Wednesday, February 8, 2017

The Malagasy Dinosaur

When I first read the name Malagasy Dinosaur, my eyes rearranged the letters and I thought I had read “Madagascar Dinosaur”. Then I thought, Of course not. Madagascar isn’t big enough to have had a population of dinosaurs.

Well, it turns out Madagascar is big enough. I guess you can’t judge a place by how it looks on a map. Especially not when it’s snuggled up next to a continent as big as Africa.

Madagascar is an island, and it’s believed it separated from the super-continent Gondwana about 85 million years ago. It has plenty of wildlife of some pretty strange species, as evolution has worked to fill all the niches in the food chain. Fossils found on Madagascar seem to indicate it’s had some strange species for a long, lo-o-ong time. Here’s some samples:

Beelzebofus antinga, an extinct frog that weighed up to five kilo (11 pounds). It is the heaviest extinct frog ever known. (Okay, not a dinosaur, but still…) If they were still around, maybe they’d be raised as food, like a chicken?

Rapetosaurus krausei was a dinosaur that reached 15 meters (49 feet) in length. It walked on all 4 feet and had a small head on a very long neck. It was a vegetarian, so I suppose we’d only have to worry that it might step on us, if we’d been alive at the same time as it.

Rahonavis ostromi was about 50 cm (19-20 inches), wore feathers over its entire body, had claws, a long skull and a mouth full of sharp teeth. Could this be the ‘missing link’ between dinosaurs and birds?

Sinosuchus clarki looked somewhat like a modern crocodile. Kinda. Except it was less than 80 cm (32 inches) long, including a short, broad head and a short tail. It also had teeth perfect for grazing on plants, and bone plates under its skin to protect it from predators.

Speaking of crocodile-like dinosaurs, the Araripesuchus tsangatsangana looked a lot like modern crocodiles, except it had much longer legs.

But none of these interesting creatures were the one called the Malagasy dinosaur. Only the Majungasaurus crenatissimus bears that nick-name. The Malagasy looked similar to a Tyrannosaurus rex, except it only reached a length of 6 to 8 meters (19 to 26 feet) and probably only weighed a ton. Even though it was so much smaller than its cousins, scientists say it took 20 years to reach its full size, so it grew much more slowly than the others, also. They made that discovery by studying cross-sections of several bones from a nearly complete skeleton found in 2003. The bones had marks of annual growth, rather like trees have tree rings. Of course, some bones had marrow in the center, displacing the earliest years’ record of growth. Other bones were hollow, and many of the bones were carved in order to reduce the creature’s weight.

The Malagasy lived 66 to 70 million years ago. However, it seems to have links to dinosaurs in south Asia (India) and South America (Argentina). So, could it be that Madagascar clung to Gondwana longer than was thought?

Wednesday, February 1, 2017

Ick! It’s an Ichthyosaur!

Ichthyosar means “fish reptile” in Greek. Fossils reveal that they appeared about 250 million years ago, and one branch lasted until 90 million years ago. Their ancestors were some unidentified land reptile that decided to return to the water and become fish-like, much like dolphins and whales.

Science became aware of ichthyosaurs in the early 1800s when the first complete skeleton fossil was discovered in England. Later that century, many more Ichy fossils were found in Germany, and some of them included soft tissue remains. (No longer soft, after being fossilized, of course.)

Ichys ranged from 1 meter to over 16. Some resembled modern fish, others looked more like dolphins. They had pointed heads and often pointed teeth. Some could and did attack large animals that wandered into reach. They had large eyes, probably so they could dive deep. Their legs had completely converted into flippers, although many species’ flippers had numerous digits and phalanges (bones of the digits). They were not really fish, because they breathed air, gave birth to live offspring (up to 11 at a time), and were warm-blooded.

Life as an ichy was not all hunting and reproducing. One fossil had bite marks on its snout, apparently from one of his own kind. The bites had started to heal, so it survived the attack, but was this common? Or had he/she really made someone angry? Another fossil was complete… except for its tail. The theory is that it was ambushed by another of the big ocean predators, which bit off its tail. That ichy – unable to swim – sank deeper, drowned, and eventually became a fossil.

At one of my jobs, they decided to install an aquarium. If you want a healthy aquarium, you need a bottom feeder, usually a catfish. The fish they got included a bottom feeder, probably some type of catfish, but I thought it was ugly; flat bottom, thick whiskers, brown with black spots on skin that looked slightly fuzzy. I wound up calling it ‘Ichy’. I was familiar with the name, but didn’t realize they had all died out long ago. And since this fish didn’t actually look anything like an Ichthyosar, the name really didn’t fit.

I feel sorry for that poor bottom-feeder, now. I grew to rather like him, but I still called him ‘Icky’ (my pronunciation). It really wasn’t fair. I’m sure others of his species – whichever one he belonged to – thought him quite acceptable.