Topic
Odontode
About: Odontode is a research topic. Over the lifetime, 134 publications have been published within this topic receiving 4125 citations.
Papers published on a yearly basis
Papers
TL;DR: This review deals with the following seven aspects of vertebrate skeletogenic and odontogenic tissues: innervation, chemoreception, histology, histopathology, “soft” and “hard” tissues.
Abstract: This review deals with the following seven aspects of vertebrate skeletogenic and odontogenic tissues. 1. The evolutionary sequence in which the tissues appeared amongst the lower craniate taxa. 2. The topographic association between skeletal (cartilage, bone) and dental (dentine, cement, enamel) tissues in the oldest vertebrates of each major taxon. 3. The separate developmental origin of the exo- and endoskeletons. 4. The neural-crest origin of cranial skeletogenic and odontogenic tissues in extant vertebrates. 5. The neural-crest origin of trunk dermal skeletogenic and odontogenic tissues in extant vertebrates. 6. The developmental processes that control differentiation of skeletogenic and odontogenic tissues in extant vertebrates. 7. Maintenance of developmental interactions regulating skeletogenic/odontogenic differentiation across vertebrate taxa. We derive twelve postulates, eight relating to the earliest vertebrate skeletogenic and odontogenic tissues and four relating to the development of these tissues in extant vertebrates and extrapolate the developmental data back to the evolutionary origin of vertebrate skeletogenic and odontogenic tissues. The conclusions that we draw from this analysis are as follows. 8. The dermal exoskeleton of thelodonts, heterostracans and osteostracans consisted of dentine, attachment tissue (cement or bone), and bone. 9. Cartilage (unmineralized) can be inferred to have been present in heterostracans and osteostracans, and globular mineralized cartilage was present in Eriptychius, an early Middle Ordovician vertebrate unassigned to any established group, but assumed to be a stem agnathan. 10. Enamel and possibly also enameloid was present in some early agnathans of uncertain affinities. The majority of dentine tubercles were bare. 11. The contemporaneous appearance of cellular and acellular bone in heterostracans and osteostracans during the Ordovician provides no clue as to whether one is more primitive than the other. 12. We interpret aspidin as being developmentally related to the odontogenic attachment tissues, either closer to dentine or a form of cement, rather than as derived from bone. 13. Dentine is present in the stratigraphically oldest (Cambrian) assumed vertebrate fossils, at present some only included as Problematica, and is cladistically primitive, relative to bone. 14. The first vertebrate exoskeletal skeletogenic ability was expressed as denticles of dentine. 15. Dentine, the bone of attachment associated with dentine, the basal bone to which dermal denticles are fused and cartilage of the Ordovician agnathan dermal exoskeleton were all derived from the neural crest and not from mesoderm. Therefore the earliest vertebrate skeletogenic/odontogenic tissues were of neural-crest origin.(ABSTRACT TRUNCATED AT 400 WORDS)
349 citations
11 Jan 2007
TL;DR: It is concluded that conodonts are cladistically more derived than either hagfishes or lampreys because they possess a mineralised dermal skeleton and that they are the most plesiomorphic member of the total group Gnathostomata.
Abstract: Current information on the conodonts Clydagnathus windsorensis (Globensky) and Promissum pulchrum Kova! cs‐ Endro$ dy, together with the latest interpretations of conodont hard tissues, are reviewed and it is concluded that sucient evidence exists to justify interpretation of the conodonts on a chordate model. A new phylogenetic analysis is undertaken, consisting of 17 chordate taxa and 103 morphological, physiological and biochemical characters; conodonts are included as a primary taxon. Various experiments with character coding, taxon deletion and the use of constraint trees are carried out. We conclude that conodonts are cladistically more derived than either hagfishes or lampreys because they possess a mineralised dermal skeleton and that they are the most plesiomorphic member of the total group Gnathostomata. We discuss the evolution of the nervous and sensory systems and the skeleton in the context of our optimal phylogenetic tree. There appears to be no simple evolution of free to canal-enclosed neuromasts; organised neuromasts within canals appear to have arisen at least three times from free neuromasts or neuromasts arranged within grooves. The mineralised vertebrate skeleton first appeared as odontodes of dentine or dentine plus enamel in the paraconodont}euconodont feeding apparatus. Bone appeared later, co-ordinate with the development of a dermal skeleton, and it appears to have been primitively acellular. Atubular dentine is more primitive than tubular dentine. However, the subsequent distribution of the dierent types of dentine (e.g. mesodentine, orthodentine), suggests that these tissue types are homoplastic. The topology of relationships and known stratigraphic ranges of taxa in our phylogeny predict the existence of myxinoids and petromyzontids in the Cambrian.
341 citations
TL;DR: The evolutionary links that exist between odontodes and organs that are phylogenetically related to them (teeth and scales) suggest the use of comparative approaches to study these structures, and the current state of knowledge on developmental mechanisms involved in non-mammalian odontogenesis is reviewed.
Abstract: The evolutionary links that exist between odontodes and organs that are phylogenetically related to them (teeth and scales) suggest the use of comparative approaches to study these structures. Part one of this review briefly introduces current ideas on how the pattern of odontodes and odontode-derived tissues has been established during evolution to yield the diversity of odontode-related organs currently observed in nature in the cranial and postcranial skeleton. This introductory survey is used to highlight aspects of the developmental processes underlying the formation of some of these organs and the resemblance their development bears to odontogenesis. Part two provides a concise survey of the diversity of tooth structure in the different classes of extant vertebrates, in particular with reference to enamel/enameloid and dentine structure, and tooth attachment. Against this background, the current state of knowledge is reviewed with regard to developmental mechanisms involved in non-mammalian odontogenesis. Common structure and similarities in development demonstrate that teeth and odontode derivatives should not be considered subjects of separate lines of research. On the contrary, results acquired in one of these fields are relevant to the other and may disclose model species that are relevant to studies on mammalian odontogenesis.
178 citations
TL;DR: Although knowledge on teeth and tooth nerves has increased substantially during the past 25 years, several important issues remain to be fully elucidated and can expect exciting new findings and major break-throughs in these and other areas in a near future.
175 citations
TL;DR: The phylogenetic results indicate that the new genus and species from the Tocantins River basin is a sister taxon of all the other members of the Neoplecostominae, originating during the Eocene at 47.5 Mya (32.7–64. 5 Mya 95% HPD).
Abstract: This study presents the description of a new genus of the catfish subfamily Neoplecostominae from the Tocantins River basin. It can be distinguished from other neoplecostomine genera by the presence of (1) three hypertrophied bicuspid odontodes on the lateral portion of the body (character apparently present in mature males); (2) a large area without odontodes around the snout; (3) a post-dorsal ridge on the caudal peduncle; (4) a straight tooth series in the dentary and premaxillary rows; (5) the absence of abdominal plates; (6) a conspicuous series of enlarged papillae just posterior to the dentary teeth; and (7) caudal peduncle ellipsoid in cross section. We used maximum likelihood and Bayesian methods to estimate a time-calibrated tree with the published data on 116 loricariid species using one nuclear and three mitochondrial genes, and we used parametric biogeographic analyses (DEC and DECj models) to estimate ancestral geographic ranges and to infer the colonization routes of the new genus and the other neoplecostomines in the Tocantins River and the hydrographic systems of southeastern Brazil. Our phylogenetic results indicate that the new genus and species is a sister taxon of all the other members of the Neoplecostominae, originating during the Eocene at 47.5 Mya (32.7–64.5 Mya 95% HPD). The present distribution of the new genus and other neoplecostomines may be the result of a historical connection between the drainage basins of the Paraguay and Parana rivers and the Amazon basin, mainly through headwater captures.
135 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 9 |
| 2020 | 4 |
| 2019 | 4 |
| 2018 | 2 |
| 2017 | 9 |
| 2016 | 8 |