is a 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...
Diplodocids, or members of the family Diplodocidae , are a group of sauropod dinosaurs. The family includes some of the longest creatures ever to walk the earth, including Diplodocus and Supersaurus, which may have reached lengths of up to .-Description:While still massive, when compared to the...
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 Late 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...
The United Republic of Tanzania is a country in East Africa bordered by Kenya and Uganda to the north, Rwanda, Burundi, and the Democratic Republic of the Congo to the west, and Zambia, Malawi, and Mozambique to the south. The country's eastern borders lie on the Indian Ocean.Tanzania is a state...
. It has a convoluted taxonomic history.
Discovery and naming
In 1907, German paleontologist Eberhard Fraas
Eberhard Fraas was a German geologist and paleontologist. He worked as a curator at the Stuttgarter Naturaliensammlung and discovered the dinosaurs of the Tendaguru formation in then German East Africa ....
who was working the Tendaguru Beds in German East Africa
German East Africa was a German colony in East Africa, which included what are now :Burundi, :Rwanda and Tanganyika . Its area was , nearly three times the size of Germany today....
(presently Tanzania), discovered two sauropod specimens at a single site ("Quarry A"). The two individuals, designated "Skeleton A" and "Skeleton B", each represented a different sauropod species. In 1908 he named these respectively Gigantosaurus africanus
("African giant lizard") and G. robusta
("Robust giant lizard"). A third, unrelated African species, "Gigantosaurus" dixeyi
, was named by Haughton in 1928, and has since been re-assigned to Malawisaurus
Malawisaurus was a genus of sauropod dinosaur . It lived in what is now Africa, specifically Malawi, during the Aptian age of the Early Cretaceous Period. It is one of the few titanosaurs for which skull material has been found.It was named by Louis L. Jacobs and colleagues, and was originally...
Unfortunately, the name Gigantosaurus
Gigantosaurus is a poorly known sauropod dinosaur genus from England. The type species, Gigantosaurus megalonyx, was named and described by Harry Govier Seeley in 1869...
had already been used for the European sauropod Gigantosaurus megalonyx
Seeley, 1869. Fraas, not intending to place his species in the same genus as this English form, had believed that the name was available, since at the time the latter species was considered to be a junior synonym of Ornithopsis
Ornithopsis was a medium-sized Early Cretaceous sauropod dinosaur, from England. It has been considered a synonym of the wastebasket taxon Pelorosaurus, but recent research suggests that this is not as clear-cut as supposed...
and Seeley in his opinion had not provided a sufficient description anyway. Another German paleontologist, Richard Sternfeld, renamed the Tanzanian sauropod Tornieria
in 1911, making the two species Tornieria africana
and T. robusta
. The generic name honours the German herpetologist
Herpetology is the branch of zoology concerned with the study of amphibians and reptiles...
Gustav Tornier was a German zoologist and paleontologist.-Life and career:...
A re-evaluation of Tornieria
in 1922 by Werner Janensch
Werner Ernst Martin Janensch was a German paleontologist and geologist.Janensch's most famous contributions stemmed from the expedition he led with Edwin Hennig to the Tendaguru Beds in what is now Tanzania...
concluded that one species, T. africana
, was actually an African species of the North American sauropod genus Barosaurus
Barosaurus ; Greek barys/βαρυς meaning 'heavy' and saurus/σαυρος meaning 'lizard', 'heavy lizard') was a giant, long-tailed, long-necked, plant-eating dinosaur closely related to the more familiar Diplodocus...
: Barosaurus africanus
. The other African species, T. robusta
, later turned out to belong to a 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...
. The titanosaur species for a time was called Tornieria
, but this was incorrect as T. africana
had been the 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...
. It needed a generic name of its own and this was provided in 1991 when Rupert Wild renamed it Janenschia
Janenschia was a large sauropod from Late Jurassic Africa , and therefore the earliest known titanosaur. Originally thought to be a species of the diplodocid Tornieria/Barosaurus , it was later found to be a distantly related titanosaur. So far, it is only known from Tanzania...
were the same genus as Barosaurus
, then the name Tornieria
would be abandoned as a junior subjective synonym. However, later researchers proposed generic distinction between the American and the African form. In the early 21st century this usage became prevalent and in 2006 Kristian Remes in a review concluded that Tornieria
was indeed distinct and a valid genus.
A complication is formed by the fact that Janensch in 1961 recognised a variety of B. africanus
: B. africanus
, a morph
Polymorphism in biology occurs when two or more clearly different phenotypes exist in the same population of a species — in other words, the occurrence of more than one form or morph...
distinguished by more gracile hind limbs. In 1980 John McIntosh promoted this to a full species: Barosaurus gracilis
which then would become a Tornieria gracilis
under the present usage, a combination already published by George Olshevsky
George Olshevsky is a freelance editor, writer, publisher, amateur paleontologist, and mathematician living in San Diego, California.Olshevsky maintains the comprehensive online Dinosaur Genera List...
in 1992. However, Remes in 2006 concluded that B. gracilis
had been an nomen nudum
The phrase nomen nudum is a Latin term, meaning "naked name", used in taxonomy...
, neither 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...
nor diagnosis having been provided in 1980.
Specimens and description
Elements of the original "Skeleton A" were designated by Fraas as a 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...
series: SMNS 12141a, 12145a, 12143, 12140, 12142, all from the postcrania
Postcrania[p] in zoology and vertebrate paleontology refers to all or part of the skeleton apart from the skull. Frequently, fossil remains, e.g...
. Later some other bones from the same individual were recovered. Janensch would also refer many other fossils to B. africanus
, in total 630 specimens representing at least 56 separate individuals. Of these 188 would be left after the bombardments during the Second World War. Remes, however, concluded that merely a second partial skeleton, "Skeleton k", including also some skull elements, could be reliably referred, and a series of caudal vertebrae. The remains are from the later strata of the Tendaguru, the obere Dinosauriermergel
or "Upper Dinosaur Marl", dating from the 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...
was a large sauropod, with a maximum known 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...
length of 138 centimetres (54.3 in). It shared elongated neck vertebrae and a rather long forelimb with Barosaurus
. However, it differed from the American form by details in the anterior caudal
The tail is the section at the rear end of an animal's body; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals, reptiles, and birds...
vertebrae and from Barosaurus
Diplodocus , or )is a genus of diplodocid sauropod dinosaur whose fossils were first discovered in 1877 by S. W. Williston. The generic name, coined by Othniel Charles Marsh in 1878, is a Neo-Latin term derived from Greek "double" and "beam", in reference to its double-beamed chevron bones...
both by its plesiomorphic hindlimb proportions with a short lower leg.
After performing a cladistic analysis, Remes concluded that Tornieria
was the sister taxon of a clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
formed by Barosaurus
. It would thus be a member of the Diplodocinae.