Mamenchisaurus

Type Species: Mamenchisaurus constructus

Classification: Dinosauria – Saurischia – Sauropoda – Gravisauria - Eusauropoda - Mamenchisauridae

Time Period: Late Jurassic

Location: China

Diet: Herbivorous   

The sauropod Mamenchisaurus had a remarkably long neck that made up half its body length and was longer than a school bus. Mamenchisaurus was wildly successful during the early Late Jurassic, as multiple species have been identified. While most species ranged between fifty to eighty-five feet in length, the largest species, M. sinocanadorum, reached 115 feet in length and weighed up to eighty tons. Mamenchisaurus’ neck vertebrae had long struts running between them that would’ve limited its ability to turn its neck too sharply. It had spatula-shaped teeth designed for chewing coarse plant material. Scientists believe that Mamenchisaurus was primarily a low browser; it would’ve swept its long neck across a wide area of vegetation, cutting a crescent-moon-shaped swathe of destruction before walking a bit forward to continue eating. Once Mamenchisaurus reached a good locale, it could feed for several hours without having to expend too much energy. A discovery of another species of Mamenchisaurus in 2001 allowed for more accurate reconstructions of this dinosaur, one part of which was the tip of the tail where the vertebra was more robust with taller neural spines. Current thinking for this construction is that the tip of the tail was modified to be a weapon as seen in some other Asian sauropods like Shunosaurus. Such a weapon may have been used in dominance competition between two males, although it may have been a defensive weapon against an attacking predator.

Datousaurus

Type Species: Datousaurus bashanensis
Classification: Dinosauria – Saurischia – Sauropoda – Gravisauria - Eusauropoda - Mamenchisauridae
Time Period: Middle Jurassic
Location: China
Diet: Herbivore

Datousaurus was a sauropod that lived in China between the Callovian stage of the Middle Jurassic to the Oxfordian stage of the Late Jurassic. Only two partial skeletons have been discovered; neither of these had an articulated skull, but a detached skull has been attributed to the dinosaur. Because most sauropod remains include numerous individuals of different ages, implying a herd, Datousaurus ‘loner’ status has been intriguing; this has led some paleontologists to suggest that it was a ‘rogue’ sort of sauropod that didn’t live in family herds. Datousaurus was fifty feet snout-to-tail, and it had a deep, boxlike skull similar to that of the later Camarasaurus. During the Oxfordian stage, it lived alongside the sauropod Shunosaurus; though these two sauropods lived side-by-side, they likely practiced niche partitioning so that their foodstuffs didn’t overlap. Datousaurus’ elongated vertebrae gave it a higher reach than Shunosaurus, and its teeth were more spoon-shaped than those of the rival. Differences in teeth shape may indicate diets revolving around different plants. Other contemporaries of Datousaurus included the stegosaur Huayangosaurus and the theropod hunters Gasosaurus and Yangchuanosaurus. 

Omeisaurus

Type Species: Omeisaurus junghsiensis

Classification: Dinosauria – Saurischia – Sauropoda – Gravisauria - Eusauropoda - Mamenchisauridae 

Time Period: Middle Jurassic

Location: China 

Diet: Herbivore 

Fossils of several individual Omeisaurus were discovered in Sichuan Province, China, indicating that an entire herd had died and were buried together. These sauropods grew up to sixty-six feet in length and looked a lot like the later Mamenchisaurus (to whose ‘group’ they belong). Omeisaurus had an extremely long neck, stocky limbs, and a short body. The long neck may have been used to reach food high in the trees, or it may have been held horizontally over the ground to feed on large swathes of low-growing foliage. In this second manner of feeding, Omeisaurus would take a few steps forward and then swoop its neck over the vegetation, slowly creating a crescent-shaped swathe of devastated vegetation. This would’ve required less energy than high browsing. Omeisaurus tail was relatively short, and it may have included a club like the later Shunosaurus (though most scientists believe the club did indeed belong to Shunosaurus).