Who’s who in Magelona: phylogenetic hypotheses under Magelonidae Cunningham & Ramage, 1888 (Annelida: Polychaeta)
Known as shovel head worms, members of Magelonidae comprise a group of polychaetes readily recognised by the uniquely shaped, dorso-ventrally flattened prostomium and paired ventro-laterally inserted papillated palps. The present study is the first published account of inferences of phylogenetic hyp...
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PeerJ Inc.
2021-09-01
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| author | Kate Mortimer Kirk Fitzhugh Ana Claudia dos Brasil Paulo Lana |
| author_facet | Kate Mortimer Kirk Fitzhugh Ana Claudia dos Brasil Paulo Lana |
| author_sort | Kate Mortimer |
| collection | DOAJ |
| description | Known as shovel head worms, members of Magelonidae comprise a group of polychaetes readily recognised by the uniquely shaped, dorso-ventrally flattened prostomium and paired ventro-laterally inserted papillated palps. The present study is the first published account of inferences of phylogenetic hypotheses within Magelonidae. Members of 72 species of Magelona and two species of Octomagelona were included, with outgroups including members of one species of Chaetopteridae and four of Spionidae. The phylogenetic inferences were performed to causally account for 176 characters distributed among 79 subjects, and produced 2,417,600 cladograms, each with 404 steps. A formal definition of Magelonidae is provided, represented by a composite phylogenetic hypothesis explaining seven synapomorphies: shovel-shaped prostomium, prostomial ridges, absence of nuchal organs, ventral insertion of palps and their papillation, presence of a burrowing organ, and unique body regionation. Octomagelona is synonymised with Magelona due to the latter being paraphyletic relative to the former. The consequence is that Magelonidae is monotypic, such that Magelona cannot be formally defined as associated with any phylogenetic hypotheses. As such, the latter name is an empirically empty placeholder, but because of the binomial name requirement mandated by the International Code of Zoological Nomenclature, the definition is identical to that of Magelonidae. Several key features for future descriptions are suggested: prostomial dimensions, presence/absence of prostomial horns, morphology of anterior lamellae, presence/absence of specialised chaetae, and lateral abdominal pouches. Additionally, great care must be taken to fully describe and illustrate all thoracic chaetigers in descriptions. |
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| language | English |
| last_indexed | 2024-03-09T07:07:24Z |
| publishDate | 2021-09-01 |
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| spelling | doaj.art-83b1c53a73814226b4d9b4892bb7e9862023-12-03T09:29:42ZengPeerJ Inc.PeerJ2167-83592021-09-019e1199310.7717/peerj.11993Who’s who in Magelona: phylogenetic hypotheses under Magelonidae Cunningham & Ramage, 1888 (Annelida: Polychaeta)Kate Mortimer0Kirk Fitzhugh1Ana Claudia dos Brasil2Paulo Lana3Natural Sciences, Amgueddfa Cymru–National Museum Wales, Cardiff, Wales, United KingdomNatural History Museum of Los Angeles County, Los Angeles, CA, United States of AmericaDepartamento de Biologia Animal, Instituto de Ciências Biológicas e da Saúde, Universidade Federal Rural do Rio de Janeiro, Seropédica, Rio de Janeiro, BrazilCentro de Estudos do Mar, Universidade Federal do Paraná, Pontal do Sul, Paraná, BrazilKnown as shovel head worms, members of Magelonidae comprise a group of polychaetes readily recognised by the uniquely shaped, dorso-ventrally flattened prostomium and paired ventro-laterally inserted papillated palps. The present study is the first published account of inferences of phylogenetic hypotheses within Magelonidae. Members of 72 species of Magelona and two species of Octomagelona were included, with outgroups including members of one species of Chaetopteridae and four of Spionidae. The phylogenetic inferences were performed to causally account for 176 characters distributed among 79 subjects, and produced 2,417,600 cladograms, each with 404 steps. A formal definition of Magelonidae is provided, represented by a composite phylogenetic hypothesis explaining seven synapomorphies: shovel-shaped prostomium, prostomial ridges, absence of nuchal organs, ventral insertion of palps and their papillation, presence of a burrowing organ, and unique body regionation. Octomagelona is synonymised with Magelona due to the latter being paraphyletic relative to the former. The consequence is that Magelonidae is monotypic, such that Magelona cannot be formally defined as associated with any phylogenetic hypotheses. As such, the latter name is an empirically empty placeholder, but because of the binomial name requirement mandated by the International Code of Zoological Nomenclature, the definition is identical to that of Magelonidae. Several key features for future descriptions are suggested: prostomial dimensions, presence/absence of prostomial horns, morphology of anterior lamellae, presence/absence of specialised chaetae, and lateral abdominal pouches. Additionally, great care must be taken to fully describe and illustrate all thoracic chaetigers in descriptions.https://peerj.com/articles/11993.pdfAbductive reasoningCladogramsPhylogenetic hypothesisSystematicsZoological nomenclatureEvolutionary hypotheses |
| spellingShingle | Kate Mortimer Kirk Fitzhugh Ana Claudia dos Brasil Paulo Lana Who’s who in Magelona: phylogenetic hypotheses under Magelonidae Cunningham & Ramage, 1888 (Annelida: Polychaeta) PeerJ Abductive reasoning Cladograms Phylogenetic hypothesis Systematics Zoological nomenclature Evolutionary hypotheses |
| title | Who’s who in Magelona: phylogenetic hypotheses under Magelonidae Cunningham & Ramage, 1888 (Annelida: Polychaeta) |
| title_full | Who’s who in Magelona: phylogenetic hypotheses under Magelonidae Cunningham & Ramage, 1888 (Annelida: Polychaeta) |
| title_fullStr | Who’s who in Magelona: phylogenetic hypotheses under Magelonidae Cunningham & Ramage, 1888 (Annelida: Polychaeta) |
| title_full_unstemmed | Who’s who in Magelona: phylogenetic hypotheses under Magelonidae Cunningham & Ramage, 1888 (Annelida: Polychaeta) |
| title_short | Who’s who in Magelona: phylogenetic hypotheses under Magelonidae Cunningham & Ramage, 1888 (Annelida: Polychaeta) |
| title_sort | who s who in magelona phylogenetic hypotheses under magelonidae cunningham ramage 1888 annelida polychaeta |
| topic | Abductive reasoning Cladograms Phylogenetic hypothesis Systematics Zoological nomenclature Evolutionary hypotheses |
| url | https://peerj.com/articles/11993.pdf |
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