▷ Alamosaurus – Resumenea

NameAlamosaurus sanjuanensis SizeLarge EraMesozoic PeriodCretaceous DietHerbivoreHabitatNorth America NatureAquatic

What is an Alamosaurus?

Alamosaurus was a sauropod, possibly the only one that lived in North America during the late Cretaceous period. It is believed to have been one of the last large sauropods to exist before the great mass extinction that ended the age of dinosaurs at the end of the Cretaceous.

It had its first description in 1922 by Charles Whitney Gilmore, who studied a shoulder blade and a pelvic bone. Several years later, in 1946, he found a more complete specimen in the state of Utah, which included a complete tail, a right front leg and both pelvises.

Since that time, many other finds that occurred in Texas, Utah and New Mexico have been attributed to this species, in many cases without an adequate description. The most notable case was that of a skeleton of a juvenile Alamosaurus that was in quite favorable condition.

It was found by Lehman & Coulson in 2002 in Texas and allowed specialists to draw more precise conclusions about how large an adult specimen could have been.. It consisted of isolated vertebrae and bones in the extremities.

It is estimated that its size was quite close to that of specimens such as Argentinosaurus and Puertasaurus. This places it as the largest species that has ever lived in North America, as far as what has been discovered today.

Alamosaurus discovery

The first discovery of Alamosaurus was in 1922 in the Oja Alamo Formation, better known as the Kirtland Formation. They found a scapula and both parts of the pelvic girdle. These were found in the Naashoibito Member in the corresponding rock formation.

Charles Whitney Gilmore found bone fragments in the North Horn Formation in Utah in 1946. They were the coccygeal vertebrae, the tail vertebrae, both hip bones and a right forelimb that was in excellent condition. He attributed it to this species.

These middle coccygeal vertebrae had elongated central and lateral fossae that resembled those of Saltasaurus and Malawisaurus. But these did not offer sufficient evidence to establish the characteristics of Alamosaurus.

In the 200s a juvenile specimen was found in the Black Peaks Formation in Texas that was also assigned to Alamosaurus. It is the most complete fossil found of this species that has been found today.

This did meet the necessary qualities to calculate the size of the dinosaur, so it is thought that it was practically as big as the titanosaurus known from South America. Bones from his skull have not yet been found, although some loose teeth have been found.

Charles Whitney Gilmore

The person mainly responsible for us knowing the Alamosaurus was the paleontologist Charles Whitney Gilmore. He was a vertebrate paleontologist who spent 40 years at the Smithsonian Institution. He classified and described numerous dinosaurs such as Alamosaurus, Apatosaurus, Brachyceratops, and Diplodocus among others.

He began classifying the bones that Othniel Charles Marsh obtained in the competition he had with Edward Drinker Cope in what was known as the bone war. He conducted numerous excavations at the command of the Smithsonian Institution and launched numerous important exhibits, such as the Diplodocus longus. During his career he published almost 200 scientific articles. The torture was named Gilmoermys in his honor.

What does Alamosaurus mean?

This dinosaur was named based on the place where the first specimen was found, which was the Ojo Alamo Formation. In some publications it is stated that it bears the name Alamo Fort in Texasor even that it was named after the city Alamo Mission from San Antonio. But none of these statements are true.

The suffix is added to the term saurus that comes from sauros which in Greek is lizard. This is how the nickname is formed Alamosaurus which translates as poplar lizard.

The epithet sanjuanensis It was chosen based on San Juan County, New Mexico, which was also the area where his remains were first found. This was Charles Gilmore’s choice when he appointed him in 1922.

The suborder Sauropodomorpha

The Alamosaurus is located within the Sauropodomorpha. This is a suborder that translates as lizard legs and it is in which the first dinosaurs are registered. Its oldest representatives are Chromogisaurus, Pampadromeaeus, Panphagia and Chromogisaurus, which lived in the Triassic period from 230 to 217 million years BC.

They had a small and narrow skull, along with curved and downward dentition in the jaw, more specifically in the frontal area. These were shaped like a pin. They also had a crest on top.

Its spinal column had a minimum of 10 vertebrae, and the length of each one was twice its width.. They walked on two legs and on four, but over time they lost this ability and in the end they were exclusively quadrupeds.

They were very well adapted to their environmental and feeding conditions. Due to their characteristics, they ate from the high foliage of the treetops. Their skull was generally small and located at the end of a high neck, they had a long tail that served as a counterweight.

Their teeth were narrow and shaped like a leaf or even a spoon.. These only served to tear off the plant matter and ingest it. They did not chew it, because to process it they used gastroliths (stones that they swallowed) that were very useful for the digestive process.

One of the first specimens of the species was the Saturnalia, which was initially small and slender. But at the end of the Cretaceous they were already the largest of their time. In the Jurassic, species such as Argentinosaurus, Diplodocus and Supersaurus thrived, which could measure around 40 meters long, and weighed 50 tons on average.

Their first definition was stated by Salgado in 1997. He established that they were the last common ancestor of the Prosauropoda and the Sauropoda, of all their descendants. For his part, Upschurch defined them as a group formed by the Prosauropoda, Sauropoda and the Saurischia, with a closer relationship to this group than to birds.

Later in 1998 Paul Sereno said that it was the common ancestor of Plateosaurus, Saltasaurus and all their descendants. Galto and Upschurch in 2004 described them as a group consisting of Saltasaurus and all species more closely related to Saltasaurus than to theropods.

In 2005 Paul Sereno offered a definition that was more closed and excluded ornithischia. He alludes to the possibility that the Sauropodomorpha established a group through the Phyto Dinosauria and the Theropoda, forming the Saltasaurus loricatus and all species most closely related to Saltasaurus. Such is the case of the house sparrow Passer domesticus or the triceratops horridus.

Characteristics of the Alamosaurus

The Alamosaurus was one of the largest dinosaurs in prehistory. It fed on the tops of trees and, as was the case with Titanosaurus It had a long neck and a very extensive tail. Specialists have been able to determine the following characteristics of it.

Classification

This species is located in the Sauropodomorpha suborder, and within this in the Titanosauria. In turn, it is among the Saltasauridae. Titanosaurus were the large sauropods that existed on Earth from the last phase of the Jurassic, until the end of the Cretaceous.

We must not leave aside that it includes the subfamily Opisthocoelicaudiinae, which included titanosaurus that did not have wrist and finger bones. That is why Alamosaurus lacked phalanges in its remains.

Feeding

The teeth found from the Alamosaurus were the same type that large sauropods used to have. The front ones were spatula-shaped. YesIts very long neck allowed it to eat from the high crowns of trees.. However, it is also believed that he ingested aquatic plants, submerged to a certain depth.

It is thought that they ate palm trees, magnolias and conifers. Their long necks would also have helped them ingest sycamore trees and even fern seeds.

Habitat

Specialists claim that it was a migratory dinosaur, so its habitat could be varied. She could live in different regions. These could include the forested regions of North America, which had low and tall vegetation. They may also have lived on semi-arid plains with intermittent water present in the form of lakes and swamps.

Description

The Alamosaurus was undoubtedly one of the largest dinosaurs in prehistory. It averaged 16 meters in length from head to tail. Some paleontologists claim that it could be up to 24 meters long. With its neck held high, its height was between 9 and 12 meters.

Estimates of its volume tend to be more varied. Many claim that it weighed 27 tons. But others instead They think that it was actually around between 50 and 60 tons..

Its neck was very extensive and covered 1/3 of its total length. Its head was small as is usual in titanosaurs. It had thick, muscular legs, and its long tail was strong at the base and narrower and more agile at the end.

Paleontologists believe that it was armored, due to the close relationship with the Saltasaurus that had this quality. Added to this is the fact that the juvenile specimen, which was the last to be found, showed evidence of possessing this particularity.

Possibly it would be a protective layer made of bone deposits under the skin in the form of scales or plates, similar to those worn by crocodiles today.

However, because said armor would be embedded in soft tissue, it is not possible to know for sure.

When he lived

The study of its fossil remains places Alamosaurus among the 72 and 66 million years BCtowards the end of the Cretaceous.

Who did he live with?

They were migratory dinosaurs and moved long distances in herds of about 1,000 individuals that included adults and juveniles. In this way they protected themselves against possible predators.

Reproduction

These huge sauropods reproduced by laying eggs after the mating period. It is possible that their armor played a role for the males in attracting the female.

Charles Whitney Gilmore suggested that they laid their eggs in clutches, and that care depended largely on the female, who was in charge of the juveniles or hatchlings.

Behavior

There is no indication that these enormous…