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Lin CY, Marlétaz F, Pérez-Posada A, Martínez-García PM, Schloissnig S, Peluso P, Conception GT, Bump P, Chen YC, Chou C, Lin CY, Fan TP, Tsai CT, Gómez Skarmeta JL, Tena JJ, Lowe CJ, Rank DR, Rokhsar DS, Yu JK, Su YH. Chromosome-level genome assemblies of 2 hemichordates provide new insights into deuterostome origin and chromosome evolution. PLoS Biol 2024; 22:e3002661. [PMID: 38829909 PMCID: PMC11175523 DOI: 10.1371/journal.pbio.3002661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 06/13/2024] [Accepted: 05/03/2024] [Indexed: 06/05/2024] Open
Abstract
Deuterostomes are a monophyletic group of animals that includes Hemichordata, Echinodermata (together called Ambulacraria), and Chordata. The diversity of deuterostome body plans has made it challenging to reconstruct their ancestral condition and to decipher the genetic changes that drove the diversification of deuterostome lineages. Here, we generate chromosome-level genome assemblies of 2 hemichordate species, Ptychodera flava and Schizocardium californicum, and use comparative genomic approaches to infer the chromosomal architecture of the deuterostome common ancestor and delineate lineage-specific chromosomal modifications. We show that hemichordate chromosomes (1N = 23) exhibit remarkable chromosome-scale macrosynteny when compared to other deuterostomes and can be derived from 24 deuterostome ancestral linkage groups (ALGs). These deuterostome ALGs in turn match previously inferred bilaterian ALGs, consistent with a relatively short transition from the last common bilaterian ancestor to the origin of deuterostomes. Based on this deuterostome ALG complement, we deduced chromosomal rearrangement events that occurred in different lineages. For example, a fusion-with-mixing event produced an Ambulacraria-specific ALG that subsequently split into 2 chromosomes in extant hemichordates, while this homologous ALG further fused with another chromosome in sea urchins. Orthologous genes distributed in these rearranged chromosomes are enriched for functions in various developmental processes. We found that the deeply conserved Hox clusters are located in highly rearranged chromosomes and that maintenance of the clusters are likely due to lower densities of transposable elements within the clusters. We also provide evidence that the deuterostome-specific pharyngeal gene cluster was established via the combination of 3 pre-assembled microsyntenic blocks. We suggest that since chromosomal rearrangement events and formation of new gene clusters may change the regulatory controls of developmental genes, these events may have contributed to the evolution of diverse body plans among deuterostomes.
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Affiliation(s)
- Che-Yi Lin
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Ferdinand Marlétaz
- Center for Life’s Origins and Evolution, Department of Genetics, Evolution and Environment, University College London, London, United Kingdom
| | - Alberto Pérez-Posada
- Centro Andaluz de Biología del Desarrollo, Consejo Superior de Investigaciones Científicas-Universidad Pablo de Olavide-Junta de Andalucía, Seville, Spain
- Living Systems Institute, University of Exeter, Exeter, United Kingdom
| | - Pedro Manuel Martínez-García
- Centro Andaluz de Biología del Desarrollo, Consejo Superior de Investigaciones Científicas-Universidad Pablo de Olavide-Junta de Andalucía, Seville, Spain
| | | | - Paul Peluso
- Pacific Biosciences, Menlo Park, California, United States of America
| | | | - Paul Bump
- Hopkins Marine Station, Department of Biology, Stanford University, Pacific Grove, California, United States of America
| | - Yi-Chih Chen
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Cindy Chou
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Ching-Yi Lin
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Tzu-Pei Fan
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Chang-Tai Tsai
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - José Luis Gómez Skarmeta
- Centro Andaluz de Biología del Desarrollo, Consejo Superior de Investigaciones Científicas-Universidad Pablo de Olavide-Junta de Andalucía, Seville, Spain
| | - Juan J. Tena
- Centro Andaluz de Biología del Desarrollo, Consejo Superior de Investigaciones Científicas-Universidad Pablo de Olavide-Junta de Andalucía, Seville, Spain
| | - Christopher J. Lowe
- Hopkins Marine Station, Department of Biology, Stanford University, Pacific Grove, California, United States of America
- Chan-Zuckerberg Biohub, San Francisco, California, United States of America
| | - David R. Rank
- Pacific Biosciences, Menlo Park, California, United States of America
| | - Daniel S. Rokhsar
- Chan-Zuckerberg Biohub, San Francisco, California, United States of America
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, United States of America
- Molecular Genetics Unit, Okinawa Institute for Science and Technology, Onna, Japan
| | - Jr-Kai Yu
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
- Marine Research Station, Institute of Cellular and Organismic Biology, Academia Sinica, Yilan, Taiwan
| | - Yi-Hsien Su
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
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Defourneaux É, Herranz M, Armenteros M, Sørensen MV, Norenburg JL, Park T, Worsaae K. Circumtropical distribution and cryptic species of the meiofaunal enteropneust Meioglossus (Harrimaniidae, Hemichordata). Sci Rep 2024; 14:9296. [PMID: 38654022 DOI: 10.1038/s41598-024-57591-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 03/20/2024] [Indexed: 04/25/2024] Open
Abstract
Hemichordata has always played a central role in evolutionary studies of Chordata due to their close phylogenetic affinity and shared morphological characteristics. Hemichordates had no meiofaunal representatives until the surprising discovery of a microscopic, paedomorphic enteropneust Meioglossus psammophilus (Harrimaniidae, Hemichordata) from the Caribbean in 2012. No additional species have been described since, questioning the broader distribution and significance of this genus. However, being less than a millimeter long and superficially resembling an early juvenile acorn worm, Meioglossus may easily be overlooked in both macrofauna and meiofauna surveys. We here present the discovery of 11 additional populations of Meioglossus from shallow subtropical and tropical coralline sands of the Caribbean Sea, Red Sea, Indian Ocean, and East China Sea. These geographically separated populations show identical morphology but differ genetically. Our phylogenetic reconstructions include four gene markers and support the monophyly of Meioglossus. Species delineation analyses revealed eight new cryptic species, which we herein describe using DNA taxonomy. This study reveals a broad circumtropical distribution, supporting the validity and ecological importance of this enigmatic meiobenthic genus. The high cryptic diversity and apparent morphological stasis of Meioglossus may exemplify a potentially common evolutionary 'dead-end' scenario, where groups with highly miniaturized and simplified body plan lose their ability to diversify morphologically.
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Affiliation(s)
- Éloïse Defourneaux
- Marine Biological Section, Department of Biology, University of Copenhagen, Universitetsparken 4, DK-2100, Copenhagen, Denmark
| | - Maria Herranz
- Marine Biological Section, Department of Biology, University of Copenhagen, Universitetsparken 4, DK-2100, Copenhagen, Denmark
- Area of Biodiversity and Conservation, Superior School of Experimental Science and Technology (ESCET), Rey Juan Carlos University, C/ Tulipán S/N, 28933, Mostoles, Madrid, Spain
| | - Maickel Armenteros
- Unidad Académica Mazatlán, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Av. Joel Montes Camarena S/N, 82040, Mazatlán, México
| | - Martin V Sørensen
- Natural History Museum Denmark, University of Copenhagen, Universitetsparken 15, DK-2100, Copenhagen, Denmark
| | - Jon L Norenburg
- Smithsonian National Museum of Natural History, Washington, DC, USA
| | - Taeseo Park
- Species Diversity Research Division, National Institute of Biological Resources, Hwangyeong-Ro 42, Incheon, 22689, South Korea
| | - Katrine Worsaae
- Marine Biological Section, Department of Biology, University of Copenhagen, Universitetsparken 4, DK-2100, Copenhagen, Denmark.
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Briggs DEG, Mongiardino Koch N. A Silurian pseudocolonial pterobranch. Curr Biol 2023; 33:5225-5232.e3. [PMID: 37935193 DOI: 10.1016/j.cub.2023.10.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 07/07/2023] [Accepted: 10/16/2023] [Indexed: 11/09/2023]
Abstract
Pterobranchs, a major group of the phylum Hemichordata, first appear in the fossil record during the Cambrian,1 and there are more than 600 fossil genera dominated by the mainly planktic graptolites of the Paleozoic, which are widely used as zone fossils for correlating sedimentary rock sequences.2 Pterobranchs are rare today; they are sessile marine forms represented by Rhabdopleura, which is considered the only living graptolite, and Cephalodiscus. Unlike their sister taxon, the colonial graptolites, cephalodiscids are pseudocolonial.3,4 Here, we describe a problematic fossil from the Silurian (Pridoli) Bertie Group of Ontario (420 mya), a sequence of near-shore sediments well known for its remarkably preserved diversity of eurypterids (sea scorpions).5 The fossil, Rotaciurca superbus, a new genus and species, was familiarly known as Ezekiel's Wheel,5 with reference to the unusual circular arrangement of the tubes that compose it. The structure and arrangement of the tubes identify Rotaciurca as a pterobranch, and phylogenetic analysis groups it with the cephalodiscids. We place it in a new family Rotaciurcidae to distinguish it from Cephalodiscidae. A large structure associated with the tubes is interpreted as a float, which would distinguish Rotaciurca as the only known planktic cephalodiscid-thus cephalodiscids, like the graptolites, invaded the water column. This mode of life reflects the rarity of pseudocolonial macroinvertebrates in planktic ocean communities, a role occupied by the tunicates (Chordata) known as salps today. Our estimates of divergence times, the first using relaxed total-evidence clocks, date the origins of both hemichordates and pterobranchs to the earliest Cambrian (Fortunian).
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Affiliation(s)
- Derek E G Briggs
- Department of Earth and Planetary Sciences, Yale University, New Haven, CT 06520, USA; Yale Peabody Museum, New Haven, CT 06520, USA.
| | - Nicolás Mongiardino Koch
- Marine Biology Research Division, Scripps Institution of Oceanography, UC San Diego, 9500 Gilman Drive #0202, La Jolla, CA 92093, USA.
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Abstract
Hemichordates have long been recognized as a critical group for addressing hypotheses of chordate origins. Historically this was due to anatomical traits that resembled those of chordates, most strikingly the dorsolateral gill slits. As molecular data and phylogenetic analyses were found to support a close phylogenetic relationship between hemichordates and chordates within the deuterostomes, interest was revived in hemichordates. In particular, Saccoglossus kowalevskii has been developed as a molecular model to represent hemichordate developmental biology. Herein, we highlight the considerations when choosing a particular species to study and the challenges we encountered when developing S. kowalevskii. We discuss our findings and how method and tool development enabled them, and how we envision expanding our repertoire of molecular tools in the future. Establishing a new model organism comes with many obstacles-from identifying a reliable season to collect animals, to developing modern molecular techniques. The Saccoglossus research community has benefited greatly from the collaborations and teamwork established over the years. As a result, Saccoglossus is well positioned to contribute to a new century of evolutionary developmental (evo-devo) research.
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Abstract
Hemichordates, along with echinoderms and chordates, belong to the lineage of bilaterians called the deuterostomes. Their phylogenetic position as an outgroup to chordates provides an opportunity to investigate the evolutionary origins of the chordate body plan and reconstruct ancestral deuterostome characters. The body plans of the hemichordates and chordates are organizationally divergent making anatomical comparisons very challenging. The developmental underpinnings of animal body plans are often more conservative than the body plans they regulate, and offer a novel data set for making comparisons between morphologically divergent body architectures. Here I review the hemichordate developmental data generated over the past 20 years that further test hypotheses of proposed morphological affinities between the two taxa, but also compare the conserved anteroposterior, dorsoventral axial patterning programs and germ layer specification programs. These data provide an opportunity to determine which developmental programs are ancestral deuterostome or bilaterian innovations, and which ones occurred in stem chordates or vertebrates representing developmental novelties of the chordate body plan.
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Capela R, Garric J, Castro LFC, Santos MM. Embryo bioassays with aquatic animals for toxicity testing and hazard assessment of emerging pollutants: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 705:135740. [PMID: 31838430 DOI: 10.1016/j.scitotenv.2019.135740] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 11/22/2019] [Accepted: 11/23/2019] [Indexed: 06/10/2023]
Abstract
This review article gathers the available information on the use of embryo-tests as high-throughput tools for toxicity screening, hazard assessment and prioritization of new and existing chemical compounds. The approach is contextualized considering the new legal trends for animal experimentation, fostering the 3R policy, with reduction of experimental animals, addressing the potential of embryo-tests as high-throughput toxicity screening and prioritizing tools. Further, the current test guidelines, such as the ones provided by OECD and EPA, focus mainly in a limited number of animal lineages, particularly vertebrates and arthropods. To extrapolate hazard assessment to the ecosystem scale, a larger diversity of taxa should be tested. The use of new experimental animal models in toxicity testing, from a representative set of taxa, was thoroughly revised and discussed in this review. Here, we critically review current tools and the main advantages and drawbacks of different animal models and set researcher priorities.
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Affiliation(s)
- Ricardo Capela
- CIMAR/CIIMAR - Interdisciplinary Centre for Marine and Environmental Research, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal; FCUP - Faculty of Sciences of the University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal; IRSTEA - National Research Institute of Science and Technology for Environment and Agriculture - Centre de Lyon-Villeurbanne, 5 rue de la Doua, CS20244, 69625 Villeurbanne Cedex, Lyon-Villeurbanne, France
| | - Jeanne Garric
- IRSTEA - National Research Institute of Science and Technology for Environment and Agriculture - Centre de Lyon-Villeurbanne, 5 rue de la Doua, CS20244, 69625 Villeurbanne Cedex, Lyon-Villeurbanne, France.
| | - Luís Filipe Costa Castro
- CIMAR/CIIMAR - Interdisciplinary Centre for Marine and Environmental Research, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal; FCUP - Faculty of Sciences of the University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal.
| | - Miguel Machado Santos
- CIMAR/CIIMAR - Interdisciplinary Centre for Marine and Environmental Research, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal; FCUP - Faculty of Sciences of the University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal.
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Martynov A, Lundin K, Picton B, Fletcher K, Malmberg K, Korshunova T. Multiple paedomorphic lineages of soft-substrate burrowing invertebrates: parallels in the origin of Xenocratena and Xenoturbella. PLoS One 2020; 15:e0227173. [PMID: 31940379 PMCID: PMC6961895 DOI: 10.1371/journal.pone.0227173] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 12/12/2019] [Indexed: 01/21/2023] Open
Abstract
Paedomorphosis is an important evolutionary force. It has previously been suggested that a soft-substrate sediment-dwelling (infaunal) environment facilitates paedomorphic evolution in marine invertebrates. However, until recently this proposal was never rigorously tested with robust phylogeny and broad taxon selection. Here, for the first time, we present a molecular phylogeny for a majority of the 21 families of one of the largest nudibranch subgroups (Aeolidacea) and show that the externally highly simplified vermiform nudibranch family, Pseudovermidae, with clearly defined paedomorphic traits and inhabiting a soft-substrata environment, is a sister group to the complex nudibranch family, Cumanotidae. We also report the rediscovery of one of the most enigmatic nudibranchs-Xenocratena suecica-on the Swedish and Norwegian coasts 70 years after it was first found. Xenocratena was described from the same location and environment in the Swedish Gullmar fjord as one of the most enigmatic vermiform organisms, Xenoturbella bocki, which represents either an original simple bilaterian body plan or secondary simplification of a more complex organisation. Our results show that Xenocratena suecica reveals an onset of parallel paedomorphic evolution so we have proposed the new family, Xenocratenidae fam. n., to accommodate the molecular and morphological disparities we discovered. The paedomorphic origin of another aeolidacean family, Embletoniidae, is also demonstrated for the first time. Thus, by presenting three independent lineages from non-closely related aeolidacean families, Xenocratenidae fam. n., Cumanotidae and Embletoniidae, we confirm with phylogenetic data that a soft-substrata burrowing-related environment strongly favours paedomorphic evolution. We suggest criteria to distinguish ancestral and derived characters in the context of modifications of ontogenetic cycles. Applying an evolutionary model of the soft substrate-driven multiple paedomorphic origin of several families of nudibranch molluscs we propose that it is plausible to extend this model to other marine invertebrates and suggest that the ancestral organisation of the enigmatic metazoan, Xenoturbella, might correspond to the larval part of a complex ancestral bilaterian ontogenetic cycle with sedentary/semi-sedentary adult stages and planula-like larval stages.
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Affiliation(s)
| | - Kennet Lundin
- Gothenburg Natural History Museum, Gothenburg, Sweden
- Gothenburg Global Biodiversity Centre, Gothenburg, Sweden
| | - Bernard Picton
- National Museums Northern Ireland, Holywood, Northern Ireland, United Kingdom
- Queen’s University, Belfast, Northern Ireland, United Kingdom
| | - Karin Fletcher
- Milltech Marine, Port Orchard, Washington, United States of America
| | - Klas Malmberg
- Gothenburg Global Biodiversity Centre, Gothenburg, Sweden
- Gothenburg Global Biodiversity Centre, Aquatilis, Gothenburg, Sweden
| | - Tatiana Korshunova
- Zoological Museum, Moscow State University, Moscow, Russia
- Koltzov Institute of Developmental Biology RAS, Moscow, Russia
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Vo M, Mehrabian S, Étienne S, Pelletier D, Cameron CB. The hemichordate pharynx and gill pores impose functional constraints at small and large body sizes. Biol J Linn Soc Lond 2019. [DOI: 10.1093/biolinnean/blz005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Maureen Vo
- Departement de sciences biologiques, Universite de Montreal, Montreal, Quebec, Canada
| | - Sasan Mehrabian
- Departement de sciences biologiques, Universite de Montreal, Montreal, Quebec, Canada
| | | | | | - Christopher B Cameron
- Departement de sciences biologiques, Universite de Montreal, Montreal, Quebec, Canada
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Arimoto A, Tagawa K. Regeneration in the enteropneust hemichordate, Ptychodera flava, and its evolutionary implications. Dev Growth Differ 2018; 60:400-408. [PMID: 30009383 DOI: 10.1111/dgd.12557] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 06/03/2018] [Accepted: 06/05/2018] [Indexed: 12/28/2022]
Abstract
Hemichordates are marine invertebrates that are closely related to chordates, but while their body plans are comparable to those of chordates, they possess a remarkable capacity for regeneration, even as adults. A small fragment is sufficient to form a complete individual. Unlike echinoderms, their larvae transform directly into adults; therefore, hemichordate systems offer clear morphological and molecular parallels between regeneration and development. Morphological events in regeneration are generally similar to organogenesis in juveniles. Nonetheless, comparative analysis of gene expression in these two morphological phenomena suggests that hemichordate regeneration is regulated by regeneration-specific mechanisms, as well as by developmental mechanisms. Dependency upon resident pluripotent/multipotent stem cells is a significant difference in metazoan regeneration, and such stem cells are essential for regeneration in many lineages. Based on the present gene expression study, regeneration in acorn worms is more closely related to that in vertebrates, because it employs endogenous stem cell-independent transdifferentiation.
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Affiliation(s)
- Asuka Arimoto
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, Japan
| | - Kuni Tagawa
- Marine Biological Laboratory, Graduate School of Science, Hiroshima University, Onomichi, Hiroshima, Japan
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Gonzalez P, Jiang JZ, Lowe CJ. The development and metamorphosis of the indirect developing acorn worm Schizocardium californicum (Enteropneusta: Spengelidae). Front Zool 2018; 15:26. [PMID: 29977319 PMCID: PMC6011522 DOI: 10.1186/s12983-018-0270-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 05/30/2018] [Indexed: 01/08/2023] Open
Abstract
Background Enteropneusts are benthic marine invertebrates that belong to the deuterostome phylum Hemichordata. The two main clades of enteropneusts are defined by differences in early life history strategies. In the Spengelidae and Ptychoderidae, development is indirect via a planktotrophic tornaria larva. In contrast, development in the Harrimanidae is direct without an intervening larval life history stage. Most molecular studies in the development and evolution of the enteropneust adult body plan have been carried out in the harrimanid Saccoglossus kowalevskii. In order to compare these two developmental strategies, we have selected the spengelid enteropneust Schizocardium californicum as a suitable indirect developing species for molecular developmental studies. Here we describe the methods for adult collecting, spawning and larval rearing in Schizocardium californicum, and describe embryogenesis, larval development, and metamorphosis, using light microscopy, immunocytochemistry and confocal microscopy. Results Adult reproductive individuals can be collected intertidally and almost year-round. Spawning can be triggered by heat shock and large numbers of larvae can be reared through metamorphosis under laboratory conditions. Gastrulation begins at 17 h post-fertilization (hpf) and embryos hatch at 26 hpf as ciliated gastrulae. At 3 days post-fertilization (dpf), the tornaria has a circumoral ciliary band, mouth, tripartite digestive tract, protocoel, larval muscles and a simple serotonergic nervous system. The telotroch develops at 5 dpf. In the course of 60 days, the serotonergic nervous system becomes more elaborate, the posterior coeloms develop, and the length of the circumoral ciliary band increases. At the end of the larval stage, larval muscles disappear, gill slits form, and adult muscles develop. Metamorphosis occurs spontaneously when the larva reaches its maximal size (ca. 3 mm), and involves loss and reorganization of larval structures (muscles, nervous system, digestive tract), as well as development of adult structures (adult muscles, tripartite body organization). Conclusions This study will enable future research in S. californicum to address long standing questions related to the evolution of axial patterning mechanisms, germ layer induction, neurogenesis and neural patterning, the mechanisms of metamorphosis, the relationships between larval and adult body plans, and the evolution of metazoan larval forms.
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Affiliation(s)
- Paul Gonzalez
- 1Hopkins Marine Station, Department of Biology, Stanford University, 120 Ocean View Boulevard, Pacific Grove, CA 93950 USA
| | - Jeffrey Z Jiang
- 2Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA 19104 USA
| | - Christopher J Lowe
- 1Hopkins Marine Station, Department of Biology, Stanford University, 120 Ocean View Boulevard, Pacific Grove, CA 93950 USA
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