恐龍卡第 0670 張，共 2 027 張

Fresnosaurus

名字的意思： “Fresno lizard, named after Fresno County in California”1

吃：肉蛇頸龍類白堊紀晚期嚴格來說不是恐龍

Fresnosaurus was a huge swimming reptile with a very long neck and flippers instead of legs. It lived in the sea near California during the time of the dinosaurs, but it was not a dinosaur. It probably used its long neck to sneak up on fish and other small sea creatures.1 3

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

72 到 66 百萬年前3

白堊紀晚期

化石發現地

Fresno County, California, USA, in the Moreno Formation1 2

長度

最多 9 m (30 ft)1

最高速度

時速約 23 公里（14 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 台汽車排成一排一樣長跟 50 根香蕉頭尾相接一樣長能在 7.8 秒內游完一座大泳池（50 公尺）

Fresnosaurus 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)

Fresnosaurus 時速約 23 公里 (14 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

Fresnosaurus lived about 70 to 66 million years ago, right at the end of the Age of Dinosaurs.1

The only known fossil is from a young animal, so scientists think adults might have been even bigger than 9 meters (30 feet).2

Its name honors Fresno County, and the species name 'drescheri' honors Arthur Drescher, who likely helped find the fossil.1

Fresnosaurus belonged to a group called elasmosaurids, famous for their extremely long necks and paddle-like flippers.1 3

The fossil includes bones like the coracoids (shoulder bones), humerus (upper arm bone), pelvic girdle, and femora (thigh bones), but no skull has been found.2

Scientists recently found that some extra bones labeled as Fresnosaurus might actually belong to a different, related plesiosaur called an aristonectine.2

Fresnosaurus 的 AI 繪圖 — 這是電腦根據科學家目前的知識，用 AI 畫出 Fresnosaurus 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 Fresnosaurus was a dinosaur because it lived with dinosaurs and is often shown in dinosaur books.

真相： Fresnosaurus was a plesiosaur, a marine reptile, not a dinosaur. Dinosaurs lived on land and had different body shapes.1 3

給恐龍專家

學名: Fresnosaurus
命名者: Welles 19433
類群: 蛇頸龍類
科 / 演化支: Elasmosauridae3
分類: Plesiosauria > Elasmosauridae > Sauropterygia3
岩石的年代: 72 到 66 百萬年 (Maastrichtian)3
岩層: Moreno3
國家: 美國3
化石紀錄: The Paleobiology Database 收錄 1 筆3
發現: Fresnosaurus was first described by Samuel Paul Welles in 1943, based on a fossil found in the Moreno Formation of California. The fossil was originally stored at the California Institute of Technology and is now at the Natural History Museum of Los Angeles County.1 2
仍有爭議: Scientists are still debating whether Fresnosaurus is a valid, separate genus or if it might be the same as another elasmosaurid, because the only fossil is incomplete and from a juvenile.2