Belemnites Flashcards

1
Q

What is their phylum and class

A

Mollusca

Cephalopoda

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2
Q

Is the form extinct or extant

A

Extinct

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3
Q

What kind of shell do they have and what links them

A

Chambered shell

Linked by a siphuncle

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4
Q

What is the part that is normally preserved

A

The guard (a bullet shaped calcite mass)

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5
Q

What is in the anterior of the guard

A

A chambered phragmocone

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6
Q

What do they chambers of phragmocone represent

A

The growth stages of the animal with the last body chamber open

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7
Q

What were the chambers used for

A

Buoyancy

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8
Q

What adjusts the buoyancy

A

The siphuncle which links all of the tubes up and controlled the amount of gas in each chamber

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9
Q

What is the proostracum

A

Extension of the guard which may of provided some protection

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10
Q

What is the protoconch

A

The first chamber

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11
Q

What is their mode of life

A

Swam just like squid
Nektonic
Could swim both vertically and horizontally
Tentacles used jet propulsion

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12
Q

How do these and animals provide such great evidence for the palaeocurrent

A

Upon death the guards fell down to the sea floor and aligned up with the current

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