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Ordoñez JF, Wollesen T. Unfolding the ventral nerve center of chaetognaths. Neural Dev 2024; 19:5. [PMID: 38720353 PMCID: PMC11078758 DOI: 10.1186/s13064-024-00182-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 04/17/2024] [Indexed: 05/12/2024] Open
Abstract
BACKGROUND Chaetognaths are a clade of marine worm-like invertebrates with a heavily debated phylogenetic position. Their nervous system superficially resembles the protostome type, however, knowledge regarding the molecular processes involved in neurogenesis is lacking. To better understand these processes, we examined the expression profiles of marker genes involved in bilaterian neurogenesis during post-embryonic stages of Spadella cephaloptera. We also investigated whether the transcription factor encoding genes involved in neural patterning are regionally expressed in a staggered fashion along the mediolateral axis of the nerve cord as it has been previously demonstrated in selected vertebrate, insect, and annelid models. METHODS The expression patterns of genes involved in neural differentiation (elav), neural patterning (foxA, nkx2.2, pax6, pax3/7, and msx), and neuronal function (ChAT and VAChT) were examined in S. cephaloptera hatchlings and early juveniles using whole-mount fluorescent in situ hybridization and confocal microscopy. RESULTS The Sce-elav + profile of S. cephaloptera hatchlings reveals that, within 24 h of post-embryonic development, the developing neural territories are not limited to the regions previously ascribed to the cerebral ganglion, the ventral nerve center (VNC), and the sensory organs, but also extend to previously unreported CNS domains that likely contribute to the ventral cephalic ganglia. In general, the neural patterning genes are expressed in distinct neural subpopulations of the cerebral ganglion and the VNC in hatchlings, eventually becoming broadly expressed with reduced intensity throughout the CNS in early juveniles. Neural patterning gene expression domains are also present outside the CNS, including the digestive tract and sensory organs. ChAT and VAChT domains within the CNS are predominantly observed in specific subpopulations of the VNC territory adjacent to the ventral longitudinal muscles in hatchlings. CONCLUSIONS The observed spatial expression domains of bilaterian neural marker gene homologs in S. cephaloptera suggest evolutionarily conserved roles in neurogenesis for these genes among bilaterians. Patterning genes expressed in distinct regions of the VNC do not show a staggered medial-to-lateral expression profile directly superimposable to other bilaterian models. Only when the VNC is conceptually laterally unfolded from the longitudinal muscle into a flat structure, an expression pattern bearing resemblance to the proposed conserved bilaterian mediolateral regionalization becomes noticeable. This finding supports the idea of an ancestral mediolateral patterning of the trunk nervous system in bilaterians.
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Affiliation(s)
- June F Ordoñez
- Unit for Integrative Zoology, Department of Evolutionary Biology, University of Vienna, 1030, Vienna, Austria
| | - Tim Wollesen
- Unit for Integrative Zoology, Department of Evolutionary Biology, University of Vienna, 1030, Vienna, Austria.
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Park TYS, Nielsen ML, Parry LA, Sørensen MV, Lee M, Kihm JH, Ahn I, Park C, de Vivo G, Smith MP, Harper DAT, Nielsen AT, Vinther J. A giant stem-group chaetognath. SCIENCE ADVANCES 2024; 10:eadi6678. [PMID: 38170772 PMCID: PMC10796117 DOI: 10.1126/sciadv.adi6678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 12/01/2023] [Indexed: 01/05/2024]
Abstract
Chaetognaths, with their characteristic grasping spines, are the oldest known pelagic predators, found in the lowest Cambrian (Terreneuvian). Here, we describe a large stem chaetognath, Timorebestia koprii gen. et sp. nov., from the lower Cambrian Sirius Passet Lagerstätte, which exhibits lateral and caudal fins, a distinct head region with long antennae and a jaw apparatus similar to Amiskwia sagittiformis. Amiskwia has previously been interpreted as a total-group chaetognathiferan, as either a stem-chaetognath or gnathostomulid. We show that T. koprii shares a ventral ganglion with chaetognaths to the exclusion of other animal groups, firmly placing these fossils on the chaetognath stem. The large size (up to 30 cm) and gut contents in T. koprii suggest that early chaetognaths occupied a higher trophic position in pelagic food chains than today.
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Affiliation(s)
- Tae-Yoon S. Park
- Division of Earth Sciences, Korea Polar Research Institute, 26 Songdomirae-ro Yeonsu-gu, Incheon 21990, Republic of Korea
- University of Science and Technology, 217 Gajeong-ro, Daejeon 34113, Republic of Korea
| | - Morten Lunde Nielsen
- Division of Earth Sciences, Korea Polar Research Institute, 26 Songdomirae-ro Yeonsu-gu, Incheon 21990, Republic of Korea
- School of Earth Sciences, Palaeobiology Research Group, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
- British Geological Survey, Nicker Hill, Keyworth NG12 5GG, UK
| | - Luke A. Parry
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK
| | | | - Mirinae Lee
- Division of Earth Sciences, Korea Polar Research Institute, 26 Songdomirae-ro Yeonsu-gu, Incheon 21990, Republic of Korea
| | - Ji-Hoon Kihm
- Division of Earth Sciences, Korea Polar Research Institute, 26 Songdomirae-ro Yeonsu-gu, Incheon 21990, Republic of Korea
- University of Science and Technology, 217 Gajeong-ro, Daejeon 34113, Republic of Korea
| | - Inhye Ahn
- Division of Earth Sciences, Korea Polar Research Institute, 26 Songdomirae-ro Yeonsu-gu, Incheon 21990, Republic of Korea
- University of Science and Technology, 217 Gajeong-ro, Daejeon 34113, Republic of Korea
| | - Changkun Park
- Division of Earth Sciences, Korea Polar Research Institute, 26 Songdomirae-ro Yeonsu-gu, Incheon 21990, Republic of Korea
| | - Giacinto de Vivo
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Napoli, Italy
| | - M. Paul Smith
- Oxford University Museum of Natural History, Parks Road, Oxford OX1 3PW, UK
| | - David A. T. Harper
- Palaeoecosystems Group, Department of Earth Sciences, Durham University, Durham DH1 3LE, UK
| | - Arne T. Nielsen
- Department of Geoscience and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, Copenhagen DK-1350, Denmark
| | - Jakob Vinther
- School of Earth Sciences, Palaeobiology Research Group, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
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Ortega A, Olivares-Bañuelos TN. Neurons and Glia Cells in Marine Invertebrates: An Update. Front Neurosci 2020; 14:121. [PMID: 32132895 PMCID: PMC7040184 DOI: 10.3389/fnins.2020.00121] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 01/30/2020] [Indexed: 12/18/2022] Open
Abstract
The nervous system (NS) of invertebrates and vertebrates is composed of two main types of cells: neurons and glia. In both types of organisms, nerve cells have similarities in biochemistry and functionality. The neurons are in charge of the synapse, and the glial cells are in charge of important functions of neuronal and homeostatic modulation. Knowing the mechanisms by which NS cells work is important in the biomedical area for the diagnosis and treatment of neurological disorders. For this reason, cellular and animal models to study the properties and characteristics of the NS are always sought. Marine invertebrates are strategic study models for the biological sciences. The sea slug Aplysia californica and the squid Loligo pealei are two examples of marine key organisms in the neurosciences field. The principal characteristic of marine invertebrates is that they have a simpler NS that consists of few and larger cells, which are well organized and have accessible structures. As well, the close phylogenetic relationship between Chordata and Echinodermata constitutes an additional advantage to use these organisms as a model for the functionality of neuronal cells and their cellular plasticity. Currently, there is great interest in analyzing the signaling processes between neurons and glial cells, both in vertebrates and in invertebrates. However, only few types of glial cells of invertebrates, mostly insects, have been studied, and it is important to consider marine organisms' research. For this reason, the objective of the review is to present an update of the most relevant information that exists around the physiology of marine invertebrate neuronal and glial cells.
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Affiliation(s)
- Arturo Ortega
- Laboratorio de Neurotoxicología, Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
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Steinhoff POM, Uhl G, Harzsch S, Sombke A. Visual pathways in the brain of the jumping spider Marpissa muscosa. J Comp Neurol 2020; 528:1883-1902. [PMID: 31960432 DOI: 10.1002/cne.24861] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 01/14/2020] [Accepted: 01/14/2020] [Indexed: 01/29/2023]
Abstract
Some animals have evolved task differentiation among their eyes. A particular example is spiders, where most species have eight eyes, of which two (the principal eyes) are used for object discrimination, whereas the other three pairs (secondary eyes) detect movement. In the ctenid spider Cupiennius salei, these two eye types correspond to two visual pathways in the brain. Each eye is associated with its own first- and second-order visual neuropil. The second-order neuropils of the principal eyes are connected to the arcuate body, whereas the second-order neuropils of the secondary eyes are linked to the mushroom body. We explored the principal- and secondary eye visual pathways of the jumping spider Marpissa muscosa, in which size and visual fields of the two eye types are considerably different. We found that the connectivity of the principal eye pathway is the same as in C. salei, while there are differences in the secondary eye pathways. In M. muscosa, all secondary eyes are connected to their own first-order visual neuropils. The first-order visual neuropils of the anterior lateral and posterior lateral eyes are connected with a second-order visual neuropil each and an additional shared one (L2). In the posterior median eyes, the axons of their first-order visual neuropils project directly to the arcuate body, suggesting that the posterior median eyes do not detect movement. The L2 might function as an upstream integration center enabling faster movement decisions.
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Affiliation(s)
- Philip O M Steinhoff
- General and Systematic Zoology, Zoological Institute and Museum, University of Greifswald, Greifswald, Germany
| | - Gabriele Uhl
- General and Systematic Zoology, Zoological Institute and Museum, University of Greifswald, Greifswald, Germany
| | - Steffen Harzsch
- Cytology and Evolutionary Biology, Zoological Institute and Museum, University of Greifswald, Greifswald, Germany
| | - Andy Sombke
- Department of Integrative Zoology, University of Vienna, Vienna, Austria
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Evolution of the bilaterian mouth and anus. Nat Ecol Evol 2018; 2:1358-1376. [PMID: 30135501 DOI: 10.1038/s41559-018-0641-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 06/26/2018] [Accepted: 07/11/2018] [Indexed: 12/17/2022]
Abstract
It is widely held that the bilaterian tubular gut with mouth and anus evolved from a simple gut with one major gastric opening. However, there is no consensus on how this happened. Did the single gastric opening evolve into a mouth, with the anus forming elsewhere in the body (protostomy), or did it evolve into an anus, with the mouth forming elsewhere (deuterostomy), or did it evolve into both mouth and anus (amphistomy)? These questions are addressed by the comparison of developmental fates of the blastopore, the opening of the embryonic gut, in diverse animals that live today. Here we review comparative data on the identity and fate of blastoporal tissue, investigate how the formation of the through-gut relates to the major body axes, and discuss to what extent evolutionary scenarios are consistent with these data. Available evidence indicates that stem bilaterians had a slit-like gastric opening that was partially closed in subsequent evolution, leaving open the anus and most likely also the mouth, which would favour amphistomy. We discuss remaining difficulties, and outline directions for future research.
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Steinhoff POM, Sombke A, Liedtke J, Schneider JM, Harzsch S, Uhl G. The synganglion of the jumping spider Marpissa muscosa (Arachnida: Salticidae): Insights from histology, immunohistochemistry and microCT analysis. ARTHROPOD STRUCTURE & DEVELOPMENT 2017; 46:156-170. [PMID: 27845202 DOI: 10.1016/j.asd.2016.11.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 10/30/2016] [Accepted: 11/04/2016] [Indexed: 06/06/2023]
Abstract
Jumping spiders are known for their extraordinary cognitive abilities. The underlying nervous system structures, however, are largely unknown. Here, we explore and describe the anatomy of the brain in the jumping spider Marpissa muscosa (Clerck, 1757) by means of paraffin histology, X-ray microCT analysis and immunohistochemistry as well as three-dimensional reconstruction. In the prosoma, the CNS is a clearly demarcated mass that surrounds the esophagus. The anteriormost neuromere, the protocerebrum, comprises nine bilaterally paired neuropils, including the mushroom bodies and one unpaired midline neuropil, the arcuate body. Further ventrally, the synganglion comprises the cheliceral (deutocerebrum) and pedipalpal neuropils (tritocerebrum). Synapsin-immunoreactivity in all neuropils is generally strong, while allatostatin-immunoreactivity is mostly present in association with the arcuate body and the stomodeal bridge. The most prominent neuropils in the spider brain, the mushroom bodies and the arcuate body, were suggested to be higher integrating centers of the arthropod brain. The mushroom body in M. muscosa is connected to first and second order visual neuropils of the lateral eyes, and the arcuate body to the second order neuropils of the anterior median eyes (primary eyes) through a visual tract. The connection of both, visual neuropils and eyes and arcuate body, as well as their large size corroborates the hypothesis that these neuropils play an important role in cognition and locomotion control of jumping spiders. In addition, we show that the architecture of the brain of M. muscosa and some previously investigated salticids differs significantly from that of the wandering spider Cupiennius salei, especially with regard to structure and arrangement of visual neuropils and mushroom body. Thus, we need to explore the anatomical conformities and specificities of the brains of different spider taxa in order to understand evolutionary transformations of the arthropod brain.
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Affiliation(s)
- Philip O M Steinhoff
- Zoological Institute and Museum, General and Systematic Zoology, University of Greifswald, Anklamer Straße 20, 17489 Greifswald, Germany.
| | - Andy Sombke
- Zoological Institute and Museum, Cytology and Evolutionary Biology, University of Greifswald, Soldmannstraße 23, 17487 Greifswald, Germany.
| | - Jannis Liedtke
- Zoological Institute, Biozentrum Grindel, University of Hamburg, Martin-Luther-King Platz 3, 20146 Hamburg, Germany
| | - Jutta M Schneider
- Zoological Institute, Biozentrum Grindel, University of Hamburg, Martin-Luther-King Platz 3, 20146 Hamburg, Germany
| | - Steffen Harzsch
- Zoological Institute and Museum, Cytology and Evolutionary Biology, University of Greifswald, Soldmannstraße 23, 17487 Greifswald, Germany
| | - Gabriele Uhl
- Zoological Institute and Museum, General and Systematic Zoology, University of Greifswald, Anklamer Straße 20, 17489 Greifswald, Germany.
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Gavilán B, Perea-Atienza E, Martínez P. Xenacoelomorpha: a case of independent nervous system centralization? Philos Trans R Soc Lond B Biol Sci 2016; 371:20150039. [PMID: 26598722 DOI: 10.1098/rstb.2015.0039] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Centralized nervous systems (NSs) and complex brains are among the most important innovations in the history of life on our planet. In this context, two related questions have been formulated: How did complex NSs arise in evolution, and how many times did this occur? As a step towards finding an answer, we describe the NS of several representatives of the Xenacoelomorpha, a clade whose members show different degrees of NS complexity. This enigmatic clade is composed of three major taxa: acoels, nemertodermatids and xenoturbellids. Interestingly, while the xenoturbellids seem to have a rather 'simple' NS (a nerve net), members of the most derived group of acoel worms clearly have ganglionic brains. This interesting diversity of NS architectures (with different degrees of compaction) provides a unique system with which to address outstanding questions regarding the evolution of brains and centralized NSs. The recent sequencing of xenacoelomorph genomes gives us a privileged vantage point from which to analyse neural evolution, especially through the study of key gene families involved in neurogenesis and NS function, such as G protein-coupled receptors, helix-loop-helix transcription factors and Wnts. We finish our manuscript proposing an adaptive scenario for the origin of centralized NSs (brains).
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Affiliation(s)
- Brenda Gavilán
- Departament de Genètica, Universitat de Barcelona, Avinguda Diagonal, 643, Barcelona 08028, Spain
| | - Elena Perea-Atienza
- Departament de Genètica, Universitat de Barcelona, Avinguda Diagonal, 643, Barcelona 08028, Spain
| | - Pedro Martínez
- Departament de Genètica, Universitat de Barcelona, Avinguda Diagonal, 643, Barcelona 08028, Spain Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluís Companys, 23, Barcelona 08010, Spain
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Krieger J, Braun P, Rivera NT, Schubart CD, Müller CH, Harzsch S. Comparative analyses of olfactory systems in terrestrial crabs (Brachyura): evidence for aerial olfaction? PeerJ 2015; 3:e1433. [PMID: 26713228 PMCID: PMC4690415 DOI: 10.7717/peerj.1433] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Accepted: 11/03/2015] [Indexed: 11/30/2022] Open
Abstract
Adaptations to a terrestrial lifestyle occurred convergently multiple times during the evolution of the arthropods. This holds also true for the "true crabs" (Brachyura), a taxon that includes several lineages that invaded land independently. During an evolutionary transition from sea to land, animals have to develop a variety of physiological and anatomical adaptations to a terrestrial life style related to respiration, reproduction, development, circulation, ion and water balance. In addition, sensory systems that function in air instead of in water are essential for an animal's life on land. Besides vision and mechanosensory systems, on land, the chemical senses have to be modified substantially in comparison to their function in water. Among arthropods, insects are the most successful ones to evolve aerial olfaction. Various aspects of terrestrial adaptation have also been analyzed in those crustacean lineages that evolved terrestrial representatives including the taxa Anomala, Brachyura, Amphipoda, and Isopoda. We are interested in how the chemical senses of terrestrial crustaceans are modified to function in air. Therefore, in this study, we analyzed the brains and more specifically the structure of the olfactory system of representatives of brachyuran crabs that display different degrees of terrestriality, from exclusively marine to mainly terrestrial. The methods we used included immunohistochemistry, detection of autofluorescence- and confocal microscopy, as well as three-dimensional reconstruction and morphometry. Our comparative approach shows that both the peripheral and central olfactory pathways are reduced in terrestrial members in comparison to their marine relatives, suggesting a limited function of their olfactory system on land. We conclude that for arthropod lineages that invaded land, evolving aerial olfaction is no trivial task.
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Affiliation(s)
- Jakob Krieger
- Zoological Institute and Museum, Department of Cytology and Evolutionary Biology, Ernst-Moritz-Arndt Universität Greifswald, Greifswald, Germany
| | - Philipp Braun
- Zoological Institute and Museum, Department of Cytology and Evolutionary Biology, Ernst-Moritz-Arndt Universität Greifswald, Greifswald, Germany
| | - Nicole T. Rivera
- Institute for Zoology, Department of Zoology & Evolution, Universität Regensburg, Regensburg, Germany
| | - Christoph D. Schubart
- Institute for Zoology, Department of Zoology & Evolution, Universität Regensburg, Regensburg, Germany
| | - Carsten H.G. Müller
- Zoological Institute and Museum, Department of General and Systematic Zoology, Ernst-Moritz-Arndt Universität Greifswald, Greifswald, Germany
| | - Steffen Harzsch
- Zoological Institute and Museum, Department of Cytology and Evolutionary Biology, Ernst-Moritz-Arndt Universität Greifswald, Greifswald, Germany
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Shen X, Sun S, Zhao FQ, Zhang GT, Tian M, Tsang LM, Wang JF, Chu KH. Phylomitogenomic analyses strongly support the sister relationship of the Chaetognatha and Protostomia. ZOOL SCR 2015. [DOI: 10.1111/zsc.12140] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xin Shen
- Jiangsu Key Laboratory of Marine Biotechnology/Co-Innovation Center of Jiangsu Marine Bio-industry Technology; Huaihai Institute of Technology; Lianyungang 222005 China
- Beijing Institutes of Life Science; Chinese Academy of Sciences; Beijing 100101 China
- Simon F. S. Li Marine Science Laboratory; School of Life Sciences; The Chinese University of Hong Kong; Shatin Hong Kong China
| | - Song Sun
- KLMEES and JBMERS; Institute of Oceanology; Chinese Academy of Sciences; Qingdao 266071 China
| | - Fang Qing Zhao
- Beijing Institutes of Life Science; Chinese Academy of Sciences; Beijing 100101 China
| | - Guang Tao Zhang
- KLMEES and JBMERS; Institute of Oceanology; Chinese Academy of Sciences; Qingdao 266071 China
| | - Mei Tian
- Jiangsu Key Laboratory of Marine Biotechnology/Co-Innovation Center of Jiangsu Marine Bio-industry Technology; Huaihai Institute of Technology; Lianyungang 222005 China
| | - Ling Ming Tsang
- Institute of Marine Biology; National Taiwan Ocean University; Keelung 20224 Taiwan
| | - Jin Feng Wang
- Beijing Institutes of Life Science; Chinese Academy of Sciences; Beijing 100101 China
| | - Ka Hou Chu
- Simon F. S. Li Marine Science Laboratory; School of Life Sciences; The Chinese University of Hong Kong; Shatin Hong Kong China
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Abstract
The apical organ of ciliated larvae of cnidarians and bilaterians is a true larval organ that disappears before or at metamorphosis. It appears to be sensory, probably involved in metamorphosis, but knowledge is scant. The ciliated protostome larvae show ganglia/nerve cords that are retained as the adult central nervous system (CNS). Two structures can be recognized, viz. a pair of cerebral ganglia, which form the major part of the adult brain, and a blastoporal (circumblastoporal) nerve cord, which becomes differentiated into a perioral loop, paired or secondarily fused ventral nerve cords and a small perianal loop. The anterior loop becomes part of the brain. This has been well documented through cell-lineage studies in a number of spiralians, and homologies with similar structures in the ecdysozoans are strongly indicated. The deuterostomes are generally difficult to interpret, and the nervous systems of echinoderms and enteropneusts appear completely enigmatic. The ontogeny of the chordate CNS can perhaps be interpreted as a variation of the ontogeny of the blastoporal nerve cord of the protostomes, and this is strongly supported by patterns of gene expression. The presence of 'deuterostomian' blastopore fates both in an annelid and in a mollusk, which are both placed in families with the 'normal' spiralian gastrulation type, and in the chaetognaths demonstrates that the chordate type of gastrulation could easily have evolved from the spiralian type. This indicates that the latest common ancestor of the deuterostomes was very similar to the latest common pelago-benthic ancestor of the protostomes as described by the trochaea theory, and that the neural tube of the chordates is morphologically ventral.
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Affiliation(s)
- Claus Nielsen
- The Natural History Museum of Denmark, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen, Denmark
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Fritzsch B, Jahan I, Pan N, Elliott KL. Evolving gene regulatory networks into cellular networks guiding adaptive behavior: an outline how single cells could have evolved into a centralized neurosensory system. Cell Tissue Res 2014; 359:295-313. [PMID: 25416504 DOI: 10.1007/s00441-014-2043-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 10/20/2014] [Indexed: 12/18/2022]
Abstract
Understanding the evolution of the neurosensory system of man, able to reflect on its own origin, is one of the major goals of comparative neurobiology. Details of the origin of neurosensory cells, their aggregation into central nervous systems and associated sensory organs and their localized patterning leading to remarkably different cell types aggregated into variably sized parts of the central nervous system have begun to emerge. Insights at the cellular and molecular level have begun to shed some light on the evolution of neurosensory cells, partially covered in this review. Molecular evidence suggests that high mobility group (HMG) proteins of pre-metazoans evolved into the definitive Sox [SRY (sex determining region Y)-box] genes used for neurosensory precursor specification in metazoans. Likewise, pre-metazoan basic helix-loop-helix (bHLH) genes evolved in metazoans into the group A bHLH genes dedicated to neurosensory differentiation in bilaterians. Available evidence suggests that the Sox and bHLH genes evolved a cross-regulatory network able to synchronize expansion of precursor populations and their subsequent differentiation into novel parts of the brain or sensory organs. Molecular evidence suggests metazoans evolved patterning gene networks early, which were not dedicated to neuronal development. Only later in evolution were these patterning gene networks tied into the increasing complexity of diffusible factors, many of which were already present in pre-metazoans, to drive local patterning events. It appears that the evolving molecular basis of neurosensory cell development may have led, in interaction with differentially expressed patterning genes, to local network modifications guiding unique specializations of neurosensory cells into sensory organs and various areas of the central nervous system.
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Affiliation(s)
- Bernd Fritzsch
- Department of Biology, University of Iowa, CLAS, 143 BB, Iowa City, IA, 52242, USA,
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Gasmi S, Nève G, Pech N, Tekaya S, Gilles A, Perez Y. Evolutionary history of Chaetognatha inferred from molecular and morphological data: a case study for body plan simplification. Front Zool 2014; 11:84. [PMID: 25473413 PMCID: PMC4254178 DOI: 10.1186/s12983-014-0084-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 10/30/2014] [Indexed: 11/18/2022] Open
Abstract
Background Chaetognatha are a phylum of marine carnivorous animals which includes more than 130 extant species. The internal systematics of this group have been intensively debated since it was discovered in the 18th century. While they can be traced back to the earlier Cambrian, they are an extraordinarily homogeneous phylum at the morphological level - a fascinating characteristic that puzzled many a scientist who has tried to clarify their taxonomy. Recent studies which have attempted to reconstruct a phylogeny using molecular data have relied on single gene analyses and a somewhat restricted taxon sampling. Here, we present the first large scale phylogenetic study of Chaetognatha based on a combined analysis of nearly the complete ribosomal RNA (rRNA) genes. We use this analysis to infer the evolution of some morphological characters. This work includes 36 extant species, mainly obtained from Tara Oceans Expedition 2009/2012, that represent 16 genera and 6 of the 9 extant families. Results Cladistic and phenetic analysis of morphological characters, geometric morphometrics and molecular small subunit (SSU rRNA) and large subunit (LSU rRNA) ribosomal genes phylogenies provided new insights into the relationships and the evolutionary history of Chaetognatha. We propose the following clade structure for the phylum: (((Sagittidae, Krohnittidae), Spadellidae), (Eukrohniidae, Heterokrohniidae)), with the Pterosagittidae included in the Sagittidae. The clade (Sagittidae, Krohnittidae) constitutes the monophyletic order of Aphragmophora. Molecular analyses showed that the Phragmophora are paraphyletic. The Ctenodontina/Flabellodontina and Syngonata/Chorismogonata hypotheses are invalidated on the basis of both morphological and molecular data. This new phylogeny also includes resurrected and modified genera within Sagittidae. Conclusions The distribution of some morphological characters traditionally used in systematics and for species diagnosis suggests that the diversity in Chaetognatha was produced through a process of mosaic evolution. Moreover, chaetognaths have mostly evolved by simplification of their body plan and their history shows numerous convergent events of losses and reversions. The main morphological novelty observed is the acquisition of a second pair of lateral fins in Sagittidae, which represents an adaptation to the holoplanktonic niche. Electronic supplementary material The online version of this article (doi:10.1186/s12983-014-0084-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Samah Gasmi
- Aix-Marseille Université, CNRS, IRD, Avignon Université, IMBE UMR 7263, 13331 Marseille cedex 3, France ; Université de Tunis El Manar, Faculté des Sciences de Tunis, UR11ES12 Biologie de la Reproduction et du Développement animal, 2092 El Manar, Tunis Tunisie
| | - Gabriel Nève
- Aix-Marseille Université, CNRS, IRD, Avignon Université, IMBE UMR 7263, 13331 Marseille cedex 3, France
| | - Nicolas Pech
- Aix-Marseille Université, CNRS, IRD, Avignon Université, IMBE UMR 7263, 13331 Marseille cedex 3, France
| | - Saïda Tekaya
- Université de Tunis El Manar, Faculté des Sciences de Tunis, UR11ES12 Biologie de la Reproduction et du Développement animal, 2092 El Manar, Tunis Tunisie
| | - André Gilles
- Aix-Marseille Université, CNRS, IRD, Avignon Université, IMBE UMR 7263, 13331 Marseille cedex 3, France
| | - Yvan Perez
- Aix-Marseille Université, CNRS, IRD, Avignon Université, IMBE UMR 7263, 13331 Marseille cedex 3, France
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Müller CHG, Rieger V, Perez Y, Harzsch S. Immunohistochemical and ultrastructural studies on ciliary sense organs of arrow worms (Chaetognatha). ZOOMORPHOLOGY 2013. [DOI: 10.1007/s00435-013-0211-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Koziol U, Krohne G, Brehm K. Anatomy and development of the larval nervous system in Echinococcus multilocularis. Front Zool 2013; 10:24. [PMID: 23642192 PMCID: PMC3658878 DOI: 10.1186/1742-9994-10-24] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 04/30/2013] [Indexed: 01/06/2023] Open
Abstract
Background The metacestode larva of Echinococcus multilocularis (Cestoda: Taeniidae) develops in the liver of intermediate hosts (typically rodents, or accidentally in humans) as a labyrinth of interconnected cysts that infiltrate the host tissue, causing the disease alveolar echinococcosis. Within the cysts, protoscoleces (the infective stage for the definitive canid host) arise by asexual multiplication. These consist of a scolex similar to that of the adult, invaginated within a small posterior body. Despite the importance of alveolar echinococcosis for human health, relatively little is known about the basic biology, anatomy and development of E. multilocularis larvae, particularly with regard to their nervous system. Results We describe the existence of a subtegumental nerve net in the metacestode cysts, which is immunoreactive for acetylated tubulin-α and contains small populations of nerve cells that are labeled by antibodies raised against several invertebrate neuropeptides. However, no evidence was found for the existence of cholinergic or serotoninergic elements in the cyst wall. Muscle fibers occur without any specific arrangement in the subtegumental layer, and accumulate during the invaginations of the cyst wall that form brood capsules, where protoscoleces develop. The nervous system of the protoscolex develops independently of that of the metacestode cyst, with an antero-posterior developmental gradient. The combination of antibodies against several nervous system markers resulted in a detailed description of the protoscolex nervous system, which is remarkably complex and already similar to that of the adult worm. Conclusions We provide evidence for the first time of the existence of a nervous system in the metacestode cyst wall, which is remarkable given the lack of motility of this larval stage, and the lack of serotoninergic and cholinergic elements. We propose that it could function as a neuroendocrine system, derived from the nervous system present in the bladder tissue of other taeniids. The detailed description of the development and anatomy of the protoscolex neuromuscular system is a necessary first step toward the understanding of the developmental mechanisms operating in these peculiar larval stages.
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Affiliation(s)
- Uriel Koziol
- University of Würzburg, Institute of Hygiene and Microbiology, Josef-Schneider-Strasse 2, Würzburg, D-97080, Germany.
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Kenning M, Müller C, Wirkner CS, Harzsch S. The Malacostraca (Crustacea) from a neurophylogenetic perspective: New insights from brain architecture in Nebalia herbstii Leach, 1814 (Leptostraca, Phyllocarida). ZOOL ANZ 2013. [DOI: 10.1016/j.jcz.2012.09.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Perez Y, Rieger V, Martin E, Müller CHG, Harzsch S. Neurogenesis in an early protostome relative: progenitor cells in the ventral nerve center of chaetognath hatchlings are arranged in a highly organized geometrical pattern. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2013; 320:179-93. [PMID: 23483730 DOI: 10.1002/jez.b.22493] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 12/29/2012] [Accepted: 01/23/2013] [Indexed: 01/08/2023]
Abstract
Emerging evidence suggests that Chaetognatha represent an evolutionary lineage that is the sister group to all other Protostomia thus promoting these animals as a pivotal model for our understanding of bilaterian evolutionary history. We have analyzed the proliferation of neuronal progenitor cells in the developing ventral nerve center (VNC) of Spadella cephaloptera hatchlings. To that end, for the first time in Chaetognatha, we performed in vivo incorporation experiments with the S-phase specific mitosis marker bromodeoxyuridine (BrdU). Our experiments provide evidence for a high level of mitotic activity in the VNC for ca. 3 days after hatching. Neurogenesis is carried by presumptive neuronal progenitor cells that cycle rapidly and most likely divide asymmetrically. These progenitors are arranged in a distinct grid-like geometrical pattern including about 35 transverse rows. Considering Chaetognaths to be an early offshoot of the protostome lineage we conclude that the presence of neuronal progenitor cells with asymmetric division seems to be a feature that is rooted deeply in the Metazoa. In the light of previous evidence indicating the presence of serially iterated peptidergic neurons with individual identities in the chaetognath VNC, we discuss if these neuronal progenitor cells give rise to distinct lineages. Furthermore, we evaluate the serially iterated arrangement of the progenitor cells in the light of evolution of segmentation.
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Affiliation(s)
- Yvan Perez
- Institut Méditerranéen de Biodiversité et d'Ecologie Evolution Genome Environment, IMBE-UMR CNRS 7263/IRD 237 Aix-Marseille Université/Centre St Charles, Marseille cedex 3, France
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Serotonin-immunoreactive neurons in scorpion pectine neuropils: similarities to insect and crustacean primary olfactory centres? ZOOLOGY 2012; 115:151-9. [PMID: 22445574 DOI: 10.1016/j.zool.2011.10.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Revised: 10/17/2011] [Accepted: 10/20/2011] [Indexed: 11/23/2022]
Abstract
The pectines of scorpions are a single pair of mechano- and chemosensory appendages located ventrally behind the most posterior pair of walking legs. They are used for probing the substrate in behaviours such as prey tracking and courtship. The sensory afferents on the pectines supply large segmental neuropils with a conspicuous glomerular structure. The pectine neuropils thus bear similarities to insect and crustacean deutocerebral chemosensory centres associated with the antennae, but they also possess idiosyncratic features. One characteristic property of many insect and decapod crustacean olfactory neuropils is their innervation by single, or very few, large serotonergic (inter-) neurons. This feature, among others, has been proposed to support homology of the olfactory lobes in the two arthropod groups. A possible serotonergic innervation of the scorpion pectine neuropils has not yet been studied, despite its apparent diagnostic and functional importance. We thus examined serotonin-immunoreactivity in the pectine neuropils of Androctonus australis and Pandinus imperator. Both scorpion species yielded similar results. The periphery of the neuropil and the matrix between the glomeruli are supplied by a dense network of serotonin-immunoreactive (5-HT-ir) arborisations and varicosities, while the glomeruli themselves are mostly free of 5-HT-ir fibres. The 5-HT-ir supply of the pectine neuropils has two origins. The first is a pair of neurons on each body side, up to 30 μm in diameter and thus slightly larger than the surrounding somata. These cell bodies are and associated with the neuromeres of the genital and pectine segments. The situation is reminiscent of the 5-HT supply of insect and crustacean olfactory and antennal neuropils. The second 5-HT innervation of the pectine neuropils is from a group of some 10-20 ipsilateral neuronal somata of slightly smaller size (15-20 μm). These are part of a much larger 5-HT-ir group comprising 70-90 somata. The whole group is located more anteriorly than the single soma mentioned above, and associated with the neuromere of the last (4th) walking leg. When compared to data from other arthropods, our findings may suggest that glomerular organisation is an ancestral feature of primary chemosensory centres innervated by arthropod appendages. This idea needs further scrutiny, although supporting evidence may have been overlooked previously, due to the small size of chemosensory neuropils in walking legs and in reduced segmental appendages.
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Abstract
The increase of bodyplan complexity in early bilaterian evolution is correlates with the advent and diversification of microRNAs. These small RNAs guide animal development by regulating temporal transitions in gene expression involved in cell fate choices and transitions between pluripotency and differentiation. One of the two known microRNAs whose origins date back before the bilaterian ancestor is mir-100. In Bilateria, it appears stably associated in polycistronic transcripts with let-7 and mir-125, two key regulators of development. In vertebrates, these three microRNA families have expanded to form a complex system of developmental regulators. In this contribution, we disentangle the evolutionary history of the let-7 locus, which was restructured independently in nematodes, platyhelminths, and deuterostomes. The foundation of a second let-7 locus in the common ancestor of vertebrates and urochordates predates the vertebrate-specific genome duplications, which then caused a rapid expansion of the let-7 family.
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Affiliation(s)
- Jana Hertel
- Bioinformatics Group, Department of Computer Science and Interdisciplinary Center for Bioinformatics, University of Leipzig, Leipzig, Germany
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20
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Krieger J, Sombke A, Seefluth F, Kenning M, Hansson BS, Harzsch S. Comparative brain architecture of the European shore crab Carcinus maenas (Brachyura) and the common hermit crab Pagurus bernhardus (Anomura) with notes on other marine hermit crabs. Cell Tissue Res 2012; 348:47-69. [DOI: 10.1007/s00441-012-1353-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 01/27/2012] [Indexed: 12/12/2022]
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21
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Rieger V, Perez Y, Müller CHG, Lacalli T, Hansson BS, Harzsch S. Development of the nervous system in hatchlings of Spadella cephaloptera (Chaetognatha), and implications for nervous system evolution in Bilateria. Dev Growth Differ 2011; 53:740-59. [PMID: 21671921 DOI: 10.1111/j.1440-169x.2011.01283.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Chaetognaths (arrow worms) play an important role as predators in planktonic food webs. Their phylogenetic position is unresolved, and among the numerous hypotheses, affinities to both protostomes and deuterostomes have been suggested. Many aspects of their life history, including ontogenesis, are poorly understood and, though some aspects of their embryonic and postembryonic development have been described, knowledge of early neural development is still limited. This study sets out to provide new insights into neurogenesis of newly hatched Spadella cephaloptera and their development during the following days, with attention to the two main nervous centers, the brain and the ventral nerve center. These were examined with immunohistological methods and confocal laser-scan microscopic analysis, using antibodies against tubulin, FMRFamide, and synapsin to trace the emergence of neuropils and the establishment of specific peptidergic subsystems. At hatching, the neuronal architecture of the ventral nerve center is already well established, whereas the brain and the associated vestibular ganglia are still rudimentary. The development of the brain proceeds rapidly over the next 6 days to a state that resembles the adult pattern. These data are discussed in relation to the larval life style and behaviors such as feeding. In addition, we compare the larval chaetognath nervous system and that of other bilaterian taxa in order to extract information with phylogenetic value. We conclude that larval neurogenesis in chaetognaths does not suggest an especially close relationship to either deuterostomes or protostomes, but instead displays many apomorphic features.
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Affiliation(s)
- Verena Rieger
- Zoologisches Institut und Museum, Cytologie und Evolutionsbiologie, Ernst Moritz Arndt Universität Greifswald, Soldmannstraße 23, 17487 Greifswald.
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Missbach C, Harzsch S, Hansson BS. New insights into an ancient insect nose: the olfactory pathway of Lepismachilis y-signata (Archaeognatha: Machilidae). ARTHROPOD STRUCTURE & DEVELOPMENT 2011; 40:317-333. [PMID: 21665539 DOI: 10.1016/j.asd.2011.03.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Revised: 03/07/2011] [Accepted: 03/30/2011] [Indexed: 05/30/2023]
Abstract
Hexapods most likely derived from an aquatic ancestor, which they shared with crustaceans. During the transition from water to land, their sensory systems had to face the new physiological demands that terrestrial conditions impose. This process also concerns the sense of smell and, more specifically, detection of volatile, air-borne chemicals. In insects, olfaction plays an important role in orientation, mating choice, and food and host finding behavior. The first integration center of odor information in the insect brain is the antennal lobe, which is targeted by the afferents from olfactory sensory neurons on the antennae. Within the antennal lobe of most pterygote insects, spherical substructures called olfactory glomeruli are present. In order to gain insights into the evolution of the structure of the central olfactory pathway in insects, we analyzed a representative of the wingless Archaeognatha or jumping bristletails, using immunocytochemistry, antennal backfills and histological section series combined with 3D reconstruction. In the deutocerebrum of Lepismachilis y-signata, we found three different neuropil regions. Two of them show a glomerular organization, but these glomeruli differ in their shape from those in all other insect groups. The connection of the glomerular neuropils to higher brain centers remains unclear and mushroom bodies are absent as reported from other archaeognathan species. We discuss the evolutionary implications of these findings.
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Affiliation(s)
- Christine Missbach
- Max-Planck-Institute for Chemical Ecology, Department of Neuroethology, Hans-Knöll-Strasse 8, D-07745 Jena, Germany.
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23
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Harzsch S, Rieger V, Krieger J, Seefluth F, Strausfeld NJ, Hansson BS. Transition from marine to terrestrial ecologies: changes in olfactory and tritocerebral neuropils in land-living isopods. ARTHROPOD STRUCTURE & DEVELOPMENT 2011; 40:244-257. [PMID: 21641866 DOI: 10.1016/j.asd.2011.03.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Revised: 02/25/2011] [Accepted: 03/21/2011] [Indexed: 05/30/2023]
Abstract
In addition to the ancestors of insects, representatives of five lineages of crustaceans have colonized land. Whereas insects have evolved sensilla that are specialized to allow the detection of airborne odors and have evolved olfactory sensory neurons that recognize specific airborne ligands, there is so far little evidence for aerial olfaction in terrestrial crustaceans. Here we ask the question whether terrestrial Isopoda have evolved the neuronal substrate for the problem of detecting far-field airborne chemicals. We show that conquest of land of Isopoda has been accompanied by a radical diminution of their first antennae and a concomitant loss of their deutocerebral olfactory lobes and olfactory computational networks. In terrestrial isopods, but not their marine cousins, tritocerebral neuropils serving the second antenna have evolved radical modifications. These include a complete loss of the malacostracan pattern of somatotopic representation, the evolution in some species of amorphous lobes and in others lobes equipped with microglomeruli, and yet in others the evolution of partitioned neuropils that suggest modality-specific segregation of second antenna inputs. Evidence suggests that Isopoda have evolved, and are in the process of evolving, several novel solutions to chemical perception on land and in air.
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Affiliation(s)
- S Harzsch
- Universität Greifswald, Fachbereich Biologie, Abteilung Cytologie und Evolutionsbiologie, J.-S.-Bach Strasse 11/12, D-17498 Greifswald, Germany.
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Edgecombe GD, Giribet G, Dunn CW, Hejnol A, Kristensen RM, Neves RC, Rouse GW, Worsaae K, Sørensen MV. Higher-level metazoan relationships: recent progress and remaining questions. ORG DIVERS EVOL 2011. [DOI: 10.1007/s13127-011-0044-4] [Citation(s) in RCA: 206] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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25
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Richter S, Loesel R, Purschke G, Schmidt-Rhaesa A, Scholtz G, Stach T, Vogt L, Wanninger A, Brenneis G, Döring C, Faller S, Fritsch M, Grobe P, Heuer CM, Kaul S, Møller OS, Müller CHG, Rieger V, Rothe BH, Stegner MEJ, Harzsch S. Invertebrate neurophylogeny: suggested terms and definitions for a neuroanatomical glossary. Front Zool 2010; 7:29. [PMID: 21062451 PMCID: PMC2996375 DOI: 10.1186/1742-9994-7-29] [Citation(s) in RCA: 232] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2010] [Accepted: 11/09/2010] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Invertebrate nervous systems are highly disparate between different taxa. This is reflected in the terminology used to describe them, which is very rich and often confusing. Even very general terms such as 'brain', 'nerve', and 'eye' have been used in various ways in the different animal groups, but no consensus on the exact meaning exists. This impedes our understanding of the architecture of the invertebrate nervous system in general and of evolutionary transformations of nervous system characters between different taxa. RESULTS We provide a glossary of invertebrate neuroanatomical terms with a precise and consistent terminology, taxon-independent and free of homology assumptions. This terminology is intended to form a basis for new morphological descriptions. A total of 47 terms are defined. Each entry consists of a definition, discouraged terms, and a background/comment section. CONCLUSIONS The use of our revised neuroanatomical terminology in any new descriptions of the anatomy of invertebrate nervous systems will improve the comparability of this organ system and its substructures between the various taxa, and finally even lead to better and more robust homology hypotheses.
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Affiliation(s)
- Stefan Richter
- Universität Rostock, Institut für Biowissenschaften, Abteilung für Allgemeine und Spezielle Zoologie, Universitätsplatz 2, D-18055 Rostock, Germany
| | - Rudi Loesel
- RWTH Aachen, Institute of Biology II, Department of Developmental Biology and Morphology of Animals, Mies-van-der-Rohe-Straße 15, D-52056 Aachen, Germany
| | - Günter Purschke
- Universität Osnabrück, Fachbereich Biologie/Chemie, AG Zoologie, Barbarastraße 11,, D-49069 Osnabrück, Germany
| | - Andreas Schmidt-Rhaesa
- Biozentrum Grindel/Zoological Museum, Martin-Luther-King-Platz 3, D-20146 Hamburg, Germany
| | - Gerhard Scholtz
- Humboldt-Universität zu Berlin, Institut für Biologie - Vergleichende Zoologie, Philippstraße 13, D-10115 Berlin, Germany
| | - Thomas Stach
- Freie Universität Berlin, Zoologie - Systematik und Evolutionsforschung, Königin-Luise-Straße 1-3, D-14195 Berlin, Germany
| | - Lars Vogt
- Universität Bonn, Institut für Evolutionsbiologie und Ökologie, An der Immenburg 1, D-53121 Bonn, Germany
| | - Andreas Wanninger
- University of Copenhagen, Department of Biology, Research Group for Comparative Zoology, Universitetsparken 15, DK-2100 Copenhagen, Denmark
| | - Georg Brenneis
- Universität Rostock, Institut für Biowissenschaften, Abteilung für Allgemeine und Spezielle Zoologie, Universitätsplatz 2, D-18055 Rostock, Germany
- Humboldt-Universität zu Berlin, Institut für Biologie - Vergleichende Zoologie, Philippstraße 13, D-10115 Berlin, Germany
| | - Carmen Döring
- Universität Osnabrück, Fachbereich Biologie/Chemie, AG Zoologie, Barbarastraße 11,, D-49069 Osnabrück, Germany
| | - Simone Faller
- RWTH Aachen, Institute of Biology II, Department of Developmental Biology and Morphology of Animals, Mies-van-der-Rohe-Straße 15, D-52056 Aachen, Germany
| | - Martin Fritsch
- Universität Rostock, Institut für Biowissenschaften, Abteilung für Allgemeine und Spezielle Zoologie, Universitätsplatz 2, D-18055 Rostock, Germany
| | - Peter Grobe
- Universität Bonn, Institut für Evolutionsbiologie und Ökologie, An der Immenburg 1, D-53121 Bonn, Germany
| | - Carsten M Heuer
- RWTH Aachen, Institute of Biology II, Department of Developmental Biology and Morphology of Animals, Mies-van-der-Rohe-Straße 15, D-52056 Aachen, Germany
| | - Sabrina Kaul
- Freie Universität Berlin, Zoologie - Systematik und Evolutionsforschung, Königin-Luise-Straße 1-3, D-14195 Berlin, Germany
| | - Ole S Møller
- Universität Rostock, Institut für Biowissenschaften, Abteilung für Allgemeine und Spezielle Zoologie, Universitätsplatz 2, D-18055 Rostock, Germany
| | - Carsten HG Müller
- Ernst-Moritz-Arndt-Universität Greifswald, Zoologisches Institut, Cytologie und Evolutionsbiologie, Johann-Sebastian-Bach-Straße 11/12, D-17487 Greifswald, Germany
| | - Verena Rieger
- Ernst-Moritz-Arndt-Universität Greifswald, Zoologisches Institut, Cytologie und Evolutionsbiologie, Johann-Sebastian-Bach-Straße 11/12, D-17487 Greifswald, Germany
| | - Birgen H Rothe
- Biozentrum Grindel/Zoological Museum, Martin-Luther-King-Platz 3, D-20146 Hamburg, Germany
| | - Martin EJ Stegner
- Universität Rostock, Institut für Biowissenschaften, Abteilung für Allgemeine und Spezielle Zoologie, Universitätsplatz 2, D-18055 Rostock, Germany
| | - Steffen Harzsch
- Ernst-Moritz-Arndt-Universität Greifswald, Zoologisches Institut, Cytologie und Evolutionsbiologie, Johann-Sebastian-Bach-Straße 11/12, D-17487 Greifswald, Germany
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Sombke A, Harzsch S, Hansson BS. Organization of Deutocerebral Neuropils and Olfactory Behavior in the Centipede Scutigera coleoptrata (Linnaeus, 1758) (Myriapoda: Chilopoda). Chem Senses 2010; 36:43-61. [DOI: 10.1093/chemse/bjq096] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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Krieger J, Sandeman RE, Sandeman DC, Hansson BS, Harzsch S. Brain architecture of the largest living land arthropod, the Giant Robber Crab Birgus latro (Crustacea, Anomura, Coenobitidae): evidence for a prominent central olfactory pathway? Front Zool 2010; 7:25. [PMID: 20831795 PMCID: PMC2945339 DOI: 10.1186/1742-9994-7-25] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Accepted: 09/10/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Several lineages within the Crustacea conquered land independently during evolution, thereby requiring physiological adaptations for a semi-terrestrial or even a fully terrestrial lifestyle. Birgus latro Linnaeus, 1767, the giant robber crab or coconut crab (Anomura, Coenobitidae), is the largest land-living arthropod and inhabits Indo-Pacific islands such as Christmas Island. B. latro has served as a model in numerous studies of physiological aspects related to the conquest of land by crustaceans. From an olfactory point of view, a transition from sea to land means that molecules need to be detected in gas phase instead of in water solution. Previous studies have provided physiological evidence that terrestrial hermit crabs (Coenobitidae) such as B. latro have a sensitive and well differentiated sense of smell. Here we analyze the brain, in particular the olfactory processing areas of B. latro, by morphological analysis followed by 3 D reconstruction and immunocytochemical studies of synaptic proteins and a neuropeptide. RESULTS The primary and secondary olfactory centers dominate the brain of B. latro and together account for ca. 40% of the neuropil volume in its brain. The paired olfactory neuropils are tripartite and composed of more than 1,000 columnar olfactory glomeruli, which are radially arranged around the periphery of the olfactory neuropils. The glomeruli are innervated ca. 90,000 local interneurons and ca. 160,000 projection neurons per side. The secondary olfactory centers, the paired hemiellipsoid neuropils, are targeted by the axons of these olfactory projection neurons. The projection neuron axonal branches make contact to ca. 250.000 interneurons (per side) associated with the hemiellipsoid neuropils. The hemiellipsoid body neuropil is organized into parallel neuropil lamellae, a design that is quite unusual for decapod crustaceans. The architecture of the optic neuropils and areas associated with antenna two suggest that B. latro has visual and mechanosensory skills that are comparable to those of marine Crustacea. CONCLUSIONS In parallel to previous behavioral findings that B. latro has aerial olfaction, our results indicate that their central olfactory pathway is indeed most prominent. Similar findings from the closely related terrestrial hermit crab Coenobita clypeatus suggest that in Coenobitidae, olfaction is a major sensory modality processed by the brain, and that for these animals, exploring the olfactory landscape is vital for survival in their terrestrial habitat. Future studies on terrestrial members of other crustacean taxa such as Isopoda, Amphipoda, Astacida, and Brachyura will shed light on how frequently the establishment of an aerial sense of olfaction evolved in Crustacea during the transition from sea to land. Amounting to ca. 1,000,000, the numbers of interneurons that analyse the olfactory input in B. latro brains surpasses that in other terrestrial arthropods, as e.g. the honeybee Apis mellifera or the moth Manduca sexta, by two orders of magnitude suggesting that B. latro in fact is a land-living arthropod that has devoted a substantial amount of nervous tissue to the sense of smell.
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Affiliation(s)
- Jakob Krieger
- Institute of Zoology, Department of Cytology and Evolution, University of Greifswald, Johann-Sebastian-Bach-Straße 11/12, D-17487 Greifswald, Germany
| | - Renate E Sandeman
- Justus-Liebig-Universität Gießen, Fachbereich 06 Psychologie und Sportwissenschaft, Abteilung für Entwicklungspsychologie, Otto-Behaghel-Strasse 10F, D-35394 Giessen, Germany
| | - David C Sandeman
- Wellesley College, 106 Central Street, Wellesley College, Department of Biological Sciences, Wellesley, MA 02481-8203, USA
| | - Bill S Hansson
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, Beutenberg Campus, Hans-Knöll-Str. 8, D-07745 Jena, Germany
| | - Steffen Harzsch
- Institute of Zoology, Department of Cytology and Evolution, University of Greifswald, Johann-Sebastian-Bach-Straße 11/12, D-17487 Greifswald, Germany.,Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, Beutenberg Campus, Hans-Knöll-Str. 8, D-07745 Jena, Germany
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Harzsch S, Wanninger A. Evolution of invertebrate nervous systems: the Chaetognatha as a case study. ACTA ZOOL-STOCKHOLM 2010. [DOI: 10.1111/j.1463-6395.2009.00423.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Fine structure of the ventral nerve centre and interspecific identification of individual neurons in the enigmatic Chaetognatha. ZOOMORPHOLOGY 2008. [DOI: 10.1007/s00435-008-0074-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Harzsch S, Hansson BS. Brain architecture in the terrestrial hermit crab Coenobita clypeatus (Anomura, Coenobitidae), a crustacean with a good aerial sense of smell. BMC Neurosci 2008; 9:58. [PMID: 18590553 PMCID: PMC2459186 DOI: 10.1186/1471-2202-9-58] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2007] [Accepted: 06/30/2008] [Indexed: 11/10/2022] Open
Abstract
Background During the evolutionary radiation of Crustacea, several lineages in this taxon convergently succeeded in meeting the physiological challenges connected to establishing a fully terrestrial life style. These physiological adaptations include the need for sensory organs of terrestrial species to function in air rather than in water. Previous behavioral and neuroethological studies have provided solid evidence that the land hermit crabs (Coenobitidae, Anomura) are a group of crustaceans that have evolved a good sense of aerial olfaction during the conquest of land. We wanted to study the central olfactory processing areas in the brains of these organisms and to that end analyzed the brain of Coenobita clypeatus (Herbst, 1791; Anomura, Coenobitidae), a fully terrestrial tropical hermit crab, by immunohistochemistry against synaptic proteins, serotonin, FMRFamide-related peptides, and glutamine synthetase. Results The primary olfactory centers in this species dominate the brain and are composed of many elongate olfactory glomeruli. The secondary olfactory centers that receive an input from olfactory projection neurons are almost equally large as the olfactory lobes and are organized into parallel neuropil lamellae. The architecture of the optic neuropils and those areas associated with antenna two suggest that C. clypeatus has visual and mechanosensory skills that are comparable to those of marine Crustacea. Conclusion In parallel to previous behavioral findings of a good sense of aerial olfaction in C. clypeatus, our results indicate that in fact their central olfactory pathway is most prominent, indicating that olfaction is a major sensory modality that these brains process. Interestingly, the secondary olfactory neuropils of insects, the mushroom bodies, also display a layered structure (vertical and medial lobes), superficially similar to the lamellae in the secondary olfactory centers of C. clypeatus. More detailed analyses with additional markers will be necessary to explore the question if these similarities have evolved convergently with the establishment of superb aerial olfactory abilities or if this design goes back to a shared principle in the common ancestor of Crustacea and Hexapoda.
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Affiliation(s)
- Steffen Harzsch
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, Beutenberg Campus, Hans-Knöll-Str, 8, D-07745 Jena, Germany.
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Marlétaz F, Gilles A, Caubit X, Perez Y, Dossat C, Samain S, Gyapay G, Wincker P, Le Parco Y. Chaetognath transcriptome reveals ancestral and unique features among bilaterians. Genome Biol 2008; 9:R94. [PMID: 18533022 PMCID: PMC2481426 DOI: 10.1186/gb-2008-9-6-r94] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2007] [Revised: 03/03/2008] [Accepted: 06/04/2008] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND The chaetognaths (arrow worms) have puzzled zoologists for years because of their astonishing morphological and developmental characteristics. Despite their deuterostome-like development, phylogenomic studies recently positioned the chaetognath phylum in protostomes, most likely in an early branching. This key phylogenetic position and the peculiar characteristics of chaetognaths prompted further investigation of their genomic features. RESULTS Transcriptomic and genomic data were collected from the chaetognath Spadella cephaloptera through the sequencing of expressed sequence tags and genomic bacterial artificial chromosome clones. Transcript comparisons at various taxonomic scales emphasized the conservation of a core gene set and phylogenomic analysis confirmed the basal position of chaetognaths among protostomes. A detailed survey of transcript diversity and individual genotyping revealed a past genome duplication event in the chaetognath lineage, which was, surprisingly, followed by a high retention rate of duplicated genes. Moreover, striking genetic heterogeneity was detected within the sampled population at the nuclear and mitochondrial levels but cannot be explained by cryptic speciation. Finally, we found evidence for trans-splicing maturation of transcripts through splice-leader addition in the chaetognath phylum and we further report that this processing is associated with operonic transcription. CONCLUSION These findings reveal both shared ancestral and unique derived characteristics of the chaetognath genome, which suggests that this genome is likely the product of a very original evolutionary history. These features promote chaetognaths as a pivotal model for comparative genomics, which could provide new clues for the investigation of the evolution of animal genomes.
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Affiliation(s)
- Ferdinand Marlétaz
- CNRS UMR 6540 DIMAR, Station Marine d'Endoume, Centre d'Océanologie de Marseille, Chemin de la Batterie des Lions, 13007, Marseille, France
- Université de la Méditerranée Aix-Marseille II, Bd Charles Livon, 13284, Marseille, France
| | - André Gilles
- Université de Provence Aix-Marseille I, place Victor-Hugo, 13331, Marseille, France
- CNRS UMR 6116 IMEP, Centre St Charles, place Victor-Hugo, 13331, Marseille, France
| | - Xavier Caubit
- Université de la Méditerranée Aix-Marseille II, Bd Charles Livon, 13284, Marseille, France
- CNRS UMR 6216, IBDML, Campus de Luminy, Route Léon Lachamp, 13288, Marseille, France
| | - Yvan Perez
- Université de Provence Aix-Marseille I, place Victor-Hugo, 13331, Marseille, France
- CNRS UMR 6116 IMEP, Centre St Charles, place Victor-Hugo, 13331, Marseille, France
| | - Carole Dossat
- Genoscope (CEA), rue Gaston Crémieux, BP5706, 91057 Evry, France
- CNRS, UMR 8030, rue Gaston Crémieux, BP5706, 91057 Evry, France
- Université d'Evry, Boulevard François Mitterrand, 91025, Evry, France
| | - Sylvie Samain
- Genoscope (CEA), rue Gaston Crémieux, BP5706, 91057 Evry, France
- CNRS, UMR 8030, rue Gaston Crémieux, BP5706, 91057 Evry, France
- Université d'Evry, Boulevard François Mitterrand, 91025, Evry, France
| | - Gabor Gyapay
- Genoscope (CEA), rue Gaston Crémieux, BP5706, 91057 Evry, France
- CNRS, UMR 8030, rue Gaston Crémieux, BP5706, 91057 Evry, France
- Université d'Evry, Boulevard François Mitterrand, 91025, Evry, France
| | - Patrick Wincker
- Genoscope (CEA), rue Gaston Crémieux, BP5706, 91057 Evry, France
- CNRS, UMR 8030, rue Gaston Crémieux, BP5706, 91057 Evry, France
- Université d'Evry, Boulevard François Mitterrand, 91025, Evry, France
| | - Yannick Le Parco
- CNRS UMR 6540 DIMAR, Station Marine d'Endoume, Centre d'Océanologie de Marseille, Chemin de la Batterie des Lions, 13007, Marseille, France
- Université de la Méditerranée Aix-Marseille II, Bd Charles Livon, 13284, Marseille, France
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Abstract
The advent of numerical methods for analysing phylogenetic relationships, along with the study of morphology and molecular data, has driven our understanding of animal relationships for the past three decades. Within the protostome branch of the animal tree of life, these data have sufficed to establish its two main side branches, the moulting Ecdysozoa and the non-moulting Lophotrochozoa. In this review, I explore our current knowledge of protostome relationships and discuss progress and future perspectives and strategies to increase resolution within the main lophotrochozoan clades. Novel approaches to coding morphological characters are needed by scoring real observations on species selected as terminals. Still, methodological issues, for example, how to deal with inapplicable characters or the coding of absences, may require novel algorithmic developments. Taxon sampling is another key issue, as phyla should include enough species so as to represent their span of anatomical disparity. On the molecular side, phylogenomics is playing an increasingly important role in elucidating animal relationships, but genomic sampling is still fairly limited within the lophotrochozoan protostomes, for which only three phyla are represented in currently available phylogenies. Future work should therefore concentrate on generating novel morphological observations and on producing genomic data for the lophotrochozoan side of the animal tree of life.
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Affiliation(s)
- Gonzalo Giribet
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA.
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