Moya Meredith Smith

Moya Meredith Smith
  • DSc London University
  • Professor Emeritus at King's College London

About

140
Publications
63,514
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Introduction
Differences in dentition pattern generation between sharks and rays with comparison of generation of body scale patterns. Exploring conserved dentition pattern in osteichthyans and developmental mechanisms for producing novel tooth structures. Also interpretation of enigmatic vertebrate skeletons and how dentine may play a role as a prophylactic against wear and in repair of wounds in agnathan dermal bone.
Current institution
King's College London
Current position
  • Professor Emeritus
Additional affiliations
September 1998 - October 2019
King's College London
Position
  • Professor
October 1972 - present
King's College London
Position
  • Professor Emeritus
Description
  • Associate Scientist at the Natural History Museum London with a NERC funded research group.
January 2007 - April 2007
Macquarie University
Position
  • Professor
Description
  • Developemntal studies into generation of teeth and the dentition. tracing neural crest cell origin of dentine.

Publications

Publications (140)
Article
Full-text available
The Notch pathway is an ancient, evolutionary conserved intercellular signaling mechanism that is involved in cell fate specification and proper embryonic development. The Jagged2 gene, which encodes a ligand for the Notch family of receptors, is expressed from the earliest stages of odontogenesis in epithelial cells that will later generate the en...
Article
Full-text available
A new dipnoan lower jaw from the Wood Bay Formation (Pragian) of Svalbard (Norway), preserves a partial dentary and partial toothplates referred to the new species Janvierpaucidentes tuulingi gen. et sp. nov. The more complete toothplate is elongate with three short rows of teeth but is damaged medially. A large number of dipnoans are known from th...
Article
Full-text available
A new species of Dunkleosteus, D. tuderensis sp. nov., is named based on an infragnathal from the Famennian of the Tver Region, Russia. CT scanning of the holotype revealed two high-density bony constituents comparable in position and interrelations to components described for coccosteomorph arthrodires, supported by the presence of at least two cl...
Article
Restudy of Campyloprion annectans Eastman, 1902 from North America demonstrated that neither specimen included is diagnostic at the species level; thus, the species name is a nomen dubium. Since this species was designated as the type species of the genus, this requires suppression of the generic name also. Another species earlier assigned to Campy...
Article
Full-text available
Crushing and eating hard prey (durophagy) is mechanically demanding. The cartilage jaws of durophagous stingrays are known to be reinforced relative to non-durophagous relatives, with a thickened external cortex of mineralized blocks (tesserae), reinforcing struts inside the jaw (trabeculae), and pavement-like dentition. These strategies for skelet...
Article
Two sets of teeth (diphyodonty) characterise extant mammals but not reptiles, as they generate many replacement sets (polyphyodonty). The transition in long‐extinct species from many sets to only two has to date only been reported in Jurassic eucynodonts. Specimens of the Late Triassic brasilodontid eucynodont Brasilodon have provided anatomical an...
Article
Leedsichthys problematicus is a suspension‐feeding member of the Mesozoic clade Pachycormiformes (stem‐group Teleostei), and the largest known ray‐finned fish (Actinopterygii). As in some larger fish, the skeleton is poorly ossified, but the caudal fin (tail) is well‐preserved. Bony calluses have been found here, on the dermal fin rays, and when se...
Article
Full-text available
Among the cartilaginous fishes (Chondrichthyes), the Holocephali are unique in that teeth are absent both in ontogeny and adult regenerative growth. Instead, the holocephalan dentition of ever‐growing nonshedding dental plates is composed of dentine, trabecular in arrangement, forming spaces into which a novel hypermineralized dentine (whitlockin)...
Article
The Holocephali is a major group of chondrichthyan fishes, the sister taxon to the sharks and rays (Elasmobranchii). However, the dentition of extant holocephalans is very different from that of the elasmobranchs, lacking individual tooth renewal, but comprising dental plates made entirely of self-renewing dentine. This renewal of all tissues occur...
Article
Full-text available
All extant holocephalans (Chimaeroidei) have lost the ability to make individual teeth, as tooth germs are not part of the embryonic development of the dental plates or of their continuous growth. Instead, a hypermineralized dentine with a unique mineral, whitlockin, is specifically distributed within a dentine framework into structures that give t...
Article
Full-text available
The Sinacanthida ordo nov. and Mongolepidida are spine- and scale-based taxa whose remains encompass some of the earliest reported fossils of chondrichthyan fish. Investigation of fragmentary material from the Early Silurian Tataertag and Ymogantau Formations of the Tarim Basin (Xinjiang Uygur Autonomous Region, China) has revealed a diverse mongol...
Article
Full-text available
The dentition in extant holocephalans (Chondrichthyes) comprises three pairs of continuously growing dental plates, rather than the separate teeth characterizing elasmobranchs. We investigated how different types of dentine in these plates, including hypermineralized dentine, are arranged, and how this is renewed aborally, in adult and juvenile den...
Chapter
The life of a tooth is dynamic, with several phases: Firstly, during embryogenesis the main components of the tooth are formed (i.e. enamel, cementum, pulp, and dentine). Eruption of the tooth leads to the development of root(s) and root canal systems (i.e. main root canal(s), lateral root canals, branches, and deltas). After eruption, the tooth...
Article
Full-text available
A defining feature of dentitions in modern sharks and rays is the regulated pattern order that generates multiple replacement teeth. These are arranged in labio-lingual files of replacement teeth that form in sequential time order both along the jaw and within successively initiated teeth in a deep dental lamina. Two distinct adult dentitions have...
Article
Full-text available
Placoderms (Devonian fossil fishes) are resolved phylogenetically to the base of jawed vertebrates and provide important evidence for evolutionary origins of teeth, particularly with respect to the Arthrodira. The arthrodires represent a derived group of placoderms; the dentition of other more primitive placoderms such as the acanthothoracids is le...
Article
Full-text available
Palaeospondylus gunni Traquair, 1890 is an enigmatic Devonian vertebrate whose taxonomic affinities have been debated since it was first described. Most recently, Palaeospondylus has been identified as a stem-group hagfish (Myxinoidea). However, one character questioning this assignment is the presence of three semicircular canals in the otic region of...
Article
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This is an update on our article " Jawed vertebrate dentitions – when did teeth evolve " which appeared as a review for infocus 42, June 2016 but since then two important papers have just been published on the topic we choose to headline here.
Article
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The squaliform sharks represent one of the most speciose shark clades. Many adult squaliforms have blade-like teeth, either on both jaws or restricted to the lower jaw, forming a continuous, serrated blade along the jaw margin. These teeth are replaced as a single unit and successor teeth lack the alternate arrangement present in other elasmobranch...
Article
Full-text available
Summary Our research is concerned with the question of tooth origins and the relationship of teeth with the body scales, of both modern and extinct fishes. To unravel the evolutionary steps that led to tooth origins we focus our attention on both fossil and living fishes with potential ancestral dental characters. Our emphasis is on the organisatio...
Article
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The description of a partial but well preserved head of the sclerorhynchid batoid Sclerorhynchus atavus Woodward 1889 gave the first clear indication of the presence of a puzzling group of extinct rostrum-bearing rays that resembled both the Pristidae (rays) and the Pristophoridae (sharks). Despite recognizing similarities and differences to these...
Article
Full-text available
In classical theory, teeth of vertebrate dentitions evolved from co-option of external skin denticles into the oral cavity. This hypothesis predicts that ordered tooth arrangement and regulated replacement in the oral dentition were also derived from skin denticles. The fossil batoid ray Schizorhiza stromeri (Chondrichthyes; Cretaceous) provides a...
Conference Paper
Full-text available
Chondrichthyans possess both true teeth within their mouth and tooth-like denticles on their skin, both outside and inside the mouth. Understanding the relationships between teeth and denticles is fundamental to the interpretation of the origins of teeth within the gnathostomes. Superficially tooth-like structures on the body surface of sharks and...
Article
Full-text available
A well-known characteristic of chondrichthyans (e.g. sharks, rays) is their covering of external skin denticles (placoid scales), but less well understood is the wide morphological diversity that these skin denticles can show. Some of the more unusual of these are the tooth-like structures associated with the elongate cartilaginous rostrum ‘saw’ in...
Article
Full-text available
Origins of the vertebrate dentition, as a patterned, functional unit associated with the jaws, remain contentious. Hypotheses suggest dentitions evolved from external placoid scales, or alternatively, from denticles within the oropharyngeal cavity, with no input from external dermal structures. The latter hypothesis suggests that oral dentitions an...
Article
Full-text available
Ray-finned fishes (Actinopterygii) are the dominant vertebrate group today (+30 000 species, predominantly teleosts), with great morphological diversity, including their dentitions. How dental morphological variation evolved is best addressed by considering a range of taxa across actinopterygian phylogeny; here we examine the dentition of Polyodon...
Article
Full-text available
Shark and ray (elasmobranch) dentitions are well known for their multiple generations of teeth, with isolated teeth being common in the fossil record. However, how the diverse dentitions characteristic of elasmobranchs form is still poorly understood. Data on the development and maintenance of the dental patterning in this major vertebrate group wi...
Article
Ray-finned fishes (Actinopterygii) are the dominant vertebrate group today (+30 000 species, predominantly teleosts), with great morphological diversity, including their dentitions. How dental morphological variation evolved is best addressed by considering a range of taxa across actinopterygian phylogeny; here we examine the dentition of Polyodon...
Article
Full-text available
The outer armour of fossil jawless fishes (Heterostraci) is, predominantly, a bone with a superficial ornament of dentine tubercles surrounded by pores leading to flask-shaped crypts (ampullae). However, despite the extensive bone present in these early dermal skeletons, damage was repaired almost exclusively with dentine. Consolidation of bone, by...
Article
Previously described scale morphotypes of Silurian thelodonts, constrained by their representation as isolated dermal denticles are reassessed to provide a more robust character basis for their inclusion in future phylogenetic studies. As relatively common microfossils, thelodonts are important biostratigraphical markers, but their interrelationshi...
Article
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Teleost fishes comprise approximately half of all living vertebrates. The extreme range of diversity in teleosts is remarkable, especially, extensive morphological variation in their jaws and dentition. Some of the most unusual dentitions are found among members of the highly derived teleost order Tetraodontiformes, which includes triggerfishes, bo...
Article
Full-text available
Cartilaginous vertebrate skeletons leave few records as fossils, unless mineralized. Here, we report outstanding preservation of early stages of cartilage differentiation, present in the Devonian vertebrate Palaeospondylus gunni. In large specimens of Palaeospondylus, enlarged, hypertrophic cell spaces (lacunae) are dominant in the cartilage matrix...
Article
Full-text available
The mode of tooth development displayed in Chondrichthyans (sharks, rays and holocephalans), one of frequent tooth replacement, was possible once a dental lamina had evolved, and since 1982 this has been known as the odontode regulation theory after Reif. Today, Reif's concepts need to be transformed into those of modern biology, the crosstalk betw...
Article
Classically the oral dentition with teeth regulated into a successional iterative order was thought to have evolved from the superficial skin denticles migrating into the mouth at the stage when jaws evolved. The canonical view is that the initiation of a pattern order for teeth at the mouth margin required development of a sub-epithelial, permanen...
Chapter
Full-text available
Lungfi sh have a long evolutionary history, fi rst appearing in the Early Devonian, with three genera extant. Lungfi sh dentitions were particularly diverse and have been a focus of study for many years. Although diverse, all dentitions can be derived from a toothplated dentition, where components of this dentition, in terms of tooth structures and...
Article
Full-text available
The bearing that agnathans have on the origin of jawed vertebrates is one of the great unsolved problems in vertebrate phylogeny. Here we propose a mechanism for the evolution of jaws in vertebrates based on a combination of evidence from the fossil record and from experimental developmental biology. In chick embryos, osteogenesis can be evoked exp...
Article
Full-text available
Palaeospondylus gunni (Devonian, Scotland) is an enigmatic vertebrate, assigned to various jawless and jawed groups since its original description. New sections through the whole body allow description of a novel skeletal tissue for Palaeospondylus, comprising the entire skeleton. This tissue is mineralized cartilage and is characterized by large c...
Article
Full-text available
An investigation with the scanning electron microscope into the microstructure of the surface layer covering the oral teeth of Latimeria chalumnae has shown this tissue to be enamel of the type found in amphibians, reptiles and mammals. It is not comparable with enameloid, cuticular enamel or terminal membrane enamel as described in scanning electr...
Article
Scales from four specimens of Latimeria chalumnae were examined in a dissecting microscope and then X‐rayed. Some were demineralized and prepared for routine histology. Others were cleared in cedarwood oil. Ground sections of plastic embedded scales were micro‐radiographed and electronmicrographs made of araldite embedded frozen scales. Correspondi...
Article
Full-text available
This study considers stem cells for odontogenic capability in biological tooth renewal in the broad context of gnathostome dentitions and the derivation of them from oral epithelium. The location of the developmental site and cell dynamics of the dental lamina are parameters of a possible source for odontogenic epithelial stem cells, but the phylog...
Article
Full-text available
For a dentition representing the most basal extant gnathostomes, that of the shark can provide us with key insights into the evolution of vertebrate dentitions. To detail the pattern of odontogenesis, we have profiled the expression of sonic hedgehog, a key regulator of tooth induction. We find in the catshark (Scyliorhinus canicula) that intense s...
Article
Since the 1980s, a renewed understanding of molecular development has afforded an unprecedented level of knowledge of the mechanisms by which phenotype in animals and plants has evolved. In this volume, top scientists in these fields provide perspectives on how molecular data in biology help to elucidate key questions in estimating paleontological...
Article
Full-text available
We report a temporal order of tooth addition in the Australian lungfish where timing of tooth induction is sequential in the same pattern as osteichthyans along the lower jaw. The order of tooth initiation in Neoceratodus starts from the midline tooth, together with left and right ones at jaw position 2, followed by 3 and then 1. This is the patter...
Article
Experimental evidence that the neural crest participates in tooth development in any osteichthyan fish has so far been lacking. Using vital dye cell-lineage tracking, we demonstrate that trigeminal stream neural crest cells contribute to the dental papilla of developing teeth in the Australian lungfish. Trigeminal neural crest cells labeled before...
Article
A new actinopterygian fish Yaomoshania minutosquama gen. & sp. nov., from the Upper Permian of the Dzungaria [Junggar] Basin in China is described. The material consists of two very fragmentary specimens showing almost exclusively scale rows. The arrangement of the scale rows of the holotype resembles the reversion lines of acanthodian caudal fins...
Article
Full-text available
Regular scale patterning, restricted to the caudalmost tail and organized into two opposing rows on each side of the tail, is observed in few chondrichthyans. These evenly spaced scales, in dorsal and ventral rows, develop in an iterative sequence from the caudal tip, either side of the notochord. They are subsequently lost as a scattered pattern o...
Article
Full-text available
In two species of Heterodontus, H. portusjacksoni and H. galeatus, the first scales to develop form two opposing rows along the caudal fin axis on both the left and right sides of the fin. The opposing rows originate from an initial scale located on either side of the posterior tip of the caudal fin, with subsequent scales erupting in a posterior t...
Article
Repeated tooth initiation occurs often in nonmammalian vertebrates (polyphyodontism), recurrently linked with tooth shedding and in a definite order of succession. Regulation of this process has not been genetically defined and it is unclear if the mechanisms for constant generation of replacement teeth (secondary dentition) are similar to those us...
Article
Full-text available
Although the lungfish (Dipnoi) belong within the Osteichthyes, their dentitions are radically different from other osteichthyans. Lungfish dentitions also show a uniquely high structural disparity during the early evolution of the group, partly owing to the independent variation of odontogenic and odontoclastic processes that are tightly and stereo...
Article
Full-text available
The rainbow trout (Oncorhynchus mykiss) as a developmental model surpasses both zebrafish and mouse for a more widespread distribution of teeth in the oro-pharynx as the basis for general vertebrate odontogenesis, one in which replacement is an essential requirement. Studies on the rainbow trout have led to the identification of the initial sequent...
Article
Full-text available
This introduction to new patterning theories for the vertebrate dentition outlines the historical concepts to explain graded sequences in tooth shape in mammals (incisors, canines, premolars, molars) which change in evolution in a linked manner, constant for each region. The classic developmental models for shape regulation, known as the 'regional...
Article
Full-text available
The rainbow trout (Oncorhynchus mykiss) as a developmental model surpasses both zebrafish and mouse for a more widespread distribution of teeth in the oro-pharynx as the basis for general vertebrate odontogenesis, one in which replacement is an essential requirement. Studies on the rainbow trout have led to the identification of the initial sequent...
Article
Full-text available
Abstract The histological composition of the galeaspid cephalothoracic skeleton has been much debated: here we attempt to resolve this through the analysis of well-preserved remains of galeaspids from Yunnan Province, and Tarim Basin, Xinjiang Uygur Autonomous Region, China. Our results indicate that the galeaspid dermoskeleton is dominantly compos...
Article
Full-text available
The histological composition of the galeaspid cephalothoracic skeleton has been much debated: here we attempt to resolve this through the analysis of well-preserved remains of galeaspids from Yunnan Province, and Tarim Basin. Xinjiang Uygur Autonomous Region, China. Our results indicate that the galeaspid dermoskeleton is dominantly composed from a...
Article
On the basis of well preserved specimens from the Lower Silurian of the Tarim Basin, Xinjiang Uygur Autonomous Region and Shiqian County, Guizhou Province, People's Republic of China we describe in detail the histological structure of sinacanthid spines, the only known remains of a group of fishes common in Silurian strata from China. The sinacanth...
Article
Full-text available
The fossil group Placodermi is the most phylogenetically basal of the clade of jawed vertebrates but lacks a marginal dentition comparable to that of the dentate Chondrichthyes, Acanthodii and Osteichthyes (crown-group Gnathostomata). The teeth of crown-group gnathostomes are part of an ordered dentition replaced from, and patterned by, a dental la...
Article
Full-text available
Odontogenesis has only been closely scrutinized at the molecular level in the mouse, an animal with an extremely restricted dentition of only two types and one set. However, within osteichthyans many species display complex and extensive dentitions, which questions the extent to which information from the mouse is applicable to all osteichthyans. W...
Article
Full-text available
The fragmentary remains of a new dipnoan, Ichnomylax karatajae, sp. nov., have been discovered in the Lower Devonian sediments of Taymir Peninsula, northern Russia. This form is characterized by a prearticular tooth plate consisting of a large, elongated, strongly convex, heel-like posterior region, which is clearly demarcated from the anterior too...
Article
Full-text available
Tesakoviaspis concentrica n. gen. et sp. is an Early Silurian vertebrate with a distinctive and unique histology. This represents a new order of a tesselate agnathan. The crown growth is cyclomorial with simple odontodes of smooth pear-shaped, morphology. These microremains, collected from the southern part of the Siberian platform, are attributed...
Article
Full-text available
The correlation of the origin of teeth with jaws in vertebrate history has recently been challenged with an alternative to the canonical view of teeth deriving from separate skin denticles. This alternative proposes that organized denticle whorls on the pharyngeal (gill) arches in the fossil jawless fish Loganellia are precursors to tooth families...
Article
Full-text available
New evidence shows that teeth evolved with a greater degree of independence from jaws than previously considered. Pharyngeal denticles occur in jawless fish and also in early gnathostomes and precede jaw teeth in phylogeny. Many of these denticles form joined polarized sets on each branchial arch; these resemble whorl-shaped tooth sets on the jaws...
Article
Full-text available
Placoderms are extinct jawed fishes of the class Placodermi and are basal among jawed vertebrates. It is generally thought that teeth are absent in placoderms and that the phylogenetic origin of teeth occurred after the evolution of jaws. However, we now report the presence of tooth rows in more derived placoderms, the arthrodires. New teeth are co...
Article
Full-text available
Placoderms are extinct jawed fishes of the class Placodermi and are basal among jawed vertebrates. It is generally thought that teeth are absent in placoderms and that the phylogenetic origin of teeth occurred after the evolution of jaws. However, we now report the presence of tooth rows in more derived placoderms, the arthrodires. New teeth are co...
Article
Full-text available
Abundant microvertebrate remains from the Siberian Platform are described as early acanthodians. All are preserved with both excellent morphology and histology. They are assigned to a new order, Tchunacanthida, with two new families, Lenacanthidae and Tchunacanthidae. These comprise two new genera, Lenacanthus and Tchunacanthus with type species L....
Article
Full-text available
The lungfish dentition is different from other osteichthyan fish because it has a characteristic and unique pattern of teeth arranged as toothplates. Growth, addition of teeth, and retention as part of a statodont dentition are determined by the initiation pattern. In adult lungfish new teeth are only added laterally to each radial row in the denti...
Article
Full-text available
Although the 3 genera of living lungfish have different-shaped adult tooth plates, their larval stages have similar patterns of development. The sequence in the pattern of initiation of teeth and their modification through ontogeny in Neoceratodus hatchlings provides a developmental model for fossil hatchling tooth plates (smallest 1–2 mm) recovere...
Article
Full-text available
Lungfish, the closest living relatives of four-limbed animals, are unique in that adults lack marginal teeth and have to rely on palatal dental plates for crushing food. We have discovered that an identical pattern of tooth development is used to shape these plates in the hatchlings of fossil and living lungfish species that are separated by 360 mi...
Article
In this field there has been an explosion of information generated by scientific research. One of the beneficiaries of this has been the study of morphology, where new techniques and analyses have led to insights into a wide range of topics. Advances in genetics, histology, microstructure, biomechanics and morphometrics have allowed researchers to...
Chapter
In this field there has been an explosion of information generated by scientific research. One of the beneficiaries of this has been the study of morphology, where new techniques and analyses have led to insights into a wide range of topics. Advances in genetics, histology, microstructure, biomechanics and morphometrics have allowed researchers to...
Article
The late Llandovery (early Silurian) of South China has yielded a locally abundant and diverse microvertebrate fauna. This includes scales of the little-known mongolepids, sinacanthid spines and a whole host of as yet unassigned forms. The material recovered provides a considerable amount of new information about the diversity of fish in the South...
Article
Full-text available
Pharyngeal arches are a prominent and critical feature of the developing vertebrate head. They constitute a series of bulges within which musculature and skeletal elements form; importantly, these tissues derive from different embryonic cell types [1]. Numerous studies have emphasised the role of the cranial neural crest, from which the skeletal co...
Article
Full-text available
Seven morphological types of actinopterygian teeth, together with one indeterminate (?Actinopterygii) tooth, plus lower actinopterygian and acanthodian dermal scales (Acanthodidae) are described from the Itaituba Formation in the Amazon Basin of Brazil. These are associated with shark remains, marine invertebrates and conodonts dated as Late Pennsy...

Questions

Questions (5)
Question
" The dipnoan dentition: a unique adaptation with a longstanding evolutionary record. pp219 - 241.
Question
Normally most sharks have an attachment base to their teeth that is more bone like than the rest of the tooth and the soft tissue of collagen fibres attaches to this part.
Question
Anatomy of all dentition and rostral process.
Question
I think you are quite familiar with our papers on shark dentitions ---
two very low key ones at the end.
Evolutionary origins and development of saw-teeth on the sawfish and sawshark rostrum (Elasmobranchii; Chondrichthyes).
         2015. Monique Welten, Moya M. Smith, Charlie Underwood, Zerina Johanson. Royal Society Open Science. 10.1098/rsos.150189.
 Early development of rostrum saw-teeth in a fossil ray tests classical theories of the evolution of vertebrate dentitions.
         2015. Moya Smith, Alex Riley, Gareth Fraser, Charlie Underwood, Monique Welten, Jurgen Kriwet, Cathrin Pfaff, Zerina Johanson.  Proc. R. Soc. B (Sept.4). 282: 20151628. DOI: 10.1098/rspb.2015.1628.
PubMed ID 26423843  
Cutting blade dentitons in squalifrom sharks by modification of inherited alternate tooth ordering patterns.
         2016. Underwood, C., Johanson, Z. and Moya M.Smith. R. Soc. Open Sci. 30, 3, 1-20. DOI: 10.1098/rsos. 160385. http://dx.doi.org/10.1098/rsos.160385
 Origin of teeth in jawed vertebrates.
2016. Moya M.Smith, Fraser G. J., Johanson, Z.  Infocus PRMS, 42, 5-17.
 How teeth are organized into functional dentitions.
         2017. Moya M.Smith, Underwood, C., Fraser, G.J. Infocus PRMS, March 45, 4-11
Question
There is currently an extensive debate on how this occurs and an agreed definition of the parameters

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