Alamosaurus
Profile Format
Scientific Classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Sauropodomorpha
Clade: Sauropoda
Clade: Macronaria
Clade: Titanosauria
Clade: Lithostrotia
Family: Saltasauridae
Subfamily: Opisthocoelicaudiinae
Genus: Alamosaurus
Type Species: Alamosaurus sanjuanensis
Described by Charles Whitney Gillmore, 1922
Current Park Population: (1; 1 adult; 1 male)
Park Diet: Elephant feed, rhino feed, conifer leaves, tree ferns, ginkgoes, apples, and lettuce.
Natural Diet: conifer leaves, tree ferns, and ginkgoes.
Lifespan: 70 years.
Habitat: Open areas like coastal floodplains, fern prairies, and open-canopy forests with large amounts of food.
Native Ecosystem: Western North America, on what was then an island continent known as Laramidia. North Horn Formation, Black Peaks Formation, El Picacho Formation, Ojo Alamo Formation, Javelina Formation, Evanston Formation, and possibly Hell Creek Formation, Utah, New Mexico, Texas, and possibly Montana, South Dakota, Wyoming, Colorado, s USA, 70-66 Million Years Ago, Maastrichtian Stage.
Breeding Season: June-July.
Gestation Period: seven-eight months.
Eggs Laid: 20-40 eggs.
Hatching Time: five to seven weeks.
Danger Level: 5 out of 10.
Summary: When people think of large dinosaurs, it's mostly the large long-necked titanic sauropod dinosaurs. These include icons like Apatosaurus, Brontosaurus, Diplodocus, Brachiosaurus, Argentinosaurus, and Dreadnoughtus. The Alamosaurus is unique as its the largest land dinosaur in North America and the only known sauropod to have inhabited North America after its nearly 30-million-year absence from the North American fossil record and probably represents an immigrant from South America in the Maastrichtian stage.
Description: The Male description of Alamosaurus almost resembles a brachiosaurus but lacks the distinct bump on its head, it was long, flat more of a titanosaur, with a thick, robust neck, It had gray dermal armor on its neck, body, and tail, The male has a row of gray long narrow spines down the back of its neck to the tip of their tails even their undersides with the longer spines near the head, two pair ventral rows of smaller spines on the lower half of its neck and towards the base of the tail, its hind legs had three sprawling claws, and one spike thumb on its front legs, It had black stripes on its legs, tail, neck, head, and upper portion of its body, the rest of the body and light underbelly was spotted, the upper portion was dark gray the neck to the base of the tail grading to a normal gra to the rest of the body, the neck and head region was lighter gray, a pair row of medium protrusions on their necks called cornified calluses, a black stripe and bright orange throat, and rows of yellow-orange of ballon gular air sacs when inflated, reddish-orange eye rings, and red nasal sacs with black stripes, the snout had a keratin beak similar to a turtle or tortoise and had thin hair-like filament over the top portion of its body similar to an elephant.
"Later detailed information descriptions on the Adult females, juveniles, and hatchlings of Alamosaurus sanjaunensis will be later added." - Lisa Loud.
Alamosaurus was a gigantic quadrupedal herbivore with a long neck, long tail, and relatively long limbs. Its body was at least partly covered in bony armor.
Size: In 2012, Thomas Holtz gave a total length of 30 meters (98 ft) or more and an approximate weight of 72.5–80 tonnes (80–88 short tons) or more. Though most of the complete remains come from juvenile or small adult specimens, three fragmentary specimens (SMP VP−1625, SMP VP−1850, and SMP VP−2104) suggest that adult Alamosaurus could have grown to enormous sizes comparable to the largest known dinosaurs, like Argentinosaurus, which has been estimated to weigh 73 metric tons (80 short tons). Scott Hartman estimates Alamosaurus, based on a huge incomplete tibia that probably refers to it, being slightly shorter at 28–30 m (92–98 ft) and equal in weight to other massive titanosaurs, such as Argentinosaurus and Puertasaurus. It is currently the only titanosaur known from North America. However, he says that, at the moment, scientists do not know whether the massive tibia belongs to an Alamosaurus or a completely new species of sauropod.
In 2019, Gregory S. Paul estimated SMP VP−1625 at 27 tonnes (30 short tons) and he also mentioned a large partial anterior caudal vertebra that suggests an Alamosaurus specimen that is 15 percent dimensionally larger and with similar mass to his Dreadnoughtus estimation of 31 tonnes (34 short tons). In 2020, Molina-Perez and Larramendi estimated the size of the largest individual at 26 meters (85.3 ft) and 38 tonnes (42 short tons).
Skeleton: Though no skull has ever been found, rod-shaped teeth have been found with Alamosaurus skeletons and probably belonged to this dinosaur. The vertebrae from the middle part of its tail had elongated centra. Alamosaurus had vertebral lateral fossae that resembled shallow depressions. Fossae that similarly resemble shallow depressions are known as Saltasaurus, Malawisaurus, Aeolosaurus, and Gondwanatitan. Venenosaurus also had depression-like fossae, but its "depressions" penetrated deeper into the vertebrae, were divided into two chambers, and extended farther into the vertebral columns. Alamosaurus had more robust radii than Venenosaurus.
History: Alamosaurus remains have been discovered throughout the southwestern United States. The holotype was discovered in June of 1921 by Charles Whitney Gilmore, John Bernard Reeside, and Charles Hazelius Sternberg at the Barrel Springs Arroyo in the Naashoibito Member of the Ojo Alamo Formation (or Kirtland Formation under a different definition) of New Mexico. This formation was deposited during the Maastrichtian age of the Late Cretaceous period. Bones have also been recovered from other Maastrichtian formations, like the North Horn Formation of Utah and the Black Peaks, El Picacho, and Javelina Formations of Texas. Undescribed titanosaur fossils closely associated with Alamosaurus have been found in the Evanston Formation in Wyoming. Three articulated caudal vertebrae were collected above Hams Fork and are housed at the Museum of Paleontology, University of California, Berkeley. However, these specimens have not been described.
Smithsonian paleontologist Gilmore originally described holotype USNM 10486, a left scapula (shoulder bone), and the paratype USNM 10487, a right ischium (pelvic bone) in 1922, naming the type species Alamosaurus sanjuanensis. Contrary to popular assertions, the dinosaur is not named after the Alamo in San Antonio, Texas, or the battle that was fought there. The holotype, the specimen the name was based on, was discovered in New Mexico and, at the time of its naming, Alamosaurus had not yet been found in Texas. Instead, the name Alamosaurus comes from Ojo Alamo, the geologic formation in which it was found and which was, in turn, named after the nearby Ojo Alamo trading post. Since this time, there has been some debate as to whether to reclassify the Alamosaurus-bearing rocks as belonging to the Kirtland Formation or if they should remain in the Ojo Alamo Formation. The term alamo itself is a Spanish word meaning "poplar" and is used for the local subspecies of the cottonwood tree. The term saurus is derived from saura (σαυρα), the Greek word for "lizard", and is the most common suffix used in dinosaur names. There is only one species in the genus, Alamosaurus sanjuanensis, which is named after San Juan County, New Mexico, where the first remains were found.
In 1946, Gilmore posthumously described a more complete specimen, USNM 15660, found on June 15, 1937, on the North Horn Mountain of Utah by George B. Pearce. It consists of a complete tail, a complete right forelimb (except for the fingers, which later research showed do not ossify with Titanosauridae), and both ischia. Since then, hundreds of other bits and pieces from Texas, New Mexico, and Utah have been referred to as Alamosaurus, often without much description. Despite being fragmentary, until the second half of the twentieth century, they represented much of the globally known titanosaurid material. The most completely known specimen, TMM 43621–1, is a juvenile skeleton from Texas that allowed educated estimates of length and mass. Some blocks cataloged under the same accession number as the relatively complete and well-known Alamosaurus specimen USNM 15660 and found in very close proximity to it based on bone impressions were first investigated by Michael Brett-Surman in 2009. In 2015, he reported that the blocks contained osteoderms, the first confirmation of their existence in Alamosaurus.
The restored Alamosaurus skeletal mount at the Perot Museum was discovered when student Dana Biasatti, a member of an excavation team at a nearby site, went on a hike to search for more dinosaur bones in the area.
Classification:
In 1922, Gilmore was uncertain about the precise affinities of Alamosaurus and did not determine it any further than a general Sauropoda. In 1927, Friedrich von Huene placed it in Titanosauridae.
Alamosaurus was, in any case, an advanced and derived member of the group Titanosauria, but its relationships within that group are far from certain. The issue is further complicated by some researchers rejecting the name Titanosauridae and replacing it with Saltasauridae. One major analysis unites Alamosaurus with Opisthocoelicaudia in the subgroup Opisthocoelicaudiinae of Saltasauridae. A major competing analysis finds Alamosaurus as a sister taxon to Pellegrinisaurus, with both genera located just outside Saltasauridae. Other scientists have also noted particular similarities with the saltasaurid Neuquensaurus and the Brazilian Trigonosaurus (the "Peiropolis titanosaur"), which is used in many cladistic and morphologic analyses of titanosaurians. A recent analysis published in 2016 by Anthony Fiorillo and Ron Tykoski indicates that Alamosaurus was a sister taxon to Lognkosauria and therefore to species such as Futalognkosaurus and Mendozasaurus, laying outside Saltasauridae (possibly being descended from close relations to the Saltasauridae), based on synapomorphies of cervical vertebral morphologies and two cladistic analyses. The same study also suggests that the ancestors of Alamosaurus hailed from South America instead of Asia.
Age: Alamosaurus fossils are most notably found in the Naashoibito member of the Ojo Alamo Formation (dated to between about 69–68 million years old) and in the Javelina Formation, though the exact age range of the latter has been difficult to determine. A juvenile specimen of Alamosaurus has been reported to come from the Black Peaks Formation, which overlies the Javelina in Big Bend, Texas, and also straddles the Cretaceous-Paleogene boundary. The Alamosaurus specimen was reported to come from a few meters below the boundary, dated to 66 million years ago, though the position of the boundary in this region is uncertain. Only one geological site in the Javelina Formation has yielded the correct rock types for radiometric dating so far. The outcrop, situated in the middle strata of the formation about 90 meters (300 ft) below the K-Pg boundary and within the local range of Alamosaurus fossils, was dated 69.0±0.9 million years old in 2010. Using this date, in correlation with a measured age from the underlying Aguja Formation and the likely location of the K-Pg boundary in the overlying Black Peaks Formation, the Alamosaurus fauna seems to have lasted from about 70–66 million years ago, with the earliest records of Alamosaurus near the base of the Javelina formation and the latest just below the K-Pg boundary in the Black Peaks Formation.
Paleobiology
Social Behavior: It is believed Alamosaurus live in small loosely-knitted herds often with a female Matriarch, although some are solitary individuals.
Diet: Being a sauropod, they mostly feed on the tops of tall trees like conifers and ginkgoes which are out of reach of other herbivores.
Biogeography: Alamosaurus is the only known sauropod to have lived in North America after the sauropod hiatus, a nearly 30-million-year interval for which no definite sauropod fossils are known from the continent. The earliest fossils of Alamosaurus date to the Maastrichtian age, around 70 million years ago, and it rapidly became the dominant large herbivore of southern Laramidia.
The origins of Alamosaurus are highly controversial, with three hypotheses that have been proposed. The first of these, which has been termed the "austral immigrant" scenario, proposes that Alamosaurus is descended from South American titanosaurs. Alamosaurus is closely related to South American titanosaurs, such as Pellegrinisaurus. Alamosaurus appears in North America at the same time that hadrosaurs closely related to North American species first appear in South America, suggesting that the Alamosaurus lineage crossed into North America on the same routes as hadrosaurs crossed into South America. The Austral immigrant hypothesis has been challenged because the routes connecting North and South America during the Maastrichtian may have consisted of separate islands, which would have presented challenges to the dispersal of titanosaurs. A second scenario termed the "inland herbivore" scenario, suggests that titanosaurs were present in North America throughout the Late Cretaceous and that their apparent absence reflects the relative rarity of fossil sites preserving the upland environments that titanosaurs favored, rather than their true absence from the continent. However, there is no evidence for sauropods in North America between the mid-Cenomanian and the early Maastrichtian, even in strata that preserve more upland environments, and the sauropods that lived in North America before the hiatus are basal titanosauriforms, such as Sonorasaurus and Sauroposeidon, not lithostrotian titanosaurs. A third option is that, as in the austral immigrant scenario, Alamosaurus is not native to North America, but originated in Asia instead of South America. Alamosaurus is commonly considered to be closely related to the Asian titanosaur Opisthocoelicaudia, but this is based on analyses that did not take Alamosaurus's South American relative Pellegrinisaurus into account. Though many dinosaurs crossed between Asia and North America across the Bering land bridge, sauropods were poorly adapted for high-latitude environments and Beringia would have been an inhospitable environment for titanosaurs. Furthermore, to reach southern Laramidia from Asia, Alamosaurus would have had to cross through Northern Laramidia, which contains no known sauropod fossils of comparable age to Alamosaurus, despite containing the best-studied dinosaur faunas on the continent. Overall, a South American origin has been favored by several studies and was regarded as "the only viable origin" for Alamosaurus by Chiarenza et al.
Based on our observation, a single adult male was sighted in the Hell Creek Formation outside their native range in the south, it could be possible the individual represents a migrant vagrant that has gotten lost in the mazes and valleys of the newly forming Rocky Mountain Range that divides the northern and southern portions of North America.
Paleoecology: Skeletal elements of Alamosaurus are among the most common Late Cretaceous dinosaur fossils found in the United States Southwest and are now used to define the fauna of that time and place, known as the "Alamosaurus fauna". In the south of Late Cretaceous North America, the transition from the Edmontonian to the Lancian faunal stages is even more dramatic than it was in the north. Thomas M. Lehman describes it as "the abrupt reemergence of a fauna with a superficially 'Jurassic' aspect. These faunas are dominated by Alamosaurus and feature abundant Quetzalcoatlus in Texas. The Alamosaurus-Quetzalcoatlus association probably represents semi-arid inland plains.
Contemporaries of Alamosaurus in the American southwest include unidentified tyrannosaurids similar to Tyrannosaurus, the oviraptorosaur Ojoraptorsaurus, the hadrosaurid Kritosaurus, the armored nodosaur Glyptodontopelta, and the chasmosaurine ceratopsids cf. Torosaurus utahensis, Bravoceratops, and Ojoceratops. Non-dinosaur taxa that had shared the same environment with Alamosaurus include the giant azhdarchid pterosaur Quetzalcoatlus, various species of fishes and rays, amphibians, lizards, turtles like Adocus, and multiple species of multituberculates like Cimexomys and Mesodma.
Interactions with other species: Vagrant individuals are often sighted with Edmontosaurus, Triceratops, Ornithomimus, Torosaurus utahensis, Thescelosaurus, and Ankylosaurus in the Hell Creek Formation. In their native range, they would form mixed species herds with Torosaurus utahensis, Bravoceratops, and Glyptodontopelta. Their long necks provide a lookout for predators and when sighted, the Alamosaurus would rumble to let everyone know of the predators and to flee.
Most media depicts Tyrannosaurus living and battling sauropods like Brontosaurus, Apatosaurus, and Brachiosaurus, the Alamosaurus is the only sauropod that lived alongside T. Rex, a full-grown adult has no threats from them, only the weak, sick, and young are vulnerable to attacks. A desperate pack of T. Rex would try to take down an adult Alamosaurus, although the Alamosaurus would fight back with its tail and strong forelimbs to slam a Tyrannosaur down.
Dakotaraptor, Dromaeosaurus, Acheroraptor, and Pectinodons would never attack an Alamosaurus vagrant.
Extinction: Alamosaurus was also one of the last sauropods ever to live when the Cretaceous-Paleocene Extinction event came. Specimens of a juvenile Alamosaurus sanjuanensis have been recovered from only a few meters below the Cretaceous-Paleogene boundary in Texas, making it among the last surviving non-avian dinosaur species. Without full-grown trees and vegetation along with their large size, they are the first dinosaurs to die out.
Danger Tip: They are mostly gentle giants, but they can be dangerous unless you get trampled by one you don't get out of their way.
Significant Events: This dinosaur is special because it's the first dinosaur to be brought back to Paleo Park,A male Vagrant Alamosaurus was sighted on the Rescue Team's second day alongside other herbivores including Triceratops, Torosaurus, Ornithomimus, Edmontosaurus, and Thescelosaurus gathered at a clearing with a creek close to camp during Day 2 of the Rescue Team's First Mission. The Next day, a pack of Tyrannosaurus attacked the multi-species herd leaving only the Alamosaurus behind. The pack turns to the sauropod in a last-ditch attempt as they attack the giant as the long neck dinosaur fights back. Charlie and Mallow waved a flag at the Sauropod to get its attention and it charges into the Time portal. This individual now resides in the Hell Creek Herbivore Paddock.
Hell Creek Herbivore Paddock: The Alamosaurus lives alongside the other herbivores including Triceratops, Torosaurus, Edmontosaurus, Ankylosaurus, and Ornithomimus in the large multi-species paddock. The Alamosaurus is often seen among the other herbivores for company. There are plans to rescue more individuals for Paleo Park.
Notable Individuals:
Custer: He is a male Alamosaurus named after Geroge Armstrong Custer, and the first dinosaur to be brought back to Paleo Park. He is a wise and gentle giant, most of the dinosaurs in the paddock see him as their leader.
Conclusion: Alamosaurus may not share the fame as their other sauropod relatives, but this dinosaur will play an important role from the very start of Paleo Park and will be enjoyed by millions who come and see this majestic giant.
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