Mamenchisaurus is an extinct genus of sauropod dinosaur including several species, known for their remarkably long necks of around 14 metres; which made up half the total body length. It is known from numerous species which ranged in time from 160 to 145 million years ago, from the Oxfordian to Tithonian ages of the late Jurassic Period of China. It may include the species Mamenchisaurus sinocanadorum.
It was intended to name the reptile after the place where its fossil was first found — a construction site next to the Mǎmíngxī (马鸣溪) Ferry Crossing by the Jinsha River (金沙江, the westernmost major headwater stream of the Yangtze River), near Yibin (宜宾) in Sichuan Province of China. However, due to an accentual mix-up by Young, the location name Mǎmíngxī (马鸣溪 'horse-neighing brook') was mistaken as Mǎménxī (马门溪 'horse-gate brook').
Discoveries and Species[]

Mounted M. hochuanensis skeleton, Field Museum
It is known from numerous species which ranged in time from 160 to 145 million years ago, from the Oxfordian to Tithonian ages of the late Jurassic Period of China, and the largest species may have reached 35 meters (115 feet) in length and possibly weighed 50 to 75 tons. It is in the Mamenchisauridae.
Mamenchisaurus was first discovered in 1952 on the construction site of the Yitang Highway in Sichuan, China. The partial skeleton fossil was then studied, and named Mamenchisaurus constructus in 1954, by the renowned Chinese paleontologist Professor C. C. Young. The type specimen had an incomplete neck with 14 vertebra preserved and none of these were complete. M. constructus has been estimated around 13 m (43 ft) and 15 m (49 ft) in length.
Mamenchisaurus hochuanensis[]

The holotype skulls of M. youngi, M. jingyanensis, and M. sinocanadorum, and a skull referred to M. hochuanensis
In 1972, a second species was described, named Mamenchisaurus hochuanensis, with a neck that reached up to 9.3 m (31 ft) in length. This species had a complete neck preserved which contained 19 vertebrae This was the longest neck known until the description of Supersaurus, based on a single neck vertebra, BYU 9024, with an estimated neck length of about 14 meters (46 feet). Another long-necked sauropod exceeding M. hochuanensis was Sauroposeidon which was discovered in 1994. Based on the Sauroposeidon holotype, which only preserved 4 neck vertebra, its neck was estimated to be between 11.25 and 12 meters (36.9–39.4 feet) long.
In 2001, another M. hochuanensis specimen was described. It had skull, pectoral girdle and forelimb material preserved, all of which were missing from the holotype. It was also found with four fused tail vertebra, which have expanded neural arches and taller neural spines, that belong at the tip of the tail. It’s thought that these could be a weapon, such as a tail club, or a sensory organ. Other Chinese sauropods, Shunosaurus and Omeisaurus, are also known to have had ’tail clubs’ but they differ in shape to that of M. hochuanensis.
Mamenchisaurus sinocanadorum[]

Location of Xinjiang province in China, where M. sinocanadorum is found; the Junggar Basin is seen in yellow.
In 1993, M. sinocanadorum was described, which consisted of skull material and the first four cervical vertebrae. This species possessed the longest cervical rib of any described sauropod dinosaur, measuring 4.1 meters (13.5 feet). This is longer than the longest Sauroposeidon cervical rib, which measures 3.42 meters (11.2 feet). Additional remains attributed to this species, but not yet formally described, belong to one of the largest dinosaurs known—the restored skeleton measuring 35 metres (115 feet) in length with a neck measuring nearly 17 metres (56 feet) long. The species designation refers to the Sino-Canadian expedition. The holotype is specimen IVPP V10603 , a skull with cervical vertebrae excavated in Xinjiang, from a layer of the Shishugou Formation, after an August 1987 find by Dong Zhiming.
Mamenchisaurus youngi[]

Artist's impression of M. youngi
The fourth species Mamenchisaurus youngi was described by Pi, Ouyang & Ye in 1996 as M. youngi was unearthed in Xinmin County, near Zigong City in Sichuan, China in 1989 from sediments of the Shangshaximiao Formation. The fossil specimen is 16 meters long with a neck of 6.5 meters, it is relatively smaller than the other Mamenchisaurus species . The specific name was given in honour of C. C. Young. The holotype specimen is ZDM 0083 , a skeleton with skull discovered by Song Renfa in December 1988, which was found particularly complete and articulated, excavated at Xinmin in Sichuan and footprints were also found on the skeleton.
Mamenchisaurus anyuensis[]
A fifth species, described by He, Yang, Cai, Li and Liu Z. in 1996 was named M. anyuensis and measured over 21 meters long. The holotype is specimen AL 001 , a fairly complete skeleton without a skull, found in 1987 in Anyue Prefecture, Sichuan, in a layer of the Penglaizhen Formation dating to the Late Jurassic. Cervical vertebrae AL002-0 03 and dorsal vertebrae AL101-106 were assigned to the species. Half a dozen skeletons were found in a nearby quarry in the older Suining Formation. In 2019, a study found the layers to be much younger than previously assumed, no older than the Aptian. That would mean the genus persisted into the Cretaceous, again raising doubts about assigning the species to the genus.
Mamenchisaurus gongjianensis[]
In 2005 Zhang & Chen named a new species of the closely related genus Omeisaurus as Omeisaurus gonjianensis , but the following year the same authors placed the remains within Mamenchisaurus , making it the sixth species of the genus by recombining it as Mamenchisaurus gongjianensis. In any case the species is considered doubtful.
Mamenchisaurus jingyanensis[]
The seventh described species is Mamenchisaurus jingyanensis described by Zhang, Li and Zeng in 1998, from the Sichuan Bajio, Suining Formation and Penglaizhen Formation. The name was already mentioned in 1996, but remained a nomen nudum due to insufficient description. The holotype is CV00734 , a partial skeleton with skull that was unearthed in a layer of the Shangshaximiao Formation in Meiwang, Jinyang Prefecture of Sichuan. Specimens CV00219 , a skeleton without skull, and JV002 , a partial skeleton without skull, were assigned to the species. The fossils were excavated since the late 1970s. In the same publication it was mentioned that there is an as yet undescribed "Mamenchisaurus guanyuanensis", so it is considered invalid. This species has not been validly named until now.
Other Mamenchisaurus species and material[]
In 2004, a new species of Mamenchisaurus , Mamenchisaurus yunnanensis , was reported from the Jurassic "red beds" in Yunnan, in the Anning Formation south of the Sichuan Shoal.
A problematic species is Mamenchisaurus fuxiensis described by Hou, Zhao & Chao in 1976 originally as a separate genus, Zigongosaurus . However, it may be a species of Omeisaurus or Mamenchisaurus . The only find consists of several disarticulated bones from the Shangshaximiao Formation of Zigong in Sichuan.

NSM PV17656
Today, the genus is generally considered to be in need of a thorough revision. It has functioned as a catch-all species. Several larger sauropod species from the Jurassic of China have been placed in Mamenchisaurus without this being sufficiently supported by phylogenetic analyses. The precise relationships to other Mamenchisauridae are therefore unclear. Furthermore, suspicion was expressed that Mamenchisaurus hochuanensis is a junior synonym of the type species Mamenchisaurus constructus since both species come from the same formation. The fact that the type is known from relatively poor remains is an obstacle to resolving this problem. The situation is exacerbated by brief descriptions and obscure publications.
Description[]

Size comparison of M. constructus, M. youngi, M. hochuanensis and M. sinocanadorum
Mamenchisaurus was a large representative of the sauropods. While Mamenchisaurus constructus , the type species and known from only a single skeleton, has been estimated to have been between 13 and 15 metres (40–50 ft) in length, Mamenchisaurus hochuanensis was likely much larger. The largest discovered specimen of this species was estimated to have been 22 metres (72 ft) long. Weight estimates for this specimen vary from 14.3 to 18.17 tonnes depending on the study. Mamenchisaurus sinocanadorum and Mamenchisaurus jingyanensis could have been up to 26 metres (82 ft) long, but only very fragmentary skeletons survive for these species.
Only one complete skull is known from the species Mamenchisaurus youngi . The skull was extremely small relative to the body, including the lower jaw measuring 51.0 centimetres in length, 19.8 in width and 40.1 in height, in which a neck length of about 6 metres. The brain cavity of this skull showed a volume of only about 60 millilitres. Overall, the skull resembled that of Camarasaurus , but was thinner and longer. Well-marked scleral rings around the eyes indicate a good sense of sight. The lower jaw was open at the front, symphysis, relatively low and showed the side of a small opening, fenestra mandibularis externa, this opening was closed in all other sauropods except Shunosaurus . The chisel-like teeth were close together. In the upper jaw, there were 14–18 teeth on each side and 4 teeth in the premaxillae in front of the upper jaw. Meanwhile, the lower jaw contained between 18 and 24 teeth on each side.
The spine was composed of 18 to 19 cervical vertebrae, 12 back vertebrae, 4 to 5 sacral vertebrae, and over 50 caudal vertebrae. The neck was one of the relatively longest of all sauropods and was more than three times as long as the body, the largest known specimens being that of Mamenchisaurus hochuanensis with a neck measuring approximately 9.8 metres (32 ft) long. Only remains from the related genus Omeisaurus suggest a neck that is even longer relative to total length. The cervical vertebrae were characterized by very long cervical ribs running down the cervical spine and in Mamenchisaurus sinocanadorum they have a length of up to 4.1 metres (13 ft). It is controversial whether Mamenchisaurus only held its neck horizontally or whether it may have erected it like a giraffe, in order to be able to eat at higher altitudes. However, a recent biomechanical study points out that the neck was too immobile to be erected due to the very long cervical ribs, unlike in diplodocids, whose neck was significantly more mobile and could possibly be elevated. In other features, the vertebral column resembled that of diplodocids in that the spinous processes were bifurcated on the cervical and anterior thoracic vertebrae. In addition, the middle caudal vertebrae bore the typical double-barred chevron bone.
Classification[]
Yang placed Mamenchisaurus as a member of Sauropoda in 1954 but did not place it in a family. By 1958 he believed it to be a member of the Titanosauridae. That would be a common view in China and the West for a time. Leonid Petrowitsj Tatarinow, however, placed it in a basic position in 1964, in the Cetiosauridae. In 1970, Rodney Steel placed it in the Euhelopodinae. In 1972, Yang named his own Mamenchisauridae. That notion was not immediately accepted. In 1990, John Stanton McIntosh thought that Mamenchisaurus was a slightly different member of Diplodocidae, based on the double-beamed chevron bone, forked spinous processes, and procoelic caudal vertebrae. But it was later revealed that these features can be found not only among representatives of Diplodocidae, but also in many other sauropod groups. In 1995, Paul Upchurch placed the animal in Euhelopodidae, this grouping is today considered paraphyletic, as Euhelopus is only distantly related to Mamenchisaurus . In 2002, Jeffrey Wilson used the term Omeisauridae, forgetting that Mamenchisauridae would take priority, to which it would again belong. In 1983, Zhao Xijin placed it in the Homalosauropodoidea, but that is a concept that is of little use according to current ideas. Current analyses indicate that mamenchisaurids form a distinct, mainly Asian clade found in Eusauropoda, outside of Neosauropoda. That branch would have reached gigantic size independently of neosauropods. Mamenchisaurus is often grouped together with probably closely related forms within Mamenchisauridae. However, which genus other than Mamenchisaurus should be assigned to this group is controversial, but the genera Chuanjiesaurus , Eomamenchisaurus , Tienshanosaurus , Tonganosaurus , Omeisaurus , and Yuanmousaurus are often included in this group.
Paleobiology[]
All species of Mamenchisaurus were herbivores. The chisel-like teeth would have been especially useful for stripping needles or leaves from branches, but could also be used to bite into fruiting bodies, for example, of seed ferns.
In 2013, Andreas Christian published a study that focused specifically on why Mamenchisaurus had such an extremely long neck. For this he used the very intact holotype ZDM0083 of M. youngi with eighteen cervical vertebrae. Christian manually determined the mobility of the cervical vertebrae. It turned out that the base of the neck could be strongly bent upwards. The first vertebral vertebra could already be curved by 20° relative to the second vertebra and a similar rotation was possible in the four posterior vertebrae so that the fifteenth vertebra could be bent backwards by 105° relative to the posterior. However, Christian did not conclude that M. youngi often held its neck vertically. It seemed unlikely to him that the cervical vertebrae were typically held in a very extreme position. It seemed more likely to him that the neck, although the base could not be bent, usually placed the head between ground level and an angle of plus 30° with the back. Plants would be foraged at low to moderate heights. Because the base of the neck could be moved strongly sideways via flattened articular protuberances, a long neck would have given a wide horizontal range. This could also be a sign that vegetation was relatively sparse. Even when walking, the neck would have been kept largely horizontal to improve stability. In all cases, the middle part of the neck was kept straight because the middle cervical vertebrae had only slight rotation possible and were further stiffened by the long ribs of the neck. Christian believed that in an alert resting state, the animal held its neck more vertically, between 30° and 40°, to survey the environment from a great height, searching for carnivorous theropods.31
In 1992, Christopher Daniels and Jonathan Pratt concluded that an animal the size and neck length of Mamenchisaurus could not have had a mammalian respiratory system, with the lungs acting like bellows; even a cold-blooded Mamenchisaurus would have taken in insufficient fresh air to deliver oxygen because of its low metabolic rate. However, an air sac system, like a bird's, could even provide a warm-blooded animal with sufficient oxygen, albeit with a warm-blooded metabolism. This confirms that the pneumatization of the vertebrae is the result of an air sac respiratory system.
Paleoecology[]
By far the largest sauropod in China at its time, Mamenchisaurus existed during the Late Jurassic period and lived through to the Early Cretaceous period, approximately 161-114 million years ago, and was relatively widespread, inhabiting various parts of China. Fossil evidence suggests it may have lived in Thailand and the Dashanpu Formation, which was once a rich forest, likely supported by a nearby lake and river. The variety of finds includes aquatic creatures, as well as numerous sauropods, indicating a diverse ecosystem. Mamenchisaurus tended to feed from large trees, using its long but relatively light neck to reach vegetation that other dinosaurs could not. Mamenchisaurus lived alongside many other dinosaurs such as the stegosauridae Chungkingosaurus, Gigantspinosaurus, Chialingosaurus, and Tuojiangosaurus, fellow sauropods Shunosaurus and Omeisaurus, as well as the massive theropod Yangchuanosaurus, which may have been the main predator of Mamenchisaurus.
JPInstitute.com Description[]
Mamenchisaurus is one of the most unique long-necked dinosaurs for a very good reason - it has a really long neck. In fact, it had the longest neck of any creature that ever lived. Stretching 46 feet (15 m), the neck on Mamenchisaurus was longer than a school bus! The rest of it was just like other members of its family; a long tail, stout legs and really big.
The architecture of the neck of this dinosaur is incredible. It had 19 neck vertebrae, more than any other dinosaur. The vertebrae had long struts running between them that would have limited the ability of Mamenchisaurus to turn its neck too sharply, but it could still reach well up into the trees to feed. This plant-eater had spatula-shaped teeth that seem to have been well designed to chew coarse plant material. This is one feature that makes it different from the members of the Diplodocidae family, which had peg shaped teeth, to which it has been thought to belong. It is now being thought of as possibly part of a group of sauropods unique to Asia. Most of the big Asian sauropods, such as Omeisaurus, had spatulate teeth. In fact, the Asian sauropods, including Mamenchisaurus, seem to share more characteristics with Brachiosaurus than with Diploducus. For evidence of this, one needs to look no further than the nose - Mamenchisaurus and other Asian sauropods are very close in evolutionary terms to that of Brachiosaurus. It is also thought that another aspect that these creatures had in common was that they were finding their food high off the ground. Diploducus and Apatosaurus on the other hand were likely feeding on low growing plants.
Note: Many people don't realize that China is one of the most prolific areas for the discovery of dinosaurs. The Sichuan Province is perhaps the best place in the world to find Jurassic dinosaurs.
Dinosaur Field Guide Description[]
Mamenchisaurus ("lizard from Mamen's Brook") is basically a giant neck attached to a small body. The neck is about 40 feet (12 m) long, and the body is about the same length! The purpose of this short, wide body is to act as a stable, heavy base to anchor the neck. At the end of the neck is a short head with thick teeth. Its length allowed Mamenchisaurus to eat the leafy parts at the tops of some Jurassic trees. By doing so, it did not have to compete with its own young, who had to eat plants closer to the ground. Functionally, this dinosaur could be called a "plant vacuum." Its super-long neck allowed it to suck up hundreds of pounds of leaves from treetops. Structurally, the neck represents the pinnacle of animal engineering. The vertebrae have hollow portions where there is little internal stress on the bones. This lightens the bones and makes them stronger. Struts and braces give added strength for load bearing. On top of the neck vertebrae are split spines that form a V-shaped trough. Inside this trough lies a series of ligaments that function like the cables on suspension bridges, holding up the neck.
Fun Facts[]
This dinosaur had the longest neck in the history of Earth.
Trivia[]
Answer: In the book by Michael Crichton, it is a Diplodocus, but in the movie it looks more like a Mamenchisaurus.
Gallery[]
Appearance in other media[]
Jurassic Park[]
- Mamenchisaurus appeared in the movie The Lost World: Jurassic Park.
- Mamenchisaurus is in the 2018 construction and park management game called Jurassic World Evolution.
Read more Mamenchisaurus on Jurassic Park Wiki |
Links[]
References[]
- http://en.wikipedia.org/wiki/Mamenchisaurus
- https://www.nhm.ac.uk/discover/dino-directory/mamenchisaurus.html
- https://www.amnh.org/exhibitions/sauropods-worlds-largest-dinosaurs/meet-mamenchisaurus
- https://www.enchantedlearning.com/subjects/dinosaurs/dinos/Mamenchisaurus.shtml
- https://australian.museum/learn/dinosaurs/fact-sheets/mamenchisaurus-youngi/
- https://dinosaurpictures.org/Mamenchisaurus-pictures
- https://nature.ca/notebooks/english/mamenchi.htm
- https://www.dkfindout.com/us/dinosaurs-and-prehistoric-life/dinosaurs/mamenchisaurus/
- https://blog.everythingdinosaur.co.uk/blog/_archives/2021/07/28/pnso-to-introduce-new-mamenchisaurus-model.html
- https://dbpedia.org/page/Mamenchisaurus