Kirk Fitzhugh’s research while affiliated with Natural History Museum of Los Angeles County and other places

The first published phylogenetic hypotheses involving members of the polychaete taxon Magelonidae Cunningham & Ramage, 1888, were reported by Mortimer et al. (2021), wherein results showed that for the two genera in the family, Magelona F. Müller, 1858, was paraphyletic relative to Octomagelona Aguirrezabalaga, Ceberio & Fiege, 2001. The only option to formally name at least some of the resultant phylogenetic hypotheses was to place Octomagelona into synonymy with Magelona, leaving the definition of Magelonidae redundant with that of a monophyletic Magelona. Meißner et al. (2023) subsequently described specimens as members of new species, Octomagelona borowskii Fiege, Knebelsberger & Meißner, 2023, and O. sp. cf. O. borowskii, with the view that Octomagelona should be maintained as distinct from Magelona. We present reasons why reestablishing the paraphyly of Magelona is scientifically unwarranted.

This opinion paper examines the recent proposal for a new nomenclatural code for prokaryotes (SeqCode). It addresses four problematic issues: (1) epistemological—failure of the SeqCode to acknowledge taxa as explanatory hypotheses, (2) conceptual—designating as a name-bearer a coded section of the genome of an organism, (3) operational—changing nomenclatural procedure as a means of resolving systematic challenges, and (4) political (policy)—SeqCode developed independent in opposition to the International Committee on Systematics of Prokaryotes (ICSP). Each of these matters should be alarms to the scientific community as the SeqCode proposal embodies many potentially negative consequences that would dramatically hinder systematics (science) and nomenclature (a tool in science) in other groups of organisms, e.g., animals, plants, fungi, if analogous proposals were sought.

Abstract Maldanids are tube-building polychaetes, known as bamboo-worms; inhabit diverse marine regions throughout the world. The subfamily Euclymeninae was proposed to include forms with anal and cephalic plates, a funnel-shaped pygidium, and a terminal anus. Euclymene, the type genus of Euclymeninae, has about 18 valid species. Euclymene vidali sp. nov. is defined and members of the species described from Northeastern Brazil. Members of this species have 23 chaetigers, and one pre-pygidial achaetous segment; nuchal grooves extend through three quarters of the cephalic plate, and there is one acicular spine with a denticulate tip. Euclymene africana, and E. watsoni, are here recognized, respectively, as Isocirrus africana comb. nov., and I. watsoni comb. nov. Three monotypic genera are invalid: Macroclymenella, Eupraxillella, and Pseudoclyemene; their species should be recognized as Clymenella stewartensis com. nov., Praxillella antarctica com. nov., and Praxillela quadrilobata com. nov., respectively. An identification key and a comparative table for all species of Euclymene are provided. A comparative table for all genera of Euclymeninae is also furnished. The paraphyletic status of Euclymene and Euclymeninae is discussed. The taxon Maldanoplaca is not code compliant and should only be regarded as an informal name.

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.

Three competing 'methods' have been endorsed for inferring phylogenetic hypotheses: parsimony, likelihood, and Bayesianism. The latter two have been claimed superior because they take into account rates of sequence substitution. Can rates of substitution be justified on its own accord in inferences of explanatory hypotheses? Answering this question requires addressing four issues: (1) the aim of scientific inquiry, (2) the nature of why-questions, (3) explanatory hypotheses as answers to why-questions, and (4) acknowledging that neither parsimony, likelihood, nor Bayesianism are inferential actions leading to explanatory hypotheses. The aim of scientific inquiry is to acquire causal understanding of effects. Observation statements of organismal characters lead to implicit or explicit why-questions. Those questions, conveyed in data matrices, assume the truth of observation statements, which is contrary to subsequently invoking substitution rates within inferences to phylogenetic hypotheses. Inferences of explanatory hypotheses are abductive in form, such that some version of an evolutionary theory(ies) is/are included or implied. If rates of sequence evolution are to be considered, it must be done prior to, rather than within abduction, which requires renaming those putatively-shared nucleotides subject to substitution rates. There are, however, no epistemic grounds for renaming characters to accommodate rates, calling into question the legitimacy of causally accounting for sequence data.

In 1989, Donald Reish hosted the 3rd International Polychaete Conference (IPC3) in Long Beach, on the campus of California State University Long Beach. In 2015 he asked one of us (Bruno Pernet) if it might be possible to bring IPC13 back to Long Beach, thirty years later. Bruno assembled a planning committee consisting of himself and Christine Whitcraft (CSU Long Beach), Kirk Fitzhugh and Leslie Harris (Natural History Museum of Los Angeles County), and Larry Lovell (Dancing Coyote Environmental). The committee’s proposal was accepted at the International Polychaetology Association (IPA) general meeting in Wales in 2016, and the planning committee morphed into an organizational committee!

Scanning electron (SEM) and light microscope examinations of members of Levinsenia Mesnil, 1897, species from California yielded a new species, new characters, emended name and range extension for L. kirbyorum Lovell, 2002. Specimens of L. gracilis (Tauber, 1879) from Sweden, Iceland, and California were compared and could not be distinguished on the basis of morphology. Two other Californian species, L. multibranchiata (Hartman, 1957) and L. oculata (Hartman, 1957), were also examined. SEM revealed features previously undescribed for the genus. Additional prostomial ciliary bundles, dorsal transverse ciliary branchial connections, notopodial sensory pores, and neurochaetal fascicle configurations. Levinsenia barwicki n.sp. possessing a terminal sensory organ, 4-8 leaf-like ciliate branchiae, and recurved neurochaete with distal hood is described More SEM work is necessary to confirm if these features are present among other members of Levinsenia and other Paraonidae genera. The status of Levinsenia according to the phylogenetic analysis performed by Langeneck et al. (2019, Molecular Phylogenetics and Evolution, 136, 1-13) is discussed.

Members of the 12 known species of the family Telothelepodidae, plus individuals of three additional undescribed species, were examined to infer phylogenetic relationships within the family and evaluate the status of genera. The outgroups include members of three species of Polycirridae and three of Thelepodidae. Members of 21 species, including both in- and outgroups, were coded for 47 subjects (‘characters’) and 109 characters sensu stricto (subject-predicate relations or ‘states’). The results, based on 15 minimum-length trees, each 103 steps long, suggest that telothelepodids should be divided into four genera, according to the morphology of the lower lip, presence or absence of eyespots, and visibility of segment 1. By necessity two of these genera are monotypic and plesiomorphic to two monophyletic genera; the latter two genera with five and eight species, respectively. Telothelepus, Parathelepus and Rhinothelepus are redefined, and the new genus Mesopothelepus gen. nov. is erected, all to accommodate the phylogenetic hypotheses presented. The problem of properly defining monotypic supraspecific taxon names as representative of phylogenetic hypotheses is discussed in relation to the inherent limitations of Article 13.1.1 of the International Code of Zoological Nomenclature. http://zoobank.org/urn:lsid:zoobank.org:pub:8C05DBD2-8226-4738-BF4A-E623A97ACB75