32
beak surfaces meet at a ridged surface that can be knife-sharp like in case of the
marine loggerhead turtle ( Caretta caretta ). This animal is capable of slicing through
prey as hard as mineralized molluscs or crabs shells (see for review Wyneken 2001 ).
From biomaterials point of view, the multiscale structure, material properties,
and mechanical responses (Richmond 1964 ) of the turtles shells were recently
intensively studied to better understand “naturally occurring biological penetratorarmor systems,” (Rhee et al. 2009 ; additionally see for review Krauss et al. 2009 ;
Balani et al. 2011 ; Damiens et al. 2012 ). Both, the chemical analysis and the structural
observations revealed that the turtle shell carapace “comprises a multiphase sandwich
composite structure of functionally graded material having exterior bone layers with
a foam-like bony network of closed-cells between the two layers,” (Rhee et al. 2009 ).
The eggshell in turtles is of interest for biomaterials science community. This
structure is nothing else as a protective multilayered barrier between the external
environment and the embryo (Decker 1967 ). Additionally to protection of the embryo
from any mechanical injury, the eggshell is responsible for moisture, heat and mostly
for gas exchanges. It also can function as a substrate for rotational movements of
the embryo within the egg (Ewert 1979 ; Al–Bahry et al. 2009 ). Recently, numerous
comparative studies on structural biology and chemistry of various aspects of
eggshell formation in some sea turtles (Erben 1970 ; Schleich and Kastle 1988 ),
including biomineralization features, have been reported (Al–Bahry et al. 2009 ).
Order Squamata
Sixty percent of all reptiles (5,500 species) are Lizards (Suborder Sauria), the very
specious and diverse group of reptiles which includes marine animals, too (Uetzt
2011 ). With exception of worm lizard (Amphisbaenia) which usually is legless,
lizards usually have four legs with claws. These mostly insectivores reptiles inhabit
shrubs, rocks and trees. However, some species will eat plants or even other
vertebrates. They range from a few centimeters to nearly 3 m long.
Iguanas are representatives of lizards. The only iguana of the 416 known species
that ventures into the ocean is distributed on the Galapagos Islands, which arose
through volcanic activity 960 km off the coast of Ecuador. It is suggested that “lizards
and other animals probably reached the island on rafts of vegetation washed down
the rivers of western South America” (Rasmussen et al. 2011b ).
Thus, the Galapagos marine iguana ( Amblyrhynchus cristatus ) (Bell 1825 )
represents the diverse and species rich family of Iguanidae (see for review Carpenter
1966 ; Dawson et al. 1977 ). Amblyrhynchus , however, is unique because of the
feeding specialization. The diet of these marine animals is based predominantly on
soft- bodied macrophytic algae (Dawson et al. 1977 ). Some authors (Hobson 1965 ;
Bartholomew et al. 1976 ) described their behavior as follow: “These lizards must
swim through the surf zone, dive beneath the surface (lungs remain infl ated during
diving so that the animals must initially overcome their own buoyancy), hold their
breath during submergence, surface, and then swim back to shore through the surf”
(Dawson et al. 1977 ). Adult marine iguanas cruise at velocities averaging about
1 Introduction
beak surfaces meet at a ridged surface that can be knife-sharp like in case of the
marine loggerhead turtle ( Caretta caretta ). This animal is capable of slicing through
prey as hard as mineralized molluscs or crabs shells (see for review Wyneken 2001 ).
From biomaterials point of view, the multiscale structure, material properties,
and mechanical responses (Richmond 1964 ) of the turtles shells were recently
intensively studied to better understand “naturally occurring biological penetratorarmor systems,” (Rhee et al. 2009 ; additionally see for review Krauss et al. 2009 ;
Balani et al. 2011 ; Damiens et al. 2012 ). Both, the chemical analysis and the structural
observations revealed that the turtle shell carapace “comprises a multiphase sandwich
composite structure of functionally graded material having exterior bone layers with
a foam-like bony network of closed-cells between the two layers,” (Rhee et al. 2009 ).
The eggshell in turtles is of interest for biomaterials science community. This
structure is nothing else as a protective multilayered barrier between the external
environment and the embryo (Decker 1967 ). Additionally to protection of the embryo
from any mechanical injury, the eggshell is responsible for moisture, heat and mostly
for gas exchanges. It also can function as a substrate for rotational movements of
the embryo within the egg (Ewert 1979 ; Al–Bahry et al. 2009 ). Recently, numerous
comparative studies on structural biology and chemistry of various aspects of
eggshell formation in some sea turtles (Erben 1970 ; Schleich and Kastle 1988 ),
including biomineralization features, have been reported (Al–Bahry et al. 2009 ).
Order Squamata
Sixty percent of all reptiles (5,500 species) are Lizards (Suborder Sauria), the very
specious and diverse group of reptiles which includes marine animals, too (Uetzt
2011 ). With exception of worm lizard (Amphisbaenia) which usually is legless,
lizards usually have four legs with claws. These mostly insectivores reptiles inhabit
shrubs, rocks and trees. However, some species will eat plants or even other
vertebrates. They range from a few centimeters to nearly 3 m long.
Iguanas are representatives of lizards. The only iguana of the 416 known species
that ventures into the ocean is distributed on the Galapagos Islands, which arose
through volcanic activity 960 km off the coast of Ecuador. It is suggested that “lizards
and other animals probably reached the island on rafts of vegetation washed down
the rivers of western South America” (Rasmussen et al. 2011b ).
Thus, the Galapagos marine iguana ( Amblyrhynchus cristatus ) (Bell 1825 )
represents the diverse and species rich family of Iguanidae (see for review Carpenter
1966 ; Dawson et al. 1977 ). Amblyrhynchus , however, is unique because of the
feeding specialization. The diet of these marine animals is based predominantly on
soft- bodied macrophytic algae (Dawson et al. 1977 ). Some authors (Hobson 1965 ;
Bartholomew et al. 1976 ) described their behavior as follow: “These lizards must
swim through the surf zone, dive beneath the surface (lungs remain infl ated during
diving so that the animals must initially overcome their own buoyancy), hold their
breath during submergence, surface, and then swim back to shore through the surf”
(Dawson et al. 1977 ). Adult marine iguanas cruise at velocities averaging about
1 Introduction