMC 4680613. PMID 26715998.
  132. ^ Páramo et al. (2016); in passim.
  133. ^ Daniel Madzia (2016). "A reappraisal of Polyptychodon (Plesiosauria) from the Cretaceous of England". PeerJ. 4: e1998. doi:10.7717/peerj.1998. PMC 4867712. PMID 27190712.
  134. ^ José P. O'Gorman (2016). "Reappraisal of Fresnosaurus drescheri (Plesiosauria; Elasmosauridae) from the Maastrichtian Moreno Formation, California, USA". Cretaceous Research. 68: 9–20. doi:10.1016/j.cretres.2016.07.009.
  135. ^ Sven Sachs; Jahn J. Hornung; Benjamin P. Kear (2016). "Reappraisal of Europe's most complete Early Cretaceous plesiosaurian: Brancasaurus brancai Wegner, 1914 from the "Wealden facies" of Germany". PeerJ. 4: e2813. doi:10.7717/peerj.2813. PMC 5183163. PMID 28028478.
  136. ^ Laura C. Soul; Roger B. J. Benson (2017). "Developmental mechanisms of macroevolutionary change in the tetrapod axis: A case study of Sauropterygia". Evolution. 71 (5): 1164–1177. doi:10.1111/evo.13217. PMC 5485078. PMID 28240769.
  137. ^ Leslie F. Noè; Michael A. Taylor; Marcela Gómez-Pérez (2017). "An integrated approach to understanding the role of the long neck in plesiosaurs" (PDF). Acta Palaeontologica Polonica. 62 (1): 137–162. doi:10.4202/app.00334.2016.
  138. ^ Tanja Wintrich; Martin Scaal; P. Martin Sander (2017). "Foramina in plesiosaur cervical centra indicate a specialized vascular system". Fossil Record. 20 (2): 279–290. doi:10.5194/fr-20-279-2017.
  139. ^ Luke E. Muscutt; Gareth Dyke; Gabriel D. Weymouth; Darren Naish; Colin Palmer; Bharathram Ganapathisubramani (2017). "The four-flipper swimming method of plesiosaurs enabled efficient and effective locomotion". Proceedings of the Royal Society B: Biological Sciences. 284 (1861): 20170951. doi:10.1098/rspb.2017.0951. PMC 5577481. PMID 28855360.
  140. ^ Samuel L. Tutin; Richard J. Butler (2017). "The completeness of the fossil record of plesiosaurs, marine reptiles from the Mesozoic". Acta Palaeontologica Polonica. 62 (3): 563–573. doi:10.4202/app.00355.2017. PMC 5828107. PMID 29497243.
  141. ^ Aubrey J. Roberts; Patrick S. Druckenmiller; Lene L. Delsett; Jørn H. Hurum (2017). "Osteology and relationships of Colymbosaurus Seeley, 1874, based on new material of C. svalbardensis from the Slottsmøya Member, Agardhfjellet Formation of central Spitsbergen". Journal of Vertebrate Paleontology. 37 (1): e1278381. doi:10.1080/02724634.2017.1278381. S2CID 26328874.
  142. ^ Benjamin P. Kear; Dennis Larsson; Johan Lindgren; Martin Kundrát (2017). "Exceptionally prolonged tooth formation in elasmosaurid plesiosaurians". PLOS ONE. 12 (2): e0172759. Bibcode:2017PLoSO..1272759K. doi:10.1371/journal.pone.0172759. PMC 5328283. PMID 28241059.
  143. ^ José P. O'Gorman; Rodrigo A. Otero; Norton Hiller; John Simes; Marianna Terezow (2017). "Redescription of Tuarangisaurus keyesi (Sauropterygia; Elasmosauridae), a key species from the uppermost Cretaceous of the Weddellian Province: Internal skull anatomy and phylogenetic position". Cretaceous Research. 71: 118–136. doi:10.1016/j.cretres.2016.11.014.
  144. ^ José P. O'Gorman; Marta S. Fernandez (2017). "Neuroanatomy of the vertebral column of Vegasaurus molyi (Elasmosauridae) with comments on the cervico-dorsal limit in plesiosaurs". Cretaceous Research. 73: 91–97. doi:10.1016/j.cretres.2016.11.018.
  145. ^ José P. O'Gorman; Marianella Talevi; Marta S. Fernández (2017). "Osteology of a perinatal aristonectine (Plesiosauria; Elasmosauridae)". Antarctic Science. 29 (1): 61–72. Bibcode:2017AntSc..29...61O. doi:10.1017/S0954102016000365.
  146. ^ F. Robin O'Keefe; Rodrigo A. Otero; Sergio Soto-Acuña; Jose P. O'gorman; Stephen J. Godfrey; Sankar Chatterjee (2017). "Cranial anatomy of Morturneria seymourensis from Antarctica, and the evolution of filter feeding in plesiosaurs of the Austral Late Cretaceous". Journal of Vertebrate Paleontology. 37 (4): e1347570. doi:10.1080/02724634.2017.1347570. S2CID 91144814.
  147. ^ Norton Hiller; José P. O’Gorman; Rodrigo A. Otero; Al A. Mannering (2017). "A reappraisal of the Late Cretaceous Weddellian plesiosaur genus Mauisaurus Hector, 1874". New Zealand Journal of Geology and Geophysics. 60 (2): 112–128. doi:10.1080/00288306.2017.1281317. S2CID 132037930.
  148. ^ Sven Sachs; Benjamin P. Kear (2017). "Redescription of the elasmosaurid plesiosaurian Libonectes atlasense from the Upper Cretaceous of Morocco". Cretaceous Research. 74: 205–222. doi:10.1016/j.cretres.2017.02.017.
  149. ^ José P. O’Gorman; Rodolfo A. Coria (2017). "A new elasmosaurid specimen from the upper Maastrichtian of Antarctica: new evidence of a monophyletic group of Weddellian elasmosaurids". Alcheringa: An Australasian Journal of Palaeontology. 41 (2): 240–249. doi:10.1080/03115518.2016.1224318. hdl:11336/79006. S2CID 132473041.
  150. ^ María Eurídice Páramo-Fonseca; Cristian David Benavides-Cabra; Ingry Esmirna Gutiérrez (2018). "A new large pliosaurid from the Barremian (Lower Cretaceous) of Sáchica, Boyacá, Colombia". Earth Sciences Research Journal. 22 (4): 223–238. doi:10.15446/esrj.v22n4.69916.
  151. ^ Carlos de Miguel Chaves; Francisco Ortega; Adán Pérez‐García (2018). "New highly pachyostotic nothosauroid interpreted as a filter-feeding Triassic marine reptile". Biology Letters. 14 (8): 20180130. doi:10.1098/rsbl.2018.0130. PMC 6127125. PMID 30068541.
  152. ^ Corinna V. Fleischle; Tanja Wintrich; P. Martin Sander (2018). "Quantitative histological models suggest endothermy in plesiosaurs". PeerJ. 6: e4955. doi:10.7717/peerj.4955. PMC 5994164. PMID 29892509.
  153. ^ Carlos De Miguel Chaves; Francisco Ortega; Adán Pérez-García (2018). "Cranial variability of the European Middle Triassic sauropterygian Simosaurus gaillardoti". Acta Palaeontologica Polonica. 63 (2): 315–326. doi:10.4202/app.00471.2018.
  154. ^ Sven Sachs; Jahn J. Hornung; Jens N. Lallensack; Benjamin P. Kear (2018). "First evidence of a large predatory plesiosaurian from the Lower Cretaceous non-marine 'Wealden facies' deposits of northwestern Germany". Alcheringa: An Australasian Journal of Palaeontology. 42 (4): 501–508. doi:10.1080/03115518.2017.1373150. S2CID 134114013.
  155. ^ Jose P. O’Gorman; Soledad Gouiric-Cavalli; Roberto A. Scasso; Marcelo Reguero; Juan J. Moly; Leonel Acosta-Burlaille (2018). "A Late Jurassic plesiosaur in Antarctica: Evidence of the dispersion of marine fauna through the Trans-Erythraean Seaway?". Comptes Rendus Palevol. 17 (3): 158–165. doi:10.1016/j.crpv.2017.10.005.
  156. ^ Nikolay G. Zverkov; Valentin Fischer; Daniel Madzia; Roger B.J. Benson (2018). "Increased pliosaurid dental disparity across the Jurassic–Cretaceous transition". Palaeontology. 61 (6): 825–846. doi:10.1111/pala.12367.
  157. ^ Timothy Holland (2018). "The mandible of Kronosaurus queenslandicus Longman, 1924 (Pliosauridae, Brachaucheniinae), from the Lower Cretaceous of Northwest Queensland, Australia". Journal of Vertebrate Paleontology. 38 (5): e1511569. doi:10.1080/02724634.2018.1511569. S2CID 91599158.
  158. ^ A. Yu. Berezin (2018). "Craniology of the plesiosaur Abyssosaurus nataliae Berezin (Sauropterygia, Plesiosauria) from the Lower Cretaceous of the Central Russian Platform". Paleontological Journal. 52 (3): 328–341. doi:10.1134/S0031030118030036. S2CID 91151554.
  159. ^ Bruce M. Rothschild; Neil D.L. Clark; Clare M. Clark (2018). "Evidence for survival in a Middle Jurassic plesiosaur with a humeral pathology: What can we infer of plesiosaur behaviour?". Palaeontologia Electronica. 21 (1): Article number 21.1.13A. doi:10.26879/719.
  160. ^ Ramon S. Nagesan; Donald M. Henderson; Jason S. Anderson (2018). "A method for deducing neck mobility in plesiosaurs, using the exceptionally preserved Nichollssaura borealis". Royal Society Open Science. 5 (8): 172307. Bibcode:2018RSOS....572307N. doi:10.1098/rsos.172307. PMC 6124041. PMID 30224996.
  161. ^ V. Fischer; R. B. J. Benson; P. S. Druckenmiller; H. F. Ketchum; N. Bardet (2018). "The evolutionary history of polycotylid plesiosaurians". Royal Society Open Science. 5 (3): 172177. Bibcode:2018RSOS....572177F. doi:10.1098/rsos.172177. PMC 5882735. PMID 29657811.
  162. ^ Rémi Allemand; Nathalie Bardet; Alexandra Houssaye; Peggy Vincent (2018). "New plesiosaurian specimens (Reptilia, Plesiosauria) from the Upper Cretaceous (Turonian) of Goulmima (Southern Morocco)". Cretaceous Research. 82: 83–98. doi:10.1016/j.cretres.2017.09.017.
  163. ^ Rodrigo A. Otero; José P. O'Gorman; William L. Moisley; Marianna Terezow; Joseph McKee (2018). "A juvenile Tuarangisaurus keyesi Wiffen and Moisley 1986 (Plesiosauria, Elasmosauridae) from the Upper Cretaceous of New Zealand, with remarks on its skull ontogeny". Cretaceous Research. 85: 214–231. doi:10.1016/j.cretres.2017.09.007.
  164. ^ Nikolay G. Zverkov; Alexander O. Averianov; Evgeny V. Popov (2018). "Basicranium of an elasmosaurid plesiosaur from the Campanian of European Russia". Alcheringa: An Australasian Journal of Palaeontology. 42 (4): 528–542. doi:10.1080/03115518.2017.1302508. S2CID 132125319.
  165. ^ Rodrigo A. Otero; Sergio Soto-Acuña; Frank R. O'keefe (2018). "Osteology of Aristonectes quiriquinensis (Elasmosauridae, Aristonectinae) from the upper Maastrichtian of central Chile". Journal of Vertebrate Paleontology. 38 (1): e1408638. doi:10.1080/02724634.2017.1408638. S2CID 90977078.
  166. ^ José P. O'Gorman; Rodolfo A. Coria; Marcelo Reguero; Sergio Santillana; Thomas Mörs; Magalí Cárdenas (2018). "The first non-aristonectine elasmosaurid (Sauropterygia; Plesiosauria) cranial material from Antarctica: New data on the evolution of the elasmosaurid basicranium and palate". Cretaceous Research. 89: 248–263. doi:10.1016/j.cretres.2018.03.013. hdl:11336/83625.
  167. ^ José P. O’Gorman; Karen M. Panzeri; Marta S. Fernández; Sergio Santillana; Juan J. Moly; Marcelo Reguero (2018). "A new elasmosaurid from the upper Maastrichtian López de Bertodano Formation: new data on weddellonectian diversity". Alcheringa: An Australasian Journal of Palaeontology. 42 (4): 575–586. doi:10.1080/03115518.2017.1339233. S2CID 134265841.
  168. ^ Sven Sachs; Johan Lindgren; Benjamin P. Kear (2018). "Reassessment of the Styxosaurus snowii (Williston, 1890) holotype specimen and its implications for elasmosaurid plesiosaurian interrelationships". Alcheringa: An Australasian Journal of Palaeontology. 42 (4): 560–574. doi:10.1080/03115518.2018.1508613. S2CID 134569623.
  169. ^ Judyth Sassoon (2019). "Congenital and late onset vertebral fusions in long necked plesiosaurs: The first report of spondylosis deformans in Sauropterygians". Palaeontologia Electronica. 22 (1): Article number 22.1.1. doi:10.26879/913.
  170. ^ Daniel Madzia; Sven Sachs; Johan Lindgren (2019). "Morphological and phylogenetic aspects of the dentition of Megacephalosaurus eulerti, a pliosaurid from the Turonian of Kansas, USA, with remarks on the cranial anatomy of the taxon". Geological Magazine. 156 (7): 1201–1216. Bibcode:2019GeoM..156.1201M. doi:10.1017/S0016756818000523.
  171. ^ J.M. Quesada; A. Pérez-García; J.M. Gasulla; F. Ortega (2019). "Plesiosauria remains from the Barremian of Morella (Castellón, Spain) and first identification of Leptocleididae in the Iberian record". Cretaceous Research. 94: 8–24. doi:10.1016/j.cretres.2018.10.010.
  172. ^ Donald J. Morgan III; F. Robin O'Keefe (2019). "The cranial osteology of two specimens of Dolichorhynchops bonneri (Plesiosauria, Polycotylidae) from the Campanian of South Dakota, and a cladistic analysis of the Polycotylidae". Cretaceous Research. 96: 149–171. doi:10.1016/j.cretres.2018.11.027.
  173. ^ F. R. O’Keefe; P. M. Sander; T. Wintrich; S. Werning (2019). "Ontogeny of polycotylid long bone microanatomy and histology". Integrative Organismal Biology. 1 (1): oby007. doi:10.1093/iob/oby007.
  174. ^ Satoshi Utsunomiya (2019). "Oldest Elasmosauridae(Plesiosauria) in East Asia from the Upper Cretaceous Goshoura Group, Shishijima Island, southwestern Japan". Bulletin of the Osaka Museum of Natural History. 73: 23–35. doi:10.20643/00001333.
  175. ^ Maria Eurídice Páramo-Fonseca; José Patricio O'Gorman; Zulma Gasparini; Santiago Padilla; Mary Luz Parra Ruge (2019). "A new late Aptian elasmosaurid from the Paja Formation, Villa de Leiva, Colombia". Cretaceous Research. 99: 30–40. doi:10.1016/j.cretres.2019.02.010.
  176. ^ Peggy Vincent; Glenn W. Storrs (2019). "Lindwurmia, a new genus of Plesiosauria (Reptilia: Sauropterygia) from the earliest Jurassic of Halberstadt, northwest Germany". The Science of Nature. 106 (1–2): Article 5. Bibcode:2019SciNa.106....5V. doi:10.1007/s00114-018-1600-y. PMID 30689058. S2CID 59304744.
  177. ^ Peggy Vincent; Robert Weis; Guy Kronz; Dominique Delsate (2019). "Microcleidus melusinae, a new plesiosaurian (Reptilia, Plesiosauria) from the Toarcian of Luxembourg" (PDF). Geological Magazine. 156 (1): 99–116. Bibcode:2019GeoM..156...99V. doi:10.1017/S0016756817000814.
  178. ^ Aubrey Jane Roberts; Patrick S. Druckenmiller; Benoit Cordonnier; Lene L. Delsett; Jørn H. Hurum (2020). "A new plesiosaurian from the Jurassic–Cretaceous transitional interval of the Slottsmøya Member (Volgian), with insights into the cranial anatomy of cryptoclidids using computed tomography". PeerJ. 8: e8652. doi:10.7717/peerj.8652. PMC 7120097. PMID 32266112.

ReferencesEdit

A-FEdit

G-LEdit

M-REdit

  • Mansel-Pleydell, J. C. (1888). "Fossil reptiles of Dorset". Proceedings of the Dorset Natural History and Antiquarian Field Club. 9: 1–40.
  • Mayor, Adrienne (2005). Fossil Legends of the First Americans. Princeton University Press. ISBN 978-0-691-11345-6.
  • Rebecca Schmeisser McKean (2012). "A new species of polycotylid plesiosaur (Reptilia: Sauropterygia) from the Lower Turonian of Utah: extending the stratigraphic range of Dolichorhynchops". Cretaceous Research. 34: 184–199. doi:10.1016/j.cretres.2011.10.017.
  • José P. O’Gorman; Leonardo Salgado; Eduardo B. Olivero & Sergio A. Marenssi (2015). "Vegasaurus molyi, gen. et sp. nov. (Plesiosauria, Elasmosauridae), from the Cape Lamb Member (lower Maastrichtian) of the Snow Hill Island Formation, Vega Island, Antarctica, and remarks on Wedellian Elasmosauridae". Journal of Vertebrate Paleontology. 35 (3): e931285. doi:10.1080/02724634.2014.931285. S2CID 128965534.
  • O'Keefe, F.R.; Chiappe, L.M. (2011). "Viviparity and K-selected life history in a Mesozoic marine plesiosaur (Reptilia, Sauropterygia)". Science. 333 (6044): 870–873. Bibcode:2011Sci...333..870O. doi:10.1126/science.1205689. PMID 21836013. S2CID 36165835.
  • Osborn, H. F. (1903). "The reptilian subclasses Diapsida and Synapsida and the early history of the Diaptosauria". Memoir of the American Museum of Natural History. 1: 449–507.
  • Rodrigo A. Otero; Sergio Soto-Acuña; Frank Robin O'Keefe; José P. O’Gorman; Wolfgang Stinnesbeck; Mario E. Suárez; David Rubilar-Rogers; Christian Salazar & Luis Arturo Quinzio-Sinn (2014). "Aristonectes quiriquinensis, sp. nov., a new highly derived elasmosaurid from the upper Maastrichtian of central Chile". Journal of Vertebrate Paleontology. 34 (1): 100–125. doi:10.1080/02724634.2013.780953. hdl:11336/79718. S2CID 84729992.
  • Owen, R. (1840a). "Report on British fossil reptiles. Part I.". Report of the British Association for the Advancement of Science 1839: 43–126.
  • Owen, R. (1840b). "A description of a specimen of the Plesiosaurus macrocephalus, Conybeare, in the collection of Viscount Cole, MP, DCL, FGS, &c". Transactions of the Geological Society of London. 5: 559–594.
  • Owen, R. (1860). "On the orders of fossil and Recent Reptilia, and their distribution in time". Report of the British Association for the Advancement of Science. 29: 153–166.
  • Owen, R. (1865). A monograph on the fossil Reptilia of the Liassic formations. Part I, Sauropterygia. Palaeontographical Society Monograph. 17. pp. 1–40.
  • Páramo, María E.; Gómez-Pérez, Marcela; Noé, Leslie F.; Etayo, Fernando (2016-04-06). "Stenorhynchosaurus munozi, gen. et sp. nov. a new pliosaurid from the Upper Barremian (Lower Cretaceous) of Villa de Leiva, Colombia, South America". Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales. 40 (154): 84–103. doi:10.18257/raccefyn.239. ISSN 2382-4980.
  • Parkinson, J. (1822). Outline of Oryctology: An Introduction to the Study of Fossil Organic Remains; Especially of Those Found in British Strata. London. p. 350.

S-ZEdit

  • Sauvage, H.-E. (1882). "Recherches sur les reptiles trouvé dans le Gault de l'est du Bassin de Paris". Mémoires de la Société Géologique de France. 2: 24–28.
  • Sauvage, H.-E. (1898). "Les reptiles et les poissons des terrains Mésozoîques du Portugal". Bulletin de la Société Géologique de France. 26: 442–446.
  • Schumacher, B. A.; Carpenter, K.; Everhart, M. J. (2013). "A new Cretaceous Pliosaurid (Reptilia, Plesiosauria) from the Carlile Shale (middle Turonian) of Russell County, Kansas". Journal of Vertebrate Paleontology. 33 (3): 613. doi:10.1080/02724634.2013.722576. S2CID 130165209.
  • Sciau, J.; Crochet, J.-Y.; Mattei, J. (1990). "Le premier squelette de plesiosaure de France sur le Causse du Larzac (Toarcien, Jurassique Infe'rieur)". Geobios. 23: 111–116. doi:10.1016/0016-6995(90)80021-7.
  • Seeley, H. G. (1865). "On two new plesiosaurs from the Lias". Annals and Magazine of Natural History. 16 (95): 352–359. doi:10.1080/00222936508679442.
  • Seeley, H. G. (1874). "Note on the generic modifications of the plesiosaurian pectoral arch". Quarterly Journal of the Geological Society of London. 30 (1–4): 436–449. doi:10.1144/gsl.jgs.1874.030.01-04.48. S2CID 128746688.
  • A. G. Sennikov; M. S. Arkhangelsky (2010). "On a Typical Jurassic Sauropterygian from the Upper Triassic of Wilczek Land (Franz Josef Land, Arctic Russia)". Paleontological Journal. 44 (5): 567–572. doi:10.1134/S0031030110050126. S2CID 88505507.
  • Leonie Schwermann & Martin Sander (2011). Osteologie und Phylogenie von Westphaliasaurus simonsensii: Ein neuer Plesiosauride (Sauropterygia) aus dem Unteren Jura (Pliensbachium) von Sommersell (Kreis Höxter), Nordrhein-Westfalen, Deutschland [=Osteology and Phylogeny of Westphaliasaurus simonsensii, a new plesiosaurid (Sauropterygia) from the Lower Jurassic (Pliensbachian) of Sommersell (Höxter district), North Rhine-Westphalia, Germany]. Geologie und Paläontologie in Westfalen. 79. pp. 56 pp. ISBN 978-3-940726-14-8.
  • Smith, Adam Stuart (2007). Anatomy and Systematics of the Rhomaleosauridae (Sauropterygia:Plesiosauria) (PDF) (Thesis). University of Ireland.
  • Adam S. Smith; Peggy Vincent (2010). "A new genus of pliosaur (Reptilia: Sauropterygia) from the Lower Jurassic of Holzmaden, Germany". Palaeontology. 53 (5): 1049–1063. doi:10.1111/j.1475-4983.2010.00975.x.
  • Adam S. Smith; Ricardo Araújo & Octávio Mateus (2012). "Lusonectes sauvagei, a new plesiosauroid from the Toarcian (Lower Jurassic) of Alhadas, Portugal". Acta Palaeontologica Polonica. 57 (2): 257–266. doi:10.4202/app.2011.0023. S2CID 55764533.
  • Adam S. Smith (2015). "Reassessment of 'Plesiosaurus' megacephalus (Sauropterygia: Plesiosauria) from the Triassic-Jurassic boundary, UK". Palaeontologia Electronica. 18 (1): Article number 18.1.20A.
  • Sollas, W. J. (1881). "On a new species of Plesiosaurus (P. conybeari) from the Lower Lias of Charmouth, with observations on P. megacephalus". Quarterly Journal of the Geological Society. 37 (1–4): 440–481. doi:10.1144/gsl.jgs.1881.037.01-04.42. S2CID 129977015.
  • Storrs, G. W. (1999). "An examination of Plesiosauria (Diapsida: Sauropterygia) from the Niobrara Chalk (upper Cretaceous) of central North America". Univ. Kansas Paleont. Cont. (New Ser.). 11: 15.
  • Stukeley, W. (1719). "An account of the impression of the almost entire sceleton of a large animal in a very hard stone, lately presented the Royal Society, from Nottinghamshire". Philosophical Transactions. 30 (360): 963–968. doi:10.1098/rstl.1717.0053. S2CID 186213629.
  • Stutchbury, S. (1846). "Description of a new species of Plesiosaurus, in the Museum of the Bristol Institution". Quarterly Journal of the Geological Society of London. 2 (1–2): 411–417. doi:10.1144/gsl.jgs.1846.002.01-02.58. S2CID 131463215.
  • Thulborn, T; Turner, S (1993). "An elasmosaur bitten by a pliosaur". Modern Geology. 18: 489–501.
  • Peggy Vincent; Nathalie Bardet & Emanuela Mattioli (2013). "A new pliosaurid from the Pliensbachian (Early Jurassic) of Normandy (Northern France)". Acta Palaeontologica Polonica. 58 (3): 471–485. doi:10.4202/app.2011.0113. S2CID 54695631.
  • Peggy Vincent & Roger B. J. Benson (2012). "Anningasaura, a basal plesiosaurian (Reptilia, Plesiosauria) from the Lower Jurassic of Lyme Regis, United Kingdom". Journal of Vertebrate Paleontology. 32 (5): 1049–1063. doi:10.1080/02724634.2012.686467. S2CID 86547069.
  • Peggy Vincent; Nathalie Bardet; Xabier Pereda Suberbiola; Baâdi Bouya; Mbarek Amaghzaz & Saïd Meslouh (2011). "Zarafasaura oceanis, a new elasmosaurid (Reptilia: Sauropterygia) from the Maastrichtian Phosphates of Morocco and the palaeobiogeography of latest Cretaceous plesiosaurs". Gondwana Research. 19 (4): 1062–1073. Bibcode:2011GondR..19.1062V. doi:10.1016/j.gr.2010.10.005.[dead link]
  • Watson, D. M. S. (1909). "A preliminary note on two new genera of Upper Liassic plesiosaurs". Memoirs of the Manchester Museum. 54: 1–26.
  • Welles, S. P. (1943). "Elasmosaurid plesiosaurs with description of new material from California and Colorado". Memoir of the University of California. 13: 125–215.
  • Welles, S. P. (1952). "A review of North American Cretaceous elasmosaurs". University of California Publications in the Geological Sciences. 29: 47–144.
  • Welles, S. P. (1962). "A new species of elasmosaur from the Aptian of Columbia and a review of the Cretaceous plesiosaurs". University of California Publications in the Geological Sciences. 44: 1–96.
  • Winkler, T. C. (1873). "Le Plesiosaurus dolichodeirus Conyb. du Muse'e Teyler". Achives du Muse'e Teyler. 3: 219–233.
  • Woodward, H. B. (1893). The Jurassic rocks of Britain. Volume III. The Lias of England and Wales (Yorkshire excepted). Memoir of the Geological Survey of the United Kingdom. London. p. 399.

External linksEdit