The Earth Story

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Gorgeous fossil crab, Eocene aged

I think this is a dinosaur claw from british Columbia

The world’s largest terrestrial crab

Meet the coconut crab (Birgus latro), which holds the title of the world’s largest terrestrial crab (and indeed the world’s largest terrestrial arthropod). Found on islands of the Pacific and Indian oceans, it can reach a length of up to 1 m (3 ft 3 in), and a weight of up to 4.1 kg (9.0 lb) (see an especially large individual here: http://bit.ly/1UXlLhF).

Like all arthropods, coconut crabs do not have an internal skeleton. Instead, they wear an exoskeleton like armour, which sheds as they grow. Fuelling their massive growth requires a lot of food, so the crabs eats anything they can get its claws on - from carrion to fruit, chickens to other crabs. But as their name suggests, coconuts are their favourite.

As anyone who has lived on a tropical island will know, coconuts are notoriously difficult to open. But these crabs have no problem. Equipped with a pair of massive claws, they tear away the outer fibres (which can take many days and more than one crab), and use one of their legs to puncture a hole to pry the shell open further. If this fails, some crabs have been observed to lift coconuts up trees 10 metres (33 ft) high, then drop them to reveal the inner white flesh. In fact, the crab’s claws are capable of lifting weights up to 28 kg, so this is rarely an issue.

And it seems their love of coconuts is worth it. Crabs living in coconut-rich habitats have double the average mass of those living in coconut-free habitats. I guess it’s similar to how many of our own favourite foods greatly increase our mass, though this is perhaps not so much of a good thing.

VP

References: http://bit.ly/1T6E5DQ, http://bit.ly/1OjRIzb Image credit: USFWS (https://flic.kr/p/8x28HH)

On May the 7th, 1903 William Ferguson discovered the Cape Paterson claw, Australia’s first dinosaur fossil at what is now Eagle’s Nest, , Bunurong Marine National Park located along the south coast of Victoria, approximately 150 km south-east of Melbourne. Recovered from the Strzelecki Group, comprised of interbedded sandstone and mudstone, the claw belongs to a carnivorous theropod which lived during the Early Cretaceous. During this period in Earth’s history, Victoria was located well within the polar circle, with palaeolatitude estimates varying between 75-85°S and 70-80°S.

Since the discovery of the Cape Paterson claw, there have been numerous breakthroughs within Australian dinosaur paleontology with annual digs held at the Flat Rocks site in Inverloch unearthing the remains of small ornithopods alongside crocodile, turtle and plant material. In 2007, the remains of Australia’s largest known dinosaur, a Titanosaur were discovered on the outskirts of Eromanga, in south-west Queensland. Given the vastness of the continent, it is likely that more discoveries will be made in the coming decades, enhancing our understanding of dinosaur paleontology.

AHP

Sources http://bit.ly/1O51Cor http://bit.ly/1Xdzn94 http://bit.ly/1Krp5OH http://bit.ly/1NmpNOU http://ab.co/1S29D9r

Image: copyright Museum Victoria / CC BY http://collections.museumvictoria.com.au/specimens/1045754

DON’T GO IN THE WATER: NEW EVIDENCE THAT SOME DINOSAURS WERE STRONG SWIMMERS

Claw marks left on a river bottom in Sichuan, China are evidence for dinosaurs’ ability to swim relatively long distances. According to an international team of scientists in the journal Chinese Science Bulletin, theropod species of dinosaurs were able to travel in relatively deep bodies of water.

A theropod dinosaur walked on two legs. This group of dinosaurs was carnivorous, had grasping hands with fingers, and long necks. Tyrannosaurus rex, Velociraptor, and the chicken-sized Compsognathus were all theropods, which ranged in size. Living birds of today have common ancestors with theropods.

The researchers examined a section of land that was a major transportation route for dinosaurs due to the presence of abundant footprints. While examining the tracks of other Early Cretaceous dinosaur species, scientists noticed unusual claw marks made by what is thought to be a 1-meter-tall theropod in the sediment. These marks showed a left-to-right pattern akin to bipedal movement, as if the theropods’ claws were scratching into the soil on its toes; the gouging pattern left by the dinosaur is deeper in the front of the track than in the back. This pattern continued for about 15 meters in the section.

According to the researchers, the river must have had dry and wet cycles over 100 million years ago due to the presence of ripple marks and mud cracks in the soil. In addition to theropod tracks, there are those of sauropod dinosaurs as well. Sauropods were four-legged herbivores, and were found on all landmasses with the exception of Antarctica. Finally, there are ornithopod tracks in the sediment. Ornithopod dinosaurs were also plant-eaters and mostly walked on two legs. Their tracks were in parallel formations, indicating herding behavior in walking in pairs or groups. It is unclear whether these tracks were all made during the same time period, but the sauropod and theropod tracks were deposited on the same formation. All tracks were around the same depth and similar in size, so they could have been produced at the same time.

Since there are only claw marks for the theropods present, it is difficult to determine the exact type of species that produced them. The scientists think that the theropod could have been an early tyrannosaur or a Sinocalliopteryx, which were small predatory dinosaurs 2.5 meters in length. Both species of dinosaurs have been found in this region of China.

-Jeanne K.

Illustration by Nathan E. Rogers.

References: http://link.springer.com/content/pdf/10.1007%2Fs11434-013-5802-6

http://www.eurekalert.org/pub_releases/2013-04/uoa-ned040813.php

http://www.sciencedaily.com/releases/2013/04/130408123502.htm

http://www.ucmp.berkeley.edu/diapsids/saurischia/theropoda.html

http://www.ucmp.berkeley.edu/diapsids/saurischia/sauropoda.html

http://www.bbc.co.uk/news/science-environment-19426885

http://www.ucmp.berkeley.edu/diapsids/ornithischia/ornithopoda.html