Machimosaurus
Encyclopedia
Machimosaurus is an extinct genus
of teleosaurid
crocodyliform from the Late Jurassic
(Kimmeridgian
and Tithonian
) and Early Cretaceous
(Berriasian
and Valanginian
). The type species
, Machimosaurus hugii, was found in France
. Other fossils have been found in Austria
, England
, Germany
, Portugal
and Switzerland
. Machimosaurus was not only both the largest teleosaurid and thalattosuchia
n, but with a length exceeding 9 metres (skull length 1.5 m), it was the largest crocodyliform of the Jurassic
. However, Machimosaurus became extinct during the Valanginian, and was the last of the teleosaurids.
in 1837 named isolated conical, blunt teeth with numerous longitudinal lines from Switzerland and Austria, Madrimosaurus hugii. However, in 1838, realising he had made mis-spelled the name, he emended Madrimosaurus to Machimosaurus. The teeth of Machimosaurus, with their rounded, blunt apex and stout morphology make them characteristic and easily identifiable compared to other teleosaurid teeth.
The type species, M. hugii, is known from the Kimmeridgian of Austria, England, France, Portugal and Switzerland. Machimosaurus ferox, M. recurvirostris and M. interruptus are all junior synonyms of M. hugii.
Krebs (1967), considered M. mosae to be a junior synonym of M. hugii, however a nearly complete skeleton found from the late Kimmeridgian of France supports it as a valid species. As of current knowledge, it remains the only other valid European species. The skull and post-cranial remains Richard Owen
referred to Pliosaurus trochanterius
, actually belong to M. mosae.
Two species also placed within Machimosaurus are M. bathonicus and M. rigauxi, from the Bathonian
of France. However, these are gracile species, lacking the characteristic blunted teeth of Machimosaurus.
The fossilised anterior portion of the lower jaw from the Late Jurassic (Oxfordian
or Kimmeridgian) of Ethiopia
referred to the pliosaur
Simolestes nowackianus
, is in fact a large species of Machimosaurus.
-age, semi-aquatic deposits of Oker, Lower Saxony
, Germany two genera of teleosaurids (Steneosaurus
and Machimosaurus) are known, in addition to the neosuchian genera Goniopholis
and Theriosuchus
. Machimosaurus and Steneosaurus are also found together in the same Tithonian-age deposits of western France.
) femur from Switzerland match teeth known from Machimosaurus hugii, also found in the same deposits. This suggests either scavenging on the sauropod's corpse, or active predation from the waters edge, much like living crocodilians. Kimmeridgian-age fossil turtles from "Solothurn Turtle Limestone" of northern Switzerland have bite marks, and splintered Machimosaurus teeth imbedded, while fossil turtles from the Late Jurassic of Germany also possess bite marks that match teeth of Machimosaurus found in the same deposit.
Morphofunctional analysis on the skull of Machimosaurus strongly suggests they eat turtles (chelonophagy). Morphological comparison of their teeth also confirms that they are adapted to seizing and crushing hard prey.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of teleosaurid
Teleosauridae
The teleosaurids were marine crocodyliforms similar to the modern gharial that lived from the Early Jurassic to the Early Cretaceous. They had long snouts, indicative of piscivory and were the closest relatives to the Metriorhynchidae, the Mesozoic crocodilians that returned to the sea and evolved...
crocodyliform from the Late Jurassic
Late Jurassic
The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 161.2 ± 4.0 to 145.5 ± 4.0 million years ago , which is preserved in Upper Jurassic strata. In European lithostratigraphy, the name "Malm" indicates rocks of Late Jurassic age...
(Kimmeridgian
Kimmeridgian
In the geologic timescale, the Kimmeridgian is an age or stage in the Late or Upper Jurassic epoch or series. It spans the time between 155.7 ± 4 Ma and 150.8 ± 4 Ma . The Kimmeridgian follows the Oxfordian and precedes the Tithonian....
and Tithonian
Tithonian
In the geologic timescale the Tithonian is the latest age of the Late Jurassic epoch or the uppermost stage of the Upper Jurassic series. It spans the time between 150.8 ± 4 Ma and 145.5 ± 4 Ma...
) and Early Cretaceous
Early Cretaceous
The Early Cretaceous or the Lower Cretaceous , is the earlier or lower of the two major divisions of the Cretaceous...
(Berriasian
Berriasian
In the geological timescale, the Berriasian is an age or stage of the Early or Lower Creteceous. It is the oldest or lowest subdivision in the entire Cretaceous. It spanned between 145.5 ± 4.0 Ma and 140.2 ± 3.0 Ma...
and Valanginian
Valanginian
In the geologic timescale, the Valanginian is an age or stage of the Early or Lower Cretaceous. It spans between 140.2 ± 3.0 Ma and 136.4 ± 2.0 Ma...
). The type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
, Machimosaurus hugii, was found in France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
. Other fossils have been found in Austria
Austria
Austria , officially the Republic of Austria , is a landlocked country of roughly 8.4 million people in Central Europe. It is bordered by the Czech Republic and Germany to the north, Slovakia and Hungary to the east, Slovenia and Italy to the south, and Switzerland and Liechtenstein to the...
, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
, Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
, Portugal
Portugal
Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...
and Switzerland
Switzerland
Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....
. Machimosaurus was not only both the largest teleosaurid and thalattosuchia
Thalattosuchia
Thalattosuchia is the name given to a clade of marine crocodylomorphs from the Early Jurassic to the Early Cretaceous that had a cosmopolitan distribution. They are sometimes colloquially referred to as marine crocodiles or sea crocodiles, though they are not actually members of Crocodilia.The term...
n, but with a length exceeding 9 metres (skull length 1.5 m), it was the largest crocodyliform of the Jurassic
Jurassic
The Jurassic is a geologic period and system that extends from about Mya to Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...
. However, Machimosaurus became extinct during the Valanginian, and was the last of the teleosaurids.
Discovery and species
Christian Erich Hermann von MeyerChristian Erich Hermann von Meyer
Christian Erich Hermann von Meyer was a German palaeontologist.He was born at Frankfurt am Main.In 1832 von Meyer issued a work entitled Palaeologica, and in course of time he published a series of memoirs on various fossil organic remains: molluscs, crustaceans, fishes and higher vertebrata,...
in 1837 named isolated conical, blunt teeth with numerous longitudinal lines from Switzerland and Austria, Madrimosaurus hugii. However, in 1838, realising he had made mis-spelled the name, he emended Madrimosaurus to Machimosaurus. The teeth of Machimosaurus, with their rounded, blunt apex and stout morphology make them characteristic and easily identifiable compared to other teleosaurid teeth.
The type species, M. hugii, is known from the Kimmeridgian of Austria, England, France, Portugal and Switzerland. Machimosaurus ferox, M. recurvirostris and M. interruptus are all junior synonyms of M. hugii.
Krebs (1967), considered M. mosae to be a junior synonym of M. hugii, however a nearly complete skeleton found from the late Kimmeridgian of France supports it as a valid species. As of current knowledge, it remains the only other valid European species. The skull and post-cranial remains Richard Owen
Richard Owen
Sir Richard Owen, FRS KCB was an English biologist, comparative anatomist and palaeontologist.Owen is probably best remembered today for coining the word Dinosauria and for his outspoken opposition to Charles Darwin's theory of evolution by natural selection...
referred to Pliosaurus trochanterius
Pliosaurus
Pliosaurus is a genus of extinct marine reptile. It is included in the family Pliosauridae. Its diet would have included fish, squid and other marine reptiles. This genus has contained several species in the past but it currently consists of the type species P. brachydeirus, P. macromerus and P...
, actually belong to M. mosae.
Two species also placed within Machimosaurus are M. bathonicus and M. rigauxi, from the Bathonian
Bathonian
In the geologic timescale the Bathonian is an age or stage of the Middle Jurassic. It lasted from approximately 167.7 Ma to around 164.7 Ma...
of France. However, these are gracile species, lacking the characteristic blunted teeth of Machimosaurus.
The fossilised anterior portion of the lower jaw from the Late Jurassic (Oxfordian
Oxfordian stage
The Oxfordian is, in the ICS' geologic timescale, the earliest age of the Late Jurassic epoch, or the lowest stage of the Upper Jurassic series. It spans the time between 161.2 ± 4 Ma and 155.7 ± 4 Ma...
or Kimmeridgian) of Ethiopia
Ethiopia
Ethiopia , officially known as the Federal Democratic Republic of Ethiopia, is a country located in the Horn of Africa. It is the second-most populous nation in Africa, with over 82 million inhabitants, and the tenth-largest by area, occupying 1,100,000 km2...
referred to the pliosaur
Pliosaur
Pliosauroidea is an extinct clade of marine reptiles. Pliosauroids, also commonly known as pliosaurs, are known from the Jurassic and Cretaceous Periods. The pliosauroids were short-necked plesiosaurs with large heads and massive toothed jaws. These swimming reptiles were not dinosaurs but distant...
Simolestes nowackianus
Simolestes
Simolestes is an extinct genus of pliosaurs that lived in the Middle to Late Jurassic. Three species are currently known:*Simolestes keileni from the Bajocian of France...
, is in fact a large species of Machimosaurus.
Niche partitioning
From the KimmeridgianKimmeridgian
In the geologic timescale, the Kimmeridgian is an age or stage in the Late or Upper Jurassic epoch or series. It spans the time between 155.7 ± 4 Ma and 150.8 ± 4 Ma . The Kimmeridgian follows the Oxfordian and precedes the Tithonian....
-age, semi-aquatic deposits of Oker, Lower Saxony
Lower Saxony
Lower Saxony is a German state situated in north-western Germany and is second in area and fourth in population among the sixteen states of Germany...
, Germany two genera of teleosaurids (Steneosaurus
Steneosaurus
Steneosaurus is an extinct genus of teleosaurid crocodyliform from the Early Jurassic to Early Cretaceous . Fossil specimens have been found in England, France, Germany, Switzerland and Morocco.-Species:...
and Machimosaurus) are known, in addition to the neosuchian genera Goniopholis
Goniopholis
Goniopholis is an extinct genus of crocodyliform that lived in North America, Europe and Asia during the Late Jurassic and Early Cretaceous. Being semi-aquatic it is very similar to modern crocodiles...
and Theriosuchus
Theriosuchus
Theriosuchus is an extinct genus of atoposaurid mesoeucrocodylian from the Late Jurassic of Europe, the Early Cretaceous of Asia and the Late Cretaceous of Romania. The five species are T. pusillus from England , T. ibericus from Spain , T. guimarotae from Portugal , T. sympiestodon from Romania...
. Machimosaurus and Steneosaurus are also found together in the same Tithonian-age deposits of western France.
Diet
Bite marks on an early Kimmeridgian sauropod (CetiosauriscusCetiosauriscus
Cetiosauriscus is a genus of sauropod dinosaur. It was perhaps a diplodocid, a close relative of Diplodocus, and lived in the Callovian of England Cetiosauriscus (meaning "whale-lizard-like" i.e. "Cetiosaurus-like") is a genus of sauropod dinosaur. It was perhaps a diplodocid, a close relative of...
) femur from Switzerland match teeth known from Machimosaurus hugii, also found in the same deposits. This suggests either scavenging on the sauropod's corpse, or active predation from the waters edge, much like living crocodilians. Kimmeridgian-age fossil turtles from "Solothurn Turtle Limestone" of northern Switzerland have bite marks, and splintered Machimosaurus teeth imbedded, while fossil turtles from the Late Jurassic of Germany also possess bite marks that match teeth of Machimosaurus found in the same deposit.
Morphofunctional analysis on the skull of Machimosaurus strongly suggests they eat turtles (chelonophagy). Morphological comparison of their teeth also confirms that they are adapted to seizing and crushing hard prey.