The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Michael D Rose - One of the best experts on this subject based on the ideXlab platform.
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suspensory locomotion of lagothrix lagothricha and ateles belzebuth in yasuni national park ecuador
Journal of Human Evolution, 2003Co-Authors: John G H Cant, Dionisios Youlatos, Michael D RoseAbstract:A comparative field study of the locomotion of woolly monkeys (Lagothrix lagothricha) and spider monkeys (Ateles belzebuth) in undisturbed rainforest of northeastern Ecuador reveals substantial differences in their use of suspensory modes. Ateles performed both more brachiation (by Forelimbs and tail, with trunk rotation), and forelimb swing (similar to brachiation, but without trunk rotation) than Lagothrix. In contrast, in Lagothrix 20% of suspensory movement was by pronograde forelimb swing, which resembles forelimb swing except that the body is held in a pronograde orientation due to the tail and/or feet intermittently grasping behind the trailing forelimb. Ateles never exhibited this mode. Both brachiation and forelimb swing by Ateles were more dynamic than in Lagothrix, consisting of higher proportions of full-stride bouts (versus single-step). Both species used smaller supports for suspensory than for quadrupedal locomotion, and Ateles used both smaller and larger supports for suspension than did Lagothrix. Analysis of support inclination shows that both species tended to perform more above-support movement on horizontal supports and more below-support (suspensory) movement from oblique supports. Our attempt to elucidate the aspects of canopy structure that favor suspension suggests the need for additional kinds of observational data, focusing on the “immediate structural context” of positional events.
John G H Cant - One of the best experts on this subject based on the ideXlab platform.
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suspensory locomotion of lagothrix lagothricha and ateles belzebuth in yasuni national park ecuador
Journal of Human Evolution, 2003Co-Authors: John G H Cant, Dionisios Youlatos, Michael D RoseAbstract:A comparative field study of the locomotion of woolly monkeys (Lagothrix lagothricha) and spider monkeys (Ateles belzebuth) in undisturbed rainforest of northeastern Ecuador reveals substantial differences in their use of suspensory modes. Ateles performed both more brachiation (by Forelimbs and tail, with trunk rotation), and forelimb swing (similar to brachiation, but without trunk rotation) than Lagothrix. In contrast, in Lagothrix 20% of suspensory movement was by pronograde forelimb swing, which resembles forelimb swing except that the body is held in a pronograde orientation due to the tail and/or feet intermittently grasping behind the trailing forelimb. Ateles never exhibited this mode. Both brachiation and forelimb swing by Ateles were more dynamic than in Lagothrix, consisting of higher proportions of full-stride bouts (versus single-step). Both species used smaller supports for suspensory than for quadrupedal locomotion, and Ateles used both smaller and larger supports for suspension than did Lagothrix. Analysis of support inclination shows that both species tended to perform more above-support movement on horizontal supports and more below-support (suspensory) movement from oblique supports. Our attempt to elucidate the aspects of canopy structure that favor suspension suggests the need for additional kinds of observational data, focusing on the “immediate structural context” of positional events.
Patrick T. Walsh - One of the best experts on this subject based on the ideXlab platform.
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Turning into frogs: Asymmetry in forelimb emergence and escape direction in metamorphosing anurans.
Laterality, 2016Co-Authors: Luigi Zechini, Alison Lilley, Emily H. Waddell, Thomas J. Burns, J. Roger Downie, Patrick T. WalshAbstract:ABSTRACTThere is considerable debate about the pattern and origin of laterality in forelimb emergence and turning behaviour within amphibians, with the latter being poorly investigated in tadpoles around metamorphic climax. Using 6 species of metamorphosing anurans, we investigated the effect of asymmetrical spiracle location, and disturbance at the time of forelimb emergence, on the pattern of forelimb emergence. Turning behaviour was observed to assess whether motor lateralization occurred in non-neobatrachian anurans and was linked to patterns of forelimb emergence. Biases in forelimb emergence differed among species, supporting the hypothesis that asymmetrical spiracle position results in the same asymmetry in forelimb emergence. However, this pattern only occurred when individuals were undisturbed. Therefore, context at the time of the emergence of the Forelimbs may be important, and might explain some discrepancies in the literature. Turning biases, unconnected to forelimb emergence, were found in P...
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Why do frog and toad Forelimbs suddenly (but asynchronously) appear, every time metamorphosis is near?
Functional Ecology, 2014Co-Authors: Luigi Zechini, Alison Lilley, J. Roger Downie, Patrick T. WalshAbstract:Summary The internal development and the emergence of the Forelimbs at metamorphosis is a defining feature of anuran amphibians (frogs and toads). However, although forelimb emergence is considered sudden, it is rarely synchronous. Any asynchrony may or may not exacerbate the increased drag that is predicted to occur with the emergence of the Forelimbs at metamorphic climax. Despite the impact forelimb emergence is hypothesized to have on individual survival and life-history evolution, the degree of asynchrony between forelimb emergence, and any consequences of such asymmetry, has not been investigated. The asynchrony in forelimb emergence also provides an opportunity to test the currently held evolutionary basis for the internal development and sudden emergence of the Forelimbs in anurans. Using a diverse range of anuran taxonomic groups, we measured the time between, and pattern of, the emergence of the Forelimbs across a range of species. To examine the evolutionary impacts of forelimb emergence, we assessed locomotory performance when individuals had zero, one or two Forelimbs emerged. The duration of time between the emergence of the two Forelimbs was longer and more variable than predicted. Furthermore, no species suffered impaired burst speeds nor was their angle of escape affected as the Forelimbs emerged asynchronously. In fact, burst swimming speed was faster after the emergence of one and two Forelimbs than prior to their emergence. Fundamentally, our results call into question the proposition, long accepted, that internal forelimb development is associated with locomotion and reducing drag during metamorphosis. This does not appear to be the case, and we suggest that anatomical or developmental constraints or advantages may be responsible.
Daniel Schmitt - One of the best experts on this subject based on the ideXlab platform.
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Forelimb and hindlimb forces in walking and galloping primates.
American journal of physical anthropology, 2006Co-Authors: Jandy B. Hanna, John D. Polk, Daniel SchmittAbstract:One trait that distinguishes the walking gaits of most primates from those of most mammalian nonprimates is the distribution of weight between the Forelimbs and hindlimbs. Nonprimate mammals generally experience higher vertical peak substrate reaction forces on the forelimb than on the hindlimb. Primates, in contrast, generally experience higher vertical peak substrate reaction forces on the hindlimb than on the forelimb. It is currently unclear whether this unusual pattern of force distribution characterizes other primate gaits as well. The available kinetic data for galloping primates are limited and present an ambiguous picture about peak-force distribution among the limbs. The present study investigates whether the pattern of forelimb-to-hindlimb force distribution seen during walking in primates is also displayed during galloping. Six species of primates were video-recorded during walking and galloping across a runway or horizontal pole instrumented with a force-plate. The results show that while the force differences between forelimb and hindlimb are not significantly different from zero during galloping, the pattern of force distribution is generally the same during walking and galloping for most primate species. These patterns and statistical results are similar to data collected during walking on the ground. The pattern of limb differentiation exhibited by primates during walking and galloping stands in contrast to the pattern seen in most nonprimate mammals, in which forelimb forces are significantly higher. The data reported here and by Demes et al. ([1994] J. Hum. Evol. 26:353-374) suggest that a relative reduction of forelimb vertical peak forces is part of an overall difference in locomotor mechanics between most primates and most nonprimate mammals during both walking and galloping.
Catherine Tsilfidis - One of the best experts on this subject based on the ideXlab platform.
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Growth and apoptosis during larval forelimb development and adult forelimb regeneration in the newt (Notophthalmus viridescens)
Development Genes and Evolution, 2004Co-Authors: Tatjana Vlaskalin, Christine J Wong, Catherine TsilfidisAbstract:Many of the genes involved in the initial development of the limb in higher vertebrates are also expressed during regeneration of the limb in urodeles such as Notophthalmus viridescens . These similarities have led researchers to conclude that the regeneration process is a recapitulation of development, and that patterning of the regenerate mimics pattern formation in development. However, the developing limb and the regenerating limb do not look similar. In developing urodele Forelimbs, digits appear sequentially as outgrowths from the limb palette. In regeneration, all the digits appear at once. In this work, we address the issue of whether regeneration and development are similar by examining growth and apoptosis patterns. In contrast to higher vertebrates, forelimb development in the newt, N. viridescens , does not use interdigital apoptosis as the method of digit separation. During adult forelimb regeneration, apoptosis seems to play an important role in wound healing and again during cartilage to bone turnover in the advanced digits and radius/ulna. However, similar to forelimb development, demarcation of the digits in adult forelimb regeneration does not involve interdigital apoptosis. Outgrowth, rather than regression of the interdigital mesenchyme, leads to the individualization of forelimb digits in both newt development and regeneration.
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hox c6 expression during development and regeneration of Forelimbs in larval notophthalmus viridescens
Development Genes and Evolution, 1999Co-Authors: Paul A Khan, Catherine Tsilfidis, Richard A. LiversageAbstract:A central theme concerning the epimorphic regenerative potential of urodele amphibian appendages is that limb regeneration in the adult parallels larval limb development. Results of previous research have led to the suggestion that homeobox containing genes are ”re-expressed” during the epimorphic regeneration of Forelimbs of adult Notophthalmus viridescens in patterns which retrace larval limb development. However, to date no literature exists concerning expression patterns of any homeobox containing genes during larval development of this species. The lack of such information has been a hindrance in exploring the similarities as well as differences which exist between limb regeneration in adults and limb development in larvae. Here we report the first such results of the localization of Hox C6 (formerly, NvHBox-1) in developing and regenerating Forelimbs of N. viridescens larvae as demonstrated by whole-mount in situ hybridization. Inasmuch as the pattern of Hox C6 expression is similar in developing forelimb buds of larvae and epimorphically regenerating forelimb blastemata of both adults and larvae, our results support the paradigm that epimorphic regeneration in adult newts parallels larval forelimb development. However, in contrast with observations which document the presence of Hox C6 in both intact, as well as regenerating hindlimbs and tails of adult newts, our results reveal no such Hox C6 expression during larval development of hindlimbs or the tail. As such, our findings indicate that critical differences in larval hindlimb and tail development versus adult expression patterns of this gene in these two appendages may be due primarily to differences in gene regulation as opposed to gene function. Thus, the apparent ability of urodeles to regulate genes in such a highly co-ordinated fashion so as to replace lost, differentiated, appendicular structures in adult animals may assist, at least in part, in better elucidating the phenomenon of epimorphic regeneration.
