Morphology of Stephanella hina (Bryozoa, Phylactolaemata): common phylactolaemate and unexpected, unique characters
Abstract Stephanella hina is a little studied freshwater bryozoan belonging to Phylactolaemata. It is currently the only representative of the family Stephanellidae, which in most reconstructions is early branching, sometimes even sister group to the remaining phylactolaemate families. The morpholog...
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| Format: | Article |
| Language: | English |
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BMC
2020-11-01
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| Series: | Zoological Letters |
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| Online Access: | http://link.springer.com/article/10.1186/s40851-020-00165-5 |
| _version_ | 1819172377516310528 |
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| author | Thomas F. Schwaha Masato Hirose |
| author_facet | Thomas F. Schwaha Masato Hirose |
| author_sort | Thomas F. Schwaha |
| collection | DOAJ |
| description | Abstract Stephanella hina is a little studied freshwater bryozoan belonging to Phylactolaemata. It is currently the only representative of the family Stephanellidae, which in most reconstructions is early branching, sometimes even sister group to the remaining phylactolaemate families. The morphological and histological details of this species are entirely unknown. Consequently, the main aim of this study was to conduct a detailed morphological analysis of S. hina using histological serial sections, 3D reconstruction, immunocytochemical staining and confocal laser scanning microscopy techniques. The general morphology is reminiscent of other phylactolaemates; however, there are several, probably apomorphic, details characteristic of S. hina. The most evident difference lies in the lophophoral base, where the ganglionic horns/extensions do not follow the traverse of the lophophoral arms but bend medially inwards towards the mouth opening. Likewise, the paired forked canal does not fuse medially in the lophophoral concavity as found in all other phylactolaemates. Additional smaller differences are also found in the neuro-muscular system: the rooting of the tentacle muscle is less complex than in other phylactolaemates, the funiculus lacks longitudinal muscles, the caecum has smooth muscle fibres, latero-abfrontal tentacle nerves are not detected and the medio-frontal nerves mostly emerge directly from the circum-oral nerve ring. In the apertural area, several neurite bundles extend into the vestibular wall and probably innervate neurosecretory cells surrounding the orifice. These morphological characteristics support the distinct placement of this species in a separate family. Whether these characteristics are apomorphic or possibly shared with other phylactolaemates will require the study of the early branching Lophopodidae, which remains one of the least studied taxa to date. |
| first_indexed | 2024-12-22T20:06:13Z |
| format | Article |
| id | doaj.art-e6bc80e3b61f4774891235404fd11138 |
| institution | Directory Open Access Journal |
| issn | 2056-306X |
| language | English |
| last_indexed | 2024-12-22T20:06:13Z |
| publishDate | 2020-11-01 |
| publisher | BMC |
| record_format | Article |
| series | Zoological Letters |
| spelling | doaj.art-e6bc80e3b61f4774891235404fd111382022-12-21T18:14:07ZengBMCZoological Letters2056-306X2020-11-016112310.1186/s40851-020-00165-5Morphology of Stephanella hina (Bryozoa, Phylactolaemata): common phylactolaemate and unexpected, unique charactersThomas F. Schwaha0Masato Hirose1Department of Evolutionary Biology, University of ViennaKitasato University, School of Marine BiosciencesAbstract Stephanella hina is a little studied freshwater bryozoan belonging to Phylactolaemata. It is currently the only representative of the family Stephanellidae, which in most reconstructions is early branching, sometimes even sister group to the remaining phylactolaemate families. The morphological and histological details of this species are entirely unknown. Consequently, the main aim of this study was to conduct a detailed morphological analysis of S. hina using histological serial sections, 3D reconstruction, immunocytochemical staining and confocal laser scanning microscopy techniques. The general morphology is reminiscent of other phylactolaemates; however, there are several, probably apomorphic, details characteristic of S. hina. The most evident difference lies in the lophophoral base, where the ganglionic horns/extensions do not follow the traverse of the lophophoral arms but bend medially inwards towards the mouth opening. Likewise, the paired forked canal does not fuse medially in the lophophoral concavity as found in all other phylactolaemates. Additional smaller differences are also found in the neuro-muscular system: the rooting of the tentacle muscle is less complex than in other phylactolaemates, the funiculus lacks longitudinal muscles, the caecum has smooth muscle fibres, latero-abfrontal tentacle nerves are not detected and the medio-frontal nerves mostly emerge directly from the circum-oral nerve ring. In the apertural area, several neurite bundles extend into the vestibular wall and probably innervate neurosecretory cells surrounding the orifice. These morphological characteristics support the distinct placement of this species in a separate family. Whether these characteristics are apomorphic or possibly shared with other phylactolaemates will require the study of the early branching Lophopodidae, which remains one of the least studied taxa to date.http://link.springer.com/article/10.1186/s40851-020-00165-5StephanellidaeBryozoan evolutionEpistomeMyoanatomy |
| spellingShingle | Thomas F. Schwaha Masato Hirose Morphology of Stephanella hina (Bryozoa, Phylactolaemata): common phylactolaemate and unexpected, unique characters Zoological Letters Stephanellidae Bryozoan evolution Epistome Myoanatomy |
| title | Morphology of Stephanella hina (Bryozoa, Phylactolaemata): common phylactolaemate and unexpected, unique characters |
| title_full | Morphology of Stephanella hina (Bryozoa, Phylactolaemata): common phylactolaemate and unexpected, unique characters |
| title_fullStr | Morphology of Stephanella hina (Bryozoa, Phylactolaemata): common phylactolaemate and unexpected, unique characters |
| title_full_unstemmed | Morphology of Stephanella hina (Bryozoa, Phylactolaemata): common phylactolaemate and unexpected, unique characters |
| title_short | Morphology of Stephanella hina (Bryozoa, Phylactolaemata): common phylactolaemate and unexpected, unique characters |
| title_sort | morphology of stephanella hina bryozoa phylactolaemata common phylactolaemate and unexpected unique characters |
| topic | Stephanellidae Bryozoan evolution Epistome Myoanatomy |
| url | http://link.springer.com/article/10.1186/s40851-020-00165-5 |
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