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Friday, June 10, 2011

Dinosaurs of Japan

Author's collection of dinosaur fossils
Today I am speaking to you from 2011. It's been some 18 years since I last lived in Japan as a junior high school assistant English teacher in Ohtawara-shi (Ohtawara City), Tochigi-ken (Tochigi Prefecture). Now 18 years is a long time ago, but in the grand scheme of things, it's barely a drop in the bucket.

I've been interested in paleontology ever since I can remember, well, anything. I am interested in dinosaurs and what they ate and how they lived and died.

In Japan, I was lucky enough to find a couple of like-minded individuals... who shared my passion for fossils... as well as one such person who shared a passion for me.

A teacher at Wakakusa Chu Gakko (Wakakusa Junior High School) who knew nothing of me, showed me some of the  fossils he found while on a vacation/dig in Argentina a year ago. Seeing my fascination to finally touch a fossil for the first time ever--and realizing that I also knew a fair bit of paleontology, he presented me with a few pieces from his collection... ... some sea life gastropod shells, a sea ammonite... and my favourite—a portion of a spine bone and a partial rib section of a dinosaur I'd estimate to be the size of a chicken. I have no idea what the heck it is, suffice to say that I love them.

Down in Utsunomiya-shi (Utsunomiya City), the capital of Tochigi, I happened to stumble upon a traveling dinosaur exhibit one day—perhaps one of the only times I traveled successfully by myself. I purchased a few small shards of dinosaur eggshell—a Hypselosaurus found in France, from the Upper Cretaceous period of 80,000,000 years ago. I also spent most of the money I had on me for a large chunk of rock that was cracked open (and shaped to a globe), containing two trilobite fossils. How do I know they are real? The smell... the rock and fossil smell like nothing I've ever smelled before... it smells ancient... and it smells exactly like all of the other fossils I have (mentioned in this blog in the paragraph above and below).
 
Later, with my girlfriend Noboko (the one who shared a passion for me), we drove to a place where we could dig our own fossils up, called Mine-shi (Mine City) fossil field in Yamaguchi-ken (Yamaguchi Prefecture). Granted the majority of fossils people could find are of the odd bug and leaves, it was still exciting. Take it from me... of the 30 people there, only I managed to find a near complete fossilized leaf. Everyone else only managed to find detritus... specks of leaves. Noboko, to her credit, had no interest in dinosaurs or fossils, but knew I did, so going on such a big trip with me and for me spoke volumes.  

Anyhow, glancing at my fossil collection (photo above), it got me thinking... just what type of dinosaurs roamed Japan? No... I'm not talking about Godzilla, Mothra, Rhodan or Gamara.

There have been relatively few dinosaur bones found in Japan. Those that have been found have been from the prefectures of Hyogo, Hokkaido, Fukui, Mie, Kumamoto and Fukushima.

Among some of the dinosaur fossils found are:
  • a Spinosaurus, a Tyrannosaurus-like carnivore, 17 meters long, six tons in weight;
  • Tanbaryu and Mamenchisaurus (aka Titanosaurus) - the largest known Japanese dinosaurs, were herbivoe, sauropods with names like Tanbaryu and Mamenchisaurus . The Mamenchisaurus is thought to be the largest and one of the oldest dinosaurs that lived in Japan. It lived 120 million years ago and reached a length of 20 meters. Fossils of these creatures have been found in Katsuyama, Fukui-ken. Tanburyu fossils been found in the in the Tanba area of Hyogo-ken and Mie-ken. It to is guesstimated to have lived 120 million years ago.
  • Hadrosaurus—an 85 million-year-old skull of a seven-meter long, duck-billed, herbivorous  found in the a mountains in Mifune-machi, Kumamoto-ken
  • The oldest mammal fossils found in Japan have been dated to 136 million to 140 million year ago. They came from three small shrew-like species found near Kobe in Hyogo-ken.
There is also a pair of dinosaurs that seem specific to Japan, a herbivore and a carnivore named Fukuisaurus and Fukuiraptor, respectively.

Fukuisaurus
The image to the right is a Fukuisaurus, which translates from Latin to English into Fukui Lizard.
This herbivore is 4.7 meters long, with the top of its head at perhaps 2.0 meters. It's weight is estimated at 400 kilograms. Discovered in 1989 in the Kitadani quarry in Katsuyama, Fukui-ken, its full name is Fukuisaurus tetoriensis.
Fukuisaurus is a relatively small species and is bipedal, but could go down onto all fours.
The dinosaur lived during the Lower Cretaceous era of 99- to 121 million years ago.


Fukuiraptor
The Fukuiraptor's name means Fukui plunderer/thief. (See image to the left). Considered a medium-sized carnivore alongside its more famous kin—the Velociraptor--featured in the Jurassic Park films and books. It lived in the Lower Cretaceous period of 99- to 121-million years ago. About 4.2 meters long, as judged by the skeletons found, scientist are convinced that all fossils found so far are those of juveniles, and thus have not yet determined the true height or weight of the  creature. This specimen caused some confusion upon its initial discovery because its hand claw was mistaken for the killer claw on the foot of a dromaeosaur. It is now considered to be a basal member of the Allosaurus family.

A more recent find in Japan, is the oldest known plant-eating lizard, consisting of a 130-million-year-old jaw and skull bones found in Ishikawa-ken (see map of Japan). Known as Kuwajimalla kagaensis,
and based on the size of the skull, scientists estimate it measures between 10 to 12 inches (25 to 30 centimeters) in length. Before the discovery, the oldest known plant-eating lizard was Dicothodon, which lived in North America about 100 million years ago.
Even today, fully herbivorous, or plant-eating lizards are rare, with only about three per cent of modern lizards belonging to the group. Nowadays, most lizards eat flesh, usually insects, or a combination of flesh and plants.Those lizards that are herbivorous, eat flowering plants, or angiosperms, whose buds and leaves are typically softer than non-flowering plants.
This Kuwajimalla kagaensis fossil could therefore indicate that angiosperms were already in existence and perhaps widespread millions of years earlier than what had been previously thought.
"By finding this particular fossil from Japan, it might suggest that flowering plants were already there, but we don't have direct evidence yet," states study team member Manabe Makoto (surname first), of the National Science Museum in Tokyo.

Somewhere sniffing dinosaur fossils,
Andrew Joseph
PS: In the top most photo, you see some fossils in a shadow box. My wife and a friend of hers did that for me just a few weeks ago. Awesome!

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