scholarly journals Tiger Salamanders (Ambystoma tigrinum) Increase Foot Contact Surface Area on Challenging Substrates During Terrestrial Locomotion

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Christine M Vega ◽  
Miriam A Ashley-Ross

Synopsis Animals live in heterogeneous environments must navigate in order to forage or capture food, defend territories, and locate mates. These heterogeneous environments have a variety of substrates that differ in their roughness, texture, and other properties, all of which may alter locomotor performance. Despite such natural variation in substrate, many studies on locomotion use noncompliant surfaces that either are unrepresentative of the range of substrates experienced by species or underestimate maximal locomotor capabilities. The goal of this study was to determine the role of forefeet and hindfeet on substrates with different properties during walking in a generalized sprawling tetrapod, the tiger salamander (Ambystoma tigrinum). Adult salamanders (n = 4, SVL = 11.2–14.6 cm) walked across level dry sand (DS), semi-soft plaster of Paris (PoP), wet sand (WS), and a hard, noncompliant surface (table)—substrates that vary in compliance. Trials were filmed in dorsal and anterior views. Videos were analyzed to determine the number of digits and surface area of each foot in contact with the substrate. The surface area of the forelimbs contacting the substrate was significantly greater on DS and PoP than on WS and the table. The surface area of the hindlimbs contacting the substrate was significantly greater on DS than on all other substrates. There were no significant differences in the time that the fore- or hindfeet were in contact with the substrate as determined by the number of digits. We conclude that salamanders modulate the use of their feet depending on the substrate, particularly on DS which is known to increase the mechanical work and energy expended during locomotion owing to the fluid nature of its loose particles. More studies are needed to test a wider range of substrates and to incorporate behavioral data from field studies to get a better understanding of how salamanders are affected by different substrates in their natural environment.

1992 ◽  
Vol 162 (1) ◽  
pp. 107-130 ◽  
Author(s):  
LARRY M. FROLICH ◽  
ANDREW A. BIEWENER

Aquatic neotenic and terrestrial metamorphosed salamanders {Ambystoma tigrinum) were videotaped simultaneously with electromyographic (EMG) recording from five epaxial myotomes along the animal's trunk during swimming in a flow tank and trotting on a treadmill to investigate axial function during aquatic and terrestrial locomotion. Neotenic and metamorphosed individuals swim using very similar axial wave patterns, despite significant differences in axial morphology. During swimming, both forms exhibit traveling waves of axial flexion and muscle activity, with an increasing EMG-mechanical delay as these waves travel down the trunk. In contrast to swimming, during trotting metamorphosed individuals exhibit a standing wave of axial flexion produced by synchronous activation of ipsilateral epaxial myotomes along the trunk. Thus, metamorphosed individuals employ two distinct axial motor programs -- one used during swimming and one used during trotting. The transition from a traveling axial wave during swimming to a standing axial wave during trotting in A. tigrinum may be an appropriate analogy for similar transitions in axial locomotor function during theoriginal evolution of terrestriality in early tetrapods.


1991 ◽  
Vol 12 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Scott C. Pedersen

AbstractCannibalistic behavior is accompanied by a robust dental and skeletal polymorphism in cannibal tiger salamanders, Ambystoma tigrinum. This study describes the dental polymorphism in terms of hypertrophy, recurvature, and surface detail as revealed by scanning electron microscopy. Vomerine and dentary teeth in cannibals are longer than those of non-cannibals of the same head size. While cannibals exhibit recurved teeth on each dentigerous bone, straight peg-like teeth appear occasionally. Conversely, isolated recurved teeth may be present in non-cannibals. No consistent differences between cannibal and noncannibal teeth with respect to the surface geography of the pedicel, shaft, or pedicel shaft junction were observed. Hypertrophy of the horizontally ankylosed vomerine teeth is associated with a distortion of the underlying vomer. This suggests that alterations in odontogenesis may effect changes in the morphogenesis of underlying dentigerous bones. Differential rates of development (heterochrony) between the skull (dentigerous bones) and the dentition may be a characteristic feature in the evolution of cranial morphology in cannibal tiger salamanders.


1997 ◽  
Vol 75 (3) ◽  
pp. 505-508 ◽  
Author(s):  
G. Thomas Watters

Larval tiger salamanders (Ambystoma tigrinum ssp.) were infected with glochidia of the freshwater mussel Lampsilis cardium in laboratory experiments. At 20–21 °C, metamorphosis occurred from 9 to 39 days, primarily between 9 and 17 days. The percentage of attached glochidia that metamorphosed varied from 0.27 to 15.7%. Metamorphosis on the salamanders occurred more quickly than on a known piscine host, largemouth bass (Micropterus salmoides), but a smaller percentage of the total attached glochidia metamorphosed. The role of amphibians as hosts of freshwater mussels in North America has not been addressed. Recognizing such a relationship could have important consequences for our understanding of mussel zoogeography.


1994 ◽  
Vol 72 (10) ◽  
pp. 1780-1787 ◽  
Author(s):  
Howard H. Whiteman ◽  
Scott A. Wissinger ◽  
Andrew J. Bohonak

Seasonal movements of a subalpine population of metamorphic tiger salamanders, Ambystoma tigrinum nebulosum, were explored from 1990 to 1992. Metamorphic adults bred in permanent and semipermanent habitats during June of each year. After breeding, soma individuals returned to the terrestrial environment, but many remained and congregated in nonpermanent ponds. Metamorphic adults in nonpermanent ponds included those that moved from permanent ponds, those that bred and remained in semipermanent ponds, and those that did not breed but migrated from the terrestrial environment after the breeding season. Dietary analyses indicated that metamorphic adults in nonpermanent ponds have significantly greater numbers, biomass, and calories of prey in their gut than the few metamorphic adults remaining in permanent ponds. This difference was due to the presence of fairy shrimp (Branchinecta coloradensis), which composed 91 % of metamorphic adult diets in nonpermanent ponds and accounted for three times the average caloric value of all prey in gut samples from metamorphic adults in permanent ponds. Intraspecific competition also may have contributed to movement into nonpermanent ponds: post-breeding densities of metamorphic adults in permanent ponds were inversely related to the densities of other morphs (paedo-morphic adults and large larvae). We conclude that metamorphic A. t. nebulosum in this population utilize nonpermanent ponds after the breeding season because of the abundance of high-quality aquatic prey and reduced competition from con-specific morphs.


2021 ◽  
pp. 105643
Author(s):  
Jose F. Gomes ◽  
Michael Davies ◽  
Peter Smith ◽  
Franca Jones
Keyword(s):  

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Axel H. Newton ◽  
Andrew J. Pask

AbstractRunt-related transcription factor 2 (RUNX2) is critical for the development of the vertebrate bony skeleton. Unlike other RUNX family members, RUNX2 possesses a variable poly-glutamine, poly-alanine (QA) repeat domain. Natural variation within this repeat is able to alter the transactivation potential of RUNX2, acting as an evolutionary ‘tuning knob’ suggested to influence mammalian skull shape. However, the broader role of the RUNX2 QA repeat throughout vertebrate evolution is unknown. In this perspective, we examine the role of the RUNX2 QA repeat during skeletal development and discuss how its emergence and expansion may have facilitated the evolution of morphological novelty in vertebrates.


Author(s):  
Changjian Xie ◽  
Yuhui Ma ◽  
Peng Zhang ◽  
Junzhe Zhang ◽  
Xiaowei Li ◽  
...  

With the increasing environmental application and discharge of nano cerium dioxide (nano-CeO2), it is urgent to fully understand its ecotoxicological effects on the aquatic environment. This study for the first...


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