Nothosaurus

Nothosaurus ('false lizard', from the Ancient Greek νόθος, nothos, 'illegitimate' and σαῦρος, sauros, 'lizard') is an extinct genus of sauropterygianreptile from the Triassic period, approximately 245–228 million years ago, with fossils being distributed throughout the former Tethys Ocean, from North Africa and Europe to China. It is the best known member of the nothosaur order.

Nothosaurus was a semi-oceanic animal which most likely had a lifestyle similar to that of today's seals. It was about 4 metres (13 ft), with long, webbed toes and possibly a fin on its tail.^[1] However, some species such as N. zhangi and N. giganteus were larger, up to 5–7 metres (16–23 ft).^[2] When swimming, Nothosaurus would use its tail, legs, and webbed feet to propel and steer it through the water. The skull was broad and flat, with long jaws, lined with needle teeth, it probably caught fish and other marine creatures. Trackways attributed, partly by process of elimination, to a nothosaur that was reported from Yunnan, China in June 2014, were interpreted as the paddle impressions left as the animals dug into soft seabed with rowing motions of their paddles, churning up hidden benthic creatures that they snapped up.^[3] Once caught, few animals would be able to shake themselves free from the mouth of Nothosaurus.

In many respects its body structure resembled that of the much later plesiosaurs, but it was not as well adapted to an aquatic environment. It is thought that one branch of the nothosaurs may have evolved into pliosaurs such as Liopleurodon, a short-necked plesiosaur that grew up to 6.4 metres (21 ft), and the long-necked Cryptoclidus, a fish eater with a neck as long as 1.3 metres (4.3 ft).

Hay casi una docena de especies conocidas de Nothosaurus . La especie tipo es N.  mirabilis , nombrada en 1834 del germánico Muschelkalk . Otras especies incluyen N.  giganteus (anteriormente conocido como Paranothosaurus ) de Osnabrück , Alemania; ^{[ 4 ]} N.  juvenilis , también de Alemania; ^{[ 5 ]} N.  edingerae del Alto Muschelkalk y del Bajo Keuper ; ^{[ 6 ]} N.  haasi y N.  tchernovi de Makhtesh Ramon , Israel ; ^{[ 7 ] [ 8 ]} N.  cymatosauroides del Muschelkalk español ; ^{[ 9 ]} N.  jagisteus del Alto Muschelkalk de Hohenlohe , Alemania; ^{[ 10 ]} y N.  youngi , N.  yangjuanensis (y su sinónimo menor N.  rostellatus ) y el recientemente nombrado N.  zhangi de Guizhou , China . ^{[ 11 ] [ 12 ] [ 13 ] [ 14 ]} Se han descrito varias especies del Muschelkalk Inferior en Winterswijk , Países Bajos , incluyendo N.  marchicus ^{[ 15 ]} (y su sinónimo menor ^{[ 16 ]} N.  winterswijkensis ^{[ 15 ]} ) y N.  winkelhorsti . ^{[ 17 ]} Recientemente, el material tipo de N.  schimperi Meyer, 1842, considerado perdido durante mucho tiempo, procedente del Muschelkalk Inferior de Soultz-les-Bains, Alsacia, Francia, ha sido redescubierto y se ha designado un lectotipo. ^{[ 18 ]}

Klein y Albers (2009) realizaron un análisis filogenético , pero no probaron la monofilia de Nothosaurus , ya que otros notosauridos no fueron incluidos en su análisis. ^{[ 17 ]}

Several other species have been named but are now generally considered invalid. One such species, N. procerus, is now considered a junior subjective synonym of N. marchicus.^[19][20] Other species now considered junior synonyms of N. marchicus include N. crassus, N. oldenburgi, N. raabi, N. schroderi, N. venustus and the recently named N. winterswijkensis.^[16] Junior synonyms of N. giganteus, the second largest Nothosaurus species, include N. andriani, N. angustifronis, N. aduncidens, N. baruthicus and N. chelydrops.^[14]

A species level phylogenetic analysis of Nothosauridae was performed by Liu et al. (2014), and included all known valid species of the family and Nothosaurus apart from Lariosaurus stensioi(type of Micronothosaurus), Nothosaurus cymatosauroides, and Ceresiosaurus lanzi. Due to the inclusion of other nothosaurids other than Nothosaurus, the monophyly of Nothosaurus was tested for the first time. The analysis found both Lariosaurus and Nothosaurus to be polyphyletic in regard to each other and all the other genera of the family, making a systematic revision of these two genera necessary. Below, their results are shown with type species of named nothosaurid genera noted.^[14] Later, in 2017, the species N. juvenilis, N. youngi, and N. winkelhorsti were formally moved to Lariosaurus.^[21]

• Parker, Steve. Dinosaurus: la guía completa de los dinosaurios. Firefly Books Inc, 2003. Pág. 384