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The work was led by Hui Dai, a paleontologist at the Institute of Paleontology<\/a> in southwest China.<\/p>\n His research focuses on Jurassic sauropod evolution and on how long-necked dinosaurs spread and diversified across East Asia.<\/p>\n In a new study, the team described neck, back, hip, tail, and hind limb bones from the Upper Shaximiao Formation near Chongqing.<\/p>\n Those bones lay in mudstones near a shallow lake, indicating deposition during the Oxfordian, a Late Jurassic<\/a> stage about 160 million years ago.<\/p>\n Comparisons with better-known Mamenchisaurus skeletons suggest M. sanjiangensis was a huge animal, likely tens of feet long and weighing many tons.<\/p>\n Naming Mamenchisaurus sanjiangensis<\/p>\n The species name, sanjiangensis, refers to the Hechuan District of Chongqing, where three rivers meet near the fossil site.<\/p>\n Geologically, the layers belong to the early part of the Late Jurassic, near the transition between Middle and Late intervals.<\/p>\n Using measurements of the bones, the authors classified the animal as a mamenchisaurid, a long-necked sauropod lineage that is common in Jurassic East Asia.<\/p>\n Results from phylogenetic analysis, a method using shared traits to reconstruct ancestry, place Finding Mamenchisaurus sanjiangensis among relatives including M. hochuanensis and M. youngi.<\/p>\n Five fused sacral vertebrae form a platform for the hips, suggesting a sturdy connection between spine and pelvis that helped carry enormous weight.<\/p>\n Inside the neck and back vertebrae, the bone had a camellate structure with many small, air-filled chambers. This honeycomb pattern lightened the skeleton without sacrificing strength.<\/p>\n The femur is unusually wide for its length, hinting at powerful hind limbs that stabilized the enormous torso as the animal walked.<\/p>\n At the front of the tail, curved neural spines and bony ridges suggest strong muscle attachments. The massive tail likely helped with balance during movement.<\/p>\n Long-necked clan of Mamenchisaurus<\/p>\n Dinosaurs in the genus Mamenchisaurus belong to the sauropod group. These were large, long-necked, plant-eating<\/a> dinosaurs that dominated Jurassic and Cretaceous ecosystems worldwide.<\/p>\n A reanalysis<\/a> of Mamenchisaurus sinocanadorum suggested its neck stretched about 49.5 feet (15 meters) \u2013 the longest dinosaur neck ever measured.<\/p>\n Mamenchisaurus sanjiangensis fits within this long-necked clan, reinforcing the idea that East Asia hosted several lineages of neck specialists during Jurassic time.<\/p>\n Anatomical details show similarities with neosauropods, later evolving sauropods that spread worldwide, hinting that mamenchisaurids and these relatives sometimes occupied overlapping ecological roles.<\/p>\n The Sichuan Basin in southwestern China is a region rich in dinosaurs, with Jurassic rocks yielding abundant sauropod skeletons<\/a> and tracks.<\/p>\n That research shows that during the Middle and Late Jurassic, dinosaurs from the Mamenchisauridae family dominated the basin\u2019s fauna, especially in the Upper Shaximiao and Suining formations.<\/p>\n Adding Mamenchisaurus sanjiangensis from the Upper Shaximiao and Tongnanlong zhimingi from the Suining Formation reveals a more diverse sauropod community than previously recognized.<\/p>\n \u201cLate Jurassic sedimentary units of China preserve rich sauropod records, and most of them are dominated by mamenchisaurids,\u201d said Dr. Dai.<\/p>\n East Asia was different<\/p>\n For decades, paleontologists discussed the East Asian Isolation hypothesis, the idea that Jurassic East Asia was geographically isolated from other continents.<\/p>\n Newly described neosauropods from China and mamenchisaurids from Africa now show that many dinosaur lineages<\/a> ranged widely, softening claims of strict East Asian isolation.<\/p>\n Comprehensive reviews of sauropod fossils indicate that animals achieved global distribution by the Middle Jurassic, with diversity peaking in the Late Jurassic.<\/p>\n Mamenchisaurus sanjiangensis and Tongnanlong zhimingi show that East Asia followed a boom in sauropod diversity, while keeping a distinctive set of species.<\/p>\n Long necks and evolution<\/p>\n The researchers argue that mamenchisaurids developed neck and body features similar to neosauropods, increasing competition where herbivores overlapped in time and space.<\/p>\n Detailed biomechanical work<\/a> suggests that sauropods supported massive bodies by using air-filled vertebrae and limb bones. In this way, they reduced skeletal weight while maintaining strength.<\/p>\n The camellate internal structure of bones in Mamenchisaurus sanjiangensis fits that pattern, hinting at a balance between extreme size and reasonable agility across its habitat.<\/p>\n Long-necked sauropods could browse over wide areas while staying stationary, cutting the energy cost of moving heavy bodies between scattered tree patches.<\/p>\n Field crews uncovered the bones from purplish-red mudstones in the Upper Shaximiao Formation, where erosion in Chongqing had exposed the fossilized skeleton.<\/p>\n Paleontologists mapped each bone in place before encasing it in a protective plaster jacket, a methodical process that preserves<\/a> how the dinosaur originally lay.<\/p>\n So far Mamenchisaurus sanjiangensis is known from this single partial skeleton, which means estimates of its size and neck length still carry uncertainty.<\/p>\n According to Dai and colleagues, reexamining museum specimens from East Asia will help clarify relationships and close remaining gaps in the family tree.<\/p>\n Lessons from Mamenchisaurus sanjiangensis<\/p>\n \u201cSauropod dinosaur diversity reached an apparent peak in the Late Jurassic,\u201d said Dr. Dai, summarizing the broader backdrop for Mamenchisaurus sanjiangensis.<\/p>\n Because the fossil comes from the early Oxfordian stage, an under-sampled slice of time, it helps fill gaps in East Asian sauropod records.<\/p>\n Its combination of old and new traits hints at a transition from Middle Jurassic<\/a> sauropod communities to Late Jurassic faunas in East Asia.<\/p>\n Together with other recent finds, the new species suggests that mamenchisaurids remained important in East Asian ecosystems late into the Jurassic Period.<\/p>\n Many Mamenchisaurus species and related genera are still known from fragmentary material, so refining their relationships will require revisiting classic specimens using updated methods.<\/p>\n Finding more complete necks from Chongqing would reveal whether Mamenchisaurus sanjiangensis matched the extreme neck proportions of relatives or followed a different design.<\/p>\n High-resolution scans and comparative studies of vertebrae may show how bone, air spaces, and tissues interacted in supporting a long neck.<\/p>\n For now, the partial skeleton from Hechuan shows that careful fieldwork and collaborative study can still reveal surprising details about familiar dinosaur groups<\/a>.<\/p>\n The study is published in Nature<\/a>.<\/p>\n \u2014\u2013<\/p>\n Like what you read? Subscribe to our newsletter<\/a> for engaging articles, exclusive content, and the latest updates.<\/p>\n Check us out on EarthSnap<\/a>, a free app brought to you by Eric Ralls<\/a> and Earth.com.<\/p>\n \u2014\u2013<\/p>\n","protected":false},"excerpt":{"rendered":"Researchers in southwest China have identified a new plant-eating dinosaur species with an extraordinary neck. The animal, named…\n","protected":false},"author":2,"featured_media":207670,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[264,61,60,82],"class_list":["post-207669","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-animals","tag-ie","tag-ireland","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/207669","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/comments?post=207669"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/207669\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media\/207670"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media?parent=207669"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/categories?post=207669"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/tags?post=207669"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"Geographic](\"https:\/\/www.newsbeep.com\/ie\/wp-content\/uploads\/2025\/12\/dinosaur-long-necked_Mamenchisaurus-sanjiangensis_map_SciReports_1s.webp.webp\")
<\/a>Geographic and geological setting of the palaeontological site. (A) geological map of Hochuan (Chongqing, China); (B) Type specimen of Mamenchisaurus sanjiangensis sp. nov. in the field; (C) the field map of the elements; (D) the compose of the elements. Credit: Scientific Reports. Click image to enlarge.Digging fossils out of purple mudstones<\/p>\n