''Lariosaurus'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

nothosaurid Nothosauridae are an extinct family of carnivorous aquatic sauropterygian reptiles from the Triassic time period of China, France, Germany, Israel, Italy, Netherlands, Russia, Switzerland, and northern Africa. Phylogeny The cladogram shown bel ...

from the

Middle Triassic In the geologic timescale, the Middle Triassic is the second of three epochs of the Triassic period or the middle of three series in which the Triassic system is divided in chronostratigraphy. The Middle Triassic spans the time between Ma and ...

(late

Anisian In the geologic timescale, the Anisian is the lower stage or earliest age of the Middle Triassic series or epoch and lasted from million years ago until million years ago. The Anisian Age succeeds the Olenekian Age (part of the Lower Triassic Ep ...

to late

Ladinian The Ladinian is a stage and age in the Middle Triassic series or epoch. It spans the time between Ma and ~237 Ma (million years ago). The Ladinian was preceded by the Anisian and succeeded by the Carnian (part of the Upper or Late Triassic). ...

stage) of central and western

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

and

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

. With a length of just , it was one of the smallest known nothosaurs. First discovered at

Perledo Perledo (Comasco, Lecchese: ) is a ''comune'' (municipality) in the Province of Lecco in the Italian region Lombardy, located about north of Milan and about northwest of Lecco. As of 31 December 2004, it had a population of 900 and an area of . ...

on the

Lake Como Lake Como ( it, Lago di Como , ; lmo, label=Western Lombard, Lagh de Còmm , ''Cómm'' or ''Cùmm'' ), also known as Lario (; after the la, Larius Lacus), is a lake of glacial origin in Lombardy, Italy. It has an area of , making it the thir ...

in 1830, it was named in 1847 by Curioni, its name meaning "Lizard from Larius", the ancient name of the

lake A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...

. This makes it one of the earliest studied reptiles from the Alps. It is known from an almost complete skeleton holotype and several other fairly complete fossils. The nothosaur ''Eupodosaurus'', initially classified as a

stegosauria Stegosauria is a group of herbivorous ornithischian dinosaurs that lived during the Jurassic and early Cretaceous periods. Stegosaurian fossils have been found mostly in the Northern Hemisphere, predominantly in what is now North America, Europe, ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

, is now considered synonymous with ''Lariosaurus''. In 1998 Rieppel synonymised ''Lariosaurus, Silvestrosaurus'' and ''

Ceresiosaurus ''Ceresiosaurus'' is an extinct aquatic genus of lariosaurine nothosaurid sauropterygian known from the Middle Triassic (Anisian-Ladinian boundary) of Monte San Giorgio, southern Switzerland and northern Italy. Ceresiosaurus, meaning "Lizard of C ...

,'' but this is disputed by many authors and they are usually considered close relatives.

Features

For a nothosaur, ''Lariosaurus'' was primitive, possessing a short neck and small flippers in comparison to its relatives. This would have made it a relatively poor swimmer, and it is presumed to have spent much time on dry land, or hunting in shallows. It had a large postorbital region of the

skull The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, the ...

with the

temporal fossae The temporal fossa is a fossa (shallow depression) on the side of the skull bounded by the temporal lines and terminating below the level of the zygomatic arch. Boundaries * Medial: frontal bone, parietal bone, temporal bone, and sphenoid bon ...

noticeably larger than the orbits. The

premaxillary The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has ...

and anterior dentary

teeth A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ...

are strongly elongated, like fangs, and could have acted as a 'fish trap'. The parietal and

squamosal The squamosal is a skull bone found in most reptiles, amphibians, and birds. In fishes, it is also called the pterotic bone. In most tetrapods, the squamosal and quadratojugal The quadratojugal is a skull bone present in many vertebrates, including ...

bones are elongated into a small occipital crest for the attachment of jaw muscles. The

vertebrae The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic i ...

are

pachyostotic Pachyostosis is a non-pathological condition in vertebrate animals in which the bones experience a thickening, generally caused by extra layers of lamellar bone. It often occurs together with bone densification (osteosclerosis), reducing inner ca ...

and have a low neural spine. Ribs are present from the neck all the way down to the

sacrum The sacrum (plural: ''sacra'' or ''sacrums''), in human anatomy, is a large, triangular bone at the base of the spine that forms by the fusing of the sacral vertebrae (S1S5) between ages 18 and 30. The sacrum situates at the upper, back part ...

, which has a cluster of four or five pairs. There are caudal ribs, but they are very small and not present beyond the 15th caudal vertebra. The gastral ribs are made up of multiple elements and form a sturdy kind of armour. The

humerus The humerus (; ) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a roun ...

has a weakly developed deltapectoral crest, and increases gradually in width towards the distal end. There is a distinct space between the

radius In classical geometry, a radius ( : radii) of a circle or sphere is any of the line segments from its center to its perimeter, and in more modern usage, it is also their length. The name comes from the latin ''radius'', meaning ray but also the ...

and the more slender

ulna The ulna (''pl''. ulnae or ulnas) is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. That is, the ulna is on the same side of t ...

. The fingers have more bones than the toes and clearly show how ''Lariosaurus'' was unique among nothosaurs because its front legs were adapted into paddles, while the back legs remained five-toed. The femur is more lightly built than the humerus but longer. There is less difference between tibia and fibula than between radius and ulna. Further, based on skeletal findings of immature lariosaurs inside the adults, ''Lariosaurus'' is believed by many to be

viviparous Among animals, viviparity is development of the embryo inside the body of the parent. This is opposed to oviparity which is a reproductive mode in which females lay developing eggs that complete their development and hatch externally from the m ...

, or able to bear live young. Another ''Lariosaurus'' skeleton was found with two juvenile

placodont Placodonts (" Tablet teeth") are an extinct order of marine reptiles that lived during the Triassic period, becoming extinct at the end of the period. They were part of Sauropterygia, the group that includes plesiosaurs. Placodonts were genera ...

s of the genus ''

Cyamodus ''Cyamodus'' (pron.: SIE-ah-MO-dus) is a genus of placodonts known from several species described from Middle-Late Triassic of Europe and China. The genus was described by Christian Erich Hermann von Meyer in 1863, based on specimens found in Germ ...

'' in its stomach, giving an indication of its diet. In 2014 a skull was found in the Winterswijk Muschekalk quarry, of what appeared to be a new species, that was named ''Lariosaurus vosseveldensis''. In 2015 it was added to the collection of Museum TwentseWelle in Enschede. It was registered TW.480000504. Also found was an isolated, fused parietal, that was registered TW.4800000505.

In popular culture

Loch Ness mocking Lariosaurus sightings are often reported on the newspapers of the Lake Como area. The myth has been cited in various books, songs and TV programmes.

References

* Triassic reptiles of Europe Nothosaurs Fossils of Italy Triassic sauropterygians Anisian genus first appearances Ladinian genus extinctions Sauropterygian genera {{paleo-reptile-stub