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Belemnite attentuatus (Jurassic)
Structural diagram of Belemnite attenuatus (after drawing by Dinkell in Mantell 1848,pl.15 )
Belemnites are extinct, squid-like cephalopods which are commonly found as fossils in the Jurassic Blue Lias Formation in southern England. They belong to the subclass Coleoidea and the order Belemnitida.
This diagram of the anatomical structure of Belemnite attentuatus,
a representative Middle to Late Jurassic belemnite, was drawn by
Joseph Dinkell in the textbook published by Gideon Mantell in 1848.
Most commonly found as fossils are the pointed, rodlike
"guard" formations, shown at bottom in the figure. The
guard formed a kind of forward armor attached to the belemnite's
many-chambered, cone-shaped midsection, called a phragmacone. As the
animal grew, it moved forward in the body chamber and secreted a
septum, which became a series of phragmocone chambers (Owen 1844;
Mantell 1848). Behind this trailed multiple arms, as seen
on modern squids when swimming.
In
1826, Mary Anning discoverd fossilized ink chambers of belemnites at
Lyme Regis. Together with her brother Joseph and a friend, Elizabeth
Philpot, she was reportedly able to retrieve some of the carbonized
ink.
References:
Owen 1844
Mantell, Gideon 1848
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