BRACHYTRACHELOPAN “Short-necked Pan” Late Jurassic, 150 million years ago (uncertain)
This unique sauropod measured only 30 feet in
length. It set itself apart from its relatives with its unusually short neck – less
than a quarter of its body length. While species like Diplodocus evolved longer and longer necks along the course of the evolutionary
arms race, Brachytrachelopan practiced
an adaptation strategy commonly known as “giving up.”
AMARGASAURUS “La Amarga lizard” Early Cretacous, 129.4-122.46 million years ago
Amargasaurus was not large compared to its sauropod
relatives; it grew to only about 33 feet in length. It stood out, however,
because of its double row of long vertebral spines. Some experts have
interpreted these spines as supporting sails, much like Spinosaurus, and others have suggested they were for thermoregulation.
The current consensus is that Amargasaurus clattered the spines together as a sound display, making it the annoying
toddler of the sauropod world.
A new sauropod has been named, and it has been named Dreadnoughtus. Why would anyone name a terrestrial animal that? Maybe a massive mosasaur or shark, but not a sauropod. Sigh. At least it’s not Dracorex hogwartsia.
GIRAFFATITAN “Giant giraffe” Late Jurassic, 150-145 million years ago
Originally classified as a species of Brachiosaurus, this massive sauropod (of the titanosaur family) grew up to 74 feet long! For several decades it was the largest dinosaur known. Although it may have since been eclipsed in size, this majestic creature retains the dignity of dying before hearing itself called “Giraffatitan.”
Pantydraco was another sauropomodomorph dinosaur from the Late Triassic, specifically the Rhaetian age, and potentially into the early Jurassic, around 208 to 200 million years ago. It was originally described as a species of Thecodontosaurus and was only known from a skull and partial skeleton of a juvenile individual. However, understanding basal sauropodomorphs more lead to its reclassification and its own genus. It was probably an omnivore, and mostly bipedal. It was found in the Pantyffynnon quarry of Wales in the United Kingdom.
For the last 75 years or so, Australia has been a relative wasteland when it comes to sauropod discoveries.
That all changed in 2009, with the announcement of not one, but two new sauropod genera: Diamantinasaurus and Wintonititan, comparably sized titanosaurs
represented by sparse fossil remains. Like most titanosaurs,
Wintonititan probably had a rudimentary layer of armored skin along its
back, the better to deter the large, hungry theropods
of its Australian ecosystem. (As to how titanosaurs wound up in
Australia in the first place, tens of millions of years ago, this
continent was part of the giant landmass Pangaea.)
CAMARASAURUS “Chambered lizard” Late Jurassic, 155-145 million years ago
Camarasaurus had a domed skull like Brachiosaurus, but the “chambers” referred to in its name are actually
in its backbone – hollow vertebrae housed air sacs that reduced weight and helped
such a large animal move. Its strong teeth would have been excellent for grinding
tough vegetation, allowing it to occupy an ecological niche separate from its
slender-toothed contemporary, Diplodocus.
In fact, Camarasaurus was the most
common sauropod of the Jurassic, and familiarity breeds contempt.
BAROSAURUS “Heavy lizard” Late Jurassic, 152-150 million years ago
Although its neck was
longer and its tail was shorter, Barosaurus
was roughly the same size as its close relative Diplodocus. It was dubbed “Heavy lizard” because at 85 feet long
and 20 tons, this powerful plant-eater still couldn’t escape reductive ideals of
PLATEOSAURUS “Broad lizard” Triassic, 214-204 million years ago
Plateosaurus is considered a basal (basic/early) sauropodomorph (long-necked, quadrupedal herbivore like Diplodocus or Brachiosaurus). As such, many of its features make for an interesting crossroads in dinosaur evolution. One, it was still bipedal, probably only resting on its forelimbs while grazing. Two, it was almost certainly an herbivore (or omnivore), whereas its immediate ancestors were carnivorous. Three, it had bird-like air sacs in its bones, making it lighter and (at least partially) warm-blooded – traits otherwise recognized mostly in therapod dinosaurs. And four, it ranged in size widely – anywhere from 16 to 33 feet long for adults within the same species. While calling it a “missing link” between therapods and sauropods might be an exaggeration, it is safe to say that Plateosaurus couldn’t make up its damn mind.
Ruehleia was a basal sauropodomorph from the Norian age of the Late Triassic, somewhere between 216 and 203 million years ago. It is known from scattered remains including the neck, back and tail, and partially complete hands. It was found in the Trossingen Formation in Germany. It would have been about 8 meters long and still would have walked around bipedally, though it may have gone on all fours for feeding and drinking. Its diet, like that of all early sauropodomorphs, is under some debate - while it could have been herbivorous like its descendants, some early members of the group may have been omnivorous while transitioning to a primarily herbivorous lifestyle.
Plateosauravus was originally thought to be a species of Plateosaurus, however it was reassessed soon afterwards as a separate genus. As such, it was named in honor of the original genus; though it is unknown what its classification really is. It is known from more than a dozen partial skeletons, including juveniles. The exact age of the animal is unknown, however it did come from the Late Triassic. Furthermore, it was discovered in South Africa, including Kruger National Park.
Nambalia was a sauropodomorph discovered in Andhra Pradesh in central India. It lived between the late Norian and earliest Rhaetian ages of the Late Triassic, around 208 million years ago. It is known from scattered skeletal remains and no heads, though there is material from multiple individuals. It was more primitive than Efraasia, Plateosauravus and Ruehleia, but more derived than Thecodontosaurus and Pantydraco. It was found with the plateosaurid Jaklapallisaurus, a guaibasaurid, and two dinosauriforms.
Asylosaurus was a basal sauropodomorph from Durdham Down, Clifton, Bristol, in England. It lived in the Rhaetian age of the Late Triassic, between 208 and 201 million years ago. The original remains were attributed to Thecodontosaurus, but after review they were established as a new genus. These particular specimens had actually been shipped from England to the United States; leading to its name: if they had stayed in England, they would have been destroyed during the World War Two bombings. It differs from its contemporaries Thecodontosaurus and Pantydraco due to the structure of its upper arm; and may have occupied a separate ecological niche depending on whether it was omnivorous or herbivorous.
Pampadromaeus was a basal sauropodomorph from about 225 million years ago, in the Carnian age of the Late Triassic. It was found in the Alemoa Member of the Santa Maria Formation in Brazil. It is known from a partial, well preserved skeleton, including most of the skull. It was a small, bipedal animal, with a mixture of basal and more advanced traits. It even had some characters of theropods. It had large, elongated, slightly recurved teeth that were coarsely serrated. The lower leg was much longer than the thighbone, implying it was a good runner.