Sabellid Polychaete Research Articles

When a Worm Loves a Coral: A Symbiotic Relationship from the Jurassic/Cretaceous Boundary

Reefal limestones of the Štramberk Carbonate Platform are preserved as olistoliths and pebbles in deep-water flysch of the Outer Carpathians (Czech Republic, Poland). They contain the richest coral assemblages of the Jurassic/Cretaceous transition (Tithonian–Berriasian). Symbiotic associations between corals and tube-dwelling macroorganisms were recognized only in the branching scleractinian corals Calamophylliopsis flabellum and Calamophylliopsis sp. One to seven calcareous tubes were recognized either in coral calyces, embedded in the wall, or attached to it. Two types of tubes were recognized: Type 1: tubes with a diameter of 0.3–0.6 mm and a very thin wall (ca. 0.05 mm), mostly occurring inside corallites, and nearly exclusively in the Štramberk-type limestone of Poland; Type 2: tubes with an outer diameter of 0.8–2.0 mm and a thick wall (ca. 0.1 mm, some even up to 0.2 mm), mostly found in the Štramberk Limestone of the Czech Republic. Growth lamellae were observed in some thick walls. Most tubes are almost straight, some are curved. The tubes were probably produced by serpulids or by embedment of organic-walled sabellid polychaete worms. It is likely the oldest record of a sabellid–coral association. Modification of the coral skeleton in contact with tubes indicates that the worms were associated with live corals. For many modern and fossil worm–coral associations, this symbiotic association is interpreted as mutualistic or commensal.

Ecological role and phylogenetic position of a new habitat-forming species (Canalipalpata, Sabellidae) from the Mediterranean mesophotic soft bottoms

This study presents a description of Bispira riccardi sp. nov., a new habitat-forming sabellid polychaete from the mesophotic NW Mediterranean Sea. Individuals, up to 20 cm long, show a peculiar morphology of radioles, thoracic uncini, companion chaetae and ventral shield of the collar. The phylogenetic position of this new taxon in the genus Bispira has been validated using nuclear (18S rRNA) and mitochondrial (COI) markers.Aggregations of B. riccardi sp. nov. were found by ROV on horizontal muddy bottoms between 56 and 85 m, in areas subjected to high trophic inputs. Patches are fragmented and dense (up to 943 individuals m−2) probably accounting for various hectares. A 5-days continuous monitoring, carried out using an autonomous lander, revealed that the contraction of the branchial crown was positively affected by temperature and current, rapidly responding to meteorological events. The filtering activity and high density of these fields suggest a considerable impact on the pelagic-benthic coupling and the amount of organic matter in the sediments. Indeed, meiofaunal abundance and diversity within the aggregations resulted significantly higher than in outer stations. These findings highlight the undisclosed potential of the deep Mediterranean Sea for sabellid diversity and their importance as habitat-forming species on mesophotic soft bottoms.

To the Mediterranean and beyond: An integrative approach to evaluate the spreading of Branchiomma luctuosum (Annelida: Sabellidae)

The non-indigenous sabellid polychaete Branchiomma luctuosum (Grube, 1870) has spread along the Mediterranean coast in a short time period. Well-established populations were recorded for 9 marinas and 3 natural habitats along the southern Iberian Peninsula, including the first record of the species in Portugal. The highest abundances (>60 ind./m2) were found in the Gulf of Cádiz (Atlantic coast of Spain). The ability to colonize artificial structures has also been tested experimentally; although the species showed high colonization rates, high water-flow rate and turbidity might adversely affect larval settlement. The tubes of B. luctusoum hosted a very diverse epibiota, comprising 79 taxa, many of which are considered to be introduced or cryptogenic species. The ability of this polychaete to facilitate the spread of these species when attached to vessel hulls is discussed. Our results suggest that this species is in a phase of active colonization by successfully colonizing both natural and artificial habitats.

The Occurrence of Amphiglena mediterranea (Leydig, 1851) (Annelida: Sabellidae) at the Romanian Coast of the Black Sea: A Case on an Unsuccessful Invasion?

During a study of fauna associated with a shallow-water Zostera (Zosterella) noltei meadow from the southern part of the Romanian Black Sea coast, in August 2015, a sabellid polychaete identified as Amphiglena mediterranea was found. This represents a new record for the Romanian coast of the Black Sea. Three individuals were collected from muddy fine sand at 1.5 m depth at Mangalia, at salinity of 17.4 PSU and temperature of 23.2°C. Subsequent repeated sampling in the same area (in 2018 and 2019) did not revealed any additional individuals of this species. Therefore, the occurrence of A. mediterranea at the Romanian Black Sea coast might be regarded as an unsuccessful invasion.

An abundant new genus and species of fan worms (Polychaeta: Sabellidae) from Hawaii.

A new genus and species of Hawaiian sabellid polychaete, Euchonoides moeone n. gen. et n. sp. is described. This new species has consistently been one of the most abundant polychaetes collected in Mamala Bay, Hawaii, reaching densities of 141,046 ind. m-2 and representing up to 30.6% of all polychaetes collected in that region. The species has a small body (~2 mm length) with a reduced number of abdominal chaetigers (8-10), and is distinguished by the presence of the following features: 1) three pairs of radioles; 2) radiolar skeleton with two longitudinal rows of cells from radiole base to third proximal pair of pinnules, remainder of each radiole skeleton with single rows of cells; 3) pinnules unpaired, alternating (snowflake arrangement); 4) thoracic uncini acicular with a large tooth above the main fang followed by a series of small ones; 5) thoracic chaetiger 3 enlarged; 6) a wide belt on third abdominal chaetiger; and 7) a pre-pygidial depression composed of three chaetigers, with lateral wings, among a combination of several others features. Histological sections have shown that the abdominal belt seems to be a clitellum-like structure where oogenesis takes place. The new genus is compared with other plesiomorphic genera sharing similar morphological features. Patterns of abundance of the new species are presented for the past 27 years in Mamala Bay.

A new species of Claviramus (Annelida, Sabellida, Sabellidae) from the Ariake Inland Sea, Kyushu, Japan.

A new species of the sabellid polychaete genus Claviramus Fitzhugh, 2002, is described from Ariake Inland Sea, Kyushu, Japan. Claviramus is a small genus, composed of three species worldwide. Its distinctive feature is the presence of foliaceous flanges at the distal ends of the radioles. Claviramus kyushuensissp. nov. here described is characterized by the presence of a glandular ridge on chaetiger 2, glandular shields on the abdomen, thoracic uncini bidentate, and the presence of a short, distal filament in some radioles. A key and a comparative table of diagnostic characters for species of Claviramus are provided.

First Myxozoan Infection (Cnidaria: Myxosporea) in a Marine Polychaete from North America and Erection of Actinospore Collective Group Saccimyxon

In a survey of marine annelids for myxosporean infection in Charleston Harbor, South Carolina, we collected 3,214 polychaetes from 21 families and found infections in 6 spionid individuals. Based on gross morphology and COI sequencing, all infected spionids were identified as Streblospio benedicti. Infection prevalence was 0.8% (6/734) of that species of spionid, and 0.2% of all 3,214 polychaetes examined. Pansporocysts contained 8 actinospores and developed in the tegument of the annelid host. This is the first myxozoan infection recorded from this polychaete species, second in the family, and the first marine myxozoan found in the Americas. It is the first marine species found to develop in the tegument of its annelid host; a site of development observed only once before, in Ceratonova shasta infections of its freshwater sabellid polychaete host. Mature actinospores were morphologically simple, truncated ellipsoids, lacking processes or ornamentation, 9.0 ± 0.5 μm × 6.0 ± 0.4 μm. Their sack-like shape was similar to 9 of the 12 actinospores described previously from polychaetes; 10/12 had been and ascribed originally to the morphological collective group Tetractinomyxon despite 9 of these having few similarities to the original description of this group. We propose to name the simple, spherical to ellipsoidal spore morphotype Saccimyxon to encompass both our novel actinospore and the 9 other sack-like polychaete actinospore types in the literature. In the present study, 18S rDNA sequencing demonstrated that the myxozoans that infected the 6 spionids were genetically the same species (type sample 1,737 nucleotides, GenBank accession number MH791159) and was not >95% similar to any sequence in GenBank. Phylogenetic analysis showed that the myxozoan species we encountered is basal to the kudoids and thus likely to have a morphologically simple myxospore stage with fewer than 4 valves. However, without a genetic match, the presumptive vertebrate host remains unknown.

Tube microstructure and formation in some feather duster worms (Polychaeta, Sabellidae)

Species of the sabellid polychaete genera Anamobaea, and Notaulax, are some of the most attractive sabellid polychaetes from coral reef areas due to their large colorful radiolar crowns. Tube microstructures of Anamobaea orstedi, Notaulax tenuitorques, and Notaulax sp. nov. are described. The studied sabellid tubes have three different types of microstructure. Most simple is irregular mesh microstructure which is composed of thin, long, and variously curved fibers of somewhat chaotic orientation (Notaulax tenuitorques). The irregular mesh microstructure could be plesiomorphic among sabellid tube structures. Oriented fibers in homogeneous matrix microstructure involves some kind of chemical control mechanisms that asserts the same orientation of all fibers (Notaulax sp. nov.). Anamobaea orstedi shows the most advanced pattern, a regular plywood structure, which is composed of thin subparallel or parallel to each other fibers that have different orientation in adjacent lamellae. Regular plywood structure has apparently greatest strength among organic tube structures of sabellids combined with good flexibility. Organic sabellid tube microstructures are likely species specific and have a taxonomic value.

Sabellid worms from the Patagonian Shelf and Humboldt Current System (Annelida, Sabellidae): Phyllis Knight-Jones’ and José María Orensanz’s collections

The South American sabellid polychaete worm collections of Phyllis Knight-Jones and José María Orensanz were recovered, curated and specimens identified, comprising fourteen species grouped in nine genera. Five species belonging to the genera Chone Krøyer, 1856, Acromegalomma Gil and Nishi, 2017, Notaulax Tauber, 1879, Parasabella Bush, 1905, and Pseudopotamilla Bush, 1905, are described as new to science from the Patagonian Shelf (Argentina). Jasmineira crumenifera Hartmann-Schröder, 1986, Myxicola sulcata Ehlers, 1912, Parasabella columbi (Kinberg, 1867), Perkinsiana antarctica (Kinberg, 1867) and Perkinsiana assimilis (McIntosh, 1885) are redescribed and reported from several Patagonian localities. Three new combinations are made: Sabella tilosaula Schmarda, 1861, is transferred to Notaulax, Sabella magalhaensis Kinberg, 1867, to Perkinsiana Knight-Jones, 1983, and Potamilla platensis Hartman, 1953, to Pseudopotamilla. Potamethus littoralis Hartman, 1967, was synonymized with Perkinsiana magalhaensis. Notaulax tilosaula, Perkinsiana antarctica and P. magalhaensis are reported from the biogeographical subregion Humboldt Current System, whereas Bispira sp., Chone orensanzi sp. nov., Jasmineira crumenifera, Acromegalomma schwindtae sp. nov., M. sulcata, Notaulax salazari sp. nov., Parasabella columbi, P. yonowae sp. nov., Perkinsiana assimilis, Pseudopotamilla platensis, and P. knightjonesae sp. nov., are reported from the Patagonian Shelf.

Heteromysis sabelliphila sp. nov. (Mysida, Mysidae, Heteromysinae) in facultative association with sabellids from the Cape Verde Islands (subtropical N.E. Atlantic)

A survey of crustaceans associated with benthic invertebrates in near-shore habitats at islands of the Cape Verde archipelago yielded a new species belonging to the genus Heteromysis, subgenus Olivemysis: H. sabelliphila sp. nov. shows a non-obligatory association with the sabellid polychaete Branchiomma nigromaculatum only during the night. This is the first documented mysid–polychaete association. The mysids apparently took particles collected by the polychaete, suggesting a kleptoparasitic interspecific relationship. A set of three specifically modified setae on the antennular trunk is shared by the new species with two Heteromysis species from Madeira (subtropical N.E. Atlantic), suggesting a close morphological relationship within the subgenus Olivemysis: with H. wirtzi, commensal of the sea anemone Telmatactis cricoides, and with H. dardani, commensal of the hermit crab Dardanus calidus. A key to the Heteromysinae of the E. Atlantic and Mediterranean is given.

First report of the invasive species Branchiomma bairdi McIntosh, 1885 (Annelida: Sabellidae) along the Tunisian coast (Mediterranean Sea)

The invasive sabellid polychaete Branchiomma bairdi McIntosh, 1885 was collected in the Boughrara Lagoon (southern Tunisian coast) between 2012 and 2013. This species was originally described from Bermuda and has been widely reported in the Caribbean Sea. It has been considered as non-indigenous species on the Pacific coast of Panama and the California Gulf. Recently, B. bairdi was recorded along the Italian and Turkish coasts, Australia, Canary and Madeira Islands. It was suggested that the commercial shipping is the most likely vector for the introduction of the species to Mediterranean Sea. A description of the species along with a discussion of its systematic position and ecology are provided.

Primer registro de <i>Branchiomma coheni</i> (Polychaeta: Sabellidae) en las costas del Caribe colombiano

La especie invasora Branchiomma coheni Tovar-Hernández y Knight-Jones, 2006, familia Sabellidae, ha sido recolectada en la Bahía de Cispatá, Morrosquillo y en la Ciénaga Grande de Santa Marta, en las raíces de los mangles y en La Escollera en Gaira sobre recolectores de ostras. Esta especie de la comunidad bentónica cubre las raíces de mangle compartiendo el sustrato con otros invertebrados. Este es el primer registro de B. coheni para el Caribe colombiano.

Apparent parasitism of Sabella melanostigma (Polychaeta) by Ammothella spinifera (Pycnogonida) from the Gulf of California

Juveniles of the ammotheid pycnogonid ? Ammothella spinifera were found apparently as ectoparasites on the sabellid polychaete Sabella melanostigma from Bahia Concepcion, Gulf of California. Nineteen out of 23 sabellids were parasitized (83% incidence) by one to five (x = 1.5) juveniles that prefered the abdomen over the thorax (25 vs. 9). Four adult A. spinifera were found in less close association with sabellids, as well as 12 other annelids without ectoparasites.

A new genus and family of copepods (Crustacea: Copepoda) parasitic <br />on polychaetes of the genus Jasmineira Langerhans, 1880 (family Sabellidae) in the northeastern Atlantic

A new genus and species of copepod, Jasmineiricola mackiei n. gen. et n. sp., parasitic on at least three species of the sabellid polychaete genus Jasmineira Langerhans, 1880 is described. The adult female is mesoparasitic, living with part of its body (the endosoma) embedded within the host and part (the ectosoma) protruding through the host's body wall. The endosoma consists of a well defined head region carried anteriorly on the trunk which has paired lateral lobes housing the ovaries. The head bears a rosette-like array of eight slender lobes, which are probably derived from the mouthparts. The only limbs present on the trunk are the subchelate maxillipeds positioned immediately posterior to the head. The ectosoma consists of a posterior genito-abdominal lobe bearing paired genital apertures. The male is unknown. The new genus cannot be placed in any of the five existing families of mesoparasitic copepods on polychaete hosts and is treated as the type of a new monotypic family, the Jasmineiricolidae. The new species occurs over a depth range from 19 to 279 m, and is widely distributed from UK coastal waters to Norwegian waters inside the Arctic Circle.

First record of Branchiomma bairdi McIntosh, 1885 (Annelida: Sabellidae) from Madeira Island, Portugal (northeastern Atlantic Ocean)

During a field survey to monitor marine non-indigenous species in several marinas of the Archipelago of Madeira (Portugal), the invasive sabellid polychaete Branchiomma bairdi McIntosh, 1885 was detected for the first time on Madeira Island, reaching densities of 238–516 ind.m -2 . B. bairdi was originally described from the western Atlantic (from Bermuda to Caribbean Sea) but the origin of this species is still unknown. This species has been recorded as an invasive species for the Pacific coast of Panama, Gulf of California, Mediterranean Sea, Canary Islands, and Australia. Hull fouling is the most likely vector for the introduction of the species.

Chaetal loss and replacement in Pseudopotamilla reniformis (Sabellida, Annelida)

AbstractChaetae are continually being replaced during the life of a polychaete, but the process of chaetal degeneration during replacement is still poorly known. Chaetal loss occurs either one at a time through special degenerative sites, or all chaetae in a chaetal sac are lost simultaneously in the absence of degenerative sites. Old chaetae can be either resorbed inside the coelom or shed. This study describes chaetal degradation, loss, and subsequent replacement during experimentally induced regeneration in the sabellid polychaete Pseudopotamilla reniformis. During post‐traumatic regeneration in P. reniformis, abdominal‐type chaetae fall from the chaetal sac simultaneously without degenerative sites, and are replaced by thoracic‐type chaetae. Chaetal sac degradation occurs in three main stages: (1) formation of numerous lysosomes and small electron‐transparent vesicles in follicle cell cytoplasm; (2) disintegration of follicular cell membranes; and (3) disintegration of follicular cell cytoplasm. Description of changes during parapodial transformation allows identification of signs of degradation that can serve as histological indicators of chaetal degeneration in a wide range of polychaetes. Our study suggests that chaetal degeneration and loss in polychaetes can occur either with degenerative sites or without them, depending on the type of chaetal replacement.

A new species of Sabellacheres M. Sars, 1862 (Copepoda: Gastrodelphyidae) from a deep-water benthic polychaete in Antarctic waters, with a key to the species of the genus

Specimens of a deep-living sabellid polychaete of the genus Perkinsiana Knight-Jones dredged in Antarctic waters were found to be parasitised by an undescribed species of the cyclopoid copepod genus Sabellacheres M. Sars, 1862. Specimens of both sexes were studied using light microscopy and SEM, and compared with its congeners. The new species, Sabellacheres antarcticus n. sp., can be distinguished from its congeners by the shape and proportions of the body and brood-pouch, its 4-segmented antennae, the shape and length of the distal process of the second antennular segment, the position of leg 3, and the structure of the male maxilliped. This is only the second record of a species of this genus from the southern hemisphere. The new species was found on a single host species, as is typical for most species of Sabellacheres. A key for the identification of both sexes of the species of Sabellacheres is included.

Reproductive biology and population ecology of the marine fan worm Sabella pavonina (Savigny) (Polychaeta: Sabellidae)

The reproductive biology and population ecology of the sabellid polychaete, Sabella pavonina (Savigny) inhabiting an intertidal sand bank in Langstone Harbour, Portsmouth, was investigated between February 2007 and June 2009. ‘Blind’ thrown quadrats and sediment cores were used to characterise population distribution patterns at the site, and monthly coelomic fluid samples from 30 individuals were used to investigate the reproductive biology of the population, sex of the specimen, the presence of coelomocytes and the development of oocytes. Highest population densities (30.58 m−2 ± 8.05) were recorded on the low shore (0.4 m above chart datum) where the largest size particle fractions and lowest percentage organic content were found. Poisson distribution analysis showed the population was ‘clumped’ at the shore level, with a maximum number of 188 individuals in a 0.25 m2 quadrat, and within individual quadrats with up to 23 individuals in a 100 cm2 subsection. Sabella pavonina has an annual reproductive cycle which culminates in May/June spawning period. Oogenesis was a long process, first observed by the presence of small eggs (20 µm) from September onwards and maximum oocyte diameters were recorded (270 µm) between May and June prior to spawning. Between- and within-individual synchronicity was greatest in the early stages of oogenesis (October to February) when oocyte diameters ranged from 50–100 µm; however, increasing oocyte diameters were observed from March when rapid growth was initiated. Day length and sea temperature are candidates for exogenous cues controlling gametogenesis and possible mechanisms concerning fertilization in the species are discussed.

Branchiomma bairdi: a Caribbean hermaphrodite fan worm in the south-eastern Gulf of California (Polychaeta: Sabellidae)

Branchiomma bairdi, a fouling non-indigenous sabellid polychaete has been detected in the south-eastern Gulf of California, representing the first record in the eastern tropical Pacific, as its original distribution is the Caribbean Sea. The species was commonly found as isolated specimens but small aggregates with 4–12 individuals were also found on floating docks, on dock pilings, buoys and on hulls of vessels in the port of Mazatlan. Branchiomma bairdi is a simultaneous hermaphrodite with male and female gametes developing separately in the same segments. The sperm morphology suggests that the species is a free-spawner with external fertilization (ect-aquasperm type). A complete diagnosis is provided and a discussion about its systematics, reproduction and ecology is included.

Importance of seep primary production to Lophelia pertusa and associated fauna in the Gulf of Mexico

To investigate the importance of seep primary production to the nutrition of Lophelia pertusa and associated communities and examine local trophic interactions, we analyzed stable carbon, nitrogen, and sulfur compositions in seven quantitative L. pertusa community collections. A significant seep signature was only detected in one of the 35 species tested ( Provanna sculpta, a common seep gastropod) despite the presence of seep fauna at the three sample sites. A potential predator of L. pertusa was identified ( Coralliophila sp.), and a variety of other trophic interactions among the fauna occupying the coral framework were suggested by the data, including the galatheid crab Munidopsis sp. 2 feeding upon hydroids and the polychaete Eunice sp. feeding upon the sabellid polychaete Euratella sp. Stable carbon abundances were also determined for different sections of L. pertusa skeleton representing different stages in the growth and life of the aggregation. There was no temporal trend detected in the skeleton isotope values, suggesting that L. pertusa settles in these areas only after seepage has largely subsided. Isotope values of individual taxa that were collected from both L. pertusa and vestimentiferan habitats showed decreasing reliance upon seep primary production with average age of the vestimentiferan aggregation, and finally, no seep signature was detected in the coral collections. Together our data suggest that it is the presence of authigenic carbonate substrata, a product of past seep microbial activity, as well as hydrodynamic processes that drive L. pertusa occurrence at seep sites in the Gulf of Mexico, not nutritional dependence upon primary production by seep microbes.