CR is present in reptiles
The chart shows that the four major modes of CR are practiced by reptiles.
For Alternate symmetrical walking and running gait is applicable to nearly all reptilians. Swimming by lizards is not documented (for GT, can they swim?O^O!!), except for the a large aquatic iguanid lizards. Body and/or tail undulation in aquqatic
locomotion is found in crocodilians and is the only available one for in snakes and other limbless reptiles. An interesting example of the asymmetric gait in static use is well documented in torrid desert lizards, as they syand on hot sand alternately lifti
ng diagonally opposed limbs. The Chelonid sea turtles nest by digging sand with their hind limbs in alternate strokes.
The adult crocodilian swims fast with undulating tail. But the slow moving adult and the young, at any speed, adopt a mixture of parallel and alternate limb paddling.
Alternate asymmetry is seen in the bipedal running of Chlamydosaurus? ... and Basiliscus... which hold the arms unmoving and close to the body, although a small amount of arm movement is discernible even here (see video). Bipedal
running- monitor lizards?? O^O TV Video!!
Parallel symmetrical action is basic to jumping and gliding by the flying lizards (Genus Draco, family Agamidae) and flying gekkos (Genus Ptychozoon in subfamily Gekkonidae). The head raising and strike by snakes is possibly a parallel asymm
etric move in that the head undulates in the horizontal plane, while the body stays stable in an alternate undulative position, namely in a curved configuration which can be regarded as extending a single one-sided alternating half-cycle along the whole bod
y. It was a srurpise when in the 1990s it was discovered that the African crocodile
Crocodylus johnsoni (?) briefly attains high speed by galloping. (see video, photo)
Parallel asymmetrical mode appears in sea turtles, which swim with powerful forelimb strokes. In contrast, fresh water turtles chiefly swim with hind limbs.
On land sea turtles walk with ath alternating gait when moving at maximum speed, but when slow all four their limbs act in parallel as they synchrounously place fore- and hindlimbs forward and then push all backward with force to move the body forward.
The hatchling and juvenile sea turtles exhibit a large variaety of gaits. During their so-called "frenzy swimming" or hyperactive first day(s), the green and loggerhead turtels propel themselves on the water surface with alternate paddle strokes, and switch
to parallel forelimb movement when under water, which they prefer also use at the surface. Lethareback young practice parallel foelimb strokes at all times. After the frenzy period they both swim with both of the above means and add parallel hind leg propu
lsion as well. Source: SeaVertb.sam
The amphisbaean reptiles are legless and like the legless caecilian amphibians they burrow with concertina-like axial pulsation of the body. In open space and on land they move by body-tail undulation. ?O^O?
Terrestrial and aquatic turtles can be expected ?MUST? swim with both alternate symmetrical and asymmetrical motion depending on the speed, as we find with Anurans.
Conclusion: Excepting the mixed mode reptilian locomotion presents a full range of CR., continued from the earlier amphibian evolutionary rank. As in the pectoral propulsion of fish, a form of the flight-stroke has been noted that sea turtle forelar
m porpulsion employs both drag- and lift-based methods. (Source???)