Calcarichelys
Name:
Calcarichelys
(rough turtle?).
Phonetic: Kal-cah-re-shel-iss.
Named By: Rainer Zangerl - 1953.
Classification: Chordata, Reptilia, Testudines,
Cryptodira, Protostegidae, Chelospharginae.
Species: C. gemma (type).
Diet: Omnivore?
Size: Around 30 centimetres long.
Known locations: USA - Alabama - Selma
Formation.
Time period: Campanian to possibly Maastrichtian of
the Cretaceous.
Fossil representation: At least two specimens.
Calcarichelys
was a relatively small late Cretaceous turtle but one with a highly
specialised shell. Instead of the usual concave curve across the
back, a series of enlarged spikes ran down the middle of the back.
These are taken as being almost certainly a defensive adaptation to
make it more difficult for predators such as the smaller mosasaurs to
close their mouths around the body. With the mouth wedged open a
predators teeth could not be brought to bear to damage the shell. The
total effectiveness of these dorsal spikes however may not have been
absolute since the spikes could only possibly protect against a jaw
closing from above. Predators with more patience may have tried
attacking exposed extremities such as flippers which were not
protected, and some predators such as the large shark Cretoxyrhina
had especially toughened teeth with thick enamel for biting through
armoured prey like turtles.
Like
with its relatives Archelon
and Protostega,
Calcarichelys did not
have a solid shell but instead a framework of struts that were filled
in between by softer tissue. In terms of diet Calcarichelys
probably
fed like modern turtles perhaps eating everything from seaweed to
jellyfish to even sponges, which could all have been easily tackled
with its shearing beak. A possible close relative of Calcarichelys
is
Chelosphargis
from the same formation and also named by Zangerl in 1953.
Further reading
- The vertebrate fauna of the
Selma Formation of Alabama. Part III. The turtles of the family
Protostegidae. - Fieldiana: Geology Memoirs 3(3):63-133. - R. Zangerl -
1953.
- Systematic revision of the Protostegidae, with a redescription of
Calcarichelys gemma Zangerl, 1953. - Journal of Vertebrate
Paleontology. 18 (1): 85–98. - G. E. Hooks - 1998.
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