Erectopus
Encyclopedia
Erectopus is an allosauroid theropod from the Lower Cretaceous of France
.
The material comprising the type series was discovered in the late 19th century from the Phosphate-bearing beds of La Penthèive (Mammilatum Zone; lower Albian
) at Louppy-le-Château
in eastern France, which have also produced remains of plesiosaur
s, ichthyosaur
s, and crocodile
s. The fossils originally resided in the private collection of Louis Pierson. The first, two teeth and a vertebra, were first described by Charles Barrois
in 1875. After more remains had been found, in 1882 Henri-Émile Sauvage made them the basis for a new taxon
, Megalosaurus
superbus. In 1923, the material was redescribed by Friedrich von Huene
(1875–1969), who argued that it could not be included within the genus
Megalosaurus and created for the Pierson theropod a separate genus, naming the species Erectopus superbus. The etymology
of Erectopus is based on the structure of the foot (Latin
erectus = "upright" + Greek
pous = "foot"). The specific name superbus means "proud" in Latin. In 1932 von Huene concluded that the original fossils described by Barrois were not necessarily of the same species as the later finds. Assuming that Sauvage had used the former as the holotype
of Megalosaurus superbus, he therefore created another species: Erectopus sauvagei. Von Huene even declined to use the generic name Erectopus for the first species, indicating it as "Gen. indeterm. superbus", which however does not constitute a valid name.
Subsequently, the Pierson collection was dispersed after the death of its owner and the holotype was long believed lost to science. However, casts of some of the bones have been located in the Muséum National d'Histoire Naturelle
(MNHN, Paris
), and the anterior part of a left maxilla
, described by Sauvage in 1882, was found through a Parisian fossil dealer in the late 20th century and purchased by Christian de Muison, a paleontologist at the MNHN. The casts and the incomplete maxilla allowed for a reevaluation of Erectopus by Ronan Allain in 2005, which determined that the correct taxonomic name for the material is E. superbus, as nothing indicated that Sauvage had limited the holotype to the original teeth. The recovered maxilla has been designated a lectotype
, and the casts of Pierson's specimen has become the plastotype for the taxon. The plastotype includes a partial right manus, the left femur
, left calcaneum, the proximal and distal halves of the left tibia
, and right metatarsal II. The combined inventory number for the syntype
s is MNHN 2001-4.
Based on the morphology
of the distal end of the tibia and the inferred morphology of the astragalus
, Allain (2005, p. 83) placed Erectopus superbus within the Allosauroidea
(a concept equivalent to Carnosauria
, a term some researchers prefer). It is the third youngest carnosaur known from the Europe
an Lower Cretaceous, after the "Montmirat theropod" (Valangian) of southern France and Neovenator
salerii (Barremian
) from the Isle of Wight
.
Allain estimated the weight at two hundred kilogrammes.
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...
.
The material comprising the type series was discovered in the late 19th century from the Phosphate-bearing beds of La Penthèive (Mammilatum Zone; lower Albian
Albian
The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous epoch/series. Its approximate time range is 112.0 ± 1.0 Ma to 99.6 ± 0.9 Ma...
) at Louppy-le-Château
Louppy-le-Château
Louppy-le-Château is a commune in the Meuse department in Lorraine in north-eastern France.-Geography:The village lies in the middle of the commune, on the left bank of The Chée, which flows northwestward through the middle of the commune.-See also:...
in eastern France, which have also produced remains of plesiosaur
Plesiosaur
Plesiosauroidea is an extinct clade of carnivorous plesiosaur marine reptiles. Plesiosauroids, are known from the Jurassic and Cretaceous Periods...
s, ichthyosaur
Ichthyosaur
Ichthyosaurs were giant marine reptiles that resembled fish and dolphins...
s, and crocodile
Crocodile
A crocodile is any species belonging to the family Crocodylidae . The term can also be used more loosely to include all extant members of the order Crocodilia: i.e...
s. The fossils originally resided in the private collection of Louis Pierson. The first, two teeth and a vertebra, were first described by Charles Barrois
Charles Barrois
Charles Barrois was a French geologist and palaeontologist.Barrois was born at Lille and educated at the college in that town, where he studied geology under Professor Jules Gosselet...
in 1875. After more remains had been found, in 1882 Henri-Émile Sauvage made them the basis for a new taxon
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
, Megalosaurus
Megalosaurus
Megalosaurus is a genus of large meat-eating theropod dinosaurs of the Middle Jurassic period of Europe...
superbus. In 1923, the material was redescribed by Friedrich von Huene
Friedrich von Huene
Friedrich von Huene was a German paleontologist who named more dinosaurs in the early 20th century than anyone else in Europe.-Biography:...
(1875–1969), who argued that it could not be included within the genus
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...
Megalosaurus and created for the Pierson theropod a separate genus, naming the species Erectopus superbus. The etymology
Etymology
Etymology is the study of the history of words, their origins, and how their form and meaning have changed over time.For languages with a long written history, etymologists make use of texts in these languages and texts about the languages to gather knowledge about how words were used during...
of Erectopus is based on the structure of the foot (Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
erectus = "upright" + Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
pous = "foot"). The specific name superbus means "proud" in Latin. In 1932 von Huene concluded that the original fossils described by Barrois were not necessarily of the same species as the later finds. Assuming that Sauvage had used the former as the holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
of Megalosaurus superbus, he therefore created another species: Erectopus sauvagei. Von Huene even declined to use the generic name Erectopus for the first species, indicating it as "Gen. indeterm. superbus", which however does not constitute a valid name.
Subsequently, the Pierson collection was dispersed after the death of its owner and the holotype was long believed lost to science. However, casts of some of the bones have been located in the Muséum National d'Histoire Naturelle
Muséum national d'histoire naturelle
The Muséum national d'Histoire naturelle is the National Museum of Natural History in Paris, France.- History :The museum was formally founded on 10 June 1793, during the French Revolution...
(MNHN, Paris
Paris
Paris is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...
), and the anterior part of a left maxilla
Maxilla
The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...
, described by Sauvage in 1882, was found through a Parisian fossil dealer in the late 20th century and purchased by Christian de Muison, a paleontologist at the MNHN. The casts and the incomplete maxilla allowed for a reevaluation of Erectopus by Ronan Allain in 2005, which determined that the correct taxonomic name for the material is E. superbus, as nothing indicated that Sauvage had limited the holotype to the original teeth. The recovered maxilla has been designated a lectotype
Lectotype
In botanical nomenclature and zoological nomenclature, a lectotype is a kind of name-bearing type. When a species was originally described on the basis of a name-bearing type consisting of multiple specimens, one of those may be designated as the lectotype...
, and the casts of Pierson's specimen has become the plastotype for the taxon. The plastotype includes a partial right manus, the left femur
Femur
The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...
, left calcaneum, the proximal and distal halves of the left tibia
Tibia
The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....
, and right metatarsal II. The combined inventory number for the syntype
Syntype
In biological nomenclature, a syntype is a term used to indicate a specimen with a special status.In zoological nomenclature, a syntype is defined as "Each specimen of a type series from which neither a holotype nor a lectotype has been designated [Arts. 72.1.2, 73.2, 74]. The syntypes...
s is MNHN 2001-4.
Based on the morphology
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
of the distal end of the tibia and the inferred morphology of the astragalus
Talus bone
-External links:* *...
, Allain (2005, p. 83) placed Erectopus superbus within the Allosauroidea
Allosauroidea
Allosauroidea is a superfamily or clade of theropod dinosaurs which contains four families — the Sinraptoridae, Allosauridae, Carcharodontosauridae, and Neovenatoridae...
(a concept equivalent to Carnosauria
Carnosauria
Carnosauria is a group of large predatory dinosaurs that lived during the Jurassic and Cretaceous periods. While it originally contained a wide assortment of giant theropods that were not closely related, the group has since been defined to encompass only the allosaurs and their closest kin...
, a term some researchers prefer). It is the third youngest carnosaur known from the Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
an Lower Cretaceous, after the "Montmirat theropod" (Valangian) of southern France and Neovenator
Neovenator
Neovenator is a genus of allosauroid dinosaur. Since its discovery on the Isle of Wight, UK, it has become one of the best-known large carnivorous dinosaurs in Europe. Neovenator was at first considered possibly a new species of Megalosaurus. It measured approximately 7.5 meters in length,...
salerii (Barremian
Barremian
The Barremian is an age in the geologic timescale between 130.0 ± 1.5 Ma and 125.0 ± 1.0 Ma). It is a subdivision of the Early Cretaceous epoch...
) from the Isle of Wight
Isle of Wight
The Isle of Wight is a county and the largest island of England, located in the English Channel, on average about 2–4 miles off the south coast of the county of Hampshire, separated from the mainland by a strait called the Solent...
.
Diagnosis
Allain (2005 pp. 75–76) diagnoses Erectopus superbus as follows: "Rounded anterior ramus of maxilla; slender neck of femur; posterior curvature of proximal half of femur; anterodorsal edge of calcaneum dorsally projected; calcaneum twice as long as deep vertically; posteromedial process for tibia on articular surface of astragalus; length of second metatarsal equal to half the length of femur; lateral margin of proximal end of second metatarsal regularly concave."Allain estimated the weight at two hundred kilogrammes.