Machimosaurus (lat.) Is a genus of extinct reptiles from the family of teleosaurids , living from the Late Jurassic to the Early Cretaceous [2] [3] . A type species , Machimosaurus hugii , was discovered in Switzerland . Several other species were also found in Spain , England , France , Germany , Portugal , Switzerland and Tunisia [3] [4] [5] . Some samples of Machimosaurus have a length of more than 9 meters, which makes it the largest representative of its family and the largest crocodilomorph of the Jurassic period [2] [3] [4] .
| † Machimosaurus |
Mounted Skeleton of the Indescribable View, National Museum of Natural History, Brussels |
| Scientific classification |
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| No rank : | Bilateral symmetrical |
| Infraclass : | Archosauromorphs |
| No rank : | Archosauriformes |
| Squadron : | Crocodilomorphs |
| Suborder : | † Talattosuchia |
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| International scientific name |
|---|
Machimosaurus Meyer , 1837 |
| Views [1] |
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- Machimosaurus buffetauti
Young et al. , 2014 - Machimosaurus hugii
Meyer, 1837 typus - Machimosaurus mosae
Sauvage & Lienard, 1879 - Machimosaurus nowackianus
(Huene, 1938) - Machimosaurus rex Fanti et al. , 2016
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Content
Reconstruction of three European species
In 1837, Hermann von Mayer described numerous conical, blunt teeth with a large number of longitudinal grooves, discovered in Switzerland as a new genus and species - Madrimosaurus hugii . However, in 1838 it became clear that the spelling mistake was made in the name and the name was replaced by Machimosaurus hugii [6] . The generic name is derived from the ancient Greek word " makhimos ", which means "ready for war." Dull conical teeth with longitudinal grooves are a very characteristic sign of the genus [7] .
Type fossils, in addition to Switzerland, are also known from Spain, Portugal and Tunisia [2] [6] . M. ferox and M. interruptus were previously considered synonyms of the type species, but now they are considered possible synonyms of M. mosae [8] [9] .
Krebs (1967) [8] considered M. mosae a synonym for M. hugii , but M. mosae is now considered the second real species of the genus [10] [6] .
Two species (M. bathonicus and M. rigauxi ) are known from the Batian tier of France [11] , however, the absence of characteristic blunt conical teeth may indicate Steneosaurus [6] .
Young and his colleagues [6] [12] carried out a revision of the genus, indicating the actual species M. hugii , M. mosae and M. nowackianus , and also identified a new species - Machimosaurus buffauti . They suggested that Machimosaurus was similar to a modern crocodile : there is one large species in the genus that can move to the sea, and the rest of the species are in conditional geographical isolation.
The front of the lower jaw, attributed to simolest , probably belongs to the large species Machimosaurus [13] .
In 2016, a new species, Machimosaurus rex, was described from the Lower Cretaceous deposits of Tunisia. Currently, it is considered the largest species of the genus, reaching a length of about 9.6 m [3] [4] . Later estimates give a shorter length - about 6.9–7.15 m [14] . The discovery of M. rex proves that teleosaurids survived the Cretaceous – Paleogene extinction . A detailed study of the holotype skull showed that the species was a non-specialized predator. This conclusion was made on the basis of strong, relatively short and blunt teeth [3] [2] .
Separation of habitat niches
Two genera of teleosaurids ( Steneosaurus and Machimosaurus ) and two genera of Neosuchia ( Goniopholis and Theirosuchus ) were found in the Kimmeridge deposits of Lower Saxony [15] . Machimosaurus and Steneosaurus were also found in sediments dating from the Tithonian layer of western France [16] .
Nutrition
Tooth. Longitudinal grooves are clearly visible
Teeth marks of Machimosaurus huggi were found on the femur of the sauropod Cetiosauriscus from Switzerland. This indicates either eating a corpse, or an active hunt for dinosaurs [17] . Fossil turtles of the Kimmeridgian era from the “ Solothurn tortoise limestone ” bear the bite and fragmentation marks left by Machimosaurus [18] . Tortoises from the late Jurassic Germany suffer similar damage [19] .
An analysis of the anatomy of the skull of Machimosaurus indicates chelonophagy (eating turtles) of an animal [8] [9] . The morphology of teeth also indicates the nutrition of animals with a shell or a hard outer shell [7] [20] .
Movement
Based on the structural features of the spine , some species of the genus Machimosaurus are considered to be inhabitants of the open sea. Like modern crocodiles, Machimosaurus bent its tail from side to side in wavy movements, and thereby moved in the water column. The limbs were used as rudders and for better balance during swimming. The muscles of the head and neck were well developed, this is evidenced by the increased place of their attachment [8] .
