... ( Fig. 1 ). In addition, each study must have measured one or more of the following post-hatching phenotypes: incubation duration, survival (hatching success), sex ratio (proportion male), morphology (mass or length) or performance (speed – swim speed for turtles and snakes and terrestrial speed...

... conduction system (AVCS), which coincides with the completion of ventricular septation. We investigated whether AVCS formation coincides with ventricular septation in developing Siamese crocodiles ( Crocodylus siamensis ). Comparisons were made with Amazon toadhead turtle ( Mesoclemmys heliostemma...

...Katie L. Willis; Catherine E. Carr ABSTRACT The physiological hearing range of turtles is approximately 50–1000 Hz, as determined by cochlear microphonics ( Wever and Vernon, 1956a ). These low frequencies can constrain sound localization, particularly in red-eared slider turtles, which...

... of lever systems may be coupled with changes in muscle use and give rise to novel muscle functions. The two extant turtle lineages, cryptodires and pleurodires, exhibit differences in hindlimb structure. Cryptodires possess the ancestral musculoskeletal morphology, with most hip muscles originating...

... and then recovers quickly after dives. In laboratory studies of submerged freshwater turtles, arterial O 2 depletion typically follows a similar pattern. However, in these studies, turtles were disturbed, frequently tethered to external equipment and confined either to small tanks or breathing holes. Aquatic...

... impaired by even brief periods of low oxygen supply. This review describes recent research on physiological mechanisms that have evolved in certain vertebrate species to cope with brain hypoxia. Four model systems are considered: freshwater turtles that can survive for months trapped in frozen-over lakes...

...Gina L. J. Galli; Gigi Y. Lau; Jeffrey G. Richards SUMMARY The freshwater turtle Trachemys scripta can survive in the complete absence of O 2 (anoxia) for periods lasting several months. In mammals, anoxia leads to mitochondrial dysfunction, which culminates in cellular necrosis and apoptosis...

... and that swimming animals might utilize kinematic strategies or possess morphological adaptations that reduce recoil motions and produce more stable trajectories. We used high-speed video to assess hydrodynamic stability during rectilinear swimming in the freshwater painted turtle ( Chrysemys picta ). Parameters...

...Angela R. V. Rivera; Richard W. Blob SUMMARY Turtles use their limbs during both aquatic and terrestrial locomotion, but water and land impose dramatically different physical requirements. How must musculoskeletal function be adjusted to produce locomotion through such physically disparate habitats...

...Minoru Uchiyama; Ryosuke Kikuchi; Norifumi Konno; Tatsuya Wakasugi; Kouhei Matsuda SUMMARY Urea is the major excretory end product of nitrogen metabolism in most chelonian reptiles. In the present study, we report the isolation of a 1632 base pair cDNA from turtle kidney with one open reading frame...

...Tobias Wang; James W. Hicks SUMMARY The breathing pattern of many different air-breathing vertebrates,including lungfish, anuran amphibians, turtles, crocodiles and snakes, is characterized by brief periods of lung ventilation interspersed among apnoeas of variable duration. These intermittent...

...Michael T. Butcher; Nora R. Espinoza; Stephanie R. Cirilo; Richard W. Blob SUMMARY Previous analyses of ground reaction force (GRF) and kinematic data from river cooter turtles ( Pseudemys concinna ) during terrestrial walking led to three primary conclusions about the mechanics of limb bone...

.... Turtles are an interesting lineage in this context. Although their slow walking speeds and robust limb bones might lead to low locomotor forces and limb bone stresses similar to other non-avian reptiles, their highly sprawled posture could produce high bending loads,leading to high limb bone stresses...

...Jonathan A. W. Stecyk; Anthony P. Farrell SUMMARY Heart rate ( f H ) of the anoxia-tolerant freshwater turtle ( Trachemys scripta ) during prolonged anoxia exposure is 2.5-to 5-times lower than the normoxic rate, but whether alterations in blood composition that accompany prolonged anoxia...

... and agility have yet to be examined. Turtles represent the oldest extant lineage of rigid-bodied vertebrates and the only aquatic rigid-bodied tetrapods. We evaluated the aquatic turning performance of painted turtles, Chrysemys picta (Schneider, 1783) using the minimum length-specific radius of the turning...

...Gina L. J. Galli; Hans Gesser; Edwin W. Taylor; Holly A. Shiels; Tobias Wang SUMMARY The functional significance of the sarcoplasmic reticulum (SR) in the generation of high heart rates and blood pressures was investigated in four species of reptile; the turtle, Trachemys scripta ; the python...

...Nini Skovgaard; Daniel E. Warren; Donald C. Jackson; Tobias Wang SUMMARY The effects of endothelin-1 (ET-1) on systemic and pulmonary circulation were investigated in anaesthetised freshwater turtles ( Trachemys scripta ) instrumented with arterial catheters and blood flow probes. Bolus intra...

...Mary J. Packard; Gary C. Packard SUMMARY Hatchling painted turtles ( Chrysemys picta ) typically spend their first winter of life in a shallow, subterranean hibernaculum (the natal nest),where they may be exposed for extended periods to ice and cold. The key to their survival seems to be to avoid...

...Peter L. Lutz; Sarah L. Milton SUMMARY The turtle brain's extraordinary ability to tolerate anoxia is based on constitutive and expressed factors. Constitutive factors that predispose for anoxia tolerance include enhanced levels of glycogen stores, increased densities of protective receptors...

...Gary C. Packard; Mary J. Packard SUMMARY Many physiologists believe that hatchling painted turtles ( Chrysemys picta ) provide a remarkable, and possibly unique, example of `natural freeze-tolerance' in an amniotic vertebrate. However, the concept of natural freeze-tolerance in neonatal painted...