恐龍卡第 0164 張，共 2 027 張

Argentinonectes

名字的意思： “Lake Argentino swimmer”1

吃：肉蛇頸龍類白堊紀晚期嚴格來說不是恐龍

Argentinonectes was a huge, long-necked marine reptile that swam in the seas near Antarctica 66 million years ago. It had four flipper-like legs and a stiff tail that may have had a fin on the end. This plesiosaur is the most complete one ever found in Argentina!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

72 到 66 百萬年前3

白堊紀晚期

化石發現地

Calafate Formation, Santa Cruz Province, Argentina1 2

長度

7 到 9 m (23 到 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）

Argentinonectes 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)

Argentinonectes 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

The fossil was found under 50 cm (20 inches) of water in Lake Argentino, making it tricky to dig out.1

Its rib cage and belly bones were very stiff, which helped it dive without its lungs collapsing.1

Shark teeth and scratches on its bones show that sharks ate the dead plesiosaur's body.1

The tail had eight tightly locked vertebrae at the tip, probably supporting a small tail fin.1

Its forelimbs were about 1.8 metres (5.9 feet) long, and the hindlimbs were a bit shorter at 1.3 metres (4.3 feet).1

The skeleton is missing the skull and most of the neck, possibly because they floated away after death.1

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

你們都在問

關於 Argentinonectes 最常被問的問題

?How big was Argentinonectes?

It was about 7 to 9 metres (23 to 30 feet) long. That is roughly as long as a school bus.1

?What did Argentinonectes eat?

Scientists do not know for sure because the skull is missing. But like other plesiosaurs, it probably ate fish and squid.1

?When did Argentinonectes live?

It lived at the very end of the Cretaceous Period, about 66 million years ago.1

?Is Argentinonectes a dinosaur?

No, it is a plesiosaur, a marine reptile that swam in the ocean. It is not a dinosaur.1

迷思破解王

迷思： Some people think all plesiosaurs were slow and clumsy on land.

真相： Argentinonectes and other plesiosaurs were fully aquatic and never came onto land. They were fast swimmers in the ocean.1

給恐龍專家

學名: Argentinonectes
命名者: Novas et al. 20263
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: Calafate3
國家: 阿根廷3
化石紀錄: The Paleobiology Database 收錄 1 筆3
發現: The fossil was found in 2009 in Lake Argentino, Argentina, and was named Argentinonectes calafatensis by Fernando Novas and colleagues in 2026.1
仍有爭議: Scientists are not sure why the skull and neck are missing. They may have been eroded by waves or detached when the body bloated and floated.1