Puertasaurus
Encyclopedia
Puertasaurus is a genus
of titanosaur
id sauropod that appeared during the Late Cretaceous
. It lived in what is now Patagonia
. The type species
, Puertasaurus reuili, is named in honor of Pablo Puerta and Santiago Reuil, the co-discoverers in January 2001 of the specimen. Puertasaurus is based on a partial spinal column: a neck vertebra, a dorsal (back) vertebra, and two tail vertebrae.
MPM 10002, the most impressive is the back vertebra measuring 1.06 meters (3.48 ft) tall and 1.68 meters (5.51 ft) wide. This is the broadest sauropod vertebra known, and two-thirds of its width is made up of the huge wing-like diapophyses (side processes which supported the ribs), which are heavily buttresed and merge with both the centrum and the neural spine, forming a wide spade-like shape (in most sauropods, like Argentinosaurus, they are far less large, lack buttresses, and form a simple cross-bar shape). The huge size of the diapophyses indicated a very wide rib cage, which would have been anywhere from 5 to 8 meters wide, which would make it not just one of the largest dinosaurs, but also possibly the widest and heaviest. The neck was also unusual; based on the single known neck vertebra, Puertasaurus had a very long, squat neck with wide cervical ribs and thick but short neural spines (unlike its relative Futalognkosaurus, whose neck was also very long, but was much deeper, with tall "shark fin" neural spines). This gave the neck a huge vertical range of motion and flexibility, and it may have been able to "bend over backwards" so that Puertasaurus could reach higher branches behind its head, without having to move its whole body - as a trade-off, the neck's sideways flexibility was more limited, though the extreme width of the neck may indicate a wide head as well, the jaws of which could take in more food per bite to make up for the lack of lateral flexibility. This strange, highly specialized squat-neck design is seen nowhere else in the Dinosauria.
, one of the paleontologists who described Puertasaurus reuili, estimated that the new species was approximately 35 to 40 meters (115 to 131 ft) long and weighed between 80 and 100 metric tons (88 to 110 short ton
s). If correct, this would place it as one of the biggest dinosaurs (and the biggest titanosaur) ever to walk the earth, though rivaled in size by the more primitive Argentinosaurus
. It would also extend the period of time in which such very large sauropods lived; this species roamed what is now Patagonia towards the end of the Cretaceous period, some 70 million years ago, in the early Maastrichtian
.
Titanosauria. Based on the shape of its known vertebrae, it is most closely related to the lognkosaurians
, a transitional group within Titanosauria which includes the gigantic Futalognkosaurus and the somewhat smaller Mendozasaurus
, known for their hefty necks and wide rib cages, as well as similar wing-like diapophyses. If it is a lognkosaurian, Puertasaurus would be not only the largest but also the last known member of the group. Lognkosaurians were common in the Turonian
and Coniacian
epochs, but Puertasaurus lived in the Maastrichtian
, the very last stage of the Late Cretaceous, when the much smaller Saltasaurids
were the most common titanosaur group.
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 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 sauropod that appeared during the Late Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
. It lived in what is now Patagonia
Patagonia
Patagonia is a region located in Argentina and Chile, integrating the southernmost section of the Andes mountains to the southwest towards the Pacific ocean and from the east of the cordillera to the valleys it follows south through Colorado River towards Carmen de Patagones in the Atlantic Ocean...
. 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...
, Puertasaurus reuili, is named in honor of Pablo Puerta and Santiago Reuil, the co-discoverers in January 2001 of the specimen. Puertasaurus is based on a partial spinal column: a neck vertebra, a dorsal (back) vertebra, and two tail vertebrae.
Anatomy
Of the four neck, back and tail vertebrae discovered, together forming the holotypeHolotype
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...
MPM 10002, the most impressive is the back vertebra measuring 1.06 meters (3.48 ft) tall and 1.68 meters (5.51 ft) wide. This is the broadest sauropod vertebra known, and two-thirds of its width is made up of the huge wing-like diapophyses (side processes which supported the ribs), which are heavily buttresed and merge with both the centrum and the neural spine, forming a wide spade-like shape (in most sauropods, like Argentinosaurus, they are far less large, lack buttresses, and form a simple cross-bar shape). The huge size of the diapophyses indicated a very wide rib cage, which would have been anywhere from 5 to 8 meters wide, which would make it not just one of the largest dinosaurs, but also possibly the widest and heaviest. The neck was also unusual; based on the single known neck vertebra, Puertasaurus had a very long, squat neck with wide cervical ribs and thick but short neural spines (unlike its relative Futalognkosaurus, whose neck was also very long, but was much deeper, with tall "shark fin" neural spines). This gave the neck a huge vertical range of motion and flexibility, and it may have been able to "bend over backwards" so that Puertasaurus could reach higher branches behind its head, without having to move its whole body - as a trade-off, the neck's sideways flexibility was more limited, though the extreme width of the neck may indicate a wide head as well, the jaws of which could take in more food per bite to make up for the lack of lateral flexibility. This strange, highly specialized squat-neck design is seen nowhere else in the Dinosauria.
Length
Fernando NovasFernando Novas
Fernando Emilio Novas is an Argentine paleontologist working for the Comparative Anatomy Department of the Bernardino Rivadavia Natural History Argentine Museum in Buenos Aires...
, one of the paleontologists who described Puertasaurus reuili, estimated that the new species was approximately 35 to 40 meters (115 to 131 ft) long and weighed between 80 and 100 metric tons (88 to 110 short ton
Short ton
The short ton is a unit of mass equal to . In the United States it is often called simply ton without distinguishing it from the metric ton or the long ton ; rather, the other two are specifically noted. There are, however, some U.S...
s). If correct, this would place it as one of the biggest dinosaurs (and the biggest titanosaur) ever to walk the earth, though rivaled in size by the more primitive Argentinosaurus
Argentinosaurus
Argentinosaurus is a genus of titanosaur sauropod dinosaur first discovered by Guillermo Heredia in Argentina. The generic name refers to the country in which it was discovered...
. It would also extend the period of time in which such very large sauropods lived; this species roamed what is now Patagonia towards the end of the Cretaceous period, some 70 million years ago, in the early 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...
.
Relationships to other titanosaurs
Puertasaurus belonged to the cladeClade
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...
Titanosauria. Based on the shape of its known vertebrae, it is most closely related to the lognkosaurians
Lognkosauria
Lognkosauria is a group of giant long-necked sauropod dinosaurs within the clade Titanosauria, and includes some of the largest and heaviest dinosaurs to ever walk the earth.-Defining characteristics:...
, a transitional group within Titanosauria which includes the gigantic Futalognkosaurus and the somewhat smaller Mendozasaurus
Mendozasaurus
Mendozasaurus is a genus of sauropod dinosaur. It was a member of Titanosauria, which were massive sauropods that were common on the southern landmasses during the Cretaceous period....
, known for their hefty necks and wide rib cages, as well as similar wing-like diapophyses. If it is a lognkosaurian, Puertasaurus would be not only the largest but also the last known member of the group. Lognkosaurians were common in the Turonian
Turonian
The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous epoch, or a stage in the Upper Cretaceous series. It spans the time between 93.5 ± 0.8 Ma and 89.3 ± 1 Ma...
and Coniacian
Coniacian
The Coniacian is an age or stage in the geologic timescale. It is a subdivision of the Late Cretaceous epoch or Upper Cretaceous series and spans the time between 89.3 ± 1 Ma and 85.8 ± 0.7 Ma...
epochs, but Puertasaurus lived in 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 very last stage of the Late Cretaceous, when the much smaller Saltasaurids
Saltasauridae
Saltasauridae is a family of titanosaurian dinosaurs known from the late Cretaceous period of South America, Spain, Madagascar and Mongolia....
were the most common titanosaur group.