Though dinosaur finds are revealed on a fairly regular basis, very few result in as much excitement as the latest two. On Thursday, September 4th, a team of scientists led by Kenneth Lacovara, an associate professor at Philadelphia's Drexel University unveiled the Dreadnoughtus schrani, which they believe is the biggest known land animal to have ever inhabited Earth. While dinosaur fans were still digesting the facts, on September 11th, came news of the re-discovery of the Spinosaurus aegyptiacus, the only known semi-aquatic dinosaur.

Dreadnoughtus schrani

Discovered in Argentina's Patagonia desert, the Dreadnoughtus schrani, measured an astounding 85-feet long and 30-feet wide and weighed 65-tons, more than the weight of seven Tyrannosaurus rex (T-rex) put together! What's even more amazing is that fossil scans revealed that the dinosaur was not done growing, when it died. It is no wonder that the researchers chose to name it Dreadnoughtus, which means 'fear nothing'.

Believed to be a a member of the titanosaur family that roamed the southern continents 66-to-100 million years ago, its peg-shaped teeth, plank-like ribs and long legs, all indicate that similar to other dinosaur giants, the Dreadnoughtus was herbivorous.

While the dinosaur's giant size is certainly exciting, what is even more so, is how complete and pristinely preserved its skeleton is. The scientists who conducted the excavation over four seasons - from 2005 to 2009 - unearthed approximately 100 perfectly preserved fossils. Using these they have been able to reconstruct a majority of the giant's 30-foot-long tail vertebrae, its 3-foot diameter neck vertebra, as well as some toes, claws and even a tooth. This extensive find has helped the researchers who published their study in the online journal, Scientific Reports, on September 4th, to fine-tune their perception of what the mighty giants looked like. Turns out that they had shorter, muscular tails and longer necks than had been previously believed.

Of course, not everyone agrees that the Dreadnoughtus is the biggest dinosaur that ever walked the earth. Some researchers maintain that that title belongs to the Argentinosaurus, which they estimate weighed between 70-90 tons, while others are convinced that it should go to a more recent, yet-to-be named dinosaur, that was also discovered in Patagonia, in May 2014.

Lacovara says that while they may indeed be right, there is no real evidence. That's because those size estimates are based upon a few bones or on analysis that hasn't yet been reviewed by other experts. In contrast, the estimates made by his team are from the more than 100 fossils that represent almost 70% of the bone types found below the dinosaur's skull. Hence, while the Dreadnoughtus may not have been the largest land animal to walk the globe, it is definitely the largest one that experts can confirm, without any doubt!

Spinosaurus aegyptiacus

Though Dreadnoughtus may be the size winners, it is the Spinosaurus aegyptiacus, unveiled by University of Chicago's paleontologists Nizar Ibrahim and Paul Sereno on September 11th, that takes top billing for unusual features and characteristics. What makes the 50-foot creature, which sported a crocodile snout as big as a person and webbed duck feet intriguing, is that until its discovery, dinosaurs were thought to be land dwellers who made an occasional trip to nearby ponds or lakes.

However close examination of the Spinosaurus fossils revealed hip bones similar to that of a whale, nostrils positioned high on the skull and dense penguin-like bones - all indications that this giant spent a large part of its life in water! Paul Sereno believes that while the Spinosaurus was capable of walking and nesting on land, it most likely lumbered on its two back feet because its powerful forelegs complete with sharp curved claws were designed to kill, not walk!

Yes, that's right - This was no gentle giant but a predator that measured 9-feet longer than the dreaded T-rex and feasted on aquatic creatures like 25-foot sharks, giant saw fish and humongous crocodiles that inhabited the world, 95-million years ago!

And if the Spinosaurus aegyptiacus, sounds familiar from its epic land battle with the T-rex in the movie, Jurassic Park III, it's because the species is not new. German paleontologist Ernst Stromer uncovered the fossils of this bizarre dinosaur in Egypt, all the way back in 1912. However, the fossils were destroyed in the 1944 bombing of Munich in World War 11. This meant that experts had never been able to really examine this alien-like dinosaur. It is only thanks to a new fossil find in Morocco in 2008, that its secrets have finally been revealed.

As for the battle with the T-rex? The researchers say that two would have probably never encountered one another given that they lived on different continents during different eras. However, if they there had been a battle, especially in water, the Spinosaurus would have won hands down!

Resources: nbcnews.com,news.yahoo.com,nationalgeographic.com