Herbstosaurus
Encyclopedia
Herbstosaurus is the name given to a genus
of pterosaur
that lived during the Jurassic
period, in what is now Argentina
.
In 1969 Argentine paleobotanist Rafael Herbst in the province Neuquén
at Picun Leufú
dug up a piece of sandstone holding a number of disarticulated bones of a small reptile. At the time it was assumed the rock dated from the Middle Jurassic
(Callovian
), about 163 million years ago.
In 1974/1975 paleontologist Rodolfo Magín Casamiquela named the find as a new genus. The type species
is Herbstosaurus pigmaeus. The genus name honours Herbst and connects his name to Greek sauros, "lizard", a usual element in the name of dinosaurs — Casamiquela assumed the new genus was a theropod dinosaur
. The specific name is derived from Greek pygmaios, "dwarf": it was thought the form presented a small Compsognathus
-like coelurosauria
n belonging to the Coeluridae
and one of the smallest dinosaurs then known.
The holotype
is CTES-PZ-1711, consisting of a sacrum, pelvic elements and both femora. The dispersed bones are compressed, crushed by the weight of the layers above.
Casamiquela had already indicated that the new species was very distinct because of an atypically long ilium
and short ischium. In 1978 John Ostrom
, while reviewing the relations of Compsognathus, concluded that these qualities were best explained by the hypothesis that Herbstosaurus was not a dinosaur but a pterosaur, for which such proportions are normal. The new identification allowed some fragmentary pterosaur material found in the same layers to be referred to Herbstosaurus, among which a wing bone.
The phylogenetic position of Herbstosaurus has proven difficult to determine with no consensus developing. In 1981 Peter Galton
stated it was a member of the Pterodactyloidea
. Robert Carroll
in his 1988 general textbook on vertebrate paleontology narrowed that down to the Pterodactylidae. Peter Wellnhofer
however, in 1991 suggested it was not a pterodactyloid but a more basal pterosaur, in view of the form of the pelvis. In 1996 David Unwin concluded Herbstosaurus was a basal member of the Dsungaripteroidea
. This was again doubted by Laura Codorniú and Zulma Gasparini in 2007.
Herbstosaurus has generated a special interest because it was possibly one of the earliest pterodactyloids known. However, it was later determined it had been found in the Vaca Muerta Formation from the Upper Jurassic (Tithonian
).
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 pterosaur
Pterosaur
Pterosaurs were flying reptiles of the clade or order Pterosauria. They existed from the late Triassic to the end of the Cretaceous Period . Pterosaurs are the earliest vertebrates known to have evolved powered flight...
that lived during 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...
period, in what is now Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
.
In 1969 Argentine paleobotanist Rafael Herbst in the province Neuquén
Neuquén Province
Neuquén is a province of Argentina, located in the west of the country, at the northern end of Patagonia. It borders Mendoza Province to the north, Rio Negro Province to the southeast, and Chile to the west...
at Picun Leufú
Picún Leufú
Picún Leufú is a second category municipality and the capital of Picún Leufú Department located in Neuquén Province, Argentina....
dug up a piece of sandstone holding a number of disarticulated bones of a small reptile. At the time it was assumed the rock dated from the Middle Jurassic
Middle Jurassic
The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from 176-161 million years ago. In European lithostratigraphy, rocks of this Middle Jurassic age are called the Dogger....
(Callovian
Callovian
In the geologic timescale, the Callovian is an age or stage in the Middle Jurassic, lasting between 164.7 ± 4.0 Ma and 161.2 ± 4.0 Ma. It is the last stage of the Middle Jurassic, following the Bathonian and preceding the Oxfordian....
), about 163 million years ago.
In 1974/1975 paleontologist Rodolfo Magín Casamiquela named the find as a new genus. 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...
is Herbstosaurus pigmaeus. The genus name honours Herbst and connects his name to Greek sauros, "lizard", a usual element in the name of dinosaurs — Casamiquela assumed the new genus was a theropod 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...
. The specific name is derived from Greek pygmaios, "dwarf": it was thought the form presented a small Compsognathus
Compsognathus
Compsognathus was a small, bipedal, carnivorous theropod dinosaur. The animal was the size of a turkey and lived around 150 million years ago, the early Tithonian stage of the late Jurassic Period, in what is now Europe. Paleontologists have found two well-preserved fossils, one in Germany...
-like coelurosauria
Coelurosauria
Coelurosauria is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs. In the past, it was used to refer to all small theropods, although this classification has been abolished...
n belonging to the Coeluridae
Coeluridae
Coeluridae is a historically polyphyletic family of generally small, carnivorous dinosaurs from the late Jurassic Period...
and one of the smallest dinosaurs then known.
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...
is CTES-PZ-1711, consisting of a sacrum, pelvic elements and both femora. The dispersed bones are compressed, crushed by the weight of the layers above.
Casamiquela had already indicated that the new species was very distinct because of an atypically long ilium
Ilium
-Places:* Ilion or, Latinized, Ilium, another name for the legendary city of Troy, hence the title of Homer's Iliad*Ilium , an ancient city in Epirus...
and short ischium. In 1978 John Ostrom
John Ostrom
John H. Ostrom was an American paleontologist who revolutionized modern understanding of dinosaurs in the 1960s, when he demonstrated that dinosaurs are more like big non-flying birds than they are like lizards , an idea first proposed by Thomas Henry Huxley in the 1860s, but which had garnered...
, while reviewing the relations of Compsognathus, concluded that these qualities were best explained by the hypothesis that Herbstosaurus was not a dinosaur but a pterosaur, for which such proportions are normal. The new identification allowed some fragmentary pterosaur material found in the same layers to be referred to Herbstosaurus, among which a wing bone.
The phylogenetic position of Herbstosaurus has proven difficult to determine with no consensus developing. In 1981 Peter Galton
Peter Galton
Peter M. Galton is a British vertebrate paleontologist working in America, who has to date written or co-written about a hundred papers in scientific journals or chapters in paleontology textbooks, especially on ornithischian and prosauropod dinosaurs.With Robert Bakker in a joint article...
stated it was a member of the Pterodactyloidea
Pterodactyloidea
Pterodactyloidea forms one of the two suborders of pterosaurs , and contains the most derived members of this group of flying reptiles...
. Robert Carroll
Robert L. Carroll
Robert Lynn Carroll is a vertebrate paleontologist who specialises in Paleozoic and Mesozoic amphibians and reptiles.Carroll was an only child and grew up on a farm near Lansing, Michigan...
in his 1988 general textbook on vertebrate paleontology narrowed that down to the Pterodactylidae. Peter Wellnhofer
Peter Wellnhofer
Peter Wellnhofer is a German paleontologist at the "Bayerische Staatssammlung fur Paläontologie" in Munich. He is best known for his work on the various fossil specimens of Archaeopteryx or "Urvogel", the first known bird...
however, in 1991 suggested it was not a pterodactyloid but a more basal pterosaur, in view of the form of the pelvis. In 1996 David Unwin concluded Herbstosaurus was a basal member of the Dsungaripteroidea
Dsungaripteroidea
Dsungaripteroidea is a group of pterosaurs within the suborder Pterodactyloidea.-Classification:Listing of families and genera after Unwin 2006 unless otherwise noted.* Superfamily Dsungaripteroidea** Herbstosaurus** Kepodactylus...
. This was again doubted by Laura Codorniú and Zulma Gasparini in 2007.
Herbstosaurus has generated a special interest because it was possibly one of the earliest pterodactyloids known. However, it was later determined it had been found in the Vaca Muerta Formation from the Upper Jurassic (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...
).