Octomagelona Aguirrezabalaga, Ceberio and Fiege 2001
Genus Octomagelona Aguirrezabalaga, Ceberio and Fiege,2001 Type species: Octomagelona bizkaiensis Aguirrezabalaga et al., 2001. Gender: female. Diagnosis: [Aguirrezabalaga et al. (2001) and Mortimer (2019), emended.] Body divided into thoracic region comprising achaetous first segment and eight chae...
| Main Authors: | , , , |
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| Format: | Other/Unknown Material |
| Language: | unknown |
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Zenodo
2023
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| Online Access: | https://doi.org/10.5281/zenodo.10497556 http://treatment.plazi.org/id/743EE917FFE5FF98FCD3273C1CB2F982 |
| Summary: | Genus Octomagelona Aguirrezabalaga, Ceberio and Fiege,2001 Type species: Octomagelona bizkaiensis Aguirrezabalaga et al., 2001. Gender: female. Diagnosis: [Aguirrezabalaga et al. (2001) and Mortimer (2019), emended.] Body divided into thoracic region comprising achaetous first segment and eight chaetigers, and abdominal region with unknown number of segments. Prostomium large, flaưened, wider than long with small frontal horns. Parapodia biramous, with noto- and neuropodial lateral lamellae filiform if present, superior dorsal lobes [DML of Jones (1963)] absent. Branchiae absent. Thoracic chaetae long, limbate capillaries, abdominal chaetae tridentate hooded hooks. Posterior part and pygidium unknown. Lateral pouches not observed. Remarks: Members of the genus Octomagelona are characterized by the presence of eight instead of nine thoracic chaetigers in contrast to all species of Magelona Müller, 1858, the only other genus in Magelonidae. Instead of being a kind of intermediate segment sometimes equipped with special chaetae, chaetiger 9 represents the first abdominal segment in Octomagelona . The generic diagnoses provided by Aguirrezabalaga et al. (2001) and Mortimer (2019) has been slightly emended due to abdominal hooded hooks being tridentate in both species belonging to the genus Octomagelona , i.e. O. bizkaiensis and O. borowskii sp. nov. Mortimer et al . (2021), considered Octomagelona a junior synonym of Magelona following their phylogenetic analysis based on morphological characters. We agree with these authors that the ‘magelonid-like body regionation’ is an important synapomorphy for Magelonidae (Mortimer et al . 2021: 67 and abstract) but we regard the two different character states for the thoracic body region, i.e. the presence of eight versus nine thoracic chaetigers, as an easy to observe and taxonomically sufficient character to distinguish between the two genera. Therefore, we prefer to maintain Octomagelona as a valid genus for the time being and hope that studies of genetic markers will add ... |
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