''Lariosaurus'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

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 epoch (geology), epochs of the Triassic period (geology), period or the middle of three series (stratigraphy), series in which the Triassic system (stratigraphy), system is di ...

(late

Anisian In the geologic timescale, the Anisian is the lower stage (stratigraphy), stage or earliest geologic age, age of the Middle Triassic series (stratigraphy), series or geologic epoch, epoch and lasted from million years ago until million years ag ...

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 continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

and

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

. With a complete specimen of ''L. xingyiensis'' measuring long and ''L. hongguoensis'' possibly measuring up to long, 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 Lecco (, , ; ) is a city of approximately 47,000 inhabitants ...

on the

Lake Como Lake Como ( , ) also known as Lario, is a lake of glacial origin in Lombardy, Italy. It has an area of , making it the third-largest lake in Italy, after Lake Garda and Lake Maggiore. At over deep, it is one of the deepest lakes in Europe. ...

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

lake A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from ...

. 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 Herbivore, herbivorous ornithischian dinosaurs that lived during the Jurassic and early Cretaceous Period (geology), periods. Stegosaurian fossils have been found mostly in the Northern Hemisphere (North America, Europe a ...

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

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

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

,'' 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, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate. In the human, the skull comprises two prominent ...

with the temporal fossae 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 mammals 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 bones form the cheek series of the skull. The bone forms an ancestra ...

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

vertebrae Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spinal ...

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

sacrum The sacrum (: sacra or sacrums), in human anatomy, is a 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 of the pelvic cavity, ...

, 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 (; : humeri) 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 (bone), radius and ulna, and consists of three sections. The humeral upper extrem ...

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 or radiuses) of a circle or sphere is any of the line segments from its Centre (geometry), center to its perimeter, and in more modern usage, it is also their length. The radius of a regular polygon is th ...

and the more slender

ulna The ulna or ulnar bone (: ulnae or ulnas) is a long bone in the forearm stretching from the elbow to the wrist. It is on the same side of the forearm as the little finger, running parallel to the Radius (bone), radius, the forearm's other long ...

. 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 In animals, viviparity is development of the embryo inside the body of the mother, with the maternal circulation providing for the metabolic needs of the embryo's development, until the mother gives birth to a fully or partially developed juve ...

, 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 generall ...

s of the genus '' Cyamodus'' 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. Corosaurus

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

* {{Taxonbar, from=Q1187367 Triassic reptiles of Europe Nothosaurs Fossils of Italy Triassic sauropterygians Anisian genus first appearances Ladinian genus extinctions Sauropterygian genera