Cyclostomes

Berkovitz, Β.Κ.B.

doi:10.1016/b978-0-12-802850-6.00001-1

Cited by 25 publications

(59 citation statements)

References 10 publications

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“…The enamel on the labial surfaces of the dentary teeth is rapidly worn away due to attrition, exposing a broad plane of orthodentine along the shearing surface ( Fig 3F ). The orthodentine is similar to that of most other amniotes in that it is avascular, tubular, and is thicker in older teeth due to the centripetal deposition of dentine matrix in life [ 5 , 8 , 43 ]. The orthodentine along the shearing surfaces of the functional teeth shows no evidence of complex vascular structures or sclerotic dentine, like those proposed for hadrosaurid dinosaurs [ 2 , 9 ].…”

Section: Resultsmentioning

confidence: 99%

Tooth development, histology, and enamel microstructure in Changchunsaurus parvus: Implications for dental evolution in ornithopod dinosaurs

et al. 2018

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The great diversity of dinosaurian tooth shapes and sizes, and in particular, the amazing dental complexity in derived ornithischians has attracted a lot of attention. However, the evolution of dental batteries in hadrosaurids and ceratopsids is difficult to understand without a broader comparative framework. Here we describe tooth histology and development in the "middle" Cretaceous ornithischian dinosaur Changchunsaurus parvus, a small herbivore that has been characterized as an early ornithopod, or even as a more basal ornithischian. We use this taxon to show how a "typical" ornithischian dentition develops, copes with wear, and undergoes tooth replacement. Although in most respects the histological properties of their teeth are similar to those of other dinosaurs, we show that, as in other more derived ornithischians, in C. parvus the pulp chamber is not invaded fully by the newly developing replacement tooth until eruption is nearly complete. This allowed C. parvus to maintain an uninterrupted shearing surface along a single tooth row, while undergoing continuous tooth replacement. Our histological sections also show that the replacement foramina on the lingual surfaces of the jaws are likely the entry points for an externally placed dental lamina, a feature found in many other ornithischian dinosaurs. Surprisingly, our histological analysis also revealed the presence of wavy enamel, the phylogenetically earliest occurrence of this type of tissue. This contradicts previous interpretations that this peculiar type of enamel arose in association with more complex hadrosauroid dentitions. In view of its early appearance, we suggest that wavy enamel may have evolved in association with a shearing-type dentition in a roughly symmetrically-enameled crown, although its precise function still remains somewhat of a mystery.

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Section: Resultsmentioning

confidence: 99%

Tooth development, histology, and enamel microstructure in Changchunsaurus parvus: Implications for dental evolution in ornithopod dinosaurs

et al. 2018

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“…In Agamidae for instance, the most mesial teeth are pleurodont whereas all remaining distal teeth are acrodont. Teiidae also display variability in implantation geometry, and their dentition have been considered alternatively as pleurodont ( Romer, 1956 ; Presch, 1974 ; Berkovitz and Shellis, 2017 ), or subthecodont ( Edmund, 1969 ; Berkovitz and Shellis, 2017 ). The way teeth are implanted in Tupinambis teguixin illustrates the difficulty of accurately determining the geometry of implantation in Teiidae (Figures 2C , 5 ).…”

Section: Diversity Of Tooth Attachment Implantation and Replacement mentioning

confidence: 99%

“…The acquisition of a dentition has led to a diversification of predation and oral processing patterns that can, at least in part, explain the tremendous evolutionary success of vertebrates ( Pough et al, 2009 ). Today, vertebrates display a great diversity of dentitions in terms of tooth location, number, shape, occlusion, attachment, implantation, and replacement ( Ungar, 2010 ; Berkovitz and Shellis, 2017 ). Teeth are highly mineralized organs that consist of the hardest known tissues, dentin and especially enamel, composed of, respectively, 70 and 96% mineral matrix ( Nanci, 2003 ).…”

Section: Introductionmentioning

confidence: 99%

Current Perspectives on Tooth Implantation, Attachment, and Replacement in Amniota

et al. 2018

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Teeth and dentitions contain many morphological characters which give them a particularly important weight in comparative anatomy, systematics, physiology and ecology. As teeth are organs that contain the hardest mineralized tissues vertebrates can produce, their fossil remains are abundant and the study of their anatomy in fossil specimens is of major importance in evolutionary biology. Comparative anatomy has long favored studies of dental characters rather than features associated with tooth attachment and implantation. Here we review a large part of the historical and modern work on the attachment, implantation and replacement of teeth in Amniota. We propose synthetic definitions or redefinitions of most commonly used terms, some of which have led to confusion and conflation of terminology. In particular, there has long been much conflation between dental implantation that strictly concerns the geometrical aspects of the tooth-bone interface, and the nature of the dental attachment, which mostly concerns the histological features occurring at this interface. A second aim of this work was to evaluate the diversity of tooth attachment, implantation and replacement in extant and extinct amniotes in order to derive hypothetical evolutionary trends in these different dental traits over time. Continuous dental replacement prevails within amniotes, replacement being drastically modified only in Mammalia and when dental implantation is acrodont. By comparison, dental implantation frequently and rapidly changes at various taxonomic scales and is often homoplastic. This contrasts with the conservatism in the identity of the tooth attachment tissues (cementum, periodontal ligament, and alveolar bone), which were already present in the earliest known amniotes. Because the study of dental attachment requires invasive histological investigations, this trait is least documented and therefore its evolutionary history is currently poorly understood. Finally, it is essential to go on collecting data from all groups of amniotes in order to better understand and consequently better define dental characters.

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“…Lastly, it is important to mention that the jaw ontogenetically increases posteriorly in length and dorsoventrally in width, with the articular increasing in robustness, and the coronoid process moving posteriorly relative to the tooth row. This ontogenetic change effectively creates more space for the posterior addition of teeth to the dentary, a feature that is frequently seen in lepidosaurs ( Berkovitz & Shellis, 2016 and referances therein).…”

Section: Resultsmentioning

confidence: 97%

Histological analysis of post-eruption tooth wear adaptations, and ontogenetic changes in tooth implantation in the acrodontan squamate Pogona vitticeps

Haridy

2018

PeerJ

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Teeth have been a focus of research in both extinct and extant taxa alike; a significant portion of dental literature is concerned with dental patterning and replacement. Most non-mammalian vertebrates continuously replace their dentition but an anomalous group of squamates has forgone this process in only having one tooth generation; these squamates all have apically implanted teeth, a condition known as acrodonty. Acrodont dentition and various characteristics attributed to it, including a lack of replacement, have often been defined ambiguously. This study explores this type of implantation through histology in the ontogeny of the acrodont agamid Pogona vitticeps. The non-replacing teeth of this squamate provides an opportunity to study wear adaptations, maintenance of occlusion in a non-mammalian system, and most importantly post-eruption changes in the tooth bone interface. In this study the post-eruption changes combined with dental wear likely gives the appearance of acrodont implantation.

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Cyclostomes

Cited by 25 publications

References 10 publications

Tooth development, histology, and enamel microstructure in Changchunsaurus parvus: Implications for dental evolution in ornithopod dinosaurs

Tooth development, histology, and enamel microstructure in Changchunsaurus parvus: Implications for dental evolution in ornithopod dinosaurs

Current Perspectives on Tooth Implantation, Attachment, and Replacement in Amniota

Histological analysis of post-eruption tooth wear adaptations, and ontogenetic changes in tooth implantation in the acrodontan squamate Pogona vitticeps

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