near Boulogne-sur-Mer, France, in layers dating from the Callovian, and was named Liopleurodon ferox. Another from Charly, France, measuring long and with a crown length of , was named Liopleurodon grossouvrei. The third, discovered near Caen, France, was originally attributed to Poikilopleuron bucklandi by Eudes Deslongchamps. While the tooth could have come from the megalosaur, Sauvage considered this identity unsubstantiated, and assigned it to the species Liopleurodon bucklandi. Sauvage did not ascribe the genus to any particular group of reptiles in his descriptions. However, in 1880, Sauvage synonymized Liopleurodon with Polyptychodon, noting that it was similar to this genus, but distinct from Plesiosaurus and Pliosaurus. In 1888, Richard Lydekker, after studying some teeth attributable to Liopleurodon ferox in the Leeds Collection, concluded that they were so similar to those of Pliosaurus that they should be placed in that genus. These teeth had been collected by Alfred Leeds from the Oxford Clay Formation, near Peterborough, England. In 1869, Harry Govier Seeley had applied the name Pliosaurus pachydeirus to a series of cervical (neck) vertebrae representing the first 17 in the neck from the Oxford Clay Formation near Great Gransden. Other than its large size, Seeley provided no distinguishing characteristics. Lydekker stated that this neck probably belonged to Pliosaurus ferox. W. Kiprijanoff named Thaumatosaurus mosquensis in 1883 based on remains including teeth, vertebrae, and limb bones from Oxfordian-aged rocks in the Moscow Basin of Russia; however, in 1889, Lydekker considered this species to be a probable junior synonym of P. ferox. In 1905, John Frederick Blake described two teeth from Rushden, England, similar to those of other Liopleurodon ferox specimens, though from older strata than those from Peterborough. He noted that the teeth were quite different from those of Pliosaurus, while the bones were dissimilar to those of Polyptychodon. Since the species couldn't be assigned to either genus, he recommended reinstating the name Liopleurodon. After considering Liopleurodon to be a subgenus of Pliosaurus, N. Bogolubov also listed the two genera as distinct in 1912. When Lydekker had first visited the collection of Alfred Leeds (known as the Leeds Collection), the only remains of Liopleurodon in his collection were teeth. However, since then, Alfred Leeds, as well as his brother Charles Edward Leeds, had collected many more specimens of Liopleurodon, including skulls and much of the postcranial skeleton. Charles William Andrews described the anatomy of the marine reptile specimens of the Leeds Collection