恐龍卡第 1437 張，共 2 027 張

Placodus

名字的意思： “plate tooth”1

吃：肉海生爬蟲類三疊紀早期到三疊紀晚期嚴格來說不是恐龍

Placodus was a marine reptile that lived about 240 million years ago, during the Middle Triassic. It had a stocky body, a long tail, and a heavy skull with flat teeth for crushing shellfish. It swam in shallow seas and probably spent most of its time on the seafloor looking for food.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

251 到 227 百萬年前3

三疊紀早期到三疊紀晚期

化石發現地

Central Europe (Germany, France, Poland) and China1 3

長度

2.5 到 3 m (8.2 到 9.8 ft)1

最高速度

時速約 16 公里（10 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 3 隻狗從鼻子接到尾巴一樣長跟 17 根香蕉頭尾相接一樣長能在 11 秒內游完一座大泳池（50 公尺）

Placodus 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)

Placodus 時速約 16 公里 (10 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

Placodus had a rigid body because the bones in its spine were dovetailed together, making its trunk stiff.1

Its belly was covered with special armor made of bent, right-angled abdominal ribs, and it had a row of bony knobs above its backbone.1

Placodus was negatively buoyant, meaning it was heavy and could easily stay on the seafloor without floating up.1

Before scientists knew what Placodus looked like, its teeth were mistaken for fish teeth.1

Placodus was slow and clumsy on land because of its heavy body armor, so it probably only came ashore to lay eggs.1

Its short legs probably ended in webbed feet, and it used its flattened tail to push through the water.1

Placodus 的 AI 繪圖 — 這是電腦根據科學家目前的知識，用 AI 畫出 Placodus 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 Placodus 最常被問的問題

?How big was Placodus?

About 2.5 to 3 metres (8.2 to 9.8 ft) long.1

?What did Placodus eat?

Shellfish like bivalves, plus other hard-shelled prey such as molluscs, brachiopods and crustaceans. It used its chisel-like front teeth to pluck them from the sea floor and its broad, flat back teeth to crush their shells.1

?Was Placodus a dinosaur?

No, Placodus was a marine reptile called a placodont, not a dinosaur. It lived in the sea during the Triassic period.1 2

?Could Placodus swim?

Yes, it swam using its flattened tail and short legs that probably ended in webbed feet. It was not as good at swimming as later marine reptiles like plesiosaurs, but it was comfortable in the water.1

?Why did Placodus have a rigid body?

Its spine had dovetailed bones that locked together, making its trunk stiff. This helped it stay heavy on the sea floor so it could feed without floating up.1

?When did Placodus live?

About 240 million years ago, in the Middle Triassic period.1

給恐龍專家

學名: Placodus
命名者: Agassiz 18333
類群: 海生爬蟲類
科 / 演化支: Placodontidae3
分類: Placodontia > Sauropterygia3
岩石的年代: 251 到 227 百萬年 ()3
岩層: Jena, Wellenkalk, Vossenveld3
國家: 德國, 以色列, 波蘭, 荷蘭, 義大利, 中國3
化石紀錄: The Paleobiology Database 收錄 34 筆3
又名: Anomosaurus, Crurosaurus （舊名稱現在也算作同一種動物）3
發現: Placodus was named by the Swiss naturalist Louis Agassiz in 1833. He originally thought the fossils were fish teeth.1 3