Beiträge zur Entwicklungsgeschichte von Zähnen und Gebiss der Reptilien

Woerdeman, M. W.

doi:10.1007/bf02977303

Cited by 35 publications

(11 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In geckos, it is the paired first generation tooth germs that are believed to develop into the two egg teeth. This conclusion is based on the appearance, in Pachydactylus and Gecko specimens examined, of a third, medially positioned tooth germ located between the paired egg teeth, which was homologized with the right, second generation tooth germ of other squamates (Woerderman, 1919a,b,c). Dibamus is the only other squamate known to have two egg teeth (Underwood and Lee, 2000; the condition in Anelytropsis remains unknown).…”

Section: Two Examples: Flowering Plants and Lizardsmentioning

confidence: 99%

Are monophyly and synapomorphy the same or different? Revisiting the role of morphology in phylogenetics

Assis

Rieppel

2011

Cladistics

View full text Add to dashboard Cite

Species are groups of organisms, marked out by reproductive (replicative) properties. Monophyletic taxa are groups of species, marked out by synapomorphies. In NelsonÕs analysis, monophyly and synapomorphy are identical relations. Monophyly and synapomorphy, however, are not equivalent relations. Monophyly is epistemically not accessible, whereas synapomorphy is epistemically accessible through character analysis. Monophyly originates with speciation, the two sister-species that come into being through the splitting of the ancestral species lineage forming a monophyletic taxon at the lowest level of inclusiveness. Synapomorphy provides the empirical evidence for monophyly, inferred from character analysis in the context of a three-taxon statement. If synapomorphy and monophyly were equivalent, phylogenetic systematists should find a single tree, instead of multiple equally parsimonious trees. Understanding synapomorphy as the relevant evidence for phylogenetic inference reveals a category mistake in contemporary phylogenetics: the treatment of morphological characters mapped onto molecular trees as synapomorphies and homoplasies. The mapping of morphological characters onto nodes of a molecular tree results in an empirically empty procedure for synapomorphy discovery. Morphological synapomorphies and homoplasies can only be discovered by morphological and combined analyses. The use of morphology in phylogenetic inference in general is defended by examples from Laurales and Squamata in particular. To make empirical evidence scientifically relevant in order to search for concordance, or dis-concordance, of phylogenetic signal, is certainly more fruitful for phylogenetics than the uncritical mapping of morphological traits on a molecular scaffold.

show abstract

Section: Two Examples: Flowering Plants and Lizardsmentioning

confidence: 99%

Are monophyly and synapomorphy the same or different? Revisiting the role of morphology in phylogenetics

Assis

Rieppel

2011

Cladistics

View full text Add to dashboard Cite

show abstract

“…The cycle of tooth replacement in reptiles has been a subject of interest for over a century. The careful work of Edmund, Osborn, and others on lizards (Cooper et al .,1970; Edmund,1960; Osborn,1971; Westergaard,1988; Woerdeman,1919) and Westergaard on alligator teeth (Westergaard and Ferguson,1986a,b,1987) have described in detail the formation of generations of teeth and how they replace the functional set. The common theme to these studies is that tooth replacement in reptiles is a similar process to diphyodont mammals since teeth are shed on a schedule, independent of wear or injury.…”

Section: Introductionmentioning

confidence: 99%

Reptilian tooth development

Richman

Handrigan

2011

Genesis

View full text Add to dashboard Cite

Summary: Dental patterns in vertebrates range from absence of teeth to multiple sets of teeth that are replaced throughout life. Despite this great variation, most of our understanding of tooth development is derived from studies on just a few model organisms. Here we introduce the reptile as an excellent model in which to study the molecular basis for early dental specification and, most importantly, for tooth replacement. We review recent snake studies that highlight the conserved role of Shh in marking the position of the odontogenic band. The distinctive molecular patterning of the dental lamina in the labial-lingual and oral-aboral axes is reviewed. We explain how these early signals help to specify the tooth-forming and non-tooth forming sides of the dental lamina as well as the presumptive successional lamina. Next, the simple architecture of the reptilian enamel organ is contrasted with the more complex, mammalian tooth bud and we discuss whether or not there is an enamel knot in reptilian teeth. The role of the successional lamina during tooth replacement in squamate reptiles is reviewed and we speculate on the possible formation of a vestigial, post-permanent dentition in mammals. In support of these ideas, we present data on agamid teeth in which development of a third generation is arrested. We suggest that in diphyodont mammals, similar mechanisms may be involved in reducing tooth replacement capacity. Finally, we review the location of label-retaining cells and suggest ways in which these putative dental epithelial stem cells contribute to continuous tooth replacement. genesis 49:247-260, 2011.

show abstract

“…Based on these data, several scientists have concluded that teeth at different positions along the jaw initiate independently. 30,34 Woerdeman 35 was the first person to propose that teeth arise and replace in waves and coined the term Zahnreihen to describe this pattern. In its purest sense, a Zahnreihe consists of a group of neighboring (adjacent) teeth from different tooth families that are at a similar stage of development (anterior to posterior diagonal lines, Figure 2).…”

Section: Jaw-wide Patterns Of Tooth Replacementmentioning

confidence: 99%

Biology of tooth replacement in amniotes

Whitlock

Richman

2013

Int J Oral Sci

View full text Add to dashboard Cite

Tooth replacement is a common trait to most vertebrates, including mammals. Mammals, however, have lost the capacity for continuous tooth renewal seen in most other vertebrates, and typically have only 1–2 generations of teeth. Here, we review the mechanisms of tooth replacement in reptiles and mammals, and discuss in detail the current and historical theories on control of timing and pattern of tooth replacement and development.

show abstract

Beiträge zur Entwicklungsgeschichte von Zähnen und Gebiss der Reptilien

Cited by 35 publications

References 8 publications

Are monophyly and synapomorphy the same or different? Revisiting the role of morphology in phylogenetics

Are monophyly and synapomorphy the same or different? Revisiting the role of morphology in phylogenetics

Reptilian tooth development

Biology of tooth replacement in amniotes

Contact Info

Product

Resources

About