scholarly journals Kinematics of the transition between aquatic and terrestrial locomotion in the newt Taricha torosa

2004 ◽  
Vol 207 (3) ◽  
pp. 461-474 ◽  
Author(s):  
M. A. Ashley-Ross
Keyword(s):  
Terrestrial Locomotion ◽  
Taricha Torosa

The hominin lineage

2017 ◽  
Author(s):  
Francisco J. Ayala ◽  
Camilo J. Cela-Conde
Keyword(s):  
Rift Valley ◽  
Climate Changes ◽  
Human Lineage ◽  
Terrestrial Locomotion ◽  
Geological Formations ◽  
Difficult Issue ◽  
Human Fossils

This chapter describes the origin of the human lineage within the evolution of the hominoids, which raises the difficult issue of how to integrate the evolution of dentition and terrestrial locomotion. Next is the investigation of the appearance and initial dispersal of the hominins toward the end of the Miocene, with particular attention to the models of colonization of new territories as a function of climate changes. The hypothesis of the adaptation to the open savanna by bipedalism is explored. Finally, there is a summary description of the different deposits and localities of the main African localities with human fossils, pointing out the different geological formations and exemplars found in each deposit, including two sites north of the Rift Valley of great importance: Toros-Menalla (Tchad) and Dmanisi (Georgia).

Effects of Solar UV-B Radiation on Embryonic Development in Hyla cadaverina, Hyla regilla, and Taricha torosa

1998 ◽  
Vol 12 (3) ◽  
pp. 646-653 ◽  
Author(s):  
Christopher R. Anzalone ◽  
Lee B. Kats ◽  
Malcolm S. Gordon
Keyword(s):  
Embryonic Development ◽  
Hyla Regilla ◽  
Taricha Torosa ◽  
Solar Uv

The Role of the ‘Walking Legs’ in Aquatic and Terrestrial Locomotion of the Crayfish Austropotamobius Pallipes (Lereboullet)

1975 ◽  
Vol 62 (2) ◽  
pp. 447-454 ◽  
Author(s):  
CAROLINE M. POND
Keyword(s):  
The Body ◽  
Hydrodynamic Drag ◽  
Terrestrial Locomotion ◽  
Austropotamobius Pallipes ◽  
The Third ◽  
Fourth Pair

1. The hydrodynamic drag acting on the crayfish Austropotamobius pallipes is measured and it is concluded that, in the range of velocities used in walking, the drag is independent of the posture of the limbs and the direction of motion of the body. At swimming velocities the streamlining caused by promotion of the legs reduces the drag losses to half that of a crayfish moving in the forwards walking posture at the same speed. 2. The forwards walking of intact crayfish is compared with that of the same animal after amputation of one or more pairs of legs. It is concluded that the third and fourth pair of legs provide most of the propulsion under water and the second pair is not essential to locomotion under any of the conditions tried.

scholarly journals Terrestrial force production by the limbs of a semi-aquatic salamander provides insight into the evolution of terrestrial locomotor mechanics

2021 ◽  
Author(s):  
Sandy Momoe Kawano ◽  
Richard W. Blob
Keyword(s):  
Adult Life ◽  
Force Production ◽  
Rear Wheel ◽  
Ambystoma Tigrinum ◽  
Terrestrial Locomotion ◽  
Hind Limbs ◽  
Wheel Drive ◽  
Reaction Forces ◽  
Pleurodeles Waltl ◽  
Insight Into

Amphibious fishes and salamanders are valuable functional analogs for vertebrates that spanned the water-to-land transition. However, investigations of walking mechanics have focused on terrestrial salamanders and, thus, may better reflect the capabilities of stem tetrapods that were already terrestrial. The earliest tetrapods were aquatic, so salamanders that are not primarily terrestrial may yield more appropriate data for modelling the incipient stages of terrestrial locomotion. In the present study, locomotor biomechanics were quantified from semi-aquatic Pleurodeles waltl, a salamander that spends most of its adult life in water, and then compared to a primarily terrestrial salamander (Ambystoma tigrinum) and semi-aquatic fish (Periophthalmus barbarus) to evaluate whether walking mechanics show greater similarity between species with ecological versus phylogenetic similarities. Ground reaction forces (GRFs) from individual limbs or fins indicated that the pectoral appendages of each taxon had distinct patterns of force production, but hind limb forces were comparable between the salamanders. The rate of force development ('yank') was sometimes slower in P. waltl but generally comparable between the three species. Finally, medial inclination of the GRF in P. waltl was intermediate between semi-aquatic fish and terrestrial salamanders, potentially elevating bone stresses among more aquatic taxa as they move on land. These data provide a framework for modelling stem tetrapods using an earlier stage of quadrupedal locomotion that was powered primarily by the hind limbs (i.e., "rear-wheel drive"), and reveal mechanisms for appendages to generate propulsion in three locomotor strategies that are presumed to have occurred across the water-to-land transition in vertebrate evolution.

scholarly journals Relative skull size as one of the factors limiting skull shape variation in passerines

2021 ◽  
Author(s):  
Oksana Shatkovska ◽  
Maria Ghazali
Keyword(s):  
Body Mass ◽  
Shape Variation ◽  
Absolute Size ◽  
Terrestrial Locomotion ◽  
Skull Shape ◽  
Skull Size ◽  
Dietary Preferences ◽  
Wide Range ◽  
Body Sizes ◽  
Biomechanical Constraints

Despite a considerable interest of researchers to the issue of variation in skull shapes of birds and factors influencing it, some drivers associated with the design features of an entire bird body, which are important for both successful terrestrial locomotion and flight, are overlooked. One of such factors, in our opinion, is relative skull size (skull length in relation to body mass), which can affect the position of the body's center of gravity. We tested effects of relative skull size, allometry (i.e. absolute skull size), and diet on variation in skull shape. The study was conducted on 50 songbird species with a wide range of body mass (8.3g to 570g) and dietary preferences (granivores, insectivores/granivores, insectivores, omnivores). Skull shape was analyzed using 2D geometric morphometrics. We revealed that similar patterns of skull shape occur among passerines with different body sizes and diets. The relative skull size predicted skull shape to a similar extent and with a similar pattern as the absolute size. In our opinion, the effect of the relative skull size on skull shape variation is likely due to biomechanical constraints related to flight.

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