恐龍卡第 1862 張，共 2 027 張

Unktaheela

名字的意思： “from the Lakota word for a mythical water creature”1

吃：肉蛇頸龍類白堊紀晚期嚴格來說不是恐龍

Unktaheela was a small, fast-swimming marine reptile that lived in the sea that once covered North America. It had a short neck, a big head with a long snout, and four flippers that worked like paddles. It was one of the smallest plesiosaurs ever found.2

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3

白堊紀晚期

化石發現地

Wyoming and South Dakota, USA3 1

長度

2.3 到 2.6 m (7.5 到 8.5 ft)2

最高速度

時速約 27 公里（17 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 2.5 隻狗從鼻子接到尾巴一樣長跟 14 根香蕉頭尾相接一樣長能在 6.7 秒內游完一座大泳池（50 公尺）

Unktaheela 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)

Unktaheela 時速約 27 公里 (17 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

Unktaheela is the smallest known adult polycotylid plesiosaur, measuring only about 2.3 to 2.6 metres long.2

It had bony ledges over its large eyes that may have shaded them from sunlight, like built-in sunglasses.2

Its skull was wide at the back and short behind the eyes, which helped it spot and catch prey.2

Unktaheela lived about 80 million years ago in the Western Interior Seaway, a shallow sea that split North America in two.2

Scientists think Unktaheela was a visual pursuit predator, meaning it chased its food using its sharp eyesight.2

The first fossil of Unktaheela was found in 1975 near Redbird, Wyoming, but it was not named until 2024.1 2

Unktaheela 的 AI 繪圖 — 這是電腦根據科學家目前的知識，用 AI 畫出 Unktaheela 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。

給恐龍專家

學名: Unktaheela
命名者: Clark et al. 20243
類群: 蛇頸龍類
科 / 演化支: Polycotylidae3
分類: Plesiosauria > Sauropterygia3
岩石的年代: 84 到 72 百萬年 (Campanian)3
岩層: Sharon Springs3
國家: 美國3
化石紀錄: The Paleobiology Database 收錄 2 筆3
發現: Unktaheela was named in 2024 by Robert O. Clark, F. Robin O'Keefe, and Sara E. Slack based on two fossils from Wyoming and South Dakota.3 1
仍有爭議: Scientists are still debating exactly how Unktaheela used its unusual eye ledges and wide skull to hunt.2