1
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Nguyen JKB, Gómez-Picos P, Liu Y, Ovens K, Eames BF. Common features of cartilage maturation are not conserved in an amphibian model. Dev Dyn 2023; 252:1375-1390. [PMID: 37083105 DOI: 10.1002/dvdy.594] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 03/04/2023] [Accepted: 04/09/2023] [Indexed: 04/22/2023] Open
Abstract
BACKGROUND Mouse, chick, and zebrafish undergo a highly conserved program of cartilage maturation during endochondral ossification (bone formation via a cartilage template). Standard histological and molecular features of cartilage maturation are chondrocyte hypertrophy, downregulation of the chondrogenic markers Sox9 and Col2a1, and upregulation of Col10a1. We tested whether cartilage maturation is conserved in an amphibian, the western clawed frog Xenopus tropicalis, using in situ hybridization for standard markers and a novel laser-capture microdissection RNAseq data set. We also functionally tested whether thyroid hormone drives cartilage maturation in X tropicalis, as it does in other vertebrates. RESULTS The developing frog humerus mostly followed the standard progression of cartilage maturation. Chondrocytes gradually became hypertrophic as col2a1 and sox9 were eventually down-regulated, but col10a1 was not up-regulated. However, the expression levels of several genes associated with the early formation of cartilage, such as acan, sox5, and col9a2, remained highly expressed even as humeral chondrocytes matured. Greater deviances were observed in head cartilages, including the ceratohyal, which underwent hypertrophy within hours of becoming cartilaginous, maintained relatively high levels of col2a1 and sox9, and lacked col10a1 expression. Interestingly, treating frog larvae with thyroid hormone antagonists did not specifically reduce head cartilage hypertrophy, resulting rather in a global developmental delay. CONCLUSION These data reveal that basic cartilage maturation features in the head, and to a lesser extent in the limb, are not conserved in X tropicalis. Future work revealing how frogs deviate from the standard cartilage maturation program might shed light on both evolutionary and health studies.
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Affiliation(s)
- Jason K B Nguyen
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Patsy Gómez-Picos
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Yiwen Liu
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Katie Ovens
- Department of Computer Science, University of Calgary, Calgary, Alberta, Canada
| | - B Frank Eames
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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2
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Lukas P. Embryonic pattern of cartilaginous head development in the European toad, Bufo bufo. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART B, MOLECULAR AND DEVELOPMENTAL EVOLUTION 2023; 340:437-454. [PMID: 37358281 DOI: 10.1002/jez.b.23214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 04/17/2023] [Accepted: 06/12/2023] [Indexed: 06/27/2023]
Abstract
The craniofacial skeleton of vertebrates is a major innovation of the whole clade. Its development and composition requires a precisely orchestrated sequence of chondrification events which lead to a fully functional skeleton. Sequential information on the precise timing and sequence of embryonic cartilaginous head development are available for a growing number of vertebrates. This enables a more and more comprehensive comparison of the evolutionary trends within and among different vertebrate clades. This comparison of sequential patterns of cartilage formation enables insights into the evolution of development of the cartilaginous head skeleton. The cartilaginous sequence of head formation of three basal anurans (Xenopus laevis, Bombina orientalis, Discoglossus scovazzi) was investigated so far. This study investigates the sequence and timing of larval cartilaginous development of the head skeleton from the appearance of mesenchymal Anlagen until the premetamorphic larvae in the neobatrachian species Bufo bufo. Clearing and staining, histology, and 3D reconstruction enabled the tracking of 75 cartilaginous structures and the illustration of the sequential changes of the skull as well as the identification of evolutionary trends of sequential cartilage formation in the anuran head. The anuran viscerocranium does not chondrify in the ancestral anterior to posterior direction and the neurocranial elements do not chondrify in posterior to anterior direction. Instead, the viscerocranial and neurocranial development is mosaic-like and differs greatly from the gnathostome sequence. Strict ancestral anterior to posterior developmental sequences can be observed within the branchial basket. Thus, this data is the basis for further comparative developmental studies of anuran skeletal development.
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Affiliation(s)
- Paul Lukas
- Institute of Zoology and Evolutionary Research, Friedrich-Schiller-University Jena, Jena, Germany
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3
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Shan Z, Li S, Yu C, Bai S, Zhang J, Tang Y, Wang Y, Irwin DM, Li J, Wang Z. Embryonic and skeletal development of the albino African clawed frog (Xenopus laevis). J Anat 2023; 242:1051-1066. [PMID: 36708289 PMCID: PMC10184547 DOI: 10.1111/joa.13835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 01/14/2023] [Accepted: 01/16/2023] [Indexed: 01/29/2023] Open
Abstract
The normal stages of embryonic development for wild-type Xenopus laevis were established by Nieuwkoop and Faber in 1956, a milestone in the history of understanding embryonic development. However, this work lacked photographic images and staining for skeleton structures from the corresponding stages. Here, we provide high-quality images of embryonic morphology and skeleton development to facilitate studies on amphibian development. On the basis of the classical work, we selected the albino mutant of X. laevis as the observation material to restudy embryonic development in this species. The lower level of pigmentation makes it easier to interpret histochemical experiments. At 23°C, albino embryos develop at the same rate as wild-type embryos, which can be divided into 66 stages as they develop into adults in about 58 days. We described the complete embryonic development system for X. laevis, supplemented with pictures of limb and skeleton development that are missing from previous studies, and summarized the characteristics and laws of limb and skeleton development. Our study should aid research into the development of X. laevis and the evolution of amphibians.
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Affiliation(s)
- Zhixin Shan
- College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, China
| | - Shanshan Li
- College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, China
| | - Chenghua Yu
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Shibin Bai
- College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, China
| | - Junpeng Zhang
- College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, China
| | - Yining Tang
- College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, China
| | - Yutong Wang
- College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, China
| | - David M Irwin
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Jun Li
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Zhe Wang
- College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, China
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4
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Rose CS. The cellular basis of cartilage growth and shape change in larval and metamorphosing Xenopus frogs. PLoS One 2023; 18:e0277110. [PMID: 36634116 PMCID: PMC9836273 DOI: 10.1371/journal.pone.0277110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 10/19/2022] [Indexed: 01/13/2023] Open
Abstract
As the first and sometimes only skeletal tissue to appear, cartilage plays a fundamental role in the development and evolution of vertebrate body shapes. This is especially true for amphibians whose largely cartilaginous feeding skeleton exhibits unparalleled ontogenetic and phylogenetic diversification as a consequence of metamorphosis. Fully understanding the evolutionary history, evolvability and regenerative potential of cartilage requires in-depth analysis of how chondrocytes drive growth and shape change. This study is a cell-level description of the larval growth and postembryonic shape change of major cartilages of the feeding skeleton of a metamorphosing amphibian. Histology and immunohistochemistry are used to describe and quantify patterns and trends in chondrocyte size, shape, division, death, and arrangement, and in percent matrix from hatchling to froglet for the lower jaw, hyoid and branchial arch cartilages of Xenopus laevis. The results are interpreted and integrated into programs of cell behaviors that account for the larval growth and histology, and metamorphic remodeling of each element. These programs provide a baseline for investigating hormone-mediated remodeling, cartilage regeneration, and intrinsic shape regulating mechanisms. These programs also contain four features not previously described in vertebrates: hypertrophied chondrocytes being rejuvenated by rapid cell cycling to a prechondrogenic size and shape; chondrocytes dividing and rearranging to reshape a cartilage; cartilage that lacks a perichondrium and grows at single-cell dimensions; and an adult cartilage forming de novo in the center of a resorbing larval one. Also, the unexpected superimposition of cell behaviors for shape change onto ones for larval growth and the unprecedented exploitation of very large and small cell sizes provide new directions for investigating the development and evolution of skeletal shape and metamorphic ontogenies.
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Affiliation(s)
- Christopher S. Rose
- Department of Biology, James Madison University, Harrisonburg, Virginia, United States of America
- * E-mail:
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5
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Lukas P, Ziermann JM. Sequence of chondrocranial development in basal anurans-Let's make a cranium. Front Zool 2022; 19:17. [PMID: 35505372 PMCID: PMC9066780 DOI: 10.1186/s12983-022-00462-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 04/22/2022] [Indexed: 11/10/2022] Open
Abstract
Background The craniofacial skeleton is an evolutionary innovation of vertebrates. Due to its complexity and importance to protect the brain and aid in essential functions (e.g., feeding), its development requires a precisely tuned sequence of chondrification and/or ossification events. The comparison of sequential patterns of cartilage formation bears important insights into the evolution of development. Discoglossus scovazzi is a basal anuran species. The comparison of its chondrocranium (cartilaginous neuro- & viscerocranium) development with other basal anurans (Xenopus laevis, Bombina orientalis) will help establishing the ancestral pattern of chondrification sequences in anurans and will serve as basis for further studies to reconstruct ancestral conditions in amphibians, tetrapods, and vertebrates. Furthermore, evolutionary patterns in anurans can be studied in the light of adaptations once the ancestral sequence is established. Results We present a comprehensive overview on the chondrocranium development of D. scovazzi. With clearing and staining, histology and 3D reconstructions we tracked the chondrification of 44 elements from the first mesenchymal Anlagen to the premetamorphic cartilaginous head skeleton and illustrate the sequential changes of the skull. We identified several anuran and discoglossoid traits of cartilage development. In D. scovazzi the mandibular, hyoid, and first branchial arch Anlagen develop first followed by stepwise addition of the branchial arches II, III, and IV. Nonetheless, there is no strict anterior to posterior chondrification pattern within the viscerocranium of D. scovazzi. Single hyoid arch elements chondrify after elements of the branchial arch and mandibular arch elements chondrify after elements of the branchial arch I. Conclusions In Osteichthyes, neurocranial elements develop in anterior to posterior direction. In the anurans investigated so far, as well as in D. scovazzi, the posterior parts of the neurocranium extend anteriorly, while the anterior parts of the neurocranium, extend posteriorly until both parts meet and fuse. Anuran cartilaginous development differs in at least two crucial traits from other gnathostomes which further supports the urgent need for more developmental investigations among this clade to understand the evolution of cartilage development in vertebrates.
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Affiliation(s)
- Paul Lukas
- Institute of Zoology and Evolutionary Research, Friedrich-Schiller-University, Jena, Germany.
| | - Janine M Ziermann
- Howard University College of Medicine, 520 W St NW, Washington, DC, 20059, USA.
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6
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MacKenzie EM, Atkins JB, Korneisel DE, Cantelon AS, McKinnell IW, Maddin HC. Normal development in Xenopus laevis: A complementary staging table for the skull based on cartilage and bone. Dev Dyn 2022; 251:1340-1356. [PMID: 35247013 DOI: 10.1002/dvdy.465] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 02/10/2022] [Accepted: 02/15/2022] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Xenopus laevis is a widely used model organism in the fields of genetics and development, and more recently evolution. At present, the most widely used staging table for X. laevis is based primarily on external features and does not describe the corresponding skull development in detail. Here, we describe skull development in X. laevis, complete with labelled figures, for each relevant stage in the most widely used staging table. RESULTS We find skull development in X. laevis is, for the most part, distinct at each of the previously established stages based on external anatomy. However, variation does exist in the timing of onset of ossification of certain bones in the skull, which results in a range of stages where a skull element first ossifies. The overall sequence of ossification is less variable than the timing of ossification onset. CONCLUSIONS While events in skull development vary somewhat between specimens, and in comparison, to external events, this staging table is useful in showing both when bones first appear and for documenting the range of temporal variance in X. laevis skull development more accurately than previously done. Furthermore, when only skull data is available, the approximate stage of a specimen can now be determined. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Erin M MacKenzie
- Department of Earth Sciences, Carleton University, Ottawa, Ontario, Canada
| | - Jade B Atkins
- Department of Earth Sciences, Carleton University, Ottawa, Ontario, Canada
| | - Dana E Korneisel
- Department of Earth Sciences, Carleton University, Ottawa, Ontario, Canada
| | - Alanna S Cantelon
- Department of Earth Sciences, Carleton University, Ottawa, Ontario, Canada
| | - Iain W McKinnell
- Department of Biology, Carleton University, Ottawa, Ontario, Canada
| | - Hillary C Maddin
- Department of Earth Sciences, Carleton University, Ottawa, Ontario, Canada
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7
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Araújo OGS, Pugener LA, Haddad CFB, Da Silva HR. Ontogeny as a way to understand morphology of nasal capsule structures in Pipidae, with focus on Pipa arrabali (Lissamphibia: Anura). Zool J Linn Soc 2021. [DOI: 10.1093/zoolinnean/zlab054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
After more than one-hundred years of studies, there is still no consensus regarding the names for the nasal elements in Pipidae and their correspondence to that of other frogs. Names vary depending on authors’ preferences for an explanatory process associated with the observed state of the structure. Some of the names indicate absence, while others indicate fusion. As naming morphological structures relates to some sort of consensus regarding systematics’ knowledge, one would expect results of the two activities to go hand-in-hand. Within the monophyletic Pipidae, one would expect that the names of structures would be all settled. However, the situation is the contrary. Our efforts to pursue such a research and properly name the involved structures resulted in a deeper understanding of the evolution within the taxa involved. Herein we present the results of the study of embryos and juveniles of P. arrabali; based on which we offer additional evidence for the proper naming of the involved elements of the nasal region. Furthermore, using key structures as topographical markers, and by comparing our evaluation to those presented by previous researchers, we have sorted out the compound nature of some key structures and present a proper naming for the morphology investigated.
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Affiliation(s)
- O G S Araújo
- Departamento de Biodiversidade, Instituto de Biociências, Universidade Estadual Paulista, Rio Claro, São Paulo, Caixa Postal 199, CEP, Brazil
| | - L A Pugener
- Facultad de Ciencias Exactas y Naturales, Universidad Nacional de La Pampa, Uruguay 151, Código Postal 6300, Santa Rosa, La Pampa, Argentina
| | - C F B Haddad
- Departamento de Biodiversidade e Centro ode Aquicultura, Instituto de Biociências, Universidade Estadual Paulista, Rio Claro, São Paulo, Caixa Postal 199, CEP, Brazil
| | - H R Da Silva
- Departamento de Biologia Animal, Instituto de Ciências Biológicas e da Saúde, Universidade Federal Rural do Rio de Janeiro, Seropédica, Rio de Janeiro, Caixa Postal 74524, CEP, Brazil
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8
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Hüppi E, Werneburg I, Sánchez-Villagra MR. Evolution and development of the bird chondrocranium. Front Zool 2021; 18:21. [PMID: 33926502 PMCID: PMC8082637 DOI: 10.1186/s12983-021-00406-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 04/08/2021] [Indexed: 01/29/2023] Open
Abstract
Background Birds exhibit an enormous diversity in adult skull shape (disparity), while their embryonic chondrocrania are considered to be conserved across species. However, there may be chondrocranial features that are diagnostic for bird clades or for Aves as a whole. We synthesized and analyzed information on the sequence of chondrification of 23 elements in ten bird species and five outgroups. Moreover, we critically considered the developmental morphology of the chondrocrania of 21 bird species and examined whether the diversity in adult skull shape is reflected in the development of the embryonic skull, and whether there are group-specific developmental patterns. Results We found that chondrocranial morphology is largely uniform in its major features, with some variation in the presence or absence of fenestrae and other parts. In kiwis (Apteryx), the unique morphology of the bony skull in the orbito-nasal region is reflected in its chondrocranial anatomy. Finally, differences in morphology and chondrification sequence may distinguish between different Palaeognathae and Neognathae and between the Galloanserae and Neoaves. The sequence of chondrification is largely conserved in birds, but with some variation in most regions. The peri- and prechordal areas in the base of the chondrocranium are largely conserved. In contrast to the outgroups, chondrification in birds starts in the acrochordal cartilage and the basicranial fenestra is formed secondarily. Further differences concern the orbital region, including early chondrification of the pila antotica and the late formation of the planum supraseptale. Conclusion Synthesizing information on chondrocranial development confronts terminological issues and a lack of comparable methods used (e.g., different staining; whole-mounts versus histology). These issues were taken into consideration when assessing differences across species. The summary of works on avian chondrocranial development, covered more than a century, and a comparison of the chondrification sequence among birds could be conducted. Future studies could test the hypothesis that chondrocranial disparity in Aves, in terms of the shape and proportion of individual elements, could be as large as adult skull disparity, despite conserved developmental patterns and the richness of forms in other (dermal) portions of the skull. Supplementary Information The online version contains supplementary material available at 10.1186/s12983-021-00406-z.
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Affiliation(s)
- Evelyn Hüppi
- Universität Zürich, Paläontologisches Institut und Museum, Karl-Schmid-Straße 4, 8006, Zürich, Switzerland.
| | - Ingmar Werneburg
- Senckenberg Center for Human Evolution and Palaeoenvironment (HEP) an der Eberhard Karls Universität, Sigwartstraße 10, 72076, Tübingen, Germany.,Fachbereich Geowissenschaften der Eberhard-Karls-Universität Tübingen, Hölderlinstraße 12, 72074, Tübingen, Germany
| | - Marcelo R Sánchez-Villagra
- Universität Zürich, Paläontologisches Institut und Museum, Karl-Schmid-Straße 4, 8006, Zürich, Switzerland
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9
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Lukas P. Larval cranial anatomy of the Eastern Ghost Frog (
Heleophryne orientalis
). ACTA ZOOL-STOCKHOLM 2020. [DOI: 10.1111/azo.12352] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Paul Lukas
- Institut für Zoologie und Evolutionsforschung mit Phyletischem Museum, Ernst‐Haeckel‐Haus und Biologiedidaktik Friedrich‐Schiller‐University Jena Germany
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10
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Gabner S, Böck P, Fink D, Glösmann M, Handschuh S. The visible skeleton 2.0: phenotyping of cartilage and bone in fixed vertebrate embryos and foetuses based on X-ray microCT. Development 2020; 147:dev187633. [PMID: 32439754 DOI: 10.1242/dev.187633] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Accepted: 04/23/2020] [Indexed: 01/14/2023]
Abstract
For decades, clearing and staining with Alcian Blue and Alizarin Red has been the gold standard to image vertebrate skeletal development. Here, we present an alternate approach to visualise bone and cartilage based on X-ray microCT imaging, which allows the collection of genuine 3D data of the entire developing skeleton at micron resolution. Our novel protocol is based on ethanol fixation and staining with Ruthenium Red, and efficiently contrasts cartilage matrix, as demonstrated in whole E16.5 mouse foetuses and limbs of E14 chicken embryos. Bone mineral is well preserved during staining, thus the entire embryonic skeleton can be imaged at high contrast. Differences in X-ray attenuation of ruthenium and calcium enable the spectral separation of cartilage matrix and bone by dual energy microCT (microDECT). Clearing of specimens is not required. The protocol is simple and reproducible. We demonstrate that cartilage contrast in E16.5 mouse foetuses is adequate for fast visual phenotyping. Morphometric skeletal parameters are easily extracted. We consider the presented workflow to be a powerful and versatile extension to the toolkit currently available for qualitative and quantitative phenotyping of vertebrate skeletal development.
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Affiliation(s)
- Simone Gabner
- Histology and Embryology, Department for Pathobiology, University of Veterinary Medicine Vienna, Veterinärplatz 1, A-1210 Vienna, Austria
| | - Peter Böck
- Histology and Embryology, Department for Pathobiology, University of Veterinary Medicine Vienna, Veterinärplatz 1, A-1210 Vienna, Austria
| | - Dieter Fink
- Institute of Laboratory Animal Science, University of Veterinary Medicine Vienna, Veterinaärplatz 1, A-1210 Vienna, Austria
| | - Martin Glösmann
- VetCore Facility for Research/Imaging Unit, University of Veterinary Medicine Vienna, Veterinärplatz 1, A-1210 Vienna, Austria
| | - Stephan Handschuh
- VetCore Facility for Research/Imaging Unit, University of Veterinary Medicine Vienna, Veterinärplatz 1, A-1210 Vienna, Austria
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11
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Lukas P, Olsson L. Sequence of chondrocranial development in the oriental fire bellied toad Bombina orientalis. J Morphol 2020; 281:688-701. [PMID: 32383540 DOI: 10.1002/jmor.21138] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 04/14/2020] [Accepted: 04/21/2020] [Indexed: 01/18/2023]
Abstract
The vertebrate head as a major novelty is directly linked to the evolutionary success of the vertebrates. Sequential information on the embryonic pattern of cartilaginous head development are scarce, but important for the understanding of its evolution. In this study, we use the oriental fire bellied toad, Bombina orientalis, a basal anuran to investigate the sequence and timing of larval cartilaginous development of the head skeleton from the appearance of mesenchymal Anlagen in post-neurulation stages until the premetamorphic larvae. We use different methodological approaches like classic histology, clearing and staining, and antibody staining to examine the larval skeletal morphology. Our results show that in contrast to other vertebrates, the ceratohyals are the first centers of chondrification. They are followed by the palatoquadrate and the basihyal. The latter later fuses to the ceratohyal and the branchial basket. Anterior elements like Meckel's cartilage and the rostralia are delayed in development and alter the ancestral anterior posterior pattern observed in other vertebrates. The ceratobranchials I-IV, components of the branchial basket, follow this strict anterior-posterior pattern of chondrification as reported in other amphibians. Chondrification of different skeletal elements follows a distinct pattern and the larval skeleton is nearly fully developed at Gosner Stage 28. We provide baseline data on the pattern and timing of early cartilage development in a basal anuran species, which may serve as guidance for further experimental studies in this species as well as an important basis for the understanding of the evolutionary changes in head development among amphibians and vertebrates.
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Affiliation(s)
- Paul Lukas
- Institut für Zoologie und Evolutionsforschung mit Phyletischem Museum, Ernst-Haeckel-Haus und Biologiedidaktik, Friedrich-Schiller-University, Jena, Germany
| | - Lennart Olsson
- Institut für Zoologie und Evolutionsforschung mit Phyletischem Museum, Ernst-Haeckel-Haus und Biologiedidaktik, Friedrich-Schiller-University, Jena, Germany
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12
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13
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Atkins JB, Reisz RR, Maddin HC. Braincase simplification and the origin of lissamphibians. PLoS One 2019; 14:e0213694. [PMID: 30901341 PMCID: PMC6430379 DOI: 10.1371/journal.pone.0213694] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 02/26/2019] [Indexed: 12/26/2022] Open
Abstract
Dissorophoidea, a group of temnospondyl tetrapods that first appear in the Late Carboniferous, is made up of two clades ⎼ Olsoniformes and Amphibamiformes (Branchiosauridae and Amphibamidae) ⎼ the latter of which is widely thought to have given rise to living amphibians (i.e., Lissamphibia). The lissamphibian braincase has a highly derived morphology with several secondarily lost elements; however, these losses have never been incorporated into phylogenetic analyses and thus the timing and nature of these evolutionary events remain unknown. Hindering research into this problem has been the lack of phylogenetic analyses of Dissorophoidea that includes both taxonomically dense sampling and specific characters to document changes in the braincase in the lineage leading to Lissamphibia. Here we build on a recent, broadly sampled dissorophoid phylogenetic analysis to visualize key events in the evolution of the lissamphibian braincase. Our ancestral character state reconstructions show a clear, step-wise trend towards reduction of braincase ossification leading to lissamphibians, including reduction of the sphenethmoid, loss of the basioccipital at the Amphibamiformes node, and further loss of both the basisphenoid and the hypoglossal nerve foramina at the Lissamphibia node. Our analysis confirms that the highly derived condition of the lissamphibian braincase is characterized by overall simplification in terms of the number and extent of chondrocranial ossifications.
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Affiliation(s)
- Jade B. Atkins
- Department of Earth Sciences, Carleton University, Ottawa, ON, Canada
- * E-mail:
| | - Robert R. Reisz
- Department of Biology, University of Toronto at Mississauga, Mississauga, ON, Canada
- International Center of Future Science, Dinosaur Evolution Research Center, Jilin University, Changchun, China
| | - Hillary C. Maddin
- Department of Earth Sciences, Carleton University, Ottawa, ON, Canada
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14
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Lukas P, Olsson L. Bapx1
is required for jaw joint development in amphibians. Evol Dev 2018; 20:192-206. [DOI: 10.1111/ede.12267] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Paul Lukas
- Institut für Zoologie und Evolutionsforschung mit Phyletischem Museum, Ernst‐Haeckel‐Haus und BiologiedidaktikFriedrich‐Schiller‐Universität JenaJenaGermany
| | - Lennart Olsson
- Institut für Zoologie und Evolutionsforschung mit Phyletischem Museum, Ernst‐Haeckel‐Haus und BiologiedidaktikFriedrich‐Schiller‐Universität JenaJenaGermany
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