The Nereididae (Annelida) - diagnoses, descriptions, and a key to the genera.

Nereididae is among the most familiar of marine annelid families, common and well-studied in most marine environments but paradoxically no recent key or identification guide exists to the world's genera. Here updated generic descriptions, a list of characters, a linear key to genera, and minimal diagnoses that distinguish each genus from all others in the family are provided. This information is generated from a Delta database of 186 morphological characters and a link is provided to downloadable software allowing the same data to be interrogated using the open-source Delta program Intkey - a nonlinear multiple entry point computerised interactive key. For each genus the recent literature is also summarised, comments on taxonomic status provided, and published keys to species cited. Nexus format matrices are provided for all 45 genera and 158 Nereididae species, representing all genera, scored for 146 multistate characters from the same character list to facilitate future phylogenetic studies.

Nereididae (Annelida: Phyllodocida) from intertidal macroalgae in Western Australia.

The last extensive exploration of Nereididae diversity within coastal waters of Western Australia was done in 1975-1984. We collected Nereididae associated with macroalgae from 38 rocky intertidal shores of Western Australia (18°S to 34°S). Eighteen species belonging to seven genera are described and illustrated. Two new species, Nereis edentata n. sp. and Nereis yuedensis n. sp., were found. Nereis edentata n. sp. differs from other Nereis species having one row of paragnaths on Areas VII-VIII and smooth notopodial homogomph falcigers in posterior chaetigers. Nereis yuedensis n. sp. differs from other Nereis species having one row of paragnaths on Areas VII-VIII and notopodial homogomph falcigers with at least one large lateral tooth, and also species having notopodial homogomph falcigers starting from chaetiger 3. The distribution of N. yuedensis n. sp. was found to be restricted within temperate Australia and N. edentata n. sp. appears to be transitional between temperate and tropical regions. Also, we remove from synonymy the probable Western Australian endemic species, Pseudonereis rottnestiana (Augener, 1913), and provide a key to all known genera and species of Nereididae from Western Australian waters.

Three new species of the genus Perinereis (Annelida, Nereididae) from Egyptian coasts.

Despite being one of the most common groups of polychaetes on intertidal shores, the genus Perinereis (Nereididae) is comparatively poorly known taxonomically, with confusion still existing due to the lack of comprehensive systematic studies. The systematics of Perinereis species from the intertidal Egyptian coasts of the Red Sea, Gulf of Suez and Suez Canal have been investigated using morphology and the mitochondrial barcoding marker cytochrome oxidase subunit I (COI). New sequence data was obtained for 102 Perinereis specimens and analysis included all publicly available COI data from other Perinereis species. The COI data indicate that monophyly of the P.nuntia species group is doubtful, as specimens identified in this species group from south-eastern Asia and Australia form a monophyletic group exclusive of the three new species described in this study from the Red Sea region. A morphometric character set (26 characters) was used to identify and characterize each specimen in the study. Three distinct morphospecies belonging to the P.nuntia species group were found, each differentiated by the number and type of paragnaths on pharyngeal areas V and VI, relative sizes of parapodial lobes, type of notochaetae and neurochaetae, and form of the neurochaetal falciger blades. The three morphospecies were well supported by COI data: two of the three new species, Perinereissuezensis sp. nov. and Perinereisfayedensis sp. nov., are closely similar to P.nuntia sensu stricto, while the other, Perinereisdamietta sp. nov., is similar to P.heterodonta. The new species are described and illustrated, and bring the number of species in Perinereis to 97. The new species are compared and contrasted to the closely similar P.heterodonta, P.nuntia and other congeners from the region.

Integrative anatomical study of the branched annelid Ramisyllis multicaudata (Annelida, Syllidae).

The sponge-dwelling Syllidae Ramisyllis multicaudata and Syllis ramosa are the only annelid species for which a branched body with one head and multiple posterior ends is known. In these species, the head is located deep within the sponge, and the branches extend through the canal system of their host. The morphology of these creatures has captivated annelid biologists since they were first discovered in the late XIXth century, and their external characteristics have been well documented. However, how their branched bodies fit within their symbiotic host sponges and how branches translate into internal anatomy has not been documented before. These features are crucially relevant for understanding the body of these animals, and therefore, the aim of this study was to investigate these aspects. In order to assess these questions, live observation, as wells as histology, immunohistochemistry, micro-computed tomography, and transmission electron microscopy techniques were used on specimens of R. multicaudata. By using these techniques, we show that the complex body of R. multicaudata specimens extends greatly through the canal system of their host sponges. We demonstrate that iterative external bifurcation of the body is accompanied by the bifurcation of the longitudinal organ systems that are characteristic of annelids. Additionally, we also highlight that the bifurcation process leaves an unmistakable fingerprint in the form of newly-described "muscle bridges." These structures theoretically allow one to distinguish original and derived branches at each bifurcation. Last, we characterize some of the internal anatomical features of the stolons (reproductive units) of R. multicaudata, particularly their nervous system. Here, we provide the first study of the internal anatomy of a branched annelid. This information is not only crucial to deepen our understanding of these animals and their biology, but it will also be key to inform future studies that try to explain how this morphology evolved.

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.

Pilargidae (Annelida: Phyllodocida) from coastal and deep waters of the Southwestern Atlantic, with descriptions of two new species.

We describe seven species of Pilargidae from the coast and deep sea (300-1400 m deep) of southeastern Brazil, belonging to the genera Ancistrosyllis McIntosh, 1878, Cabira Webster, 1879, Glyphohesione Friedrich, 1950, Hermundura Müller, 1858, and Pilargis Saint-Joseph, 1899. Of those, two are new species (Glyphohesione campensis sp. nov. and Pilargis falconae sp. nov.) and two are new records of Ancistrosyllis for Brazil. Glyphohesione campensis sp. nov. is distinguished from its congeners by fewer neurochaetae, the anteriormost appearance of first notopodial spines, and intermediate relative length of dorsal and ventral cirri. Pilargis falconae sp. nov. is diagnosed by the presence of parapodial glands from the first chaetiger on the dorsal surface and from the sixth chaetiger on the ventral surface; and neurochaetae smooth capillaries and limbates with unidentate tips. Keys to pilargid species reported from, or likely to occur in, Brazilian waters are provided.

A new species of Marphysa (Annelida: Eunicida: Eunicidae) from India, with notes on previously described or reported species from the region.

A new species of Marphysa is described from India using both morphology and molecular data. The new species, Marphysa madrasi, belonging to the Teretiuscula-group, is characterised by having antennae about 2x longer than the prostomium, maxillae II and IV with a relatively large number of teeth (Mx II with 8+9; Mx IV with 7+11), compound spinigers present on a large range of mid-body chaetigers (at least 83-159), and pectinate chaetae present from the first few anterior chaetigers. We discuss all the species of this genus lacking compound falcigers (i.e., those belonging to the Sanguinea-, Mossambica- and Teretiuscula-groups), which have been reported from India and compare them to our new species. Only two accepted species in these groups can be confirmed as occurring in India, M. madrasi n. sp. and M. gravelyi Southern, 1921. We provide a table that summarises the important characters useful to identify species in this group of Marphysa with compound spinigers.

A new species of the sanguinea-group Quatrefages, 1866 (Annelida: Eunicidae: Marphysa) from the Philippines.

A new species of the Marphysa sanguinea group, M. iloiloensis n. sp. (Annelida: Eunicida: Eunicidae), is described from the Marine Annelids Hatchery of the Southeast Asian Fisheries Development Center, Aquaculture Department (SEAFDEC- AQD), Iloilo Province, Philippines. It represents the first record of this group in the Philippines. The new species is most similar morphologically to M. hongkongensa Wang, Zhang Qiu, 2018, but can be distinguished from it by having fewer branchial filaments, a pair of faint eyes (absent in M. hongkongensa), and in slight differences in jaw morphology and chaetation. The embryos of the new species develop inside a jelly cocoon attached to the entrance of the adult burrow; this is the first time that egg-containing cocoons have been found in any species of the sanguinea-group. Phylogenetic analysis based on the mitochondrial gene cytochrome c oxidase subunit I (COI) revealed that Marphysa iloiloensis n. sp. is genetically distinct from all other analysed Marphysa species and forms a sister group to M. hongkongensa. A revised identification key to members of the sanguinea-group in Southeast Asia is provided.

Discovery of a silicate rock-boring organism and macrobioerosion in fresh water.

Macrobioerosion is a common process in marine ecosystems. Many types of rock-boring organisms break down hard substrates, particularly carbonate rocks and calcareous structures such as dead corals and shells. In paleontology, the presence of rocks with boreholes and fossil macroboring assemblage members is one of the primary diagnostic features of shallow marine paleo-environments. Here we describe a silicate rock-boring organism and an associated community in submerged siltstone rock outcrops in Kaladan River, Myanmar. The rock-boring mussel Lignopholas fluminalis is a close relative of the marine piddocks, and its borings belong to the ichnospecies Gastrochaenolites anauchen. The neotectonic uplift of the area leading to gradual decrease of the sea level with subsequent shift from estuarine to freshwater environment was the most likely driver for the origin of this community. Our findings highlight that rocks with macroborings are not an exclusive indicator of marine paleo-ecosystems, but may also reflect freshwater habitats.

On the use of troglomorphic characters in Namanereidinae (Annelida; Nereididae) systematics.

The Namanereidinae are one of the most successful polychaete groups to colonize subterranean waters. Many species have evolved adaptations to underground life including elongation of appendages and reduction of eyes and pigmentation. However, the use of these troglomorphic characters in the group's systematics is contentious. The present study conducts a series of tree searching and phylogeny reconstructions to evaluate the influence of these characters in the phylogeny of the group. Results show that troglomorphic characters cause no serious errors in the phylogenetic reconstruction of Namanereidinae, and support the two existing genera, which can be unequivocally distinguished by non-troglomorphic traits. As a consequence of this phylogenetic hypothesis the following taxonomic changes are required: Lycastoides becomes a junior synonym of Namanereis, and its only species becomes a new combination, N. alticola n. comb. and Namalycastis occulta is moved to Namanereis becoming Namanereis occulta n. comb.

Nereididae (Annelida: Phyllodocida) of the Persian Gulf and Gulf of Oman, including description of two new species and 11 new records.

Currently, only 31 nereidid species are known from the Persian Gulf and Gulf of Oman. The present study was carried out in order to investigate the poorly known diversity of nereidid polychaetes from seas of the southern coasts of Iran. Specimens were collected from 23 locations along the intertidal zones of the two water bodies. Among the 26 species found: two are new, and are described here, including Simplisetia qeshmensis sp. nov. and Neanthes biparagnatha sp. nov.; 11 are new geographical records. Neanthes biparagnatha sp. nov. is most similar to N. deplanata (Mohammed, 1971), which is also found in the Persian Gulf, but can be most easily distinguished from it by the presence of bars in addition to cones in Area IV of the pharynx. Simplisetia qeshmensis sp. nov. may be distinguished from its closest congener, S. erythraeensis (Fauvel, 1918), also reported from the Persian Gulf, by having a greater number of paragnaths in Area I of the pharynx, an additional type of chaeta (homogomph spinigers) in the ventral neuropodial fascicle and having a reduced notopodial lobe in posterior chaetigers. The list of new records includes: one species from both areas, Neanthes glandicincta (Southern, 1921); eight species from the Persian Gulf, Leonnates decipiens Fauvel, 1929, Neanthes acuminata (Ehlers, 1868), Neanthes sp., Neanthes sp. cf. N. acuminata, Nereis sp. cf. N. pelagica Linnaeus, 1758, Perinereis cultrifera (Grube, 1840) species complex., Pseudonereis trimaculata (Horst, 1924), Pseudonereis sp. cf. P. variegata (Grube, 1857) and two from the Gulf of Oman, Leonnates persicus Wesenberg-Lund, 1949 and Perinereis kuwaitensis Mohammed, 1970. The present study brings to 40 the number of nereidid species currently known from the Persian Gulf and Gulf of Oman. A taxonomic key to nereidid species from the intertidal zones of the Persian Gulf and Gulf of Oman is presented to facilitate future investigations.

A new substance to relax polychaete worms (Annelida) prior to morphological study.

A variety of chemical substances have been used to relax and/or immobilize polychaete worms, and other invertebrates, prior to specimen preparation for morphological examination. To solve difficulties encountered during the study of nereidid polychaetes (Annelida: Phyllodocida), an experiment was designed and carried out to investigate a new relaxing agent to immobilize nereidid specimens and stimulate pharynx eversion. The new substance, Dentol® (Khoraman laboratory, Iran), a dental anesthetic and antiseptic medicine containing 10% Carvacrol as the effective ingredient, was used for the first time and compared with other substances that have been used traditionally in polychaete studies. Crosstab analysis showed significant differences between different treatment groups, with Dentol® providing much better results for all considered criteria.

Nereididae (Annelida: Phyllodocida) of Lizard Island, Great Barrier Reef, Australia.

Nereididae is one of the most ubiquitous of polychaete families, yet knowledge of their diversity in the northern Great Barrier Reef is poor; few species have been previously reported from any of the atolls or islands including Lizard Island. In this study, the diversity of the family from Lizard Island and surrounding reefs is documented based on museum collections derived from surveys conducted mostly over the last seven years. The Lizard Island nereidid fauna was found to be represented by 14 genera and 38 species/species groups, including 11 putative new species. Twelve species are newly reported from Lizard Island; four of these are also first records for Australia. For each genus and species, diagnoses and/or taxonomic remarks are provided in addition to notes on their habitat on Lizard Island, and general distribution; the existence of tissue samples tied to vouchered museum specimens is indicated. Fluorescence photography is used to help distinguish closely similar species of Nereis and Platynereis. A key is provided to facilitate identification and encourage further taxonomic, molecular and ecological studies on the group.

Taxonomy of reproductive Nereididae (Annelida) in multispecies swarms at Ambon Island, Indonesia.

Multispecies, or mass, spawning of different invertebrate species is well known for coral reef systems; however, incidences involving polychaetes are poorly documented. In this study we report on mass swarming, prior to spawning, of Nereididae at Ambon Island, Maluku, on three occasions: in 1866, inferred from an historical sample deposited in Naturalis, Leiden, and in March, 2009 and 2014, based on newly collected samples. The 2009 and 2014 events co-occurred with spawning of other polychaetes, known locally as wawo and including the widespread Indo-Pacific eunicid, Palola viridis (Gray in Stair). Ten species of reproductive Nereididae are described, including Composetia marmorata (Horst) new combination, formerly Ceratonereis marmorata; epitokous modifications are described for both sexes of each species including taxonomically important features such as body colour and number of pre-natatory chaetigers. Three distinct types of natatory region morphologies are recognized, which appear to characterise groups of genera. The ten new records brings to 13 the total number of nereidid species known to undergo mass swarming at Ambon Island; a key to the 13 species is provided. Species composition varies slightly between the three time periods: four species were common between all three periods, five species were in common between 1866 and 2014, and four species were in common between 1995 and 2009/14. Two species of Neanthes and one of Nereis are identified as potentially new and will be described in subsequent papers.

The making of a branching annelid: an analysis of complete mitochondrial genome and ribosomal data of Ramisyllis multicaudata.

Ramisyllis multicaudata is a member of Syllidae (Annelida, Errantia, Phyllodocida) with a remarkable branching body plan. Using a next-generation sequencing approach, the complete mitochondrial genomes of R. multicaudata and Trypanobia sp. are sequenced and analysed, representing the first ones from Syllidae. The gene order in these two syllids does not follow the order proposed as the putative ground pattern in Errantia. The phylogenetic relationships of R. multicaudata are discerned using a phylogenetic approach with the nuclear 18S and the mitochondrial 16S and cox1 genes. Ramisyllis multicaudata is the sister group of a clade containing Trypanobia species. Both genera, Ramisyllis and Trypanobia, together with Parahaplosyllis, Trypanosyllis, Eurysyllis, and Xenosyllis are located in a long branched clade. The long branches are explained by an accelerated mutational rate in the 18S rRNA gene. Using a phylogenetic backbone, we propose a scenario in which the postembryonic addition of segments that occurs in most syllids, their huge diversity of reproductive modes, and their ability to regenerate lost parts, in combination, have provided an evolutionary basis to develop a new branching body pattern as realised in Ramisyllis.

Revision of the taxonomy of Polycirrus Grube, 1850 (Annelida: Terebellida: Polycirridae).

The large polychaete genus Polycirrus (Terebellida: Polycirridae) is revised based on a morphological study of the type material of most of the approximately 74 nominal species; 59 species, including a new species, P. coibensis n.sp., from the Pacific coast of Panama, are accepted as valid. All characters are reanalysed and discussed in the light of recent phylogenetic studies of terebellomorph taxa, and a standard set of characters is developed. Most of the 59 accepted species are redescribed and illustrations provided in order to facilitate future identifications of members of the genus. We designate a neotype for the type species of the genus, Polycirrus medusa Grube, 1850, and a lectotype for P. elisabethae McIntosh, 1915, in order to stabilize the concept and type locality of these taxa. A replacement name is proposed for Polycirrus kerguelensis McIntosh, 1885, which is a secondary junior homonym of Ereutho kergulenesis McIntosh, 1885, viz. Polycirrus macintoshi new name. Two species are newly synonymised: Polycirrus insignis Gravier, 1907 (senior synonym P. antarcticus (Willey, 1902)) and Polycirrus habitats Carrerette & Nogueira, 2013 (senior synonym, P. clavatus (Kinberg, 1867)). In addition, several previously synonymised species are reinstated. All available names in the genus are tabulated with type species and type localities and their taxonomic status is assessed. A key to all valid species is provided. 

The diversity and abundance of polychaetes (Annelida) are altered in sediments impacted by alumina refinery discharge in the Northern Territory, Australia.

We collected polychaete diversity and abundance data at a range of impacted and reference sites near an alumina refinery in Melville Bay, northern Australia. The aims were to measure the impact of sediment modified by the alumina refinery discharge on polychaete communities and secondly to gather baseline data from which to measure future changes. Polychaete communities in both soft-bottom habitats and subtidal areas adjacent to mangrove forests were studied. We also developed and deployed an artificial substratum device to sample polychaetes associated with hard-substrate habitats. For each habitat, polychaete community composition was different between impacted and reference sites and at multiple time points. The impact of future changes either from bioremediation or management practices can be measured against these baseline data. Indicator species analysis was used to identify polychaete species that were significantly different at the locations tested, and we discuss their potential as indicator species.

Revision of the genus Synelmis Chamberlin, 1919 (Annelida: Phyllodocida: Pilargidae) in Australia.

We provide accounts of four species of Synelmis Chamberlin, 1919 (Annelida: Phyllodocida: Pilargidae) from Australian and adjacent seas, including one new species, S. sergi sp. nov. The only previous, positively identified, record of a Synelmis species in the region, S. gibbsi Salazar-Vallejo, 2003, has been checked and the specimens re-identified here as S. knoxi Glasby, 2003, which extends the known range of this species to include Australia as well as New Zealand. Newly collected material of S. gibbsi is described from the Joseph Bonaparte Gulf, NW Australia. Specimens collected from NE Australia are identified here as S. rigida (Fauvel, 1919). Synelmis knoxi, S. gibbsi and S. rigida are all new records for Australia. A key to Australian species of Synelmis is provided and we tabulate information on the distinguishing features of all 17 species in the genus.

Description and phylogeny of Namalycastis jaya sp. n. (Polychaeta, Nereididae, Namanereidinae) from the southwest coast of India.

Namalycastis jayasp. n. (Polychaeta: Nereididae: Namanereidinae)is described from the southern coast of Kerala in southwest India. One important characteristic feature of the species is the lack of notochaetae in all parapodia, a characteristic that it shares with at least two other species, Namalycastis elobeyensis Glasby, 1999and Namalycastis hawaiiensis Johnson, 1903. It differs from Namalycastis elobeyensis by virtue of its smaller antennae, unequal eye size, bilobed acicular neuropodial ligule and multi-incised pygidium rim. Moreover, it differs from Namalycastis hawaiiensis by having fewer teeth on the serrated blades of the sub-neuroacicular falciger in chaetiger 10, and by possessing finely serrated falcigers in posterior segments. Beyond morphological analyses, molecular phylogenetics was used for the first time for Namalycastis to support population monophyly and recognition of the new species.The analysis, using both mitochondrial and nuclear data, corroborated the morphological analysis in suggesting that our specimens represent an as yet undescribed species, Namalycastis jayasp. n., which forms a monophyletic group among the sampled nereidid taxa. Finally, a taxonomic key for Namalycastis species recorded from the Indian region is provided.