Lametasaurus
Encyclopedia
Lametasaurus named for the Lameta Formation
, Jabalpur, India
, is the generic name given to a possible dubious dinosaur
species. Originally it indicated a possible chimera
composed of several different animals.
Between October 1917 and 1919 Charles Alfred Matley
excavated fossils near Jabalpur. In 1921 he reported the find in the "Carnosaur Bed" of what he considered to be two megalosaurians, theropod dinosaurs. In 1923/1924 he named one of these as the type species
Lametasaurus indicus. The generic name refers to the Lameta Formation, dating from the Maastrichtian
, the specific name refers to India. However, Matley no longer identified it as a theropod but as a member of the Stegosauria
instead, which concept at the time also included the armoured dinosaurs today assigned to the Ankylosauria
; at first Matley had seen it as a stegosaurian in the modern sense and even intended to name it as a species of Omosaurus. The type specimen consisted of a number of dermal scutes, a sacrum
of at least five sacral vertebrae, a pelvis
, a tibia
and teeth. In 1933 Matley and Friedrich von Huene
described some more remains collected by Barnum Brown
, thought to have been part of a tail club; later this was shown to be a large osteoderm.
However, in 1935 Dhirendra Kishore Chakravarti contested the interpretation as an armoured dinosaur. He claimed that the specimen was a chimera including titanosaur
id armor
, crocodile
teeth and theropod hindlimb material. In 1964 Alick Walker
chose the scutes as the lectotype
, thus removing the teeth and the bones from the type material. The name Lametasaurus now designated the scutes only and was generally considered to represent a member of the Nodosauridae
. The pelvis and hindlimb bones have in 2003 been suggested to belong to Rajasaurus
. In 2008 Matthew Carrano e.a. discarded the possibility the scutes were ankylosaurian, stating they were probably titanosaurian or perhaps abelisaurid
, in which latter case the species would possibly not have been a chimera in the first place and be a possible senior synonym of Indosaurus
and/or Rajasaurus.
The type material has been lost, lacking a known inventory number, making it difficult to test the several hypotheses. The taxon
is today commonly seen as a nomen dubium
.
Lameta Formation
The Lameta Formation is a sedimentary rock formation found in Madhya Pradesh, Gujarat, and Maharashtra, India. It is of Maastrichtian age , and is notable for its dinosaur fossils...
, Jabalpur, India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
, is the generic name given to a possible dubious 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...
species. Originally it indicated a possible chimera
Chimera (paleontology)
In paleontology, a chimera is a fossil which was reconstructed with elements coming from more than a single species of animal. A now classic example of chimera is Protoavis.-List of paleontological chimeras:*Brontosaurus*Lametasaurus...
composed of several different animals.
Between October 1917 and 1919 Charles Alfred Matley
Charles Alfred Matley
Charles Alfred Matley was a British paleontologist and geologist in India, the British West Indies and Wales.He married Sarah A. Loach in Birmingham in 1891....
excavated fossils near Jabalpur. In 1921 he reported the find in the "Carnosaur Bed" of what he considered to be two megalosaurians, theropod dinosaurs. In 1923/1924 he named one of these as 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...
Lametasaurus indicus. The generic name refers to the Lameta Formation, dating from the 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...
, the specific name refers to India. However, Matley no longer identified it as a theropod but as a member of the Stegosauria
Stegosauria
Known colloquially as stegosaurs, the Stegosauria are a group of herbivorous dinosaurs of the Jurassic and Early Cretaceous Periods, being found mostly in the Northern Hemisphere, predominantly in what is now North America and China....
instead, which concept at the time also included the armoured dinosaurs today assigned to the Ankylosauria
Ankylosauria
Ankylosauria is a group of herbivorous dinosaurs of the order Ornithischia. It includes the great majority of dinosaurs with armor in the form of bony osteoderms. Ankylosaurs were bulky quadrupeds, with short, powerful limbs. They are first known to have appeared in the early Jurassic Period of...
; at first Matley had seen it as a stegosaurian in the modern sense and even intended to name it as a species of Omosaurus. The type specimen consisted of a number of dermal scutes, a sacrum
Sacrum
In vertebrate anatomy the sacrum is a large, triangular bone at the base of the spine and at the upper and back part of the pelvic cavity, where it is inserted like a wedge between the two hip bones. Its upper part connects with the last lumbar vertebra, and bottom part with the coccyx...
of at least five sacral vertebrae, a pelvis
Pelvis
In human anatomy, the pelvis is the lower part of the trunk, between the abdomen and the lower limbs .The pelvis includes several structures:...
, a 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 teeth. In 1933 Matley and 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:...
described some more remains collected by Barnum Brown
Barnum Brown
Barnum Brown , a paleontologist born in Carbondale, Kansas, and named after the circus showman P.T. Barnum, discovered the second fossil of Tyrannosaurus rex during a career that made him one of the most famous fossil hunters working from the late Victorian era into the early 20th century.Sponsored...
, thought to have been part of a tail club; later this was shown to be a large osteoderm.
However, in 1935 Dhirendra Kishore Chakravarti contested the interpretation as an armoured dinosaur. He claimed that the specimen was a chimera including titanosaur
Titanosaur
Titanosaurs were a diverse group of sauropod dinosaurs, which included Saltasaurus and Isisaurus. It includes some of the heaviest creatures ever to walk the earth, such as Argentinosaurus and Paralititan — which some believe have weighed up to 100 tonnes...
id armor
Armour (zoology)
Armour in animals is external or superficial protection against attack by predators, formed as part of the body , usually through the hardening of body tissues, outgrowths or secretions. It has therefore mostly developed in 'prey' species...
, 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...
teeth and theropod hindlimb material. In 1964 Alick Walker
Alick Walker
Alick Donald Walker was a British palaeontologist, after whom the Alwalkeria genus of dinosaur is named....
chose the scutes as the 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...
, thus removing the teeth and the bones from the type material. The name Lametasaurus now designated the scutes only and was generally considered to represent a member of the Nodosauridae
Nodosauridae
Nodosauridae is a family of ankylosaurian dinosaurs, from the Late Jurassic to the Late Cretaceous Period of what are now North America, Asia, Antarctica and Europe.-Characteristics:...
. The pelvis and hindlimb bones have in 2003 been suggested to belong to Rajasaurus
Rajasaurus
Rajasaurus is a genus of carnivorous abelisaurian theropod dinosaur with an unusual head crest. Between 1982 and 1984, its fossilized bones were discovered by Suresh Srivastava of the Geological Survey of India...
. In 2008 Matthew Carrano e.a. discarded the possibility the scutes were ankylosaurian, stating they were probably titanosaurian or perhaps abelisaurid
Abelisauridae
Abelisauridae is a family of ceratosaurian theropod dinosaurs. Abelisaurids thrived during the Cretaceous Period, on the ancient southern supercontinent of Gondwana, and today their fossil remains are found on the modern continents of Africa and South America, as well as on the Indian...
, in which latter case the species would possibly not have been a chimera in the first place and be a possible senior synonym of Indosaurus
Indosaurus
Indosaurus is a genus of theropod dinosaur once living in what is now India. It lived approximately 69 million years ago, in the Maastrichtian division of the Late Cretaceous...
and/or Rajasaurus.
The type material has been lost, lacking a known inventory number, making it difficult to test the several hypotheses. The 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...
is today commonly seen as a nomen dubium
Nomen dubium
In zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application...
.