Name:
Mauriciosaurus
(Mauricio’s lizard).
Phonetic: Mor-e-ko-sor-us.
Named By: Eberhard Frey, Eric W.A. Mulder,
Wolfgang Stinnesbeck, H�ctor E. Rivera-Sylva, Jos� Manuel
Padilla-Guti�rrez & Arturo Homero Gonz�lez-Gonz�lez -
2017.
Classification: Chordata, Reptilia,
Sauropterygia, Plesiosauria, Polycotylidae.
Species: M. fernandezi
(type).
Diet: Piscivore.
Size: Holotype individual 1.9 meters long, but
this was a juvenile. Fully grown adults larger.
Known locations: Mexico - Agua Nueva Formation.
Time period: Cenomanian/Turonian of the Cretaceous.
Fossil representation: Almost complete individual of
a juvenile, including soft tissue impressions revealing much of the
soft tissue body.
Mauriciosaurus
is a genus of polycotylid plesiosaur
known to have lived in waters of
what would have been the southern portion of the Western Interior
Seaway, the shallow sea that once submerged the middle portion of
North America. The holotype specimen of Mauriciosaurus
was found in
Mexico, and has proven to be a ground breaking discovery. Before
the discovery of Mauriciosaurus there was already
increasing
speculation regarding the structure of soft tissues in plesiosaurs,
and the discovery of Mauriciosaurus has helped to
prove many of these
ideas to be true.
When
the holotype individual of Mauriciosaurus died it
ended up being buried
in soft ocean sediment at a warm temperature, something that allowed
the body fat under the skin to change into adipocere instead of
decomposing. Adipocere, also known as corpse wax or grave wax is a
waxy substance that allows for a cast of soft tissues to be formed.
In Mauriciosaurus, this revealed that while Mauriciosaurus
had a
standard polycotylid skeleton, Mauriciosaurus
actually had a tear
drop shaped body formed from the fat deposits under the skin. Broad
at the shoulders and tapering down to the end of the tail, the body
and tail were basically a single shaped mass.
The
flippers of Mauriciosaurus have also been found to
not only be heavily
muscled, but also have tapering soft tissue edges that extended well
beyond the limits of the bony skeletal structure. This hydrofoil-like
appendages would have allowed for swimming that was both energy
efficient and fast. The neck of Mauriciosaurus
was relatively stiff,
something evidence by how the cervical vertebrae interlace with one
another. This means that all swimming locomotion from forward
propulsion to steering would have been entirely down to the flippers.
The
short snout of Mauriciosaurus is typical of
polycotylid plesiosaurs,
and is suggestive of a preference for smaller prey animals, from
small fish to perhaps even cephalopods such as squid. Mauriciosaurus
is named after Mauricio Fern�ndez Garza.
Further reading
- A new polycotylid plesiosaur with extensive soft tissue
preservation
from the early Late Cretaceous of northeast Mexico. - Bolet�n de la
Sociedad Geol�gica Mexicana. 69 (1): 87–134. - Eberhard
Frey, Eric W.A. Mulder, Wolfgang Stinnesbeck, H�ctor E.
Rivera-Sylva, Jos� Manuel Padilla-Guti�rrez & Arturo
Homero Gonz�lez-Gonz�lez - 2017