Some early

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Some early Ideas on conodonts
There is actually a Pander Society website
devoted to
conodonts
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Conodonts (teeth of a hagfish-like organism)
CaPO4
organics(apatite) light brown in colour

Sometimes confused with Scolecodonts which
are 50 C and 50 SiO2
Size up to 5mm but usually lt1mm
Marine, very few known whole animals
Cam. Cretaceous (not many after
Triassic) Only remains of a group that was
important and widely Distributed in the Paleozoic
oceans. Important stratigraphic In
mid-Paleozoic Mode of growth-concentric from a
center-only animal in This time period that had
concentric growth Growth- areas of fast and slow
growth-tips(cusps) fast and Basal parts
slow-response to wear? Lamellae-(note
spelling)-shape of conodont determined By how
lamellae are laid out-differential growth
occurs With thickening of lamellae Until recently
(1980) animal form was not known
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Things that Conodonts can Be confused With- A-worm
tooth B,C-fish teeth D,E-scolecodonts
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Three basic elements Of conodonts Coniform (Simple
)-1 Thorn shaped,pointed Cusp on oral
surface,expnded base Ramiform (Compound)-2 Extend
ed base bearing conical denticles Pectinoform (Pla
tform)-3 Laterally flattened, blade May be
sculptured
1
2
3
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Lamellae-differential growth occurs with
thickening White matter-most commonly in cusp or
denticle-solid Material rather than fibrous-tends
to stand out when Conodont is placed in
HCl Fibrous structure-once thought to be of
taxonomic Importance (fibrous vs. lamellar)
however some species Have both Basal filling-
usually missing, described as bone-like Material
attached to the base
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Lamellar Structure With faster Growth at The
tips (like other Types of teeth)
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Most of the white matter is an external covering
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Basal filling Is just like the Inner part of
your Teeth-it is often Missing because It would
have been Protected by gums much like Human
teeth
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Cambrian and lower Ordovician are much the same-
except that Cambrian Are all simple forms
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By upper Ordovician More compound forms Start to
show up-this is One of the few groups Where
morphological Trends can be actually Be used
stratigraphically
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Compared to previous Times there are
relatively Few conodonts in the Silurian and
most Seem to be compound
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Carboniferous ones Are mostly platforms As well
but by this time Are trending towards simplicity
H is a form that Goes into the Permian
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Triassic and Cretaceous- Blank period in the
Jurassic-if you remember Back to other invert.
groups some funny things Happen with them In the
Jurassic also- Notice here that some Compound
forms start To be prominent again
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If we look at a whole Suite of forms you can
see Trends with time

Ordovician-29-39 Silurian-25-27 Devonian-16,17,
21-24,28 Mississippian-4,8-15,18-20 Pennsylvanian-
1-3,5-7
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A fundamental change Took place in 1971
when Jeppson proposed elements Of an apparatus
A fundamental Change occurred When
assemblages Of conodonts were Found and
elements Of assemblages Named This meant that
there Could be several Different old
species In one assemblage And suddenly
there Was taxonomic chaos
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From periphery inwards ne, hi, hi, pl, Tr, and
posterior oz and sp
It turned out that parts of the assemblage Could
evolve or change independently of Other parts
further adding to chaos
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Some Carboniferous assemblages
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Assemblage In place
Obvious taxonomic Problems arise here Because for
over 100yrs Workers had been Calling each
element A different name-sowhat is the right
name?
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The single Most complicated Assemblage Ever
constructed Turns out to Be the best
Approximation Of what it would Have looked like
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The BIG discovery of the true animal
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The real picture The schematic
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The lamprey Would also Be a good candidate
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Index species for This section-notice the Short
ranges This would include The assemblage Range,
not just the elements ranges