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Purschke G, Helm C. Development and structure of the anterior nervous system and sense organs in the holopelagic annelid Tomopteris spp. (Phyllodocida, Errantia). ORG DIVERS EVOL 2023. [DOI: 10.1007/s13127-023-00603-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
AbstractTomopteridae are transparent, predatory Annelida inhabiting pelagic ocean zones. Despite being well-known for their fast metachronal swimming and species-specific bioluminescence, our knowledge of morphological adaptations in these fascinating holopelagic worms remains extremely limited. In particular, the evolutionary scenarios and adaptive changes related to the transition from putative benthic ancestors to recent free-swimming groups remain poorly investigated and understood. Therefore, we investigated different taxa and developmental stages within the holopelagic Tomopteridae. We used a comparative morphological approach, including a range of microscopic methods, in our investigations focused on the anterior nervous system and prominent sensory structures, such as nuchal organs and tentacular cirri, in early developmental and adult stages of four tomopterid species. Our data show that Tomopteridae undergo heterochronic, lecithotrophic development with early visibility of adult-like features, which is consistent with earlier investigations. Furthermore, our ultrastructural examinations of the tomopterid nuchal organ highlight the conservativism in the fine structure and development of this prominent polychaete chemosensory organ. Nevertheless, our data indicate ultrastructural differences, such as an extraordinary number of supporting cell types and a bipartite olfactory chamber, potentially related to their pelagic lifestyle. In contrast to previous assumptions, it is shown that the supporting structures in the cirrus-like appendages of the first chaetiger contain prominent intracellular skeletal elements rather than annelid chaetae. These findings highlight the need for further investigations to understand Annelida’s immense morphological diversity of organ systems. Furthermore, our data demonstrate the necessity of functional analyses to understand Annelida’s adaptive radiation of sensory and neuronal structures.
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Murdock DJE. The ‘biomineralization toolkit’ and the origin of animal skeletons. Biol Rev Camb Philos Soc 2020; 95:1372-1392. [DOI: 10.1111/brv.12614] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 04/28/2020] [Accepted: 04/30/2020] [Indexed: 12/29/2022]
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Strieker SA, Cavey MJ. Calcareous Concretions and Non-Calcified Hooks in the Body Wall of Nemertean Worms. ACTA ZOOL-STOCKHOLM 1988. [DOI: 10.1111/j.1463-6395.1988.tb00899.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Amorphous calcium phosphate in the stylets produced by a marine worm (Nemertea). ACTA ACUST UNITED AC 1985. [DOI: 10.1007/bf01964805] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Stricker SA. The ultrastructure and formation of the calcareous ossicles in the body wall of the sea cucumber Leptosynapta clarki (Echinodermata, Holothuroida). ZOOMORPHOLOGY 1985. [DOI: 10.1007/bf00311965] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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