A new species of the Spirobranchuskraussii complex, S.akitsushima (Annelida, Polychaeta, Serpulidae), from the rocky intertidal zone of Japan.

A new species of Spirobranchus (Annelida: Serpulidae) is described based on specimens collected at the coastal Shonan area of Sagami Bay and the adjacent areas of Honshu, Japan. Spirobranchusakitsushima sp. nov. forms large aggregations in the intertidal rocky zone of warm-temperate Japanese shores. This species was referred to as Pomatoleioskraussii (Baird, 1864) until the monotypic genus Pomatoleios was synonymized with Spirobranchus. This new species is formally described based on morphologically distinct Japanese specimens with supporting DNA sequence data. The calcareous opercular endplate of Spirobranchusakitsushima sp. nov. lacks a distinct talon, but some specimens have a slight rounded swelling on the endplate underside, while in other species of the S.kraussii complex a talon is present, usually extended, and with bulges. We examined sub-fossil tube aggregations of the new species and suggest that such aggregation stranded ashore is a good indicator of vertical land movements (uplift and subsidence) resulting from past events, such as earthquakes, in Honshu, Japan.

Spirobranchus bakau sp. nov. from Singapore: yet another species of S. kraussii-complex (Polychaeta: Serpulidae).

The intertidal serpulid polychaete Spirobranchus kraussii was originally described from South Africa and has since been reported in numerous sub (tropical) localities around the world. Recently, however, S. kraussii was uncovered as a complex of morphologically similar and geographically restricted species, raising the need to revise S. cf. kraussii populations. We formally describe S. cf. kraussii from Singapore mangroves as Spirobranchus bakau sp. nov. based on morphological and molecular data. Despite their morphological similarities, Maximum Likelihood and Bayesian Inference analyses of 18S and Cyt b DNA sequence data confirm that S. bakau sp. nov. is genetically distinct from S. kraussii and other known species in the complex. Both analyses recovered S. bakau sp. nov. as part of a strongly supported clade (96% bootstrap, 1 posterior probability), comprising S. sinuspersicus, S. kraussii and S. cf. kraussii from Australia and Hawaii. Additionally, paratypes of S. kraussii var. manilensis, described from Manila Bay in the Philippines, were examined and elevated to the full species S. manilensis. Finally, we tested the hypothesis that fertilisation and embryonic development of S. bakau sp. nov. can occur under the wide range of salinities (19.630.9 psu) and temperatures (2531C) reported in the Johor Strait. Fertilisation success of ≥70% was achieved across a temperature range of 2532C and a salinity range of 2032 psu. Embryonic development, however, had a narrower salinity tolerance range of 2732 psu. Clarifying the taxonomic status of S. cf. kraussii populations reported from localities elsewhere in Singapore and Southeast Asia will be useful in establishing the geographical distribution of S. bakau sp. nov. and other members of the S. kraussii-complex.

Laminatubus (Serpulidae, Annelida) from eastern Pacific hydrothermal vents and methane seeps, with description of two new species.

The bathyal serpulid Laminatubus alvini ten Hove Zibrowius, 1986 was described from the periphery of hydrothermal vents of the Galapagos Rift and has been recorded from other vent communities of the East Pacific Rise (EPR). Here we assessed the biodiversity of serpulids collected from eastern Pacific hydrothermal vents and methane seeps using DNA sequences and morphology. Laminatubus alvini showed little genetic variation over a wide geographic range from the Alarcon Rise vents in southern Gulf of California (~23°N), to at least a point at 38°S on the EPR. Specimens from several methane seeps off Costa Rica and the Gulf of California (Mexico) differed markedly from those of Laminatubus alvini on DNA sequence data and in having seven thoracic chaetigers and lacking Spirobranchus-type special collar chaetae, thus fitting the diagnosis of Neovermilia. However, phylogenetic analysis of molecular data showed that L. alvini and the seep specimens form a well-supported clade. Moreover, among the seep specimens there was minimally a ~7% distance in mitochondrial cytochrome b sequences between a shallow-water (1000 m) seep clade restricted to Costa Rica and a deep-water clade (1800 m) from Costa Rica to Gulf of California. We describe the seep taxa here as morphologically indistinguishable L. paulbrooksi n. sp. and L. joycebrooksae n. sp.

Annelids of the eastern Australian abyss collected by the 2017 RV 'Investigator' voyage.

In Australia, the deep-water (bathyal and abyssal) benthic invertebrate fauna is poorly known in comparison with that of shallow (subtidal and shelf) habitats. Benthic fauna from the deep eastern Australian margin was sampled systematically for the first time during 2017 RV 'Investigator' voyage 'Sampling the Abyss'. Box core, Brenke sledge, and beam trawl samples were collected at one-degree intervals from Tasmania, 42°S, to southern Queensland, 24°S, from 900 to 4800 m depth. Annelids collected were identified by taxonomic experts on individual families around the world. A complete list of all identified species is presented, accompanied with brief morphological diagnoses, taxonomic remarks, and colour images. A total of more than 6000 annelid specimens consisting of 50 families (47 Polychaeta, one Echiura, two Sipuncula) and 214 species were recovered. Twenty-seven species were given valid names, 45 were assigned the qualifier cf., 87 the qualifier sp., and 55 species were considered new to science. Geographical ranges of 16 morphospecies extended along the eastern Australian margin to the Great Australian Bight, South Australia; however, these ranges need to be confirmed with genetic data. This work providing critical baseline biodiversity data on an important group of benthic invertebrates from a virtually unknown region of the world's ocean will act as a springboard for future taxonomic and biogeographic studies in the area.

Mitochondrial genome of Sabella spallanzanii (Gmelin, 1791) (Sabellida: Sabellidae).

We report the mitochondrial genome of Sabella spallanzanii, an invasive Mediterranean sabellid introduced to Australia and New Zealand. The mitogenome is 15,581 bp long and consists of 38 genes, including 13 protein coding genes, two rRNA genes, and 23 tRNA genes. It shows deviations from the putative annelid ground pattern, such as gene order re-arrangements and regions encoding on the negative strand. It is, however, very different from the mitogenome of the closely related serpulid, Spirobranchus giganteus. Phylogenetic analyses of the mitochondrial genes support a sister relationship of Sabella spallanzanii and Spirobranchus giganteus.

Another blow to the conserved gene order in Annelida: Evidence from mitochondrial genomes of the calcareous tubeworm genus Hydroides.

Mitochondrial genomes are frequently applied in phylogenetic and evolutionary studies across metazoans, yet they are still poorly represented in many groups of invertebrates, including annelids. Here, we report ten mitochondrial genomes from the annelid genus Hydroides (Serpulidae) and compare them with all available annelid mitogenomes. We detected all 13 protein coding genes in Hydroides spp., including the atp8 which was reported as a missing gene in the Christmas Tree worm Spirobranchus giganteus, another annelid of the family Serpulidae. All available mitochondrial genomes of Hydroides show a highly positive GC skew combined with a highly negative AT skew - a feature consistent with that found only in the mitogenome of S. giganteus. In addition, amino acid sequences of the 13 protein-coding genes showed a high genetic distance between the Hydroides clade and S. giganteus, suggesting a fast rate of mitochondrial sequence evolution in Serpulidae. The gene order of protein-coding genes within Hydroides exhibited extensive rearrangements at species level, and were different from the arrangement patterns of other annelids, including S. giganteus. Phylogenetic analyses based on protein-coding genes recovered Hydroides as a monophyletic group sister to Spirobranchus with a long branch, and sister to the fan worm Sabellidae. Yet the Serpulidae + Sabellidae clade was unexpectedly grouped with Sipuncula, suggesting that mitochondrial genomes alone are insufficient to resolve the phylogenetic position of Serpulidae within Annelida due to its high base substitution rates. Overall, our study revealed a high variability in the gene order arrangement of mitochondrial genomes within Serpulidae, provided evidence to question the conserved pattern of the mitochondrial gene order in Annelida and called for caution when applying mitochondrial genes to infer their phylogenetic relationships.

A new species of the Spirobranchus kraussii-complex (Annelida, Serpulidae) from the Persian Gulf and Gulf of Oman.

A recent study (Simon et al. 2019) confirmed that Spirobranchus kraussii is neither a widely distributed tropical species of Indo-Pacific origin nor a Lessepsian migrant to the Mediterranean, but a large complex of species, some of which might be indeed invasive. Thus, a common intertidal gregarious serpulid, previously attributed to S. kraussii in the Persian Gulf and Gulf of Oman, is described herein as Spirobranchus sinuspersicus sp. nov., using a combination of morphological and molecular data. The new species differs from S. kraussii by smaller size, fewer abdominal chaetigers, arrangement of abdominal chaetae and shape of opercular endplate talon. Results of phylogenetic analyses of a dataset combining 18S nucleotide and Cyt-b amino-acid sequences of S. sinuspersicus sp. nov. and Spirobranchus spp. available from GenBank supported monophyly of S. kraussii complex (including S. cariniferus) nested within Spirobranchus and thus, provided molecular support for synonymy of Pomatoleios with Spirobranchus proposed based on morphological criteria. The new species forms a well-supported clade with (S. kraussii (sp. 2 Hawaii + sp. 3 Australia)) clade, which in turn forms a clade with Spirobranchus sp.1 from temperate Japan, while S. cariniferus from New Zealand forms a basal grade. Evidence of substitution saturation of Cyt-b nucleotide sequences suggests that using translated amino-acid sequences to exclude non-informative substitutions should provide a better phylogenetic resolution for the genus Spirobranchus. Further studies are required to determine the invasive status of S. sinuspersicus sp. nov. as well as taxonomic and invasive status of S. cf. kraussii populations from the Mediterranean Sea, Suez Bay, Pakistan, India, Sri Lanka, Philippines, Singapore, and Panama.

Barcoding and multi-locus phylogeography of the globally distributed calcareous tubeworm genus Hydroides Gunnerus, 1768 (Annelida, Polychaeta, Serpulidae).

Hydroides is a large and diverse group of calcareous tubeworms (Serpulidae, Annelida) recognised by a distinctive but variable two-tiered operculum. Despite considerable research using several species of Hydroides as models in ecological and biofouling studies, phylogenetic and biogeographic relationships within the genus are still poorly understood. Using combined mitochondrial (COI, cytochrome b) and nuclear (18S, 28S and ITS) gene markers for 284 individuals of 45 morphospecies of Hydroides, we investigated the global phylogenetic and biogeographic relationships within the genus. Phylogenetic topologies were well supported and indicated high genetic diversity within Hydroides, revealing potential cryptic species. Present results also include the first COI barcoding data enabling rapid and effective species identification of Hydroides on a global scale. Phylogenetic relationships within Hydroides were more concordant with geographical distributions than morphological similarity of their opercula. Molecular divergence estimates suggested the origin and subsequent diversification in the western Tethys Sea followed by a shift of the historical centre of diversity from the Indo-Mediterranean region to the central Indo-Pacific during the last 50 million years. Further studies on population genetics of species consisting of multiple lineages would provide a better understanding on the status of potential cryptic species. Furthermore, paleogeographic studies based on fossil Hydroides tubes would provide evidence to test this biogeographic hypothesis.

Notaulax yamasui sp. n. (Annelida, Sabellidae) from Okinawa and Ogasawara, Japan, with notes on its ecology.

The polychaete Notaulax yamasuisp. n. (Sabellidae) is described from Okinawa and Ogasawara, south Japan, where it was found living embedded in a dead skeleton of the coral Porites sp. The new species is characterized by the presence of a pigmented sub-distal swelling on the tips of the crown radioles, a unique feature among species of the genus. Besides, its collar chaetae have an L-shape orientation, and the dorsal basal flanges of the branchial lobes are long and have a dorsal joint.

Hydroides Gunnerus, 1768 (Annelida, Serpulidae) is feminine: a nomenclatural checklist of updated names.

As a service to taxonomists and ecologists using names in the well-known and species-rich ship-fouling serpulid genus Hydroides we present an update of all 107 non-synonymised scientific names, with additional information on Hydroides nomenclature, original names, etymologies, and type localities derived from original literature, and in accord with the World Register of Marine Species (WoRMS) database. An update is needed because the gender of genus Hydroides has from 1 January 2000 reverted to the original feminine, due to a change in the wording of International Code of Zoological Nomenclature which was overlooked at that time, and is contrary to the usage in practice of Hydroides as masculine which had started about 1992, although Code-required from the 1960s. We match 31 further original names of current WoRMS subjective junior synonyms to each non-synonymised name, and also report on the world distribution of the genus as illustrated by type localities of the valid names. We include notes on seven species inquirenda. The correct rendering is given of six names that have been altered for gender agreement for the first time herein. Hydroides gottfriedinom. n. replaces junior homonym Hydroides rostrata Pillai, 1971. Currently there are 41 non-synonymised species-group names in Hydroides which should be gender invariant, and 23 names which would only change if moved to a neuter genus; the remaining 43 names are fully gender variable. Place-names (23), and personal names (16) make up more than a third (36%) of the species names, with most of the remainder (68) being descriptive of species character states, usually of operculum morphology (54). All species, except Hydroides norvegica (63°N), have type localities in shallow-water coastal locations in temperate to tropical waters below latitude 44°, with the highest number of new species (54) from the adjoining Western Pacific and Indian Ocean areas. The other concentration of new species (31) are those first found on the Pacific and Atlantic coasts of North America and in the Caribbean.

Revision of the genus Hydroides (Annelida: Serpulidae) from Australia.

Hydroides Gunnerus, 1768 is the largest and one of the economically most important genera of calcareous tubeworms (Serpulidae, Annelida) that includes a number of notorious fouling and bioinvading species. Although the representatives of the genus are typically found in shallow waters of tropical and subtropical areas worldwide, the species composition of the genus in Australia has never been revised. We conducted the first detailed regional taxonomic revision of Hydroides species based both on the historical collections from Australian museums (Australian Museum, Museum Victoria, South Australian Museum, Western Australian Museum, Queensland Museum, and Museum and Art Gallery of Northern Territory) and newly collected material from New South Wales, Victoria, Queensland, Northern Territory, and Western Australia. In total, 25 species are currently considered valid in Australia, including three new species: H. amri n. sp. from NSW, SA, and Vic (previously referred to as H. cf. brachyacantha), as well as H. glasbyi n. sp. and H. qiui n. sp., both from NT, and two new records of H. furcifera and H. multispinosa for Australia. We have synonymised H. spiratubus with H. albiceps, and H. spiculitubus with H. tambalagamensis in this study. The status of the taxon H. cf. recta remains undecided. An identification key and diagnoses accompanied by original high-quality photographs for all species recorded in Australia are provided. Application of molecular genetics is needed to resolve the status of some problematic species.

Sabellaria jeramae, a new species (Annelida: Polychaeta: Sabellariidae) from the shallow waters of Malaysia, with a note on the ecological traits of reefs.

A new species of the genus Sabellaria Lamarck, 1818 (Annelida: Polychaeta: Sabellariidae) is described from the intertidal zone of Jeram, Selangor, Malaysia. Sabellaria jeramae n. sp. is a gregarious species that constructs large reefs several hundreds of meters long and 50-200 m wide. The new species is distinguished from other congeners by the character combination of the presence of a single kind of middle paleae with conspicuous morphology, and outer paleae with long frayed teeth. Morphological features of the species are described and compared to those of all congeneric species. We also compare the reef structure and geographical distribution of the new species to those of the members of the family Sabellariidae around the world, demonstrating the ecological traits of the reefs.

Deep-sea serpulids (Annelida: Polychaeta) in tetragonal tubes: on a tube convergence path from the Mesozoic to Recent.

Serpulids typically build cylindrical calcareous tubes attached to hard substrates. Until now, only three serpulid species inhabiting free-lying polygonal tubes were reported from the deep sea: Spirodiscus grimaldii Fauvel, 1909 with quadrangular spirally coiled tubes, Bathyditrupa hovei Kupriyanova, 1993a with quadrangular tusk-shaped tubes, and Ditrupa groenlandica McIntosh, 1877 with octagonal tusk-shaped tubes. Similar free-lying tubes with tetragonal cross-section, both coiled and tusk-shaped, are described from shallow-water Mesozoic deposits as Nogrobs de Montfort, 1808, Tetraserpula Parsch, 1956, Tetraditrupa Regenhardt, 1961, Glandifera Regenhardt, 1961 and Tubulostium Stoliczka, 1868. We have revised deep-sea serpulids with tetragonal (and secondary octagonal) tubes and compared their tube ultrastructures and mineralogies with those of morphologically similar fossils. Revision of the Recent material has revealed six species in five genera: Spirodiscus grimaldii, S. groenlandicus comb. nov., Bathyditrupa hovei, Bathyvermilia gregrousei sp. nov., Hyalopomatus dieteri sp. nov. and Zibrovermilia zibrowii gen. et sp. nov. Comparisons showed significant ultrastructural and mineralogical differences between Recent and Mesozoic species. Similar tetragonal tube morphology of the Recent forms appears to be a result of convergence due to adaptation to similar soft-sediment habitats of the deep sea. None of Recent genera should be synonymised with any fossil genus, and the genus Spirodiscus Fauvel, 1909, previously synonymised with fossil Nogrobs, should be re-instated. However, a huge stratigraphic gap (66 Myr) between the earliest known fossil tetragonal tubes and their Recent counterparts still allows the possibility that such essentially different structures is a result of ultrastructural evolution, a hypothesis that could be verified by discovery and further study of Caenozoic material.

Serpulidae (Annelida) of Lizard Island, Great Barrier Reef, Australia.

Serpulidae are obligatory sedentary polychaetes inhabiting calcareous tubes that are most common in subtropical and tropical areas of the world. This paper describes serpulid polychaetes collected from Lizard Island, Great Barrier Reef, Australia in 1983-2013 and deposited in Australian museums and overseas. In total, 17 serpulid genera were recorded, but although the study deals with 44 nominal taxa, the exact number of species remains unclear because a number of genera (i.e., Salmacina, Protula, Serpula, Spirobranchus, and Vermiliopsis) need world-wide revisions. Some species described herein are commonly found in the waters around Lizard Island, but had not previously been formally reported. A new species of Hydroides (H. lirs) and two new species of Semivermilia (S. annehoggettae and S. lylevaili) are described. A taxonomic key to all taxa found at Lizard Island is provided.