Testing microstructural adaptation in the earliest dental tools

Jones, David; Evans, Alistair R.; Rayfield, Emily J.; Siu, Karen Kit Wan; Donoghue, Philip C. J.

doi:10.1098/rsbl.2012.0487

Cited by 15 publications

(28 citation statements)

References 19 publications

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“…Conodonts are by far the best understood in terms of ecology, from functional analyses of their feeding elements using microwear, microstructural, occlusal kinematic and finite elements analyses (Purnell ; Donoghue and Purnell ; Donoghue ; Jones et al . , b ; Purnell and Jones ; Murdock et al . ; Martínez‐Pérez et al .…”

Section: What Remains?mentioning

confidence: 99%

Early vertebrate evolution

Donoghue

Keating

2014

Palaeontology

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Debate over the origin and evolution of vertebrates has occupied biologists and palaeontologists alike for centuries. This debate has been refined by molecular phylogenetics, which has resolved the place of vertebrates among their invertebrate chordate relatives, and that of chordates among their deuterostome relatives. The origin of vertebrates is characterized by wide-ranging genomic, embryologic and phenotypic evolutionary change. Analyses based on living lineages suggest dramatic shifts in the tempo of evolutionary change at the origin of vertebrates and gnathostomes, coincident with whole-genome duplication events. However, the enriched perspective provided by the fossil record demonstrates that these apparent bursts of anatomical evolution and taxic richness are an artefact of the extinction of phylogenetic intermediates whose fossil remains evidence the gradual assembly of crown gnathostome characters in particular. A more refined understanding of the timing, tempo and mode of early vertebrate evolution rests with: (1) better genome assemblies for living cyclostomes; (2) a better understanding of the anatomical characteristics of key fossil groups, especially the anaspids, thelodonts, galeaspids and pituriaspids; (3) tests of the monophyly of traditional groups; and (4) the application of divergence time methods that integrate not just molecular data from living species, but also morphological data and extinct species. The resulting framework will provide for rigorous tests of rates of character evolution and diversification, and of hypotheses of long-term trends in ecological evolution that themselves suffer for lack of quantitative functional tests. The fossil record has been silent on the nature of the transition from jawless vertebrates to the jawed vertebrates that have dominated communities since the middle Palaeozoic. Elucidation of this most formative of episodes likely rests with the overhaul of early vertebrate systematics that we propose, but perhaps more fundamentally with fossil grades that await discovery.

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Section: What Remains?mentioning

confidence: 99%

Early vertebrate evolution

Donoghue

Keating

2014

Palaeontology

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“…Functional analyses have advanced to an extent where conodont taxonomy, based on dental morphology, can be interpreted in terms of feeding ecology (Jones et al, 2012a(Jones et al, , 2012bPurnell and Jones, 2012;Martínez-Pérez et al, 2014a, 2014b, 2016Murdok et al, 2014). This opens the possibility of interpreting the conodont fossil record as a detailed and comparatively complete record of the evolution of feeding ecology through much of the Phanerozoic, including across some of the most dramatic ecological and environmental crises that have impacted animal life, such as the end-Ordovician, Frasnian-Fammenian, Hangenberg, and PermianTriassic mass extinction events.…”

Section: Introductionmentioning

confidence: 99%

Evolutionary convergence in conodonts revealed by Synchrotron-based Tomographic Microscopy

Mazza

Martínez‐Pérez

2016

Palaeontologia Electronica

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“…Integral to this hypothesis is the apparently contentious interpretation of conodont elements as dental tools (Purnell , ; Donoghue and Purnell , ; Jones et al . , ) and the observation that microstructural differentiation of conodont crown tissue coincides with, and is adapted to, implied dental stresses. This interpretation contrasts with the view of some contemporary authors (Blieck et al .…”

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confidence: 98%

Finite element, occlusal, microwear and microstructural analyses indicate that conodont microstructure is adapted to dental function

et al. 2014

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Conodonts constitute the earliest evidence of skeletal biomineralization in the vertebrate evolutionary lineage, manifest as a feeding apparatus of tooth-like elements comprised of enamel-and dentine-like tissues that evolved in parallel with these canonical tissues in other total-group gnathostomes. As such, this remarkable example of evolutionary parallelism affords a natural experiment in which to explore the constraints on vertebrate skeletal evolution. Using finite element analysis, informed by occlusal and microwear analyses, we tested the hypothesis that coincidence of complex dental function and microstructural differentiation in the enamel-like tissues of conodonts and other vertebrates is a consequence of functional adaptation. Our results show topological co-variation in the patterns of stress distribution and crystallite orientation. In regions of high stress, such as the apex of the basal cavity and inner parts of the platform, the crown tissue comprises interwoven prisms, discontinuities between which would have acted to decussate cracks, preventing propagation. These results inform a general occlusal model for platform conodont elements and demonstrate that the complex microstructure of conodont crown tissue is an adaptation to the dental functions that the elements performed.

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Testing microstructural adaptation in the earliest dental tools

Cited by 15 publications

References 19 publications

Early vertebrate evolution

Early vertebrate evolution

Evolutionary convergence in conodonts revealed by Synchrotron-based Tomographic Microscopy

Finite element, occlusal, microwear and microstructural analyses indicate that conodont microstructure is adapted to dental function

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