Dino 101: Dinosaur Paleobiology is a 12-lesson course teaching a comprehensive overview of non-avian dinosaurs. Topics covered: anatomy, eating, locomotion, growth, environmental and behavioral adaptations, origins and extinction. Lessons are delivered from museums, fossil-preparation labs and dig sites. Estimated workload: 3-5 hrs/week.
Holotype
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Из курса от партнера University of Alberta
Dino 101: Dinosaur Paleobiology
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What is a Species?
This module will teach the different ways of defining what a species is. Students will be able to compare the strengths and weaknesses of different species concepts for different situations.
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Philip John Currie, PhDProfessor and Canada Research Chair, Dinosaur Paleobiology
Department of Biological Sciences
There are other things you need as well to name a new species.
You need to describe what you are naming and
what differentiates it from other, closely related species.
You need to list all of the unique features that your
organism has that others do not.
Such features can include a certain type of coloration.
Length of limbs, oddly shaped horns, and so on.
To go along with this description,
you also need to designate something called a holotype.
This is the single specimen that you are stating is
the specimen that in itself is a definition of the species.
By looking at this holotype specimen,
other scientists should be able to identify the species.
For something like dinosaurs, the holotype would be single fossil.
This fossil then needs to be somewhere where other people can come look at it.
This is important.
The holotype needs to be accessible so
that other paleontologists have the opportunity to determine if
something that they have found is the same or different species.
Scientists can then also designate additional specimens if they wish.
But those other specimens are given alternate names.
Like paratype of lectotype.
Depending on the situation.
However, there is only one Holotype.
This requirement for
specimen availability leads to the answer of a very common question.
Why should we put dinosaur bones in museums?
Well, if they weren't put in museums, where would scientists,
like paleontologists go to study them for centuries to come?
New fossils are found all the time, and paleontologists need to be able to
determine if what they've just found in the field is a brand new holotype or
another example of an already described species.
How many species of non-avian dinosaurs
do you think have been named so far?
Is it 50, 100, 1,000, or 10,000?
So far somewhere around 1,000 species of dinosaur have been named.
The exact number is always changing,
as there are new dinosaurs being named all the time.
In fact, in 2012, there were about 30 new species of dinosaur named.
More than one every two weeks.
So C is the most correct answer.
Now that we've gone through the rules of how to name a new species,
Let's take a look at a relatively new dinosaur called Hesperonychus that was
named here at the University of Alberta.
Hesperonychus was a small carnivorous dinosaur,
probably about the size of a chicken.
It was found in Dinosaur Provincial Park.
The Holotype specimen is stored here in our collections so
that it's available for other researchers to study.
Here you can see the Holotype which is the pelvis from the animal.
If you remember back to earlier lessons, we rarely find complete skeletons.
So many species are named from partial skeletons.
This partial pelvis has enough unique characteristics that we can tell that it
is not a species that has been named before.
First off, we can see that this was an adult.
The ilium and
pubis are fused together, something that happens when an animal is mature.
All of the other small theropod dinosaurs from Dinosaur Provincial Park
are much larger than Hesperonychus as adults,
giving us a good sign that we're dealing with something new.
Because of the unique combination of features on the hips, for
example a split in the shelf on the ilium,
we can begin to see that this is something different than what we've seen before.
After looking at other examples of dinosaurs,
we see enough unique features to determine that we have discovered a new species.
We decided to name it.
We usually try to give names appropriate to the animal, and
in this case we call it Hesperonychus elizabethae.
Hesperonychus means western claw, as it has a large claw on its foot, and
is the first of this particular group of dinosaurs to be found in
the western hemisphere.
The elizabethae epithet honors Dr.
Betsy Nicholls, who originally discovered the fossil.
One we had examined, described, photographs and thought of a name for
the dinosaur.
We submitted the manuscript to a journal,
which then sent the article to several other paleontologists.
These other scientists provided comments on how to improve our work, but
everyone agreed that what he had was the holotype of a new species.
Finally, once the article was published, the name became official.
This fossil has now been added to your 3D fossil viewer.
Go and have a look at it.
Which of these things is the most reliable feature or
characteristic that a scientist can use to divide up organisms into separate species?
There's only one best answer, so consider your response carefully.
Presence of absence of antlers?
Number of fingers on the hand?
Color of the skin or feathers?
Or length of the limbs?
Of these options, the number of fingers on the hand is
the most reliable characteristic to use to separate species from one another.
That isn't to say that the other options can never be used.
And even in some things, like the number of fingers on the hand, can vary.
For example, Napoleon, when he was emperor of France, owned a horse with extra toes.
And there are many cases of humans being born with extra fingers.
However, the number of fingers is overwhelmingly constant within a species.
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