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Crazy beast clue to evolution

2020.05.13
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A PREHISTORIC opossum-sized critter dubbed the ‘crazy beast’ that inhabited Madagascar (馬達加斯加) at the end of the age of dinosaurs is providing insight into early mammalian evolution.

The exquisitely preserved fossil of the plant-eating mammal is named Adalatherium hui. Living 66 million years ago during the Cretaceous Period, it resembled a badger with long torso and stubby tail.

The fossil represents an individual not fully grown. But at about 52 cm long and 3.1 kg, it was a giant in its time as most Mesozoic mammals were mouse-sized.

Scientists have known precious little about southern hemisphere mammals during the Mesozoic Era, the age of dinosaurs.

Adalatherium offers by far the most complete skeleton of a Mesozoic mammal from Gondwana – Earth’s southern supercontinent encompassing Africa, South America, India, Australia and Antarctica.

It also is the most complete fossil of an enigmatic mammal group called gondwanatherians that thrived for tens of millions of years but died out about 45 million years ago, leaving no living relatives.

Adalatherium is dubbed the ‘crazy beast’ as its many bizarre features seem to defy explanation in relation to other mammals.

“We suspect some of this bizarreness might be due to evolution in isolation on an island,” said Simone Hoffmann, co-author of a study published in the journal Nature. Isolated with idiosyncratic food sources, competitors and predators, life on islands develops differently than on the mainland.

Madagascar at the time boasted other oddballs including a huge 40cm frog named Beelzebufo that may have eaten baby dinosaurs and a pug-nosed plant-eating crocodile named Simosuchus.

Mammals started to dominate the Earth when an asteroid struck 66 million years ago, killing the dinosaurs.

(This article is published on Junior Standard on 13 May 2020)

 

Madagascar – Wikipedia
bit.ly/2yrcRGW

Palaeontologists Find 66-Million-Year-Old Fossil of Bizarre Mammal
bit.ly/2ynVHKh


1. inhabit (v)
    居住於; 棲息

2. exquisitely (adv)
    精緻地; 優雅

3. resemble (v)
    像; 類似於

4. skeleton (n)
    骨骼標本

5. enigmatic (adj)
    神秘的; 高深

6. thrive (v)
    成功; 興旺; 繁&



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