恐龍卡第 0927 張，共 2 027 張

Jormungandr

名字的意思： “named after Jǫrmungandr, the giant sea serpent from Norse mythology”1

吃：肉滄龍類白堊紀晚期嚴格來說不是恐龍

Jormungandr was a huge, swimming lizard that lived in the sea during the time of dinosaurs. It had a long body, strong jaws, and sharp teeth for catching fish and other sea creatures. This marine reptile was not a dinosaur, but a fierce predator of the ancient oceans.1

趣味小知識：這種海生爬蟲類在海裡游泳的時候，恐龍正在陸地上走路。大家都叫牠們恐龍，但牠們其實是爬蟲類的另一個分支。

生存年代

84 到 72 百萬年前2

白堊紀晚期

化石發現地

Cavalier County, North Dakota, USA2 1

長度

5.4 到 7.3 m (18 到 24 ft)1

最高速度

時速約 37 公里（23 英里）

游泳, 估計值

牠生活在什麼時候？

三疊紀

侏羅紀

白堊紀

2 億 5200 萬年前20114566，小行星撞地球

牠有多大？

牠有多長？

跟 7 隻狗從鼻子接到尾巴一樣長跟 41 根香蕉頭尾相接一樣長能在 4.9 秒內游完一座大泳池（50 公尺）

Jormungandr 跟「你」比起來有多大？

只是在你的瀏覽器裡算算數學。什麼都不會被儲存或傳送出去。

牠有多快？

走路的人 時速約 5 公里 (3 mph)

騎腳踏車的小朋友 時速約 12 公里 (7 mph)

Jormungandr 時速約 37 公里 (23 mph)

一匹飛奔的馬 時速約 65 公里 (40 mph)

一隻獵豹 時速約 100 公里 (62 mph)

酷東西

趣味知識

Jormungandr's skull was about 72 centimeters (28 inches) long, and its lower jaw measured 80.8 centimeters (31.8 inches).1

The fossil was discovered in 2015 by a fossil collector named Deborah Shepherd near Walhalla, North Dakota.1

Jormungandr lived about 80 million years ago, during the Late Cretaceous period.1

The fourth dorsal vertebra of Jormungandr has marks that scientists think are bite marks from another mosasaur, possibly from a fight or scavenging.1

Jormungandr shares features with both primitive mosasaurs like Clidastes and more advanced ones like Mosasaurus, making it a 'missing link' in mosasaur evolution.1

The species name walhallaensis comes from the town of Walhalla, which is named after Valhalla, the hall of slain warriors in Norse mythology.1

Jormungandr 的 AI 繪圖 — 這是電腦根據科學家目前的知識，用 AI 畫出 Jormungandr 可能的樣子。這只是猜測：真正的動物可能長得不一樣，也沒有人知道牠真正的顏色。

迷思破解王

迷思： Some people think Jormungandr was a dinosaur.

真相： Jormungandr was a mosasaur, a type of marine lizard, not a dinosaur. Mosasaurs are reptiles but belong to a different group than dinosaurs.1

給恐龍專家

學名: Jormungandr
命名者: Zietlow et al. 20232
類群: 滄龍類
科 / 演化支: Mosasauridae2
分類: Mosasauroidea2
岩石的年代: 84 到 72 百萬年 (Campanian)2
岩層: Pierre Shale2
國家: 美國2
化石紀錄: The Paleobiology Database 收錄 1 筆2
發現: The only known fossil of Jormungandr was found in 2015 by fossil collector Deborah Shepherd near Walhalla, North Dakota. It was later described and named by paleontologists Amelia Zietlow, Clint Boyd, and Nathan Van Vranken in 2023.1
仍有爭議: Scientists are not sure if Jormungandr is a distinct genus or just a new species of Clidastes. Some researchers think it might be renamed Clidastes walhallaensis in the future.1