Three-dimensional limb joint mobility in the early tetrapod Ichthyostega

  title={Three-dimensional limb joint mobility in the early tetrapod Ichthyostega},
  author={Stephanie E. Pierce and Jennifer Alice Clack and John R. Hutchinson},
The origin of tetrapods and the transition from swimming to walking was a pivotal step in the evolution and diversification of terrestrial vertebrates. [] Key Result We show that Ichthyostega could not have employed typical tetrapod locomotory behaviours, such as lateral sequence walking. In particular, it lacked the necessary rotary motions in its limbs to push the body off the ground and move the limbs in an alternating sequence. Given that long-axis rotation was present in the fins of tetrapodomorph…

Propulsive forces of mudskipper fins and salamander limbs during terrestrial locomotion: implications for the invasion of land.

Examining three-dimensional ground reaction forces produced by isolated pectoral fins of mudskipper fishes during terrestrial crutching compared to isolated walking footfalls by the forelimbs and hind limbs of tiger salamanders helps to clarify how structural change may have influenced locomotor function through the evolutionary invasion of land by vertebrates.

Characteristic tetrapod musculoskeletal limb phenotype emerged more than 400 MYA in basal lobe-finned fishes

These findings suggest that the characteristic tetrapod musculoskeletal limb phenotype was already present in the Silurian last common ancestor of extant sarcopterygians, with exception to the autopod (hand/foot) structures, which have no clear correspondence with fish structures.

Low elbow mobility indicates unique forelimb posture and function in a giant extinct marsupial

This work introduces new quantitative methods and demonstrates the utility of comparative ROM mapping approaches, highlighting that Palorchestes' forelimb function was unlike its contemporaneous relatives and appears to lack clear functional analogues among living mammals.

The iliosacral joint in lizards: an osteological and histological analysis

It is hypothesized that limited torsion of the ilium at the ISJ happens when the hip is abducted, and the joint is likely able to absorb the compressional and extensional forces related to the protraction and retraction of the femur.

Pelvic girdle and fin of Tiktaalik roseae

The mosaic of primitive and derived features in Tiktaalik reveals that the enhancement of the pelvic appendage of tetrapods and, indeed, a trend toward hind limb-based propulsion have antecedents in the fins of their closest relatives.

Historical perspectives on the evolution of tetrapodomorph movement.

A phylogenetic review of modern analogs, from chondrichthyans to mammals, highlights the broad spectrum of vertebrate clades and locomotor behaviors, and proposes that various locomotion behaviors of modern quadrupeds can be ruled out for Ichthyostega, but that forelimb "crutching" motions, as seen in living mudskippers, may have been possible.

Kinematic comparisons between mudskipper fins and salamander limbs during terrestrial locomotion.

Mudskipper pectoral fins provide weight support and propulsion but have lower mobility in the proximal versus distal elements, for which greater flexibility in the latter might compensate, which provides new insights into the biomechanics of using fins versus limbs for moving over land and factors that may favor the evolution of different terrestrial gaits.

Characteristic tetrapod musculoskeletal limb phenotype

New musculoskeletal data from dissections, MRI scans, 3D reconstructions, and histological sections of coelacanths and dipnoans are obtained and will be crucial in paving the way for the use of this method in muscle reconstructions of key tetrapod and non-tetrapod sarcopterygian extinct taxa.

Late to the table: diversification of tetrapod mandibular biomechanics lagged behind the evolution of terrestriality.

The substantial temporal gap between the origin of postcranial features associated with terrestriality, such as limbs with functional elbow/knee and wrist/ankle joints capable of weight-bearing, and the onset of divergence in jaw biomechanics provides a compelling example of "functional modularity" during a major adaptive radiation.

Developmental plasticity and the origin of tetrapods

The remarkable correspondence between the environmentally induced phenotypes of terrestrialized Polypterus and the ancient anatomical changes in stem tetrapods is shown, raising the possibility that environmentally induced developmental plasticity facilitated the origin of the terrestrial traits that led to tetrapod.



Development and Evolution of the Muscles of the Pelvic Fin

It is proposed that the adoption of the fully derived mode of hindlimb muscle formation from this bimodal character state is an evolutionary innovation that was critical to the success of the tetrapod transition.

Evolutionary origins of vertebrate appendicular muscle

It is found that in the teleost, zebrafish, fin muscles arise from migratory mesenchymal precursor cells that possess molecular and morphogenetic identity with the limb muscle precursors of tetrapod species.


  • Ashley-Ross
  • Biology
    The Journal of experimental biology
  • 1994
A quantitative study of hindlimb kinematics during terrestrial locomotion in a non-specialized salamander was undertaken to allow comparisons with limb movements in other groups of tetrapods. Five

Polydactyly in the earliest known tetrapod limbs

The morphology of the specimens suggests that limbs with digits may have been adaptations to an aquatic rather than a terrestrial environment, and challenges pentadactyly as primitive for tetrapods.

The pectoral fin of Tiktaalik roseae and the origin of the tetrapod limb

The pectoral appendage of a member of the sister group of tetrapods, Tiktaalik roseae, is described, which is morphologically and functionally transitional between a fin and a limb.

The axial skeleton of the Devonian tetrapod Ichthyostega

A new reconstruction of Ichthyostega is shown based on extensive re-examination of original material and augmented by recently collected specimens and reveals hitherto unrecognized regionalization in the vertebral column.

Kinematics of level terrestrial and underwater walking in the California newt, Taricha torosa.

Quantitative analysis of limb kinematics of the California newt showed that underwater strides were more variable than terrestrial ones, but overall were strikingly similar between the two environments, with joint movement reversals occurring at similar points in the step cycle.

IX.—The Postcranial Skeleton of Ensthenopteron foordi Whiteaves

A functional analysis of the skeleton of Ensthenopteron is attempted, suggesting that it resembled the pike in its mode of life and that it may have been capable of short journeys “walking” overland.

The pectoral fin of Panderichthys and the origin of digits

A CT scan study of an undisturbed pectoral fin of Panderichthys is presented demonstrating that the plate-like ‘ulnare’ of previous reconstructions is an artefact and that distal radials are in fact present and makes a strong case for fingers not being a novelty of tetrapods but derived from pre-existing distal Radials present in all sarcopterygian fish.

Terrestrial-style feeding in a very early aquatic tetrapod is supported by evidence from experimental analysis of suture morphology

The suture morphologies of Acanthostega are inconsistent with the hypothesis that it captured prey primarily by means of suction, which suggests that it may have bitten directly on prey at or near the water's edge, and the data strongly support the hypotheses that the terrestrial mode of feeding first emerged in aquatic taxa.