Orthomerus
Encyclopedia
Orthomerus is a genus
of duckbill
dinosaur
from the Late Cretaceous
of The Netherlands
, Belgium
and possibly Ukraine
. It is today an obscure genus, but in the past was conflated with the much better known Telmatosaurus
.
Orthomerus Dolloi was in 1883 named by the well-known British
paleontologist Harry Govier Seeley
. The genus name is derived from the Greek ὀρθῶς (orthos), "straight", and μέρος (meros), "thigh". The specific name honours the French/Belgian paleontologist Louis Dollo
. Today the species name is written as Orthomerus dolloi.
The type specimen, formed by the syntype
s BMNH 42954-57, was probably found in the chalkstone quarries of the Sint-Pietersberg near the city of Maastricht
, The Netherlands. It mainly consists of a partial juvenile
skeleton. Not surprisingly these remains are from the Maastricht Formation
of the late Maastrichtian
stage of the Late Cretaceous
, about 66 million years old. The type bones include the straight left and right femora that moved Seeley to give it its name. A left tibia and a metatarsal also discovered in the collection of Jacob Gijsbertus Samuël van Breda
acquired by the British Museum of Natural History in 1871, were referred by him to the species. The leg bones are only about half the size of those belonging to the then largely unknown North America
n and Asia
n duckbills, with the femur 50 cm long (19 in). Other more fragmentary hadrosaurid remains have been found, some of them in The Netherlands, where the species is sometimes presented as a rare "Dutch dinosaur", others in Belgium where in 1882 Dollo excavated two hadrosaurid vertebrae near Zichen, a Belgian border village in Belgian Limburg
. It is hard to establish whether they belonged to the same species and not all of them have been explicitly referred to Orthomerus dolloi. Later Belgian finds included a left third metatarsal, NHMM 1996001 discovered by J.H. Kuypers near Eben Emael, where also a larger right third metatarsal was collected, NHMM RD 241, and a right maxillary tooth, NHMM 1999012, found by E. Croimans. Some phalanges and a left ulna have been reported from private collections, lacking an inventory number.
The Dutch finds include two tail vertebrae collected in the nineteenth century. A second individual dating from just below the K–T boundary
was in September 1967 discovered in a quarry near Geulhem
by L. de Heer; it consists of a fragmentary left femur (MND K 21.04.003), left tibia (MND K 21.04.004) and left fibula (MND K21.04.005). Later found limb bone fragments are OGP 0196 and OGP 2111. NHMM 2002067, a partial tibia, seems not to be cospecific with the other finds, suggesting two hadrosaurid species were present in the formation. In a quarry near Bemelen a partial right dentary was found, specimen NHMM 198027, that however lacked any teeth. However, isolated teeth have been found: NHMM 1997274 by J. Vollers near Sibbe
and left dentary tooth NHMM RD 214 from Berg en Terblijt
, where also dentary tooth NHMM RN 28 was discovered. Finally the collection of the Teylers Museum
at Haarlem
features a partial right humerus, TM 11253.
A second species, Orthomerus weberi, was first described by Anatoly Nikolaevich Riabinin in 1945 for hindlimb elements from an unnamed Maastrichtian-age formation
in the Crimea
of what is now Ukraine
(then a part of the Soviet Union
). These were found by G.F. Weber who is honoured in the specific name. As Weber was female Lev Nesov in 1995 emended the name to Orthomerus weberae.
What is sometimes listed as a third species, O. transsylvanicus, is actually the type species
of Telmatosaurus
, which Franz Nopcsa in 1915 referred to Orthomerus, an assignment still accepted by Alfred Sherwood Romer in his review of reptiles. In recent publications Telmatosaurus is seen as a separate genus, though. If Orthomerus would be identical to Telmatosaurus the latter would be its junior synonym. Forgetting this, in 1984 Dutch geologist Eric Mulder renamed O. dolloi into Telmatosaurus dolloi. A fourth species name is Orthomerus hillii, a renaming in 1915 by Nopcsa of Iguanodon hillii Newton 1892, based on a tooth fragment. It is today seen as a nomen dubium.
The two species, and by extension the genus, have been regarded as fragmentary, non-distinctive, and dubious
hadrosaurid
s, and have fallen out of use. They are mostly of interest in documenting the range of hadrosaurids in Europe.
al herbivore
, eating plant
s with a set of ever-replacing teeth
placed in jaw bones with limited mobility that provided grinding action.
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 duckbill
Hadrosaurid
Hadrosaurids or duck-billed dinosaurs are members of the family Hadrosauridae, and include ornithopods such as Edmontosaurus and Parasaurolophus. They were common herbivores in the Upper Cretaceous Period of what are now Asia, Europe and North America. They are descendants of the Upper...
dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
from the Late Cretaceous
Late Cretaceous
The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...
of The Netherlands
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...
, Belgium
Belgium
Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...
and possibly Ukraine
Ukraine
Ukraine is a country in Eastern Europe. It has an area of 603,628 km², making it the second largest contiguous country on the European continent, after Russia...
. It is today an obscure genus, but in the past was conflated with the much better known Telmatosaurus
Telmatosaurus
Telmatosaurus is a genus of basal hadrosaurid dinosaur from the Late Cretaceous. It was a relatively small hadrosaur, approximately five meters long, found in what is now Romania....
.
History
The type speciesType 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...
Orthomerus Dolloi was in 1883 named by the well-known British
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
paleontologist Harry Govier Seeley
Harry Seeley
Harry Govier Seeley was a British paleontologist.-Career:Seeley was born in London, the son of Richard Hovill Seeley, goldsmith, and his second wife Mary Govier. He attended classes at the Royal School of Mines, Kensington before becoming an assistant to Adam Sedgwick at the Woodwardian Museum,...
. The genus name is derived from the Greek ὀρθῶς (orthos), "straight", and μέρος (meros), "thigh". The specific name honours the French/Belgian paleontologist Louis Dollo
Louis Dollo
Louis Antoine Marie Joseph Dollo was a French-born Belgian palaeontologist, known for formulating Dollo's law. He graduated as an engineer at École Centrale de Lille in France. In 1878, he supervised the excavation of the famous, multiple Iguanodon find, at Bernissart, Belgium. Recently, the...
. Today the species name is written as Orthomerus dolloi.
The type specimen, formed by 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 BMNH 42954-57, was probably found in the chalkstone quarries of the Sint-Pietersberg near the city of Maastricht
Maastricht
Maastricht is situated on both sides of the Meuse river in the south-eastern part of the Netherlands, on the Belgian border and near the German border...
, The Netherlands. It mainly consists of a partial juvenile
Juvenile (organism)
A juvenile is an individual organism that has not yet reached its adult form, sexual maturity or size. Juveniles sometimes look very different from the adult form, particularly in terms of their colour...
skeleton. Not surprisingly these remains are from the Maastricht Formation
Maastricht Formation
The Maastricht Formation , named after the city of Maastricht, the Netherlands, is a geological formation in the Netherlands and Belgium whose strata date back to the Late Cretaceous, within 500k years of the K-Pg boundary, dated to 65.5 million years ago. The formation is part of the Chalk Group...
of the late Maastrichtian
Maastrichtian
The Maastrichtian is, in the ICS' geologic timescale, the latest age or upper stage of the Late Cretaceous epoch or Upper Cretaceous series, the Cretaceous period or system, and of the Mesozoic era or erathem. It spanned from 70.6 ± 0.6 Ma to 65.5 ± 0.3 Ma...
stage of the Late Cretaceous
Late Cretaceous
The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...
, about 66 million years old. The type bones include the straight left and right femora that moved Seeley to give it its name. A left tibia and a metatarsal also discovered in the collection of Jacob Gijsbertus Samuël van Breda
Jacob Gijsbertus Samuël van Breda
Jacob Gijsbertus Samuël van Breda was a Dutch biologist and geologist.Jacob was the son of Jacob van Breda, a Dutch physician, physicist and politician, and Anna Elsenera van Campen. His mother died when he was two years old...
acquired by the British Museum of Natural History in 1871, were referred by him to the species. The leg bones are only about half the size of those belonging to the then largely unknown North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
n and Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
n duckbills, with the femur 50 cm long (19 in). Other more fragmentary hadrosaurid remains have been found, some of them in The Netherlands, where the species is sometimes presented as a rare "Dutch dinosaur", others in Belgium where in 1882 Dollo excavated two hadrosaurid vertebrae near Zichen, a Belgian border village in Belgian Limburg
Limburg (Belgium)
Limburg is the easternmost province of modern Flanders, which is one of the three main political and cultural sub-divisions of modern Belgium. It is located west of the river Meuse . It borders on the Dutch provinces of North Brabant and Limburg and the Belgian provinces of Liège, Flemish Brabant...
. It is hard to establish whether they belonged to the same species and not all of them have been explicitly referred to Orthomerus dolloi. Later Belgian finds included a left third metatarsal, NHMM 1996001 discovered by J.H. Kuypers near Eben Emael, where also a larger right third metatarsal was collected, NHMM RD 241, and a right maxillary tooth, NHMM 1999012, found by E. Croimans. Some phalanges and a left ulna have been reported from private collections, lacking an inventory number.
The Dutch finds include two tail vertebrae collected in the nineteenth century. A second individual dating from just below the K–T boundary
K–T boundary
The K–T boundary is a geological signature, usually a thin band, dated to 65.5 ± 0.3 Ma ago. K is the traditional abbreviation for the Cretaceous period, and T is the abbreviation for the Tertiary period...
was in September 1967 discovered in a quarry near Geulhem
Geulhem
Geulhem is a rural village in the south-eastern Netherlands, part of the former Berg en Terblijt council, now Valkenburg aan de Geul council. It is situated between Houthem and Berg en Terblijt.-History:...
by L. de Heer; it consists of a fragmentary left femur (MND K 21.04.003), left tibia (MND K 21.04.004) and left fibula (MND K21.04.005). Later found limb bone fragments are OGP 0196 and OGP 2111. NHMM 2002067, a partial tibia, seems not to be cospecific with the other finds, suggesting two hadrosaurid species were present in the formation. In a quarry near Bemelen a partial right dentary was found, specimen NHMM 198027, that however lacked any teeth. However, isolated teeth have been found: NHMM 1997274 by J. Vollers near Sibbe
Sibbe
Sibbe is the official Dutch name of a village in the municipality of Valkenburg aan de Geul in the province of Limburg in the Southern part of the Netherlands.-History:...
and left dentary tooth NHMM RD 214 from Berg en Terblijt
Berg en Terblijt
Berg en Terblijt is the official Dutch name of a village in the municipality of Valkenburg aan de Geul in the province of Limburg in the Southern part of the Netherlands.-History:...
, where also dentary tooth NHMM RN 28 was discovered. Finally the collection of the Teylers Museum
Teylers Museum
Teyler's Museum , located in Haarlem, is the oldest museum in the Netherlands. The museum is in the former home of Pieter Teyler van der Hulst . He was a wealthy cloth merchant and Amsterdam banker of Scottish descent, who bequeathed his fortune for the advancement of religion, art and science...
at Haarlem
Haarlem
Haarlem is a municipality and a city in the Netherlands. It is the capital of the province of North Holland, the northern half of Holland, which at one time was the most powerful of the seven provinces of the Dutch Republic...
features a partial right humerus, TM 11253.
A second species, Orthomerus weberi, was first described by Anatoly Nikolaevich Riabinin in 1945 for hindlimb elements from an unnamed Maastrichtian-age formation
Geologic formation
A formation or geological formation is the fundamental unit of lithostratigraphy. A formation consists of a certain number of rock strata that have a comparable lithology, facies or other similar properties...
in the Crimea
Crimea
Crimea , or the Autonomous Republic of Crimea , is a sub-national unit, an autonomous republic, of Ukraine. It is located on the northern coast of the Black Sea, occupying a peninsula of the same name...
of what is now Ukraine
Ukraine
Ukraine is a country in Eastern Europe. It has an area of 603,628 km², making it the second largest contiguous country on the European continent, after Russia...
(then a part of the Soviet Union
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....
). These were found by G.F. Weber who is honoured in the specific name. As Weber was female Lev Nesov in 1995 emended the name to Orthomerus weberae.
What is sometimes listed as a third species, O. transsylvanicus, is actually 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...
of Telmatosaurus
Telmatosaurus
Telmatosaurus is a genus of basal hadrosaurid dinosaur from the Late Cretaceous. It was a relatively small hadrosaur, approximately five meters long, found in what is now Romania....
, which Franz Nopcsa in 1915 referred to Orthomerus, an assignment still accepted by Alfred Sherwood Romer in his review of reptiles. In recent publications Telmatosaurus is seen as a separate genus, though. If Orthomerus would be identical to Telmatosaurus the latter would be its junior synonym. Forgetting this, in 1984 Dutch geologist Eric Mulder renamed O. dolloi into Telmatosaurus dolloi. A fourth species name is Orthomerus hillii, a renaming in 1915 by Nopcsa of Iguanodon hillii Newton 1892, based on a tooth fragment. It is today seen as a nomen dubium.
The two species, and by extension the genus, have been regarded as fragmentary, non-distinctive, and dubious
Nomen dubium
In zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application...
hadrosaurid
Hadrosaurid
Hadrosaurids or duck-billed dinosaurs are members of the family Hadrosauridae, and include ornithopods such as Edmontosaurus and Parasaurolophus. They were common herbivores in the Upper Cretaceous Period of what are now Asia, Europe and North America. They are descendants of the Upper...
s, and have fallen out of use. They are mostly of interest in documenting the range of hadrosaurids in Europe.
Paleobiology
As a hadrosaurid, Orthomerus would have been a bipedal/quadrupedQuadruped
Quadrupedalism is a form of land animal locomotion using four limbs or legs. An animal or machine that usually moves in a quadrupedal manner is known as a quadruped, meaning "four feet"...
al herbivore
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
, eating plant
Plant
Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...
s with a set of ever-replacing teeth
Tooth
Teeth are small, calcified, whitish structures found in the jaws of many vertebrates that are used to break down food. Some animals, particularly carnivores, also use teeth for hunting or for defensive purposes. The roots of teeth are embedded in the Mandible bone or the Maxillary bone and are...
placed in jaw bones with limited mobility that provided grinding action.
External links
- Orthomerus in The Dinosaur Encyclopaedia at Dino Russ's Lair.