Cargando…

Within-family plasticity of nervous system architecture in Syllidae (Annelida, Errantia)

BACKGROUND: The ground pattern underlying the nervous system of the last common ancestor in annelids was long thought to be settled, consisting of a dorsal brain, circumoesophageal connectives and a subepithelial, ladder-like ventral nerve cord with segmental ganglia connected by paired connectives....

Descripción completa

Detalles Bibliográficos
Autores principales: Schmidbaur, Hannah, Schwaha, Thomas, Franzkoch, Rico, Purschke, Günter, Steiner, Gerhard
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7310387/
https://www.ncbi.nlm.nih.gov/pubmed/32582362
http://dx.doi.org/10.1186/s12983-020-00359-9
_version_ 1783549359013494784
author Schmidbaur, Hannah
Schwaha, Thomas
Franzkoch, Rico
Purschke, Günter
Steiner, Gerhard
author_facet Schmidbaur, Hannah
Schwaha, Thomas
Franzkoch, Rico
Purschke, Günter
Steiner, Gerhard
author_sort Schmidbaur, Hannah
collection PubMed
description BACKGROUND: The ground pattern underlying the nervous system of the last common ancestor in annelids was long thought to be settled, consisting of a dorsal brain, circumoesophageal connectives and a subepithelial, ladder-like ventral nerve cord with segmental ganglia connected by paired connectives. With the advent of immunocytochemical stainings and confocal laser scanning microscopy, it becomes evident that its architecture is extremely diverse, which makes the reconstruction of a ground pattern in annelida challenging. Whereas the nervous systems of many different families has already been described, only very few studies looked at the diversity of nervous systems within such clades to give a closer estimate on how plastic the annelid nervous system really is. So far, little is known on syllid nervous system architecture, one of the largest and most diverse groups of marine annelids. RESULTS: The position of the brain, the circumoesophageal connectives, the stomatogastric nervous system, the longitudinal nerves that traverse each segment and the innervation of appendages are relatively uniform within the clade. Both the number of connectives within the ventral nerve cord and the number of segmental nerves, which in earlier studies were used to infer phylogenetic relationships and to reconstruct an annelid ground pattern, are highly diverse and differ between genera or even within a given genus. Differences in the distribution of somata of the brain, the nuchal innervation and its associated cell bodies were found between Syllinae and Exogoninae and may be subfamily-specific. CONCLUSIONS: The nervous system morphology of syllids very likely depends on the taxon-specific ecological requirements. Thus, it is not surprising that in a clade, which occupies such diverse niches as the Annelida, we find similar patterns in phylogenetically widely separated species in similar niches and a high degree of modularity within a family. Only standardized protocols and staining methods can lead to comparable results, but so far different approaches have been taken to describe annelid nervous systems, making homologization of certain structures difficult. This study provides the first thorough description of the nervous system in the family Syllidae, allowing more detailed comparisons between annelid families in the future.
format Online
Article
Text
id pubmed-7310387
institution National Center for Biotechnology Information
language English
publishDate 2020
publisher BioMed Central
record_format MEDLINE/PubMed
spelling pubmed-73103872020-06-23 Within-family plasticity of nervous system architecture in Syllidae (Annelida, Errantia) Schmidbaur, Hannah Schwaha, Thomas Franzkoch, Rico Purschke, Günter Steiner, Gerhard Front Zool Research BACKGROUND: The ground pattern underlying the nervous system of the last common ancestor in annelids was long thought to be settled, consisting of a dorsal brain, circumoesophageal connectives and a subepithelial, ladder-like ventral nerve cord with segmental ganglia connected by paired connectives. With the advent of immunocytochemical stainings and confocal laser scanning microscopy, it becomes evident that its architecture is extremely diverse, which makes the reconstruction of a ground pattern in annelida challenging. Whereas the nervous systems of many different families has already been described, only very few studies looked at the diversity of nervous systems within such clades to give a closer estimate on how plastic the annelid nervous system really is. So far, little is known on syllid nervous system architecture, one of the largest and most diverse groups of marine annelids. RESULTS: The position of the brain, the circumoesophageal connectives, the stomatogastric nervous system, the longitudinal nerves that traverse each segment and the innervation of appendages are relatively uniform within the clade. Both the number of connectives within the ventral nerve cord and the number of segmental nerves, which in earlier studies were used to infer phylogenetic relationships and to reconstruct an annelid ground pattern, are highly diverse and differ between genera or even within a given genus. Differences in the distribution of somata of the brain, the nuchal innervation and its associated cell bodies were found between Syllinae and Exogoninae and may be subfamily-specific. CONCLUSIONS: The nervous system morphology of syllids very likely depends on the taxon-specific ecological requirements. Thus, it is not surprising that in a clade, which occupies such diverse niches as the Annelida, we find similar patterns in phylogenetically widely separated species in similar niches and a high degree of modularity within a family. Only standardized protocols and staining methods can lead to comparable results, but so far different approaches have been taken to describe annelid nervous systems, making homologization of certain structures difficult. This study provides the first thorough description of the nervous system in the family Syllidae, allowing more detailed comparisons between annelid families in the future. BioMed Central 2020-06-23 /pmc/articles/PMC7310387/ /pubmed/32582362 http://dx.doi.org/10.1186/s12983-020-00359-9 Text en © The Author(s) 2020 Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.
spellingShingle Research
Schmidbaur, Hannah
Schwaha, Thomas
Franzkoch, Rico
Purschke, Günter
Steiner, Gerhard
Within-family plasticity of nervous system architecture in Syllidae (Annelida, Errantia)
title Within-family plasticity of nervous system architecture in Syllidae (Annelida, Errantia)
title_full Within-family plasticity of nervous system architecture in Syllidae (Annelida, Errantia)
title_fullStr Within-family plasticity of nervous system architecture in Syllidae (Annelida, Errantia)
title_full_unstemmed Within-family plasticity of nervous system architecture in Syllidae (Annelida, Errantia)
title_short Within-family plasticity of nervous system architecture in Syllidae (Annelida, Errantia)
title_sort within-family plasticity of nervous system architecture in syllidae (annelida, errantia)
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7310387/
https://www.ncbi.nlm.nih.gov/pubmed/32582362
http://dx.doi.org/10.1186/s12983-020-00359-9
work_keys_str_mv AT schmidbaurhannah withinfamilyplasticityofnervoussystemarchitectureinsyllidaeannelidaerrantia
AT schwahathomas withinfamilyplasticityofnervoussystemarchitectureinsyllidaeannelidaerrantia
AT franzkochrico withinfamilyplasticityofnervoussystemarchitectureinsyllidaeannelidaerrantia
AT purschkegunter withinfamilyplasticityofnervoussystemarchitectureinsyllidaeannelidaerrantia
AT steinergerhard withinfamilyplasticityofnervoussystemarchitectureinsyllidaeannelidaerrantia