Euhelopus

Type Species: Euhelopus zdanskyi

Classification: Dinosauria – Saurischia – Sauropoda - Gravisauria - Eusauropoda - Neosauropoda – Macronaria – Titanosauriformes – Somphospondyli – Euhelopodidae

Time Period: Early Cretaceous

Location: China

Diet: Herbivore

The Chinese sauropod Euhelopus was the first Chinese dinosaur to be scientifically studied in 1923. It is the namesake for the family group of Euhelopopidae, all of which are found in East Asia. Euhelopus had longer forelegs than hindlegs, and it is one of the few sauropods found with a relatively complete skull. Euhelopus was a large-sized macronarian sauropod, weighing in between 17-22 tons and reaching up to 49 feet in length. 

Giraffatitan

Type Species: Giraffatitan brancai

Classification: Dinosauria – Saurischia – Sauropoda - Gravisauria - Eusauropoda - Neosauropoda – Macronaria – Titanosauriformes – Brachiosauridae

Time Period: Late Jurassic 

Location: Africa

Diet: Herbivore

Giraffatitan was originally thought to be a species of Brachiosaurus but has since been given freedom to stand on its own. It was one of the largest sauropods of the Late Jurassic, averaging between 72 and 74 feet in length but capable of reaching up to 85 feet snout-to-tail. Its neck, held vertical, reached up to forty feet in length. It had a giraffe-like build (hence its name) with long forelimbs and a long neck. It had chisel-like ‘spatulate’ teeth and the first three toes on its hind feet were clawed. Its distinctive high-crested skull was once thought to be characteristic of the brachiosaurids, to which Giraffatitan originally belonged; however, it’s possible that many brachiosaurs didn’t have this feature, since this feature is known only from African specimens now assigned to Giraffatitan – all this to say that the classic portrayal of Brachiosaurus may actually not represent Brachiosaurus at all, at least as far as the skull design goes. Like other sauropods, Giraffatitan had a sacral enlargement above the hip; scientists of an earlier age thought this housed a ‘second brain,’ given that sauropods had pretty small brains to begin with, but it’s know believed to be the location of glycogen bodies. Giraffatitan likely roamed the sweeping conifer forests of the Tendaguru Formation, avoiding the coastal environments of brackish coastal lakes, ponds, and pools where vegetation would be harder to come by. 

Giraffatitan’s nostrils were once thought to be located on the top of its head, lending earlier scientists to speculate that it was a water-dweller, snorkeling in the burgeoning North Atlantic. However, studies have shown that the water pressure placed on the rib cage would make it extremely difficult for a submerged Giraffatitan to breathe; extended time submerged would undoubtedly lead to drowning. Studies of the skull in 2001 suggested that while the nasal openings in the skull were above the eyes, this didn’t mean that the nostrils wouldn’t emerge at the tip of the snout. In this case, Giraffatitan’s tall ‘crests’ may have housed a fleshy resonating chamber. 

Australodocus

Type Species: Australodocus bohetii

Classification: Dinosauria – Saurischia – Sauropoda - Gravisauria - Eusauropoda - Neosauropoda – Macronaria – Titanosauriformes – Somphospondyli 

Time Period: Late Jurassic 

Location: Africa

Diet: Herbivore

The 56-foot-long and 8800-pound sauropod Australodocus was originally classified as a diplodocid but has since been reclassified as an early titanosauriform, making it more closely related to Brachiosaurus than Diplodocus. Australodocus is currently considered one of the first specimens of the somphospondyls, a sauropod lineage that would give birth in the Cretaceous to the larger-than-life armored titanosaur sauropods. This ‘large-nosed’ macronarian roamed the dense conifer forests of Africa’s Tendaguru Formation, separated to the south of North America by the widening strip of water that would eventually become the Atlantic Ocean. While the Morrison Formation in North America was dominated by diplodocids, the Tendaguru Formation was dominated by macronarians, likely as a result of the different environments. The Morrison was a savannah-like floodplain cut by lakes and rivers that were forested on the peripheries; the Tendaguru, however, was more densely-packed with thick conifer forests. The low-lying foliage of the Morrison was perfect eating for low-browsing diplodocids whereas macronarians with vertically-oriented necks did better with the plentiful trees of the Tendaguru. 

Lusotitan

Type Species: Lusotitan atalaiensis

Classification: Dinosauria – Saurischia – Sauropoda - Gravisauria - Eusauropoda - Neosauropoda – Macronaria – Titanosauriformes – Brachiosauridae

Time Period: Late Jurassic 

Location: Europe 

Diet: Herbivore

The Late Jurassic sauropod Lusotitan lived in prehistoric Portugal as part of Portugal’s Lourinha Formation, which resembled North America’s Morrison Formation and which emerged as a result of the genesis of the Atlantic Ocean. This brachiosaurid was related to the North American Brachiosaurus, and it grew up to seventy to eighty feet in length. Lusotitan walked on four pillar-like legs; its front legs were longer than its back legs, so that its body sloped downwards towards its short tail. Some scientists believe it could rear back on its hind legs to reach super high foliage, though some believe it kept its four legs on the ground at all times. Lusotitan’s neck reached vertical rather than horizontal like diplodocids. This gave it a feeding advantage: whereas most of its sauropod contemporaries were low-browsing diplodocids, Lusotitan could browse foliage up to fifty feet off the ground to feed on high conifers and ginkgoes. It undoubtedly practiced niche partitioning alongside the low-browsing diplodocid Dinheirosaurus. As part of the Lourinha Formation, it also lived alongside large predators such as Allosaurus and Torvosaurus, stegosaurs such as Dacentrurus and Miragaia, the early ankylosaur Dracopelta, and numerous early ornithopods. 

Brachiosaurus

Type Species: Brachiosaurus altithorax

Classification: Dinosauria – Saurischia – Sauropoda - Gravisauria - Eusauropoda - Neosauropoda – Macronaria – Titanosauriformes – Brachiosauridae

Time Period: Late Jurassic 

Location: United States and Europe

Diet: Herbivore 

The sauropod Brachiosaurus traveled in herds in the western United States during the Late Jurassic. Its stomping grounds consisted of low-lying drainage basins that swallowed runoff from the emergent Rocky Mountains to the west. These lowlands were scarred by crisscrossing streams and rivers and were dotted with swampy lowlands, lakes, river channels, and floodplains. (Brachiosaurus remains have also been allegedly found in Portugal). This infamous sauropod walked on four pillar-like legs; its front legs were longer than its back legs, so that its body sloped downwards towards its short tail. Its name means ‘arm reptile,’ in reference to the fact that its arms (forelegs) were longer than its rear legs. Some scientists believe it could rear back on its hind legs to reach super high foliage, though some believe it kept its four legs on the ground at all times. 

Brachiosaurus’ neck reached vertical rather than horizontal like diplodocids. This gave it a feeding advantage: whereas most of its sauropod contemporaries were low-browsing diplodocids, Brachiosaurus could browse foliage up to fifty feet off the ground to feed on high conifers and ginkgoes. Air sacs along the neck and trunk of Brachiosaurus lightened the strain needed to keep its neck vertical. These air sacs connected to its lungs, thus lowering the body density. Brachiosaurus couldn’t chew its food, as its jaws were only capable of opening and closing (it couldn’t move its jaws side-to-side in a grinding motion). Its 52 spatulate (spoon-like) teeth cropped conifer needles, palm-fronds, ginkgo leaves, and even towering horsetails that grew along the many waterways of the Morrison. It would’ve needed to consume up to 440 pounds of food each day, and this food was swallowed unchewed and passed into a gizzard where gastroliths (stomach stones) crushed the food to a pulp for digestion. 

Fossils similar to those of North America’s Brachiosaurus were discovered in Africa’s Tendaguru Formation in 1914; scientists believed the fossils to represent a new species of Brachiosaurus, but further study indicated significant morphological differences, so the fossils became a new genera altogether: Giraffatitan. Giraffatitan’s crest bone, rising from the top of the skull, is much larger than that in Brachiosaurus (interestingly, most modern depictions of Brachiosaurus include a crest bone more in line with that of Giraffatitan than Brachiosaurus). While it was once believed Brachiosaurus’ nostrils were set atop its skull crest, modern reconstructions place them lower down on the high forehead, right above the eyes, in a kink that angled from the forehead into the low snout. This reconstruction has led some scientists to postulate that the crest was a resonating chamber that could’ve amplified Brachiosaurus’ vocalizations. 

a scene from the Morrison Formation; Brachiosaurus in the foreground,
Camarasaurus in the background, and early ornithopods along the forest floor

Europasaurus

Type Species: Europasaurus holgeri

Classification: Dinosauria – Saurischia – Sauropoda - Gravisauria - Eusauropoda - Neosauropoda – Macronaria – Titanosauriformes – Brachiosauridae

Time Period: Late Jurassic 

Location: Europe (Germany)

Diet: Herbivore   

Europasaurus was a tiny sauropod that, in adulthood, reached only twenty feet in length, stood as tall as an eight-year-old human at the hips, and whose head reached only ten feet above the ground. Its small size has been attributed to ‘insular dwarfism,’ in which animals evolve to shrink in size in order to cope with diminished resources. Germany at this point in the Late Jurassic was mostly underwater; higher elevations emerged from the sea in a string of island archipelagos, the largest of which was only 120,000 square miles. Even an island that large likely couldn’t support a herd of normal-sized sauropods; hence Europasaurus grew smaller in order to survive. Bone analysis shows that while gigantic sauropods reached their massive size by growing quickly, Europasaurus had an unusually slow rate of growth. Other instances of ‘insular dwarfism’ have been documented from Europe around this time; in Romania, for example, we’ve discovered a dwarf titanosaur Magyarosaurus and a dwarf hadrosaur Telmatosaurus. 

Europasaurus’ remains were found in a richly marine environment that faced a large German island coated with conifers, ferns, and cycads. Pterosaurs flew about among the trees, hopping island-to-island, and early mammals scurried in the underbrush. Fossilized turtles, fish, hybodont sharks, and marine crocodylomorphs are common. At least 450 bones from Europasaurus were recovered from the Langenberg Quarry, and about a third of them had tooth marks. These tooth marks match the teeth of fish, sharks, and marine crocodylomorphs, but none were made by theropods. Scientists believe that a herd of Europasaurus were crossing a tidal zone and drowned. Other dinosaur material in the vicinity includes remains from an unknown diplodocid, a stegosaur, and multiple indeterminate theropods. Isolated teeth show that there were at least four different types of theropods living on the island, including the megalosaur Torvosaurus as well as an indeterminate megalosaur, an allosaur, and a ceratosaur. Interesting, teeth that seem to belong to Velociraptorinae, which would put the genesis of this dromaeosaur subgroup in the Late Jurassic rather than the (proposed) Early Cretaceous. 

this graphic highlights European bone-beds with their Late Jurassic counterparts
The Langenberg Quarry is #7

Dinosaur footprints preserved at the quarry have led researchers to propose a reason for Europasaurus’ eventual demise. Footprints located sixteen feet above the Europasaurus burial ground shows that 35,000 years after their burial (well into the Cretaceous), sea level dropped and allowed for what’s called a ‘faunal overrun.’ The theropods that coexisted with Europasaurus were, by and large, about thirteen feet in length; but the theropods that were able to cross to the former island via a land bridge revealed by sinking sea levels were around twenty-five feet in length (based upon their footprints). These larger theropods made windfall on the previously-isolated island: the creatures who had grown small to survive amid diminished resources were now easy pickings for large Cretaceous predators. Europasaurus wouldn’t have stood a chance in the bloodletting.