Anterior Chaetigers Research Articles

Revision of Chloeia Savigny in Lamarck, 1818 from tropical American seas (Annelida, Amphinomidae).

The species of Chloeia Savigny in Lamarck, 1818 include some of the most colorful amphinomid annelids in tropical seas. Their pigmentation patterns can be diagnostic but because some pigments may fade after ethanol preservation, they have been disregarded as useful taxonomic characters. In this contribution we revise the tropical American species of Chloeia, and we confirm stability of pigmentation patterns, the presence of cirriform branchiae along a few anterior chaetigers, and emphasize the size of eyes and of ventral cirri as diagnostic characters. Five species are redescribed and two ones are newly described; the redescribed species are C. entypa Chamberlin, 1919 from Western Mexico, C. euglochis Ehlers, 1887 from the Grand Caribbean (reinstated), C. pinnata Moore, 1911 from Southern California (extended southwards in Western Mexico), C. pseudeuglochis Augener, 1922 from Pacific Costa Rica (includes several records for a colorful shallow water species in the Eastern Pacific), and C. viridis Schmarda, 1861 from the Grand Caribbean, which is restricted to specimens having a single, dorsal longitudinal T-shaped band. New species are Chloeia nuriae sp. n. from the Gulf of California, and C. paulayi sp. n. from the Gulf of Mexico . Two other species previously recorded for the region, C. conspicua Horst, 1910 and C. flava (Pallas, 1766) are briefly characterized in order to avoid future misidentifications. Further, C. candida Kinberg, 1857 from the Virgin Islands, is regarded as indeterminable. A key to identify tropical American species of Chloeia is also included.

Revision of Meiodorvillea Jumars, 1974 (Annelida: Dorvilleidae) including descriptions of three new species from the Southwestern Atlantic Ocean.

Meiodorvillea Jumars, 1974 is a little-known genus of Dorvilleidae Chamberlin, 1919, characterized by its small size and reduced appendages and jaw apparatus. A revision of the genus is presented, including analysis of the type material of M. minuta (Hartman, 1965) and M. apalpata Jumars, 1974, as well as specimens collected from shelf and slope continental areas in Brazil. A neotype was designated for M. minuta and its distribution was extended to Brazil. The identity of M. chilensis (Hartmann-Schröder, 1965) is questioned and three new species from 21 to 1,300.7 meters depth are also described. Meiodorvillea penhae sp. nov. has furcate chaeta only in the first anterior chaetigers. In contrast, Meiodorvillea hartmanae sp. nov. has very small palps and asymmetrical thin furcate chaeta and Meiodorvillea jumarsi sp. nov. has dorsal cirri and geniculate chaeta only in the first anterior chaetigers.

Two new Scolelepis species (Annelida: Spionidae) from the Yellow Sea in Korea.

Two new spionid polychaetes of the genus Scolelepis from the intertidal habitats of the Yellow Sea in Korea are described and illustrated. Scolelepis (Parascolelepis) anterobranchiata sp. nov. is characterized by a combination of the following characteristic: palps with smooth globular expansions at the basal part, branchiae appearing in the anterior part of the body, absence of notochaetae in chaetiger 1, notopodial postchaetal lamellae partially fused with branchiae in anterior chaetigers, and neuropodial hooded hooks appearing from chaetigers 1819 with two pairs of teeth surmounting a well-developed main fang. Scolelepis (Scolelepis) rubra sp. nov. can be distinguished from its congeners by the following characteristics: reddish-pink body, presence of notochaetae in chaetiger 1, branchiae approximately twice as long as notopodial postchaetal lamellae, neuropodial bidentate hooded hooks usually appearing from chaetigers 2631, and presence of notopodial hooded hooks in posterior chaetigers. Based on molecular data, the sequences of the two new species showed relatively large genetic distances from other Scolelepis species in COI (15.819.5%) and 16S rDNA (4.915.8%). Morphological variability of prostomial shape in the genus Scolelepis is discussed for the first time.

Four new species of Pilargidae (Annelida: Pilarginae) from the Gulf of Thailand.

Four new species belonging to the Family Pilargidae, Ancistrosyllis kornkanokae sp. nov., A. nakkaritae sp. nov., Cabira saithipae sp. nov., and C. thailandica sp. nov. were collected from 927 m depth in soft sediments in the Songkhla Sea, Gulf of Thailand. Ancistrosyllis kornkanokae sp. nov. can be distinguished from other species in the genus by the presence of a small median antenna on the prostomium; two pairs of elongate tentacular cirri; and short limbate neurochaetae with unidentate curved pointed tips. Ancistrosyllis nakkaritae sp. nov. is characterized by having a conspicuous median antenna and elongate lateral antennae longer than palps; and short limbate neurochaetae with bifid tips. While Cabira saithipae sp. nov. is characterized by the presence of the first notopodial hook at chaetiger eight, large, conical papillae ont chaetigers 717 and the presence of both short, recurved tipped and short, curved tip chaetae in anterior chaetigers. Cabira thailandica sp. nov. is distinguished from other species in the genus by the first notopodial hooks occurring at chaetiger seven and the presence of long, non-limbate capillary neurochaetae with bidentate tips. Updated keys to the genera Ancistrosyllis and Cabira are also provided.

New species of Microspio Mesnil, 1896 (Annelida: Spionidae), with additions to the description of M. pigmentata (Reish, 1959) and comparative notes on all members of the genus

Three new species of Microspio were found in collections from a range of depths including shallow water in Bermuda, the continental shelf off Massachusetts, and deep water in the South China Sea off Brunei. Microspio fischeri, new species, is associated with shallow water sponges in Bermuda where it is a prey species of a predatory syllid; it is characterized by the medial placement of the first pair of branchiae as well as unusual notopodial capillaries in anterior chaetigers and enlarged notopodial lobes in posterior chaetigers. Microspio lydonia, new species, from the continental shelf on the east coast of the United States is distinguished from M. pigmentata (Reish, 1959) from the west coast by differences in the structure of the nuchal organs and hooded hooks, pigmentation, and Methyl Green staining patterns. Additions to the description of M. pigmentata include illustration of the nuchal organs and dorsal ciliary bands. Microspio ariena, new species, from deep water in the South China Sea off Brunei has enlarged branchiae with large glands that stain deeply with Methyl Green on a few anterior chaetigers, followed by much smaller branchiae on additional chaetigers. The three new species bring the total of described species in the genus to twenty-one, although some species remain problematic. A table comparing important characteristics of all 21 known species of Microspio is included.

<p class="ZootaxaTitle"><strong>New insights in the biogeographical distributions of two Spionidae (Annelida) from the NE Atlantic and Mediterranean French coasts</strong></p>

We report the first occurrences of Spiophanes afer Meißner, 2005 and Prionospio cristaventralis Delgado-Blas, Díaz-Díaz & Viéitez, 2018 from French marine waters (from the southern part of the Bay of Biscay in NE Atlantic, and the Gulf of Lion in the Mediterranean Sea). Morphological characters of S. afer include the presence of an occipital antenna, dorsal ciliated organs extending to chaetigers 13–15, neuropodial hooks from chaetiger 15, ventrolateral intersegmental pouches from chaetigers 14–15, chaetal spreaders of “2+3 type”, and conspicuous dark brown pigmentation on parapodia of chaetigers 9–13. Prionospio cristaventralis has four pairs of branchiae (1st and 4th pinnate, 2nd and 3rd apinnate), ventral crests from chaetigers 11–12, high dorsal crests on chaetigers 10–11, and very large notopodial prechaetal lamellae on anterior chaetigers. Both records represent northern extensions of their known distributions. However, the presence of S. afer on French coasts may have been overlooked for several decades. The validity of the recently proposed Spiophanes adriaticus is questioned.

Morphology and reproductive biology of a new Pseudopolydora (Annelida: Spionidae) species from the Arabian Gulf

The Asian Pacific spionid polychaete worm Pseudopolydora paucibranchiata (Okuda, 1937) has been repeatedly reported from the Arabian Gulf and the Arabian Sea. Our recent molecular study showed that the Pacific and the Arabian populations of these worms are not conspecific. Here we describe adult, gamete, and larval morphology of worms from the Arabian Gulf, Kuwait, as the new species Pseudopolydora arabica sp. nov. Adults are characterized by the presence of intense yellow pigment on the prostomium, the dorsal side of the anterior chaetigers, and up to 50 ramified yellow chromatophores on each palp. Males produce thread-like wavy spermatophores about 10 μm in diameter and up to 2 mm long. Females store sperm in seminal receptacles on the dorsal side of fertile chaetigers and lay up to 1500 eggs into 35 capsules joined to each other in a string; each is attached by one stalk to the inner wall of the tube. Eggs are 100−103 μm in diameter, with smooth and thin envelopes, which develop into 3-chaetiger larvae inside the capsules. Hatched larvae are planktotrophic and settle and metamorphose at about 17 chaetigers. Adults inhabit silty tubes in soft sediments forming aggregations of up to 50,000 individuals per 1 m2.

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.

Three new species of Syllis Savigny in Lamarck, 1818 (Annelida: Syllidae) from the south coast of South Africa.

Over the last five decades, only two new species of Syllis (Syllidae, Annelida) have been described from South Africa, suggesting a greatly underestimated richness and the expectation that many more indigenous species still remain undescribed. In this paper, we describe three new species from algal turf along a rocky shore on the south coast of South Africa. All three species are characterised by having pseudo-simple chaetae by loss of blade and enlargement of shafts together with compound heterogomph bidentate falcigers. Syllis zahri sp. nov. (up to 5 mm long) is characterised by light pink to light brown colouration on its prostomium and anterior chaetigers, dark transverse bars that fade towards the posterior region, superior anterior chaetae having short spines and posterior parapodia with distally hollow aciculae. Syllis jaylani sp. nov. (up to 7 mm long) is narrow anteriorly, relatively wider at midbody and tapers posteriorly toward the pygidium, has a pharyngeal tooth slightly back from the anterior margin, strongly bidentate chaetae with teeth perpendicular to the main shaft, thin sinuose bidentate ventral simple chaetae with a serrated edge and pseudo-simple chaetae with a serrated edge in anterior parapodia. Syllis bunaa sp. nov. (up to 9 mm long) shows a characteristic dark brown colouration on its prostomium and anterior region, is distinctly rounded dorsally, and has unidentate or minutely bidentate chaetae, up to three pseudo-simple chaetae on parapodia along the whole body and posterior ventral simple chaetae that are thick with rounded tips or sinuose with a serrated inner edge.

Revision of Fauveliopsidae Hartman, 1971 (Annelida, Sedentaria).

Revision of Fauveliopsidae Hartman, 1971 (Annelida, Sedentaria).

Sinkhole and brackish water nereidid polychaetes: Revision of Stenoninereis Wesenberg-Lund, 1958 (Annelida)

Stenoninereis species are nereidids with a small body (ca. 35 chaetigers), dorsal cirri with conspicuous cirrophores and cirrostyles, bare pharynx, and lack of neuropodial ventral ligules throughout the body. Currently, there are two valid species, S.martini Wesenberg-Lund, 1958 from the Lesser Antilles and S.tecolutlensis de León-González & Solís-Weiss, 1997 from Eastern Mexico. Niconlackeyi Hartman, 1958 has been regarded as a junior synonym of S.martini. The examination of type and topotype specimens indicated that N.lackeyi is a distinct species and both species are redescribed, S.martini is restricted to the Caribbean islands, and N.lackeyi is reinstated and transferred to Stenoninereis. Further, Puerto Rican specimens differ from these known species and a new species, S.elisae is also described, featured mainly by large cirrophores and short cirrostyles in anterior and middle chaetigers. Further discussions about their morphology and phylogenetic affinities and a key to identify all known Stenoninereis species are also included.

Species of Eunicidae (Annelida, Errantia, Eunicida) from rhodolith beds off the states of Paraíba and Pernambuco, northeastern Brazilian coast.

Members of one species of Leodice Lamarck, 1818, one species of Lysidice Lamarck, 1818, and another of Palola Gray in Stair, 1847 were found among material from rhodolith beds, collected off the states of Paraíba and Pernambuco, northeastern Brazilian coast. Of those species, one is new to science and the other two are new records for the state of Pernambuco, although their occurrence on neighbouring areas was already known. Leodice calcaricola sp. nov. resembles morphologically L. miurai (Carrera-Parra Salazar-Vallejo, 1998) as members of both species share similar body size, moniliform prostomial appendages, similar numbers of branchial filaments (1-3 per branchia), and, especially, by having falcigers with bidentate blades on anterior chaetigers, and tridentate on posterior ones. These species differ, however, since specimens of L. calcaricola sp. nov. have distinctly shorter antennae and palps, homodont and heterodont pectinate chaetae, three types of aciculae and two subacicular hooks per midbody parapodium. The other two species which members were found on the rhodolith beds are Lysidice cf. unicornis (Grube, 1840) and Palola brasiliensis Zanol, Paiva Attolini, 2000. We describe herein new species to science and provide a redescription for L. cf. unicornis because the Brazilian specimens of this species have never been formally described.

Correction: Proceraea exoryxae sp. nov. (Annelida, Syllidae, Autolytinae), the first known polychaete miner tunneling into the tunic of an ascidian.

[This corrects the article DOI: 10.7717/peerj.3374.].

Orbinia wui, a new species from China, with redescription of O. dicrochaeta Wu, 1962 (Annelida, Orbiniidae).

Two species of the genus Orbinia Quatrefages, 1865 are described including Orbinia dicrochaeta Wu, 1962 and Orbinia wui sp. n. The new species can easily be identified from other species in the genus by a combination of characters: branchiae first present from chaetiger 5, thoracic region with 14-16 chaetigers; first six thoracic neuropodia with 4-5 rows of uncini, with the last row short and curving ventral to anterior rows; subsequent thoracic neuropodia with four rows of subuluncini and one short row of uncini, arranged more densely than anterior chaetigers; both uncini and subuluncini surrounded by long sheath all of its length on concave side, sheath with developed transverse rows of barbs. This study suggests that the species of Orbinia may be divided into two groups. A taxonomic key and comparative table to all species of Orbinia is provided.

Diversity and phylogenetic relationships of North Atlantic Laonice Malmgren, 1867 (Spionidae, Annelida) including the description of a novel species

Spionid polychaetes are dominant members of many marine soft-bottom communities. As such, understanding their diversity and evolutionary history is of general interest. One spionid group in particular, Laonice, is known from the North Atlantic with several species occurring in deeper waters. We explored, as part of the IceAGE project, the biodiversity and evolution of Laonice using both morphology and mitochondrial cytochrome c oxidase subunit I (COI) gene data. Our data confirm the existence of at least seven lineages of Laonice in waters surrounding Iceland. Additionally, our sampling suggests species distributions of Laonice are similar to previous reports for other annelids, in that warmer waters south of Iceland appear to harbor more species, but further work is needed to clarify distribution patterns. Although our analysis was hampered by quality of preservation of animals from deep water, we recovered several species that were previously known to science (e.g., Laonice blakei, Laonice sarsi, Laonice cf. norgensis, and Laonice cirrata) and one new species. Laonice plumisetosa sp. nov. is characterized by having u-shaped nuchal organs not exceeding chaetiger 1 and the presence of stout capillaries with plush-like texture in parapodia of anterior chaetigers. Uncorrected genetic distances and phylogenetic analyses of COI data confirm these Laonice lineages are distinct. However, L. cirrata is composed of three subclades suggesting unrecognized diversity within this species. In the present paper, we aim to provide a preliminary phylogeny for Laonice and discuss our results in relation to the recently proposed subgenera for Laonice.

Laonicespecies (Polychaeta, Spionidae) from the Whittard Canyon (NE Atlantic) with descriptions of two new species

Four species ofLaonice(Annelida: Spionidae) were collected from the lower bathyal depths (3300–3700 m) in the Whittard Canyon, NE Atlantic. Two are herewith described as new species:Laonice whittardensissp. nov. andLaonice nataesp. nov. The other two areLaonice blakeiSikorski & Jirkov, 1988 andLaonice magnacristataMaciolek, 2000.Laonice whittardensishas genital pouches appearing from chaetiger 3, prostomium free of peristomium and bidentate hooks.Laonice nataebelongs to the subgenusAppelloefianov. with prostomium distinct from the peristomium, more than two vertical rows of capillaries in several anterior chaetigers, genital pouches present on a limited number of segments or totally absent. However, the absence of pronounced anterior widening of the body together with anterior branchiae, which are remarkably (nearly twice) longer than the notopodial postchaetal lobes, the narrow lanceolate notopodial postchaetal lobes, the pronounced pointedness of all postchaetal lobes (both notopodial and neuropodial) in the anterior half of body at least, and absence of genital pouches and the size of the body all distinguishL. nataefrom other species belonging to this subgenus. An identification key to all nine known deep-water (>400 m depth)Laonicespecies in North Atlantic is given and four previously recognized sub-generic groups are formally named:Laonice, Sarsianasubgen. nov.,Appelloefiasubgen. nov.,Norgensiasubgen. nov.

Proceraea exoryxae sp. nov. (Annelida, Syllidae, Autolytinae), the first known polychaete miner tunneling into the tunic of an ascidian.

While studying organisms living in association with the solitary tunicate Phallusia nigra (Ascidiacea, Ascidiidae) from a shallow fringing reef at Zeytouna Beach (Egyptian Red Sea), one of the collected ascidians showed peculiar perforations on its tunic. Once dissected, the perforations revealed to be the openings of a network of galleries excavated in the inner tunic (atrium) by at least six individuals of a polychaetous annelid. The worms belonged to the Autolytinae (Syllidae), a subfamily that is well known to include specialized predators and/or symbionts, mostly associated with cnidarians. The Red Sea worms are here described as Proceraea exoryxae sp. nov., which are anatomically distinguished by the combination of simple chaetae only in anterior chaetigers, and a unique trepan with 33 teeth in one outer ring where one large tooth alternates with one medium-sized tricuspid tooth, and one inner ring with small teeth located just behind the large teeth. Male and female epitokes were found together with atokous individuals within galleries. Proceraea exoryxae sp. nov. constitutes the first known miner in the Autolytinae and the second species in this taxon known to live symbiotically with ascidians. The implications of finding this specialized parasite are discussed considering that Phallusia nigra has been introduced worldwide, in tropical and sub-tropical ecosystems, where it has the potential of becoming invasive.

First Report of the Morphology and rDNA Sequences of Two Pseudopolydora Species (Annelida: Spionidae) from Japan.

The morphology of two Pseudopolydora species, P. cf. reticulata Radashevsky and Hsieh, 2000 and P. achaeta Radashevsky and Hsieh, 2000 are reported from Japan for the first time. Pseudopolydora cf. reticulata was collected from Japanese tidal flats, and individuals possess the characteristic netlike pigmentation on the dorsum of anterior chaetigers and the longitudinal black band along midline of caruncle. Pseudopolydora achaeta was collected from subtidal bottom mud of Onagawa Bay, and individuals have distinctive characteristics, such as intensive black pigmentation on dorsal and ventral sides of the anterior body and nearly straight vertical rows of major spines on the fifth chaetiger. The morphology of P. cf. reticulata is very similar to that of P. cf. kempi, with which it had been confused in Japan. We analyzed the 18S and 28S rRNA gene sequences of all five Pseudopolydora species recorded from Japan and found strong evidence that they are genetically distinct. Our analysis also suggests that boring polydorids have evolved among non-boring ones; the genus Pseudopolydora, which mostly shows the non-boring form, appears to have remained in a more ancestral condition.

Redescription of two species and five new species of Dispio Hartman, 1951(Spionidae: Polychaeta) from the eastern Pacific Coast and Caribbean Sea, with a review of the genus.

Available type material of Dispio uncinata Hartman, 1951 and D. mororoi Gibbs, 1971, as well as newly collected material from Venezuela and material deposited in the Los Angeles County Museum of Natural History, was examined. Several important differences were found between D. uncinata, D. mororoi, the new material deposited in the museum and the newly collected material from Venezuela, Panama and California. Dispio uncinata and D. mororoi are redescribed and five new species are also identified and described: D. anauncinata sp. nov., D. lenislamellata sp. nov., and D. longibranchiata sp. nov. are from Southern California, D. panamensis sp. nov. from Panama, and D. bescanzae sp. nov. from Venezuela. Morphological differences between species were recorded, particularly in reference to the shape of prostomium, and caruncle, size of peristomium, shape of notopodial and neuropodial postchaetal lamellae, branchiae from anterior chaetigers fused completely or partially to the notopodial lamellae, presence or abscent of accessory branchial pairs, structure of notopodial and neuropodial chaetae, notopodial and neuropodial lamellae overlapping or touching and other consistent characters. Results of the review of the material from Southern California indicates that D. uncinata is not found in this area of the Pacific, and we recommend that the wide distribution of this species should be taken with caution especially for those distant records from the type locality. A key to all species of Dispio is provided.

Histological and ultrastructural reconstruction of ventral epidermal glands of Spio (Polychaeta, Spionidae, Annelida)

With present study, we confirm that the ventral structures on anterior and middle chaetigers of two species of Spio are special kind of intraepidermal multicellular glands. The general anatomy and coherence morphology of these ventral epidermal glands (VEGs) were 3D-reconstructed based on semithin section series. Specific anatomical characters were explored using electron microscopy, such as scanning electron microscopy for characterization of gland pores and transmission electron microscopy for investigation into cytoanatomical details. The VEGs are tubular or acinar; their pores are spherical or lens-shaped. The glands consist of three cell types: secretory cells, sheath cells and canal cells, forming and strengthening the short gland duct and the pore region. The secretory cells are tightly packed into a single-layered, curved glandular epithelium. Secretory cells are separated from each other by thin projections of interstitial sheath cells. The apices of the secretory and sheath cells surround a tubular or vase-shaped extracellular space, the reservoir. The reservoir is traversed by microvilli of the secretory and sheath cells. Two sorts of microvilli characterize the apex of secretory cells: slender, elongated ones located at the periphery (outer microvilli), and shorter but thicker ones, arranged in a distinct collar in the centre (inner microvilli). Secretion, encased in regular secretory granules and discharged only at the apex’ centre, is guided through the space enclosed by the collar of inner microvilli. Though also consisting of numerous cells, the VEGs of Spio spp. are not comparable to parapodial glands described in other spionid taxa since they remain in a strictly intraepidermal position, are distant from parapodia and contain sheath cells. Nonetheless, the VEGs are very helpful for taxonomic work on representatives of the genus Spio and closely related genera.