birds in japan

birds in japan

According to a report in Discovery News, the world's first pterosaur tracks from Japan, documented in a new study, suggest these Dinosaur-Age flying reptiles not only coexisted with birds, but that the two groups also hung out together when they weren't soaring the Cretaceous skies.
A lone siltstone slab contains the fossilized footprints, made by pterosaurs, birds and amphibians.
It provides a literal slice of what prehistoric life was like in Japan around 127 million years ago.
"I think that a group of small pterosaurs was feeding together near a pond or near a lake," lead author Yuong-Nam Lee told Discovery News, adding "there are lots of feeding beak marks."
The scientists identified a total of 64 imprints made by five to six individuals that "show a clear quadrupedal gait pattern" with feet bearing curved "hook-like sharp" claws.
"The high density of the tracks suggest gregarious behavior, but the random orientation of the trackways does not show that they were moving in the same direction as a herd," Lee said.
He and his team instead think the pterosaurs and birds randomly gathered to feed.
The eating marks consist of "small round depressions on the slab," possibly where the animals repeatedly pecked away for food.
Since the tracks don't match up with any other known pterosaur prints, the researchers believe they were made by a new species, called Pteraichnus nipponensis.
The only other evidence for pterosaurs in Japan is an incomplete spinal column bone and a single print set, not yet fully documented, from another location.
Nevertheless, this evidence and the siltstone slab prints suggest that multiple tiny pterosaurs called Japan home from at least 113 to 127 million years ago.
Evidence for small pterosaurs at that time has also been found in Spain and Korea.
Since the tracks are similar, yet appear to have been made by different sized individuals, David Unwin, a senior researcher in paleobiology at the University of Leicester, said that it is possible "that pterosaurs of widely differing growth stages visited/walked around in the same small area."

Of Gould's various works, the works in which birds found in Japan appear most frequently are The Birds of Europe (5 vols., 1832-37) and The Birds of Great Britain (5 vols., 1862-73). Works in which Japanese birds occasionally appear are A Century of Birds from the Himalaya Mountains (1 vol., 1831-32) and The Birds of Asia (7 vols., 1849-83). Works in which they rarely appear are The Birds of Australia (7 vols. & 1 suppl., 1840-69) and The Birds of New Guinea and the adjacent Papuan Islands (5 vols., 1875-88).The reason why so many birds found in Japan appear in The Birds of Europe and The Birds of Great Britain is because many Japanese birds come from the Eurasian continent. Many migrating birds come to Japan from the continent, so there are many common species between Japan. The west part of Eurasia is Europe, and many birds in Britain come from the European continent. Thus many Japanese birds can also be seen in Britain. However, although there are many common species, the colour of their feathers are not necessarily the same.If we take a sparrow from Hokkaido and another from Okinawa and compare the colour of their heads, we will discover that their colours differ considerably. However if we examine specimens starting from Hokkaido, then the northern part of Honshu, then the Kanto region, then Kyushu, then the Southern Islands, we would find that the colours of sparrows' heads gradually and continuously change from north to south, and consequently would feel no such incongruity. In the same way, if we compare the sparrows found in Japan with those from Britain, we would feel that the features differ a little, but that they are sparrows just the same. If we examine Gould's works from this viewpoint, we can find many Japanese birds in his illustrations.

Unwin was also struck by the presence of the bird tracks.
He indicated that scientists have long puzzled over the relationship between birds and pterosaurs, wondering if they enjoyed "a long peaceful coexistence, or protracted competition."
The former now appears to be the case.