From the Google cache.
Big hedgehog. Small sand dollars. Diving schools
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Date: 10/23/05 at 3:30PM
Mood: Looking Playing: Smoke on the waters, by Deep Purple
Today, Science Day in the Natural History museum.
Including information on the palaeolontogical finds from the Gargano region in Italy.
There, you may find many fossils in fissures in the chalky soil.
With a specific island fauna, where many usually small animals could evolve into bigger island forms [however, in 2007, ”Island Rule’ Of Evolution Disputed‘] as there were no major land predators they needed to hide from.
The island had a dry climate.
What moisture there was tended to congegrate in the fissures in the rocks.
That moisture attracted the scarce trees of the island.
And those trees attracted birds of prey to sit on.
The birds of prey dropped the indigestible parts of their prey; so they fell into the fissures.
And so, since the 1970s and still today, palaeontologists from Italy and The Netherlands (including Mr L.W. van den Hoek van Ostende, who explained today) find many fossils of mice and other animals in those fissures.
Today, the museum had put microscopes on a table to see those fossils.
Children and other visitors also got a chance to extract teeth or ribs of fossil mice from the red rocks.
A frequent species in the rocks is Microtia; of which a small girl to her joy managed to find a tooth in “her” rock.
From the tooth, one could see Microtia, the Gargano giant rat, was vegetarian.
And reptiles and amphibians.
They ate few fish, as the island was dry.
Probably they sometimes ate invertebrate animals.
However, the geological situation prevented those from becoming fossils (too accessible to oxygen).
Unfortunately, that also prevented plants, including the trees where the birds of prey used to sit, from fossilizing.
So we are still missing parts of the ancient Gargano food chain.
We do know something on the birds of prey.
They included a big owl, related to the barn owl of the present.
And a buzzard species.
Also a very big eagle, maybe related to another fossil species from Spain.
It used to be called Garganoaetus, but the name changed.
The birds of prey were the top predators.
No land predators had made it to the island when it formed.
So, some smaller animals evolved into a kind of land predator.
Especially the giant hedgehog, Deinogaleryx.
However, being the size of a cat, it was not a really major predator.
A crocodile species on the island looked more like one.
Talking about water: at another table, people could learn about sand dollars; small sea urchins.
Mr Steve Donovan had found plenty of them during a family day at the beach of popular Dutch resort Zandvoort.
He displayed them in plastic Chinese takeaway trays.
The Dutch sand dollar species is small. It is Echinocyamus pusillus, the pea urchin.
They eat algae and other micro-organisms.
They are certainly too small to eat sea lilies like big sea urchins do.
Sand dollars are also not cannibals, like sea snails which one can also find on Zandvoort beach.
Another sea urchin species on Dutch beaches is the heart urchin.
It is rarely found intact, due to fragility, however.
Bigger sand dollar species from the USA are about the size of a dollar coin; hence their name.
Still bigger species occur in Africa and California.
And a very big one in Curacao and other places in the Caribbean. It is Clypeaster rosaceus.
Tiny crabs live between its spines, freeing it from parasites.
Sand dollars evolved during the Eocene, about 50 million years ago.
The Dutch species already occurred in the Pliocene; over 2 million years ago.
Then, the big species also already occurred in the Caribbean.
There was also a general marine biology table.
Mr A. Gittenberger explained there.
There was information on the research in the sea between the Indonesian islands of Bali and Lombok.
They found a new Millepora species there, a hydroid.
Most marine biologists at the museum are specialists in Indonesian marine fauna, rather than in Dutch sea animals.
Mr Gittenberger is an exception to this.
The son of a snail specialist of the museum, he himself specializes in the marine fauna of the Dutch coastal waters; sea squirts being his favourites.
This is a sea squirt video.
Recently, a sea squirt species in the Mogula genus was found for the first time in The Netherlands.
Het Zeepaardje magazine will report on this.
Basically each year, marine species new for The Netherlands are discovered.
Mr Gittenberger dives often and is also the president of the local diving club.
He said that commercial diving schools often do not pay enough attention to safety.
For instance, if teenagers have a lung injury from diving just before a growing spurt of their bodies, that may hurt their lungs for life.
So, commercial diving schools should discourage people that age from diving. But they don’t.
Also, if people just start diving, safety requires a one instructor to one newbie ratio.
However, at commercial diving schools, there often is an unsafe ratio like one instructor for four newbies.
Also in Indonesia, many new species, and other facts, are found.
The most recent marine biology expedition was to the Thousand Islands, coral islands north of the Indonesian capital Jakarta.
Jakarta being one of the biggest cities in the world with major sewage problems, marine life near the Thousand Islands suffers from pollution.
As scientists know from comparison with research there of 10 or 20 years ago.
As I walk further, I watch the water around the museum.
In the water, a mature and a young mute swan are eating water plants.
On the ditch bank close to the swans, also two birds: a mature and an immature herring gull.