individuals were discovered with embryos. 20th century In the early twentieth century, ichthyosaur research was dominated by the German paleontologist Friedrich von Huene, who wrote an extensive series of articles, taking advantage of an easy access to the many specimens found in his country. The amount of anatomical data was hereby vastly increased. Von Huene also travelled widely abroad, describing many fossils from locations outside of Europe. During the 20th century, North America became an important source of new fossils. In 1905, the Saurian Expedition led by John Campbell Merriam and financed by Annie Montague Alexander, found twenty-five specimens in central Nevada, which were under a shallow ocean during the Triassic. Several of these are now in the collection of the University of California Museum of Paleontology. After a slack during the middle of the century, with no new genera being named between the 1930s and the 1970s, the rate of discoveries picked up towards its end. Other specimens are embedded in the rock and visible at Berlin–Ichthyosaur State Park in Nye County. In 1977 the Triassic ichthyosaur Shonisaurus became the state fossil of Nevada. About half of the ichthyosaur genera today seen as valid were described after 1990. In 1992 Canadian paleontologist Elizabeth Nicholls uncovered the largest known specimen, a Shastasaurus. The new finds have allowed a gradual improvement in knowledge about the anatomy and physiology of what had already been seen as rather advanced "Mesozoic dolphins". Christopher McGowan published a larger number of articles and also brought the group to the attention of the general public. The new method of cladistics provided a means to exactly calculate the relationships between groups of animals, and in 1999, Ryosuke Motani published the first extensive study on ichthyosaur phylogenetics. In 2003, McGowan and Motani published the first modern textbook on the Ichthyosauria and their closest relatives. Evolutionary history Origin The origin of the ichthyosaurs is contentious. Until recently, clear transitional forms with land-dwelling vertebrate groups had not yet been found, the earliest known species of the ichthyosaur lineage being already fully aquatic. In 2014, a small basal ichthyosauriform from the upper Lower Triassic was described that had been discovered in China with characteristics suggesting an amphibious lifestyle. In 1937, Friedrich von Huene even hypothesised that ichthyosaurs were not reptiles, but instead represented a lineage separately developed from amphibians. Today, this notion has been discarded and a consensus exists that ichthyosaurs are