Ultrastructure of the lophophoral coelomic lining in the brachiopod Hemithiris psittacea: functional and evolutionary significance
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The ultrastructure of the lophophoral coelomic lining in the articulate brachiopod Hemithiris psittacea was studied using electron microscopy and confocal laser scanning microscopy. The coelomic system of the lophophore consists of large and small canals; both extend along each brachium. A small coelomic canal gives rise to a blind coelomic canal into each tentacle. The lophophoral coelothelium consists of two types of cells, epithelio-muscle and peritoneal cells, and exhibits different types of organization that is known in the Bilateria: from an epithelium consisting only of epithelio-muscle cells to a pseudostratified myoepithelium. The lophophoral coelothelium forms the musculature and blood vessel wall of the brachia and tentacles. The lophophoral blood vessel runs in the extracellular matrix of the septum that separates the large and small canals. In the lophophoral vessel, the upper wall consists of epithelio-muscle cells, whereas the lower wall is formed by peritoneal cells. The lophophoral vessel gives rise to blind branches into each tentacle. The lophophoral wall is highly muscular and contains both longitudinal and transverse muscles. Because the spirolophe lophophore of H. psittacea is supported only by short crura, the coelomic system of the lophophore is assumed to stabilize the lophophore by regulating the hydrostatic pressure of the coelomic fluid.
KeywordsBrachiopod anatomy Lophophore Ultrastructure Coelomic epithelium Muscular system Blood system Hemithiris psittacea
This study was supported by the Russian Foundation for Basic Research, Project no. 17-04-00586 and the Russian Foundation for Basic Research, Project no. 15-29-02601. The research was performed at the User Facilities Center of M.V. Lomonosov Moscow State University with financial support from the Ministry of Education and Science of the Russian Federation.
Compliance with ethical standards
Conflict of interest
This research is not in consideration or published elsewhere. All co-authors approve the submission of this manuscript. The authors declare that they have no conflict of interest.
The use of brachiopods in the laboratory does not raise any ethical issues, and therefore approval from regional and local research ethics committees was not required. The field sampling did not involve endangered or protected species. In accordance with local guidelines, permission for collection of material was not required.
- Bartolomeus T (1994) On the ultrastructure of the coelomic lining in the Annelida, Sipuncula and Echiura. Microfauna Marina 9:171–220Google Scholar
- Beecher CE (1897) Morphology of the Brachia. Bull US Geol Surv 87:105–112Google Scholar
- Cavey MJ, Märkel K (1994) Echinoidea. In: Harrison FW, Chia FS (eds) Microscopic anatomy of invertebrates: Echinodermata V14. Wiley-Liss, New York, pp 345–400Google Scholar
- Kuzmina TV, Malakhov VV, Temereva EN (2006) Anatomy of the coelomic system of articulate brachiopod Hemithiris psittacea (Brachiopoda, Articulata). Zool Zhurn 85:1118–1128 (Russian) Google Scholar
- Peck LS, Rhodes MC, Curry GB, Ansell AD (1997) Physiology. In: Kaesler RL (ed) Treatise on invertebrate paleontology, Part H, Brachiopoda V 1 Introduction. The Geological Society of America Inc and the University of Kansas Boulder Colorado and Lawrence, Kansas, pp 213–242Google Scholar
- Pross A (1980) Untersuchungen zur Gliederung von Lingula anatina (Brachiopoda). Archimerie bei Brachiopoden. Zool Jahrb Abt Anat Ontog Tiere 103:250–263Google Scholar
- Rickwood AE (1968) A contribution to the life history and biology of the brachiopod Pumilus antiquatus Atkins. Trans R Soc N Z (Zool) 10:163–182Google Scholar
- Rudwick MJS (1970) Living and fossil brachiopods. Hutchinson and Co. Ltd., London, p 199Google Scholar
- Storch V, Welsch U (1976) Elektronenmikroskopische und enzymhistochemische Untersuchungen über Lophophor und Tentakeln von Lingula unguis L. (Brachiopoda). Zool Jahrb Abt Anat Ontog Tiere 96:225–237Google Scholar
- Temereva EN, Kuzmina TV (2017) The first data on the innervation of the lophophore in the rhynchonelliform brachiopod Hemithiris psittacea: what is the ground pattern of the lophophore in lophophorates? BMC Evol Biol 17(1):172. https://doi.org/10.1186/s12862-017-1029-5 CrossRefPubMedPubMedCentralGoogle Scholar
- Williams A, James MA, Emig CC, Mackay S, Rhodes MC (1997) Brachiopod anatomy. In: Kaesler RL (ed) Treatise on invertebrate paleontology, Part H, Brachiopoda V 1 Introduction. The Geological Society of America Inc and the University of Kansas Boulder Colorado and Lawrence, Kansas, pp 7–189Google Scholar