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Temereva EN, Isaeva MA, Kosevich IA. Unusual lophophore innervation in ctenostome Flustrellidra hispida (Bryozoa). J Exp Zool B Mol Dev Evol 2023; 340:245-258. [PMID: 35662417 DOI: 10.1002/jez.b.23164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 04/13/2022] [Accepted: 05/24/2022] [Indexed: 06/15/2023]
Abstract
Since ctenostomes are traditionally regarded as an ancestral clade to some other bryozoan groups, the study of additional species may help to clarify questions on bryozoan evolution and phylogeny. One of these questions is the bryozoan lophophore evolution: whether it occurred through simplification or complication. The morphology and innervation of the ctenostome Flustrellidra hispida (Fabricius, 1780) lophophore have been studied with electron microscopy and immunocytochemistry with confocal laser scanning microscopy. Lophophore nervous system of F. hispida consists of several main nerve elements: cerebral ganglion, circumoral nerve ring, and the outer nerve ring. Serotonin-like immunoreactive perikarya, which connect with the circumoral nerve ring, bear the cilium that directs to the abfrontal side of the lophophore and extends between tentacle bases. The circumoral nerve ring gives rise to the intertentacular and frontal tentacle nerves. The outer nerve ring gives rise to the abfrontal neurites, which connect to the outer groups of perikarya and contribute to the formation of the abfrontal tentacle nerve. The outer nerve ring has been described before in other bryozoans, but it never contributes to the innervation of tentacles. The presence of the outer nerve ring participating in the innervation of tentacles makes the F. hispida lophophore nervous system particularly similar to the lophophore nervous system of phoronids. This similarity allows to suggest that organization of the F. hispida lophophore nervous system may reflect the ancestral state for all bryozoans. The possible scenario of evolutionary transformation of the lophophore nervous system within bryozoans is suggested.
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Affiliation(s)
- Elena N Temereva
- Department of Invertebrate Zoology, Biological Faculty, Lomonosov Moscow State University, Moscow, Russia
| | - Maria A Isaeva
- Department of Invertebrate Zoology, Biological Faculty, Lomonosov Moscow State University, Moscow, Russia
| | - Igor A Kosevich
- Department of Invertebrate Zoology, Biological Faculty, Lomonosov Moscow State University, Moscow, Russia
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McGuinness M, Brownlow H, McAllen R, Harman L, Haberlin D, Doyle TK. Abundance and seasonality of phoronid larvae in coastal temperate waters: More abundant than previously thought? Aquat Ecol 2022; 56:1315-1321. [PMID: 36330038 PMCID: PMC9618493 DOI: 10.1007/s10452-022-09982-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 08/17/2022] [Indexed: 06/16/2023]
Abstract
UNLABELLED In zooplankton surveys, many smaller taxa or species considered less important are often overlooked. One such example is the actinotrocha larvae of phoronid worms that are rarely quantified in zooplankton samples yet may play important roles in marine food webs. To gain a better understanding of phoronid ecology in coastal waters, we retrospectively analysed 145 plankton samples collected from two coastal sites in Ireland (Lough Hyne and Bantry Bay). Samples were collected using plankton nets from depths of 20 and 40 m. Phoronids were present in 37.7% and 38.2% of samples, with mean abundances of 0.3 ± 0.5 ind. m-3 and 1.2 ± 2.8 ind. m-3, respectively, and were identified as Phoronis muelleri and Phoronis hippocrepia. Phoronids were present consistently each year from April to October at Lough Hyne and from February to October at Bantry Bay. Comparisons with other taxa in Lough Hyne show that abundances are similar to those of fish larvae (1.1 ± 1.8 ind. m-3) and echinoderm larvae (2.3 ± 4.4 ind. m-3). Examination of these samples from Irish waters suggests that phoronids are more abundant in temperate waters than previously reported. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s10452-022-09982-6.
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Affiliation(s)
- Maria McGuinness
- School of Biological, Earth and Environmental Sciences, University College Cork, Distillery Fields, North Mall, Cork, Ireland
- MaREI, The SFI Research Centre for Energy, Climate and Marine, Beaufort Building, Environmental Research Centre, University College Cork, Ringaskiddy, Cork Ireland
| | - Hannah Brownlow
- School of Biological, Earth and Environmental Sciences, University College Cork, Distillery Fields, North Mall, Cork, Ireland
| | - Rob McAllen
- School of Biological, Earth and Environmental Sciences, University College Cork, Distillery Fields, North Mall, Cork, Ireland
| | - Luke Harman
- School of Biological, Earth and Environmental Sciences, University College Cork, Distillery Fields, North Mall, Cork, Ireland
| | - Damien Haberlin
- School of Biological, Earth and Environmental Sciences, University College Cork, Distillery Fields, North Mall, Cork, Ireland
- MaREI, The SFI Research Centre for Energy, Climate and Marine, Beaufort Building, Environmental Research Centre, University College Cork, Ringaskiddy, Cork Ireland
| | - Thomas K. Doyle
- School of Biological, Earth and Environmental Sciences, University College Cork, Distillery Fields, North Mall, Cork, Ireland
- MaREI, The SFI Research Centre for Energy, Climate and Marine, Beaufort Building, Environmental Research Centre, University College Cork, Ringaskiddy, Cork Ireland
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Temereva EN. Oogenesis in the viviparous phoronid, Phoronis embryolabi. J Morphol 2017; 279:199-215. [PMID: 29076541 DOI: 10.1002/jmor.20765] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2017] [Revised: 10/06/2017] [Accepted: 10/08/2017] [Indexed: 11/06/2022]
Abstract
The study of gametogenesis is useful for phylogenetic analysis and can also provide insight into the physiology and biology of species. This report describes oogenesis in the Phoronis embryolabi, a newly described species, which has an unusual type of development, that is, a viviparity of larvae. Phoronid oogonia are described here for the first time. Yolk formation is autoheterosynthetic. Heterosynthesis occurs in the peripheral cytoplasm via fusion of endocytosic vesicles. Simultaneously, the yolk is formed autosynthetically by rough endoplasmic reticulum in the central cytoplasm. Each developing oocyte is surrounded by the follicle of vasoperitoneal cells, whose cytoplasm is filled with glycogen particles and various inclusions. Cytoplasmic bridges connect developing oocytes and vasoperitoneal cells. These bridges and the presence of the numerous glycogen particles in the vasoperitoneal cells suggest that nutrients are transported from the follicle to oocytes. Phoronis embryolabi is just the second phoronid species in which the ultrastructure of oogenesis has been studied, and I discuss the data obtained comparing them with those in Phoronopsis harmeri. Finally, I discuss the distribution of reproductive patterns across both, molecular and morphological phylogenetic trees in Phoronida proving that parental care has evolved independently several times in this phylum.
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Affiliation(s)
- Elena N Temereva
- Biological Faculty, Department of Invertebrate Zoology, Moscow State University, Russia, Moscow
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