Part I. Development of the skull in sharks and rays. Acta Zool Stockh , 51— Acta Palaeontol Pol , — Broom R: On the development and morphology of the marsupial shoulder girdle. Trans Roy Soc Edin , — Organ CL: Thoracic epaxial muscles in living archosaurs and ornithopod dinosaurs.
Anat Rec , A: — Smith HM: Classification of bone. Turtox News , — Acta Chiropterol , 5: — Jellison WL: A suggested homolog of the Os penis or baculum of mammals. J Mammal , — Sereno PC: The evolution of dinosaurs.
J Syst Palaeontol , 9: 25— Hill RV: Integration of morphological data sets for phylogenetic analysis of amniota: The importance of integumentary characters and increased taxonomic sampling. Syst Biol , — PubMed Article Google Scholar. Hill RV: Comparative anatomy and histology of xenarthran osteoderms. J Anat , — London: Oxford University Press; Dev Cell , — J Vert Paleontol , — Microsc Res Techniq , — Development , — Philadelphia: W. Saunders; Witzmann F: Comparative histology of sculptured dermal bones in basal tetrapods, and the implications for the soft tissue dermis.
Palaeodiversity , 2: — Platt JB: Ectodermic origin of the cartilage of the head. Anat Anz , 8: — Oxford: Oxford University Press; New York: Oxford University Press; London: Elsevier Academic Press; Newth DR: Experiments on the neural crest of the lamprey embryo. J Exp Biol , — Newth DR: On the neural crest of the lamprey embryo.
J Embryol Exp Morph , 4: — Kuratani S, Murakami Y, Nobusada Y, Kusakabe R, Hirano S: Developmental fate of the mandibular mesoderm in the lamprey, Lethenteron japonicum : comparative morphology and development of the gnathostome jaw with special reference to the nature of the trabecula cranii. Mech Develop , — Cambridge: Cambridge University Press; Curr Biol , R—R Noden DM: Interactions and fates of avian craniofacial mesenchyme.
PubMed Google Scholar. Kuratani S: Craniofacial development and the evolution of the vertebrates: the old problems on a new background. Zool Sci , 1— Noden DM: Patterns and organization of craniofacial skeletogenic and myogenic mesenchyme: a perspective. Prog Clin Biol Res , — Noden DM: Craniofacial development: new views on old problems.
Anat Rec , 1— Dev Dyn , — Westoll TS: Ancestry of the tetrapods. Palaeontology , — Gegenbaur C: Elements of Comparative Anatomy. Gaupp E: Die Entwicklung des Kopfskelettes. Edited by Hertwig O. Jena: Gustav Fischer; — Jena: Verlag von Gustav Fischer; London: Macmillan; Book Google Scholar. New York: Academic Press; London: Cambridge University Press; Chicago: University of Chicago Press; New York: Springer Verlag; J Anat , 41— Kuratani S, Matsuo I, Aizawa S: Developmental patterning and evolution of the mammalian viscerocranium: Genetic insights into comparative morphology.
Kuratani S: Evolution of the vertebrate jaw from developmental perspectives. Evol Dev , 76— Zool Sci , — Cell , — Kessel M: Respecification of vertebral identities by retinoic acid. Van Voorst; Proc Zool Soc Lond , 9: — Olsson L, Hanken J: Cranial neural crest migration and chondrogenic fate in the oriental fire-bellied toad Bombina orientalis : defining the ancestral pattern of head development in anuran amphibians.
Gross JB, Hanken J: Segmentation of the vertebrate skull: neural-crest derivation of adult cartilages in the clawed frog, Xenopus laevis. Intg Comp Biol , — Hanken J, Gross JB: Evolution of cranial development and the role of neural crest: insights from amphibians. Jollie M: Segment theory and the homologizing of cranial bones. Thomson KS: Segmentation, the adult skull, and the problem of homology. In The Skull, Vol 2. Chicago: University of Chicago Press; — Heintz A: The structure of Dinichthys : a contribution to our knowledge of the arthrodira.
Edited by Gudger EW. Schlosser G: Making senses: development of vertebrate cranial placodes. Int Rev Cell Mol Biol , — Noden DM: The role of the neural crest in patterning of avian cranial skeletal, connective, and muscle tissues.
J Embryol Exp Morph , 17— Curr Opin Genet Dev , — Curr Biol , — J Embryol Exp Morph , 1— Evol Dev , 9: — Reif WE: Evolution of dermal skeleton and dentition in vertebrates: the odontode regulation theory.
Evol Biol , — Noden DM: Control of avian cephalic neural crest cytodifferentiation. Westoll TS: On the evolution of the Dipnoi. In Genetics, Paleontology and Evolution. Princeton: Princeton University Press; — White EI: A little on lungfishes. Proc Linn Soc Lond , 1— Gross JB, Hanken J: Cranial neural crest contributes to the bony skull vault in adult Xenopus laevis : insights from cell labeling studies.
Schneider RA: Neural crest can form cartilages normally derived from mesoderm during development of the avian head skeleton.
J Embryol Exp Morph , — Xu X, Mackem S: Tracing the evolution of avian wing digits. Narita Y, Kuratani S: Evolution of the vertebral formulae in mammals: A perspective on developmental constraints.
Malden: Wiley; Arendt D: The evolution of cell types in animals: emerging principles from molecular studies. Nat Rev Genet , 9: — Evol Dev , 8: — Scotland RW: Deep homology: A view from systematics. Bioessays , — Roth VL: The biological basis of homology.
In Ontogeny and Systematics. Edited by Humphries CJ. New York: Columbia University Press; — Evol Dev , 3: — Zeit wiss Zool , — Dev Dyn , 4— Proc Roy Soc B , — Olson ME: The developmental renaissance in adaptationism.
Trends Ecol Evol , — Duboule D: Temporal colinearity and the phylotypic progression: a basis for the stability of a vertebrate bauplan and the evolution of morphologies through heterochrony.
Irie N, Kuratani S: Comparative transcriptome analysis reveals vertebrate phylotypic period during organogenesis. During terrestrial evolution, however, it has been drastically reduced or lost in the trunk region, and the mesoderm-derived endoskeleton vertebra has become the major source of structural support 3 , 4 Fig. The emergence of the neural crest, an embryonic tissue, in early vertebrates is known to be closely related to the novel characteristics unique to vertebrates 5.
Indeed, most of the cranial exoskeletal elements in tetrapods such as teeth and dermal skull roof are derived from the neural crest 6 , 7 , 8 , 9 , 10 , However, the embryonic origin of the trunk exoskeleton remains largely unknown and thus the role of the neural crest in the early evolution of vertebrate skeletal system is still unclear.
Vertebrates have two distinct sets of skeletons, exoskeleton dermal skull roofs, teeth, scales, fin rays and so on. While the endoskeleton consists of endochondral bones that are preformed by cartilage and later replaced by mineralized bones, the major components of the exoskeleton are the dermal bones that develop in the dermis only by membranous ossification. A mineralized skeleton is thought to have emerged initially as exoskeletonal elements. Bony fish retain the exoskeleton in the form of dermal scales and fin rays.
During terrestrial evolution, however, the exoskeleton has been drastically reduced or lost in the trunk region. Outer blue circles show the exoskeleton. Inner solid pale circles show the unmineralized endoskeleton. Inner solid-dark circles show the mineralized endoskeleton. The red arrow indicates the trunk exoskeleton we focused on in the present experiment. Teleost scales elasmoid scales have recently been re-evaluated as odontogenic exoskeletal structures, like teeth, because of their development and structure 12 , During scale development, a papilla is formed in the dermis immediately adjacent to the basal layer of the epidermis, followed by differentiation of enamel-like capping tissue, a type of dentin external layer and a plywood-like tissue elasmodin.
These tissues are comparable with those of odontogenic components of ancestral rhombic scales 12 , Fin rays are also considered to be derivatives of the ancestral scales 14 , Therefore, elucidating the embryonic origin of these trunk exoskeletal elements could provide critical implications for understanding the evolution of mineralized skeletons. Previously, the contribution of the neural crest to the formation of scales and fin rays has been suspected by the observations that goldfish tumour pigment cells were able to transform into scales in vitro 16 , and that labelled neural crest cells exhibited invasive behaviour into fins in zebrafish and swordtail 17 , However, these cells had not been traced for an extended period of time to analyse their contribution to exoskeletal elements mainly due to technical difficulties in long-term cell-lineage analysis in fish.
In this study, we have applied recently developed long-term labelling methods to medaka fish. The first method was transplantation of labelled tissues, using a modified zebrafish protocol 19 , 20 Fig. S1 osterix is a transcription factor whose expression marks the intermediate stage in bone-forming cell differentiation 21 , The main results obtained were then confirmed by the second long-term labelling technique using the infrared laser-evoked gene operator IR-LEGO system Fig.
By these methods, we found that bone-forming cells in both scales and fin rays are derived from the mesoderm, not the neural crest, suggesting that the trunk neural crest has no skeletogenic capability in fish. We replaced dorsal neural tubes including neural crest cells or somites of host embryos with transgenic donor ones at the to somite stages.
After screening for successful transplants at the hatching stage, we examined the contribution of neural crest cells and somite cells to scales and fin rays. We first examined the contribution of neural crest cells to scales and median fin rays by replacing dorsal neural tubes including neural crest cells of host embryos with transgenic donor ones at the to somite stages at the level of newly formed somites.
As a transgenic line expressing a reporter gene in neural crest cells is not available in medaka, we confirmed a successful transplantation of neural crest cells by the following two methods. We observed melanophores in transplanted host embryos and juvenile fish Fig. Second, we performed a histological examination of transplanted host embryos stained with anti-DsRed antibody.
As shown in Fig. DsRed detection was performed by immunostaining. Arrows likely show migrating neural crest cells. An asterisk shows neural tube.
Dotted circles in c indicate scales. Green and yellow: GFP-positive bone-forming cells in scales. Right, the enlarged image of the region shown as the box in the middle panel. Green: GFP-positive bone-forming cells. Black and red arrows show bone-forming cells and bone matrix, respectively. All the live images are lateral views.
Anterior to the left. At the hatching stage, the successful transplants that properly exhibited DsRed-positive dorsal root ganglia and pigment cells, major neural crest derivatives in the trunk region, were screened Fig. These larvae contained a significant number of DsRed-positive cells in the trunk surface, irrespective of the level of transplantation that is, to somite levels Fig.
From colour and morphology, dorsal neural tube-derived cells are likely to include pigment cells, peripheral neurons and Schwann cells Fig.
To exclude the possibility that some populations of neural crest cells that would contribute to bone-forming cells had already migrated out from the dorsal neural tube of donor embryos at the time of operation, we checked the expression of foxd3 , a pan-neural-crest marker, in both whole donor embryos and isolated neural tubes that are to be transplanted.
We confirmed that no signal for foxd3 could be seen outside the neural tube and that foxd3 -expressing cells still remained on the dorsal neural tube in vivo and isolated ones as well, indicating that an intact neural crest cell population was replaced at the level of transplantation Supplementary Fig.
We also confirmed that the neural crest does not contribute to trunk endoskeleton such as vertebrae and fin radials data not shown. We then asked which lineage of cells contributes to scales and fin rays instead of neural crest cells. We considered the derivatives of the somite as alternative candidates because somite-derived cells are known to constitute the dermis of zebrafish 25 and median fin mesenchyme in axolotl 26 , catshark 27 and zebrafish However, in those studies cells were not traced until the stage when bone-forming cells differentiate in scales and fin rays.
Thus, we transplanted somites from the transgenic donor embryos into non-transgenic hosts at nearly the same stages and the same anteroposterior AP levels as performed in the above neural tube transplantation. Histological sections of the transplants again confirmed the accuracy of somite transplantation; only somite cells were labelled Fig.
Like the neural tube transplantation experiment, successful transplants with DsRed-positive myotome, sclerotome and mesenchyme were screened at the hatching stage Fig. GFP-positive scales were found at nearly all dorsoventral levels, overlying the DsRed-expressing myotome Fig. Similarly, in each host median fin, DsRed-positive cells invaded into young fin folds yet to develop fin rays Fig.
S3a and began to express GFP Fig. S3b when transplanted to somite for dorsal fins, to somite for anal fins, and to somite for caudal fins. To further confirm the somite origin of scales and median fin rays, we adopted the second long-term labelling method, IR-LEGO, which can induce the heat-shock response in target cells upon irradiation with an infrared laser 23 , 24 , in combination with cre-loxP We targeted cells at the lateral side because they are known to give rise to dermis and dorsal fin cells in zebrafish Three days after irradiation st.
Probably because of a smaller population of precursor cells for dorsal and caudal fin rays in somites, the labelling frequency of these fins were quite low under our experimental conditions. Dorsal views c. Labelled cells in b colonized on scales arrow. Dotted circles show scales. GFP-positive bone-forming cells black arrow are seen on the scale matrix red arrow. The arrow in g indicates bone-forming cells of the proximal radial.
The black and red arrows in h indicate chondrocytes in the proximal and distal radials, respectively. The red arrowhead in h indicates bone-forming cells of the fin ray that are surrounding the proximal radial.
The arrowheads in i show fin ray units. The arrow in i indicates bone-forming cells of the fin ray. GFP detection was performed by immunostaining in d , g — i.
The asterisks show leucophores. This suggests that the fin rays and radials share a precursor cell population, although we cannot exclude the possibility that they are formed from multiple progenitor cell populations. Taken together, we confirmed the results of somite transplantation that bone-forming cells of scales and median fin rays are derived from the somite. Additionally, we addressed the question of the embryonic origin of paired fin rays.
Skull Bone Development. Head Bones Anatomy and Distribution. Endochondral and Membranous Bone Development. Description description. External Description. Home Contact Us. This is compensated by upward growth by the bones of the lateral skull, resulting in a long, narrow, wedge-shaped head.
This condition, known as scaphocephaly, accounts for approximately 50 percent of craniosynostosis abnormalities. Although the skull is misshapen, the brain still has adequate room to grow and thus there is no accompanying abnormal neurological development. In cases of complex craniosynostosis, several sutures close prematurely. The amount and degree of skull deformity is determined by the location and extent of the sutures involved.
This results in more severe constraints on skull growth, which can alter or impede proper brain growth and development. Cases of craniosynostosis are usually treated with surgery. A team of physicians will open the skull along the fused suture, which will then allow the skull bones to resume their growth in this area. In some cases, parts of the skull will be removed and replaced with an artificial plate. The earlier after birth that surgery is performed, the better the outcome.
After treatment, most children continue to grow and develop normally and do not exhibit any neurological problems. Skip to main content.
Module 8: Axial Skeleton. Search for:. Embryonic Development of the Axial Skeleton Learning Objectives Discuss the two types of embryonic bone development within the skull Describe the development of the vertebral column and thoracic cage. View this video to review the two processes that give rise to the bones of the skull and body. Homeostatic Imbalances: Craniosynostosis The premature closure fusion of a suture line is a condition called craniosynostosis.
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