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I Know Dino Podcast: Alamosaurus

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    Episode 51 is all about Alamosaurus, the one recognized sauropod to reside within the Cretaceous in what’s now North America.

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    On this episode, we talk about:

    • The dinosaur of the day: Alamosaurus
    • Identify means “Ojo Alamo lizard”
    • Just one species: Alamosaurus sanjuanensis

    • Holotype present in June 1921, by Charles Gilmore, John Reeside and Charles Sternberg within the Ojo Alamo Formation of New Mexico (some name it the Kirtland Formation); different bones since present in Utah and Texas (juvenile present in Texas)
    • Gilmore described the species in 1922 and named it (NOT named after the Alamo in San Antonio, Texas, or after the battle there); when it was named, Alamosaurus bones had not but been present in Texas
    • Identify comes from Ojo Alamo, the geologic formation the place the bones had been discovered (which was named after the Ojo Alamo buying and selling put up); some debate although over whether or not to reclassify the world because the Kirtland Formation or keep the Ojo Alamo Formation

    • In Spanish the phrase alamo means “poplar”, which is the native cottonwood tree
    • Sanjuanensis is called after San Juan County, New Mexico the place the bones had been discovered
    • Gilmore posthumously described a extra full Alamosaurus in 1946, that was present in 1937 (in Utah, by George Pearce); discovered a whole tail, proper forelimb (no fingers)

    • Since then, a whole lot of items of fossils present in Texas, New Mexico and Utah have been known as Alamosaurus
    • Fossils have been discovered of a juvenile and three fragmentary specimens
    • Not any actually full specimens have been discovered (tends to be extra widespread to search out juveniles as a result of sediment covers smaller our bodies extra simply)

    • Most full specimen is the juvenile present in Texas
    • Bits of Alamosaurus skeletons are a number of the most typical finds of late Cretaceous fossils within the southwest of the U.S., and are used to assist outline the fauna from then, referred to as the “Alamosaurus fauna”
    • Discovered vertebrae and limb bones, which present it was across the identical measurement as Argentinosaurus and Puertasaurus (would be the largest recognized dinosaur in North America); could have weighed as a lot as 73 tons

    • Dana Biasetti, a grad scholar from the College of Texas in Dallas, discovered pelvic bones and ten articulated cervical vertebrae of an grownup Alamosaurus in 1999 within the Javelina Formation of Massive Bend Nationwide Park (“Massive Bend Alamosaurus“); could have been as much as 100 ft lengthy and weighing over 50 tons
    • Earlier than, estimate was about 65 ft or 20 m lengthy (based mostly on juvenile skeleton and partial grownup skeletons)
    • The bones had been so giant and the world so distant that Massive Bend Nationwide Park issued a allow to take away the bones through helicopter, and in 2001 it was the primary “dinosaur airlift”

    • Holly Woodward in 2009 discovered that the femur of an Alamosaurus bone was nonetheless rising, so researchers knew it received larger
    • Alamosaurus lived within the Cretaceous in North America
    • There’s a 30 million yr hole the place sauropods appear to have died out in North America and when Alamosaurus appeared

    • Sauropods appear to have been extra widespread on the finish of the Jurassic (as a substitute of Cretaceous); however may very well be we simply haven’t discovered the fossils of extra sauropods but (some sauropods from the Cretaceous in North America embrace Astrodon, Sauroposeidon and Cedarosaurus
    • Alamosaurus could show immigration from South America (seems and is dominant in North America abruptly). Some scientists suppose it emigrated from Asia, nevertheless it’s unlikely they crossed our bodies of water. Might have descended from North American family members, since there have been early Cretaceous titanosaurs within the space
    • Alamosaurus could have come from Asia crossing the Bering Strait land bridge (Alamosaurus is a part of the Opisthocoelicaudiinae group of titanosaurs, and the sort genus of that group is from Asia). However this group can also be inside Saltasauridae, and Alamosaurus has so much in widespread with Saltasaurus (so could have come from South America, although South America was most likely separated from North America by an ocean within the Cretaceous; additionally, different South American dinosaurs like abelisaur theropods, not present in North America, and North American tyrannosaurs not present in South America

    • Could possibly be convergent evolution as a substitute
    • One research discovered that as many as 350,000 Alamosaurus could have lived in Texas (space) at any given time
    • Quadrupedal, with an extended neck and tail and lengthy limbs

    • Had some bony armor
    • In 2015, Michael Brett-Surman confirmed (nased on findings in 2009) that blocks of bone impressions containe osteoderms
    • Osteoderms: bony plates on the pores and skin (present in different titanosaurs)

    • No cranium discovered, however rod-shaped tooth have been discovered close by Alamosaurus skeletons (so most likely Alamosaurus tooth)
    • Dinosaurs that lived alongside Alamosaurus included tyrannosaurs, smaller theropods, hadrosaurs, ankylosaurs, and ceratopsids
    • Juvenile Alamosaurus could have been prey to tyrannosaurs like Daspletosaurus and Bistahieversor (although grownup would have been too giant)

    • Alamosaurus seems in PBS Children’ Keep in mind the Alamosaurus
    • Gilmore solely categorized it as a common sauropod (wasn’t certain in 1922 about different classifications); Friedrich von Huene categorized it as a Titanosaur in 1927
    • Nonetheless, unclear the place precisely it falls within the Titanosaur group

    • Titanosaurs had been a bunch of sauropods, and a number of the heaviest land animals
    • Argentinosaurus is estimated to have weighed as much as 90 tons
    • They’re named for the now doubtful genus Titanosaurus (after the Titans of historical Greece)

    • Not all paleontologists contemplate it a bunch, as a result of Titanosaur is doubtful
    • Final group of sauropods
    • Widespread, lived in Antarctica and Australia and NewZealand

    • Titanosaurs had small heads, even for sauropods (additionally large heads)
    • Fragmentary fossils, and never many skulls discovered
    • Giant nostrils, and crests fashioned by nasal bones

    • Had small tooth (spoon like or pegs or pencil like)
    • Whip like tails (however not so long as diplodocids)
    • Had wider chests than most sauropods and a large stance

    • Stocky forelimbs longer than hind limbs
    • Pores and skin impressions present they could have had bead like scales, and even bony plates like ankylosaurs
    • A titanosaur nesting floor was present in Argentina and Spain (a number of hundred holes with clutches, round 25 eggs in every clutch)

    • Enjoyable reality: In Jurassic World, there’s a line on the finish of the film the place the boy Grey is including up tooth of the combating dinosaurs and says “we’d like extra tooth.” If that had been the case, he ought to have gotten a hadrosaur concerned, as a result of they may have nearly 1,000 tooth, in comparison with T-rex which solely had about 60.



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