Terrestrial turtles

Both primitive and advanced forms have been examined for vomeronasal excitation. The turtle VN nerve was the subject of EOG recordings elicited by small organic molecules and by specific signal compounds (Tucker, 1963 Hatanaka, 1987). The simple arrangement of the chelonian accessory area (Fig. 2.8) allows air or liquid delivery hence the preferred odourant vehicle varies with habitat across the aquatic or terrestrial turtles, and the land tortoises (Chap. 1 and Halpem, 1992). 

Graham, T., Georges, A., and Mcelhinney, N. (1996). Terrestrial orientation by the eastern longnecked turtle, Chelodina longicollis, from Australia. ofHerpetology 30,467-477. 

Another form of detoxified ammonia that is used in nitrogen excretion is uric acid. Uric acid is the predominant nitrogen excretory product in birds and terrestrial reptiles (turtles excrete urea, whereas alligators excrete ammonia unless they are dehydrated, in which case they, too, excrete uric acid). Uric acid formed as a product of amino acid catabolism involves the de novo pathway of purine biosynthesis therefore, its formation from NH3 liberated in amino acid catabolism is described elsewhere (see chapter 23). In mammals, uric acid is exclusively an intermediate in purine... 

Reptilia Snakes, lizards, alligators, dinosaurs, turtles Terrestrial cold-blooded animals with scaly skin, four legs, breathe only in air, some lay eggs, some give live birth... 

The shells of terrestrial tortoises and freshwater turtles have also been used in some of the same ways as the larger marine turtles. Whole turtle bodies, with the soft tissue and most of the skeleton removed, have been made into pouches and specialized containers for personal and ceremonial use. 

Metamorphosis has also been extensively studied in amphibians, a class of vertebrates which includes frogs, toads, and salamanders. Amphibian means dual (amphi ) life form (-bian) and refers to the typical life history of these animals, in which an aquatic larva metamorphoses into a terrestrial adult. The reptiles, such as turtles, lizards, and snakes, is another class of vertebrates whose species superficially resemble adult amphibians, but do not undergo metamorphosis. 

Reptiles are not usually associated with marine environments. In fact, of the 6,000 known species of reptiles, only about 1 percent inhabits the sea. Members of this select group include lizards, crocodiles, turtles, and snakes. Each of these organisms shares many of the same anatomical structures that are found in all reptiles They are cold-blooded, air-breathing, scaled animals that reproduce by internal fertilization. Yet, to live in salt water, this subgroup has evolved some special adaptations not seen in terrestrial reptiles. 

Barrick RE, Stoskopf MK, Marcot JD, Russell DA, Showers WJ (1998) The thermoregulatory functions of the Triceratops frill and horns heat flow measured with oxygen isotopes. J Vert Paleo 18 746-750 Barrick RE, Fischer AG, Showers WJ (1999) Oxygen isotopes from turtle bone applications for terrestrial paleoclimates Palaios 14 186-191... 

Arsenocholine also occurs commonly in marine animals, usually as a trace constituent. One exception is the turtle Dermochelys coriacea where arsenocholine was a significant arsenic constituent in the liver (19). Arsenocholine has been found in terrestrial organisms and can occur as the major arsenical in some species. For example, it is the major arsenical in the fungus Sparassis crispa, although the concentration of total arsenic in S. crispa is quite low ( 1 p,g As/g dry mass) (20). 

While vision is commonly rated as the dominant sensory mode in reptiles (i.e., Madison, 1977), we believe this is an impression based primarily on work with terrestrial lizards, snakes and tortoises which may not apply as well to the aquatic members of the class. Much more research needs to be done with aquatic and marine snakes and turtles whose habitats provide poor visual, but excellent chemical cueing characteristics. 

---