Paleo Profile: “Lightning Claw”

Name: There is no official name yet, but the specimen has been given the informal name “Lightning Claw”.

Meaning: The nickname comes from Lightning Ridge, where the bones were found, and the large claws that help distinguish the lineage this dinosaur belonged to.

Age: Around 110 million years ago.

Where in the world?: New South Wales, Australia.

What sort of critter?: One of the theropod dinosaurs known as megaraptorids, famous for their enlarged hand claws.

Size: Estimated at over 20 feet long.

How much of the creature’s body is known?: Natural casts of a fragmentary skeleton including elements of the lower arm, claws, lower leg, part of the hip, and pieces of ribs.

Claim to fame: No two dinosaurs look alike. This is as true in death as in life. Aside from biological differences – in species, in age, in size, and so on – the way bone becomes preserved in stone gives each skeleton its own character. In the case of a skeleton recently uncovered in the Cretaceous rock of Australia’s Lightning Ridge, the bones of a very sharp dinosaur has come down to us as a set of natural casts of opal.

The dinosaur, described by paleontologist Phil Bell and colleagues, doesn’t have a scientific name. There’s too little of the skeleton to raise the banner of a new genus or species just yet. But there’s enough of the fossil to tell that the dinosaur was one of the megaraptorids – large, predatory dinosaurs that bore extra-long claws on their hands.

Megaraptors are still mystery dinosaurs. No one’s quite sure what group of theropod dinosaur they group most closely to. But, as far as Australia goes, the “Lightning Claw” was found in rock about 12 million years older than the next megaraptor found in the country. It likely represents something new, making the fact that some of its skeleton might have been lost during opal-mining operations all the more frustrating.

Still, Bell and coauthors write, the fact that a megaraptor was found earlier in the Cretaceous than its next closest neighbor suggests that Australia may not have been the evolutionary backwater for dinosaurs that paleontologists have often thought. Cretaceous Australia has often been characterized as a place where members of different dinosaur lineages, which originated elsewhere, eventually wound up. The “Lightning Claw” might indicate that the megaraptors, at least, originated in Australia, or that the area was a critical place for their evolution before they spread elsewhere throughout the southern group of continents called Gondwana. With any luck, future finds will help explain what these dinosaurs were and how they terrorized the southern hemisphere.

Reference:

Bell, P., Cau, A., Fanti, F., Smith, E. 2015. A large-clawed theropod (Dinosauria: Tetanurae) from the Lower Cretaceous of Australia and the Gondwanan origin of megaraptorid theropods. Gondwana Research. doi: 10.1016/j.gr.2015.08.004

Previous Paleo Profiles:

Atychodracon megacephalus
Sefapanosaurus zastronensis
Huanansaurus ganzhouensis
Zhenyuanlong suni
Lepidus praecisio
Nothronychus graffami
Ganguroo robustiter
Vulpes mathisoni
Ichibengops munyamadziensis
Pulanesaura eocollum