Corresponding author: María Capa (
Academic editor: Greg Rouse
Detailed morphological study of more than 2600 North East Atlantic (NEA) sphaerodorids (
Capa M, Nygren A, Parapar J, Bakken T, Meißner K, Moreira J (2019) Systematic re-structure and new species of Sphaerodoridae (Annelida) after morphological revision and molecular phylogenetic analyses of the North East Atlantic fauna. ZooKeys 845: 1–97.
Long-bodied sphaerodorids included members of
The North East Atlantic (NEA), which includes the European part of the Atlantic, is dominated by deep ocean basins, including the Greenland, Lofoten, and Norwegian Basins, with depths down to 5000 m, and a shallow continental shelf along the European coast (Celtic Sea, Bay of Biscay and Iberian coast). This marine region holds a large diversity of
Species of
Species | Type locality | Depth |
---|---|---|
Banc Le Danois, Bay of Biscay | 1913 m | |
Kristineberg, Gullmarfjord, Sweden | 35 m | |
Off Møre og Romsdal, Norway | 960 m | |
Meriadzek Terrace, Bay of Biscay | 2156 m | |
Tarifa, Gibraltar Strait | 0.5 m | |
Dieppe, English Channel | (?) | |
North Sea | 172 m | |
Iceland | 600 m | |
Capbreton Canyon, Bay of Biscay | 984–1029 m | |
Artabro Gulf, NW Iberian Peninsula | 209 m | |
Kiel, Baltic Sea | 6–8 m | |
Bay of Biscay | 2430 m | |
Skagerrak | 460 m | |
Baiona, NW Iberian Peninsula | 7 m | |
North Iceland | 97 m | |
Western Iceland | 1162 m | |
Meriadzek Terrace, Bay of Biscay | 2325 m | |
Bay of Biscay | 4150 m | |
Banc Le Danois, Bay of Biscay | 1913 m | |
Off New England, USA, | continental shelf | |
Kara Sea | 0–220 m | |
Banc Le Danois, Bay of Biscay | 1913 m | |
Capbreton Canyon, Bay of Biscay | 990 | |
Eastern Antarctica | 380–3423 m | |
Denmark | intertidal (?) | |
Pas-de-Calais, English Channel | intertidal |
Some of the species described and reported from the NEA have a wide distribution range. For instance,
The aim of the present paper is to provide an accurate list of species of the so-called short- bodied sphaerodorids inhabiting the NEA sea floor, with updated descriptions, illustrations and a key for identification of morphospecies. DNA sequence data have been used to assess the evolutionary relationships between members of this family, evaluate the traditional classification, and better understand the boundaries between species and the genetic diversity within some of them.
Access to the following museum collections have allowed the revision of the type material of all available species and examination of additional non-type material (a total of over 2600 specimens):
Some of the contemporary expeditions that have contributed with material to this project are: BIOICE project (1991–2004) and the IceAGE project (ongoing since 2011) around Iceland (
Material examined was fixed in formalin and preserved in 70–80% ethanol or was directly preserved in 70–100% ethanol. Specimens were studied under dissecting and compound microscopes. Some dissected parapodia were mounted on a microscopic slide with glycerine. Drawings were made with an Olympus BX51 compound microscope with a drawing tube.
Micrographs were taken with a Dino-Lite digital microscope (AnMo Electronics Corporation, Taiwan) attached to the microscopes or with a LEICA DFC 420 camera attached to a Leica MZ 16A stereo microscope and a Leica DM 6000B compound microscopes (Leica Microsystems, Wetzlar, Germany). Stacks of multi-focus shots were merged into a single photograph to improve resolution with Leica APPLICATION SUITE v3.7 software (Leica Microsystems, Wetzlar, Germany).
Scanning electron micrographs were taken on specimens after dehydrating them in a series of 80, 90 and 100% ethanol before critical point or in a series of mixtures of absolute ethanol and Hexamethyldisilazane (HMDS) with the following ratios 2:1, 1:1, 1:2, and then into pure HMDS. The prepared samples were mounted on holders, sputter-coated with gold (10 nm thickness). The micromorphology and topography were determined using a Philips FEI INSPECT (Hillsboro, Oregon, USA) Scanning Electron Microscope (
Types of NEA species and others for comparison have been revisited when possible. This, together with the examination of additional material, provided additional information about the species distribution range.
Abbreviations used in figures:
A selection of specimens (86) of a variety of morphospecies collected in different localities in the North East Atlantic and some other Atlantic localities, and fixed in 100% ethanol were included in the analyses. DNA was extracted with QuickExtract DNA Extraction (Epicentre); a small piece, usually one or two parapodia, were put in 50–100 µl QuickExtract, and treated with 65 °C for 45 min followed by 2 min in 95 °C in a dry block thermostat. We used the primers 16SANNF (GCGGTATCCTGACCGTRCWAAGGTA) (
Overlapping sequence fragments were merged into consensus sequences using Geneious version 7.0.6 available from
The mitochondrial (COI and 16S rRNA) and nuclear data sets (18S rRNA and 28S rRNA) were analysed separately and combined using Bayesian inference (BA), and Maximum Likelihood (ML). Bayesian analyses (BAs) of separate and combined data sets were run in MrBayes 3.2 (
Partitions were unlinked for the parameters statefreq, revmat, shape, and pinvar. Rateprior for the partition rate multiplier was set to be variable. Number of generations was set to 3 million, with four parallel chains (three hot, one cold), sample frequency was set to 1000, and number of runs set to two. One fourth of the samples were discarded as burn-ins. Maximum likelihood analyses (ML) were performed in raxmlGUI (
The selected best-fit models were a general time reversible model with gamma distributed rate across sites and a proportion of the sites invariable (GTR+I+G) for the COI-partition with first and second positions, 16S, 18S, and 28S, while a Hasegawa, Kishino, and Yano model with gamma distributed rate across sites (HKY+G) was selected for the COI-partition with third positions.
The removal of poorly aligned positions from divergent regions of 16S, 18S and 28S from the alignments with GBLOCKS v. 0.91b did not affect the phylogenetic results, neither tree topology nor node supports (not shown); hence, all further analyses were conducted with the complete sequences for these markers.
Analyses of combined mitochondrial (COI + 16S rDNA) and nuclear DNA sequence data (18S rDNA, and 28S rDNA) recover four main well-supported clades (Fig.
Consensus tree obtained after Bayesian analysis of the combined nuclear and mitochondrial dataset. Coloured squared on nodes (as indicated in the bottom of the figure) indicate (from top left to bottom right): TBI, Bayesian posterior probabilities of total dataset; TML, Maximum Likelihood Boostrap values of total dataset; NUC, Bayesian posterior probabilities of nuclear partition; MIT, Bayesian posterior probabilities of mitochondrial partition.
The support values for Clade 1 are high after BI of the complete dataset, but moderate after ML analyses of the complete dataset or the partition of nuclear DNA. Analyses of only the mitochondrial sequence data (COI + 16S) did not recover Clade 1 as monophyletic and instead Clade 2 (Fig.
The type species of both genera are not included in the present analyses, but it is expected that
Seven subclades, congruent with the identified morphospecies, are found within Clade 1. Of these,
Six genetically distinct terminals showing long branches were recovered after analyses of molecular data besides the small morphological differences between them. Four of these specimens are herein identified as
Body generally short and ellipsoid. Head appendages smooth without spurs or basal papillae. Median antenna shorter, equal, or longer than lateral antennae; antenniform papillae absent. Dorsal macrotubercles stalked, without terminal papilla, arranged in up to six longitudinal rows, one transverse row per segment; smaller tubercles, similarly stalked, may form irregular rows on ventrum. Microtubercles (small tubercles with collar and terminal papilla) absent. Stout hooks in the first chaetiger absent. Parapodia with large ventral cirri. All chaetae compound.
The relative length of the median antenna with respect to the lateral ones was the single reported morphological feature separating the traditional
After analyses of molecular data performed in this study (Fig.
There seems to be some synapomorphies, related to the number of longitudinal rows of dorsal macrotubercles (Clade 3 and 4 in Fig.
Diagnostic features characterising
The species included in
Type locality: Zlarin, Adriatic Sea, 20–60 m.
Type locality: Elephant Island, north of Antarctic Peninsula, 262 m.
Type locality: northwest of Bermuda in 4700–3800 m.
Type locality: Off El Segundo, California, 18–45 m.
Type locality: Banc Le Danois, Bay of Biscay, 1913 m.
Type locality: Antarctic Peninsula, 128–165 m.
Type locality: North Sea, off Scotland, 172 m.
Type locality: Off Mozambique, 5119 m.
Type locality: Off Florida, Gulf of Mexico, 37 m.
Type locality: Off Florida, Gulf of Mexico, 48 m.
Banc Le Danois, Bay of Biscay,
(141 specs)
Body ellipsoid. Median antenna similar in length to lateral antennae; lateral antennae with three or four basal papillae each; antenniform papillae absent; palps with 2–3 basal papillae each. Dorsal macrotubercles stalked, without terminal papilla, arranged in five longitudinal rows in first 2–3 and last chaetigers, and six longitudinal rows in middle chaetigers; stalk and tubercle of similar length. Additional hemispherical papillae (ca. 10–12) distributed over dorsum in two irregular transverse rows, following a zig-zag pattern. Two rows of stalked smaller tubercles along ventrum, with two tubercles near each parapodium. Parapodia with acicular lobe from chaetiger 1, and large ventral cirri, surpassing length of acicular lobe. One ventral papilla from chaetiger 2–4; and one terminal postchaetal papilla from chaetiger 7–10.
Stylized drawings of selected dorsal (left) and ventral (right) segments of species of
Stylized drawings of parapodia, showing the relative position and arrangement of parapodial lobes, cirri, and papillae, in mid-body chaetigers of all sphaerodorid species reported in the North East Atlantic waters.
Intraspecific variation was assessed by examining a number of samples collected during the BIOICE project, in Iceland. Largest specimen examined 3.75 mm long, 1 mm wide and 28 chaetigers. Most Icelandic specimens measuring ca. 2 mm in length, 0.65 mm in width with 18–24 chaetigers. Median antenna usually as long as lateral antennae, depending on the state of contraction of specimens. Tentacular cirri shorter than prostomial appendages and provided each with two short papillae near the base. One dorsal transverse row of eight longer papillae (clavate or digitiform) behind median antenna and running at level of tentacular cirri; several digitiform papillae surrounding the mouth at each side (usually including one bifid and sometimes one trifid). Muscular pharynx extending over three chaetigers (5–7). In some elongated specimens stalk seems slightly longer than macrotubercle. Postchaetal papilla present from chaetiger 7 to last chaetiger. Parapodial antero-ventral papilla present from chaetigers 2–4, becoming more lateral in chaetigers 8–10; rounded to elongated in shape. Acicula is straight and chaetae blades show some gradation in length, being ventral ones slightly shorter in middle and posterior chaetigers. Several females with oocytes and males observed; both sexes show genital openings near the base of parapodia between chaetigers 8 and 9 (Fig.
The original description indicates that at least two specimens were found (holotype and another used for
Iceland (present study), Bay of Biscay (
Bathyal soft bottoms (1300–2537 m) (
North Sea,
(140 specs)
Body ellipsoid. Median antenna shorter than lateral antennae; lateral antennae and palps with 1–2 basal papillae each; antenniform papillae absent. Dorsal macrotubercles stalked, without terminal papilla, arranged in five longitudinal rows in first three chaetigers, and six longitudinal rows in following chaetigers; stalk and tubercle of similar length. Additional epithelial papillae on dorsum absent. Six to eight longitudinal rows of smaller tubercles with short stalk on ventrum; two tubercles near each parapodium slightly larger than others. Parapodia with long, oval acicular lobe from chaetiger 4; ventral cirri large, reaching or surpassing length of acicular lobe. Three parapodial papillae: one on antero-lateral surface from chaetiger 2, one ventral from chaetiger 3–4 and one terminal digitiform papilla from chaetiger 1, behind chaetae.
Additional material measuring 1.0–3.5 mm in length and 0.33–0.37 mm wide; with 10–20 (usually 17–18) chaetigers. Live specimens unpigmented, with dorsum covered with small sediment particles, except for dorsal macrotubercles (Fig.
Photographs of live specimens (included in analyses shown in Fig.
This species, originally described as
The present diagnosis is based in the original description of
We are reporting the species for the first time for the Norwegian Sea and Morocco. Previous records of the species include: North Sea (
Continental shelf, sandy sediments (70–1000 m) (
Body ellipsoid. Head with a median and a pair of lateral antennae; antenniform papillae absent; all appendages short. Tubercles sessile, conical, or pear-shaped, in four longitudinal rows, one transverse row per segment, except for first chaetiger with only two. Minute epithelial papillae on dorsal and ventral surfaces, in ca. 5–6 transverse rows per segment. Parapodia with rounded and small ventral cirri, not surpassing tip of acicular lobe. Stout hooks in anterior chaetigers absent. All chaetae simple, unidentate chaetae, enlarged subdistally, with serrated edge.
Referring to the main dorsal tubercles in
The genus is monotypic.
Type locality: Gullmarfjord, Sweden, 35 m.
Blåbergsholmen Island, Gullmarfjord, Sweden, 35 m.
(2 specs)
Body ellipsoid, up to 2.5 mm long. Head with short appendages, without spurs or basal papillae; antenniform papillae absent. Tubercles sessile, conical or pear-shaped, small, arranged in four longitudinal rows on dorsum, one transverse row per segment; except for first chaetiger with only two. Additional epithelial papillae minute over dorsal and ventral surfaces, in ca. 5–6 transverse rows per segment. Parapodia lacking papillae, acicular lobe, and ventral cirrus small and ellipsoid. Stout hooks in anterior chaetigers absent. All chaetae simple, unidentate, with broadened distal end, and serrated edge.
Largest specimens examined 4 mm long, 0.9 mm wide and 22 chaetigers. Smallest specimens with 19 chaetigers, 0.5 mm long. General morphology is homogenous among material studied. All specimens bear short prostomial appendages, ellipsoid or pear-shaped dorsal tubercles and minute epithelial papillae barely noticeable under stereomicroscope. One specimen (ZMUB 127260) is a gravid female with spheroid eggs occupying most of the body. Genital openings not observed in specimens examined.
Epithelium described as transparent in live specimens (
Skagerrak, ? United Kingdom (
Originally described as commensal of
Body short and ellipsoid. Head with short appendages, without spurs or basal papillae; antenniform papillae absent. Small tubercles or papillae spherical, sessile, smooth, without a terminal papilla, scattered over body surface and parapodia with apparent random distribution (over eight dorsal irregular longitudinal rows, and three or more transverse rows). Parapodia with short, rounded, ventral cirri, not surpassing the tip of acicular lobe. Stout hooks in anterior chaetigers absent. All chaetae simple unidentate, enlarged subdistally, with serrated edge.
The genus
The species currently considered in the genus are:
Type locality: Akutan Island, Alaska, 59 m.
Type locality: Cape Town, South Africa, unknown depth.
Type locality: Off South Carolina, USA, 799 m.
Type locality: Cádiz, Spain, 0.5–10 m.
Type locality: Greenland, Denmark Strait, 321 m.
Cádiz, South of Iberian Peninsula, 0.5–10 m.
Body short and ellipsoid, up to 0.6 mm long. Head with short appendages, without spurs or basal papillae; antenniform papillae absent. Epithelial papillae sessile, spherical, arranged in four transverse rows per segment. Ventrum with a pair of papillae near the parapodial bases and two additional longitudinal rows. Ventral papillae, in four transverse rows per segment. Microtubercles (small tubercles with a collar and terminal papillae) absent. Parapodia with a large dorsal papilla, digitiform acicular lobe, and spherical ventral cirrus. Stout hooks in anterior chaetigers absent. Six simple chaetae with serrated edge, enlarged subdistally, with a distal spine and filament in opposite directions.
No specimens were available for this study.
In the original description, the dorsal epithelial tubercles were termed macrotubercles (
Gibraltar Strait and Mediterranean coast of the Iberian Peninsula (
Littoral algae and dentritic bottoms to 10 m (
Greenland Sea, off eastern Greenland in Denmark Strait, 321 m.
Body short and ellipsoid, up to 1.5 mm long. Head with short appendages, without spurs or basal papillae; antenniform papillae absent. Dorsum with sessile spherical papillae arranged in three transverse rows, and up to 18, per segment. Ventrum with a pair of papillae near each parapodial bases and two additional longitudinal rows. Parapodia without papillae; digitiform acicular lobe and spherical ventral cirrus. Six or seven simple chaetae with serrated edges, enlarged subdistally, with a distal spine and filament in opposite directions.
Paratype 1.5 mm long, 0.6 mm wide, with 19 chaetigers (anterior end on
The epithet of this species,
The species is known from Denmark Strait, East of Greenland (holotype), and the Norwegian Sea.
The specimens were found in soft bottom, in areas influenced with cold water (approximately 0 °C). The paratype was found inside the tube of an undescribed species of
Body short and cylindrical. Head with a median and a pair of lateral antennae; antenniform papillae absent or present; all appendages short. Tubercles sessile, spherical or hemispherical, arranged in two transverse rows per segment. Additional epithelial papillae on dorsal (sometimes absent) and ventral surfaces. Parapodia with elongated ventral cirri, as long as acicular lobe. Stout hooks in anterior chaetigers absent. All chaetae compound, unidentate, with serrated edge.
Analyses of molecular data presented here reveal that members of previously considered
It is here assumed that
Type locality: South Shetland Islands, Antarctica, 265 m.
Type locality: South of Durban, South Africa, 20 m.
Type locality: Skagerrak, North East Atlantic, 460 m.
Type locality: Pt. Hedland, Western Australia, shallow depth.
Type locality: Baiona, NW Spain, 7 m.
Type locality: Western Iceland, 1162 m.
Type locality: Geelong, Victoria, Australia, shallow depth (coralline algae).
Type locality: Mtwara, Tanzania, shallow depth (in coral reef).
Type locality: Antarctic Peninsula, 412 m.
Type locality: Diaz Point, Namibia, SW Africa, unknown depth.
Type locality: Antarctic Peninsula, 650 m.
Type locality: Southern California, ca. 150 m.
Challenger Plateau, Tasman Sea, 1523–1526 m.
Type locality: Macquarie Island, Southern Ocean, unknown depth.
Type locality: Peru Basin, 4162 m.
The name of this genus,
Skagerrak,
Holotype of
(6 specs)
Body short and cylindrical, up to 2.5 mm long. Prostomial appendages smooth, lacking spurs or basal papillae. Dorsal macrotubercles sessile, hemispherical, arranged in two transverse rows per segment, with five and six macrotubercles each, from segment 2. Dorsum with 4–6 additional papillae per segment in mid body. Ventrum with 6–8 hemispherical papillae per segment, arranged in nearly Ʌ-shaped. Females with a pair of large ventral papillae, or sexual structures, between chaetigers 6 and 7. Parapodia without papilla. Acicular lobe from chaetiger 2. Stout hooks absent in anterior chaetigers. Compound chaetae in all parapodia, 4–7, with short blades (up to four times as long as wide).
Specimens studied measured between 1.5 and 2.5 mm long and 0.3–0.5 mm wide. Live specimens translucent with white spots in macrutubercles (Fig.
Additional individuals found at 1400 m in Iceland (Fig.
This is the first record for this species in Iceland and the Norwegian Sea. It had previously been reported from Skagerrak and English Channel (
Sediments from 100 to 2500 m (at least) (
West Iceland,
Body short and cylindrical, up to 3.5 mm long. Prostomial appendages smooth, lacking spurs or basal papillae. Dorsal macrotubercles sessile, almost spherical, arranged in two transverse rows per segment, with six and seven macrotubercles each, from segment 3. Dorsum with seven additional rounded papillae per segment in mid body, arranged in seven longitudinal rows. Ventrum with up to eight papillae per segment in mid body, arranged in six longitudinal rows and forming a V on each segment. Females with a pair of larger tubercles in chaetigers 7–9. Parapodia with one papilla on anterior surface from chaetiger 3. Acicular lobe from chaetiger 1–2. Compound chaetae, 4–8, with short blades (up to five times as long as wide), showing some intra-fascicle variation in size.
Some males filled with sperm and females with oocytes. Sexual structures of males as ventral cirri basally inflated, and with pores on ventral surface on chaetiger 6. Females with pair of oval, distally opened tubercle located ventro-laterally to parapodia on chaetigers 6–7 (Fig.
Size range (type series): 2.5–3.1 mm long, 0.4 mm wide, with 17–20 chaetigers. Pigmentation absent in fixed specimens.
West Iceland (
Sandy sediments, at depths of 1162–1558 m (
Ensenada de Baiona, NW Iberian Peninsula,
(2 specs)
Body short and cylindrical, up to 2.5 mm long. Head appendages short, smooth, lacking spurs or basal papillae. Median antenna shorter than lateral antennae and palps. Antenniform papillae absent. Dorsal macrotubercles sessile, almost spherical, arranged in two transverse rows per segment, with six and seven macrotubercles each in midbody segments. Additional five papillae, hemispherical and small, per segment. Ventrum with six papillae per segment, hemispherical and small, arranged in a V-shape. Parapodia with one papilla on anterior surface. Acicular lobe from chaetiger 2, digitiform. Ventral cirri digitiform reaching acicular lobe tip. Compound chaetae (3–6) with short blades (up to five times as long as wide); all similar. Females with large tubercle near ventral edge of parapodia of chaetiger 6 and inflated ventral cirri of chaetigers 4–7. Males with a pair of oval tubercles, ventral cirri of chaetiger 6 also basally inflated.
The recent description of this species is complete and re-examination of material, even under the
NW Iberian Peninsula (
From gravel to muddy sand and sandy mud and seagrass (
Body generally short and ellipsoid, some species slender. Head with short appendages, with or without spurs or basal papillae; antenniform papillae absent or present. Four longitudinal rows of dorsal macrotubercles, one transverse row per segment. Macrotubercles sessile, spherical or hemispherical, pear-shaped or with terminal papilla. Microtubercles (small tubercles with a collar and terminal papillae) absent. Additional papillae over body surface and parapodia. Parapodia with cylindrical or pear-shaped ventral cirri, not surpassing the tip of acicular lobe. Stout hooks in anterior chaetigers absent. All chaetae compound.
The species included in the genus after this study are:
Type locality: North Carolina, USA, 640 m.
Type locality: Pacific Antarctic Ridge, 2216–2334 m.
Type locality: Artabro Gulf, NW Iberian Peninsula, 209 m.
Type locality: Dease Strait, northern Canadian Arctic, 82 m.
Type locality: Seno and Estero de Reloncaví, Chile, intertidal to 80 m.
Type locality: Off New England, USA, 400–1500 m.
Type locality: Peru Basin, 4152 m.
Type locality: Off Brazil, 3730–3783 m.
Type locality: Florida, Gulf of Mexico, 54 m.
Type locality: Chile-Peru Trench, Peru, 1296–1317 m.
Type locality: Bellingshausen Sea, Antarctica, 612–620 m.
Type locality: East of Malabar, Sydney, Australia, 82 m.
Type locality: São Paulo Ridge, South Atlantic, 4204 m.
Type locality: Chile-Peru Trench, Peru, 1296–1317 m.
Type locality: Terrasse de Meriadzek, Bay of Biscay, 2325 m.
?
Type locality: Antarctica, 1000 m.
Type locality: Off Bermuda, NW Atlantic, 1700 m.
Type locality: Bay of Biscay, 4150 m.
Type locality: Adriatic Sea, 20–60 m.
Type locality: Baja California, 957 m.
Type locality: Banda, Indonesia, unknown depth.
Type locality: Oahu Island, Hawaii, 68 m.
Type locality: Banc Le Danois, Bay of Biscay, 1913 m.
Type locality: Eastern Antarctica, 380–3423 m.
Type locality: Kara Sea, Artic Ocean, 220 m.
Type locality: Guinea Basin, South Atlantic, 5048–5443 m.
Type locality: Guinea and Angola basins, South Atlantic, 5048–5051 m.
Type locality: Banc Le Danois, Bay of Biscay, 1913 m.
Type locality: Baja California, 461 m.
Type locality: Capbreton Canyon, Bay of Biscay, 990–1040 m.
?
Type locality: Gulf of Suez, 30 m.
Type locality: off Durban, South Africa, 715–675 m.
Type locality: Gulf of Mexico, USA, 37–121 m.
Type locality: Jervis Bay, Australia, 1–40 m.
Ártabro Gulf, NW Iberian Peninsula,
Body short and ellipsoid, up to 1.75 mm long. Palps and antennae smooth, lacking spurs or basal papillae. Median antenna shorter than palps and lateral antennae. Antenniform papillae present. Four longitudinal rows of macrotubercles in a single transverse row per segment. Macrotubercles sessile, small, spherical to pear shaped. Additional small spherical papillae on dorsum (arranged in four irregular transverse rows with ca. 20 papillae per segment) and ventral surfaces. Parapodia conical, with 3–4 sub-equal papillae (1–2 ventral, one anterior, one dorsal). Acicular lobe from chaetiger 2. Ventral cirri digitiform as long as acicular lobe tip, or shorter. Compound chaetae with long blades (8–20 times as long as wide), unidentate and with serrated edge. Some live and fixed specimens have pigmented orange to brown macrotubercles. Some females with oocytes, without visible nucleus; genital pores observed between chaetiger 7 and 8.
Stylized drawings of selected dorsal and ventral segments of species of
This species is herein transferred to the genus
Specimens of
NW Iberian Peninsula (
Continental slope, in sandy-muddy sediments, 200–2200 m (
Meriadzek, Terrace, Bay of Biscay,
(2 specs)
Body cylindrical, with blunt anterior end, up to 4 mm long. Head appendages smooth, without spurs, median antenna shorter than other appendages. Antenniform papillae present. Dorsum with four longitudinal rows of macrotubercles in a single transverse row per segment, from segment 2. Macrotubercles sessile, spherical in anterior and pear-shaped in posterior segments. Additional small hemispherical papillae on dorsum, in four irregular transverse rows per segment, each segment with ca. 30 papillae. Ventrum with four slightly irregularly arranged transverse rows of papillae per segment, each segment with ca. 30–40 papillae. Parapodia digitiform from chaetiger 3, with ca. 12–14 rounded sub-equal papillae. Acicular lobe from segment 2. Ventral cirri digitiform surpassing acicular lobe tip. Compound chaetae with medium length blades (6–8 times as long as wide), showing slight gradation within fascicles.
For this species only the holotype is known. However, some specimens from Norway are herein considered as potentially belonging to the same species. There are, however, some differences between the holotype and the Norwegian specimens. Norwegian specimens lack antenniform papillae (Fig.
Re-examination of the holotype resulted in a different interpretation of some morphological attributes with respect of the original description. We now state the prostomial appendages to be small and simple, instead of the bifurcated median antenna described originally. The dorsal macrotubercles are not invaginated and neither dorsoventrally flattened anymore in the preserved specimen. The number and arrangement of papillae is not clear from the original description. Approximately 12–14 spherical papillae randomly distributed over parapodial surface have been counted after re-examination (Fig.
Bay of Biscay and the western Barents Sea (Desbruyères, 1980, present study).
No details were provided in the original description.
Bay of Biscay,
Body elongated, almost rounded in cross section, with blunt anterior end. Head appendages smooth, without spurs, median antenna shorter than other appendages. Antenniform papillae not conspicuous. Dorsum with four longitudinal rows macrotubercles in a single transverse row per segment, from segment 2. Macrotubercles large, sessile, spherical. Additional small spherical papillae on dorsum with unclear arrangement due to sediment covering epithelium. Ventrum with small hemispherical papillae. Parapodia digitiform from chaetiger 3, with 7–8 elongated papillae, larger papilla in dorso-distal position. Acicular lobe from segment 2. Ventral cirri digitiform surpassing acicular lobe tip. Approximately 20–25 compound chaetae with long blades (ca. 8–12 times as long as wide), showing slight gradation within fascicles.
The holotype has large, turgid, and almost spherical dorsal macrotubercles, but it is covered by a thin layer of sediment that makes the assessment of the number and arrangement of the small epithelial papillae over the dorsal and ventral body surface difficult (therefore Fig.
Only known from type locality.
No details were provided in the original description.
Banc Le Danois, Bay of Biscay,
(18 specs)
Body ellipsoid, with convex dorsum and slightly flattened dorsoventrally, up to 3 mm long. Head appendages smooth, without spurs, median antenna slightly shorter than other appendages. Antenniform papillae shorter than lateral antennae. Dorsum with four longitudinal rows of large, hemispherical sessile macrotubercles in a single transverse row per segment, from segment 2. Additional papillae on dorsum arranged in four irregular transverse rows. Ventrum with three transverse rows of papillae similar in shape and size to dorsal. Parapodia short and conical, with 2–3 small, rounded papillae: one on each anterior and posterior surfaces, one in the ventrum of some parapodia. Acicular lobe from segment 1. Ventral cirri digitiform reaching acicular lobe tip. Approx. 7–10 compound chaetae with medium length blades (ca. 5–6 times as long as wide); unidentate and with fine spinulation along its margin. Several paratypes were described as possessing orange macrotubercles (Desbruyères, 1980). One pair of genital structures between the base of parapodia 6 and 7.
Studied specimens measured 2–3 mm long. In all specimens macrotubercles are hemispherical. Some variation regarding the number of parapodial papillae has been observed. Most specimens present one hemispherical papilla on the anterior surface and a similar one on the posterior side, but a smaller ventral papilla may be also present. One pair of genital openings between the base of parapodia 6 and 7 in one specimen (
The shape of macrotubercles is remarkable: hemispherical, low and wide, with a rounded and smooth surface and
The invaginations described behind the lateral antennae in the original description, are here considered as the openings of the nuchal organs. The parapodial papillae were not described in the original description, and at least one hemispherical papilla was observed in the anterior parapodial surface, from chaetiger 6 in the holotype, and additional material present up to three parapodial papillae. Holotype is full of gametes but sexual structures or genital openings were not detected. Sexual structures are described in this species for the first time in additional material from Iceland.
The species is here newly reported for Iceland and the Barents Sea. It had previously been reported in Bay of Biscay (Desbruyères, 1980).
Sediments from 30 to 2750 m (Desbruyères, 1980, present study).
Borgenfjorden, Trondheimsfjord, 25 m.
(1 spec.)
Body ellipsoid, with convex dorsum and slightly flattened dorsoventrally, up to 1 mm long. Palps and antennae smooth, lacking spurs. Four longitudinal rows of dorsal macrotubercles, in a single transverse row per segment. Macrotubercles sessile, spherical to pear-shaped. Additional minute spherical papillae scattered on dorsum (approx. seven transverse rows with ca. 100 low papillae per segment), often inconspicuous. Ventrum with even smaller papillae in four transverse rows per segment, often inconspicuous. Parapodia with 20–40 spherical papillae. Acicular lobe from segment 1, small and rounded. Compound chaetae, numerous (up to 40 per fascicle), with blades slightly decreasing in length dorso-ventrally (3–8 times their width), unidentate, with finely serrated edge.
Size range of material examined: 0.6–0.9 mm long, 0.08–0.15 mm wide, with 21–30 chaetigers. The holotype is somehow more inflated and elongated than the paratypes. These are more flattened dorso-ventrally and bodies seem to be more ellipsoid. This could be due to body collapse or perhaps the holotype is inflated from preservation. Head appendages are small and conical in all specimens examined; antenniform papillae not observed. Paratypes are homogenous in the general shape of the body, presence of large parapodia, small ventral cirri and presence of numerous, medium length blade falcigers. They differ in the number of epithelial papillae observed, in part probably due to the different conditions of the epithelium. We suspect the body and parapodia bear numerous small spherical papillae but these are only conspicuous in well-preserved specimens, otherwise they look almost smooth. Nuchal organs pits observed in several specimens (e.g., Fig.
The specific epithet,
Most specimens were collected in the Trondheimsfjord, but also from Skagerrak.
Habitat soft bottom with mud, 10–25 m deep.
Kara Sea, Russia,
(ca 1480 specs)
Body ellipsoid, flattened dorsoventrally, up to 3 mm long. Body unpigmented; orange macrotubercles in live specimens, or brownish in fixed material. Head appendages smooth and digitiform. Tentacular cirri smaller than prostomial appendages. Dorsum with four longitudinal rows of large, spherical or pear-shaped sessile macrotubercles in a single transverse row per segment, from segment 2. Additional papillae on dorsum. First parapodia short and digitiform, with two rounded papillae on dorsal surface. Acicular lobe from segment 1. Eight to ten parapodial papillae. Ventral cirri digitiform shorter than acicular lobe tip. About eight compound chaetae with medium length blades (ca. ten times as long as wide); unidentate.
The single type specimen of this species (in the Museum natural d’Histoire naturelle in Paris) is apparently lost, and the original description and drawings (
Several of the specimens found and re-examined from museum collections had previously been identified as belonging to this species. However, they were misidentified in several cases, as there are other similar species in the North East Atlantic (as reported herein) and, as mentioned, different interpretation of the parapodial papillae and chaetal morphology according to previous records. The description and drawings by
The numerous specimens found from different localities in northern latitudes (and herein assigned to
It would therefore be most interesting to study in detail more material from intermediate localities (not found so far), as well as the genetic structures of these populations to test if they actually belong to a single lineage with a range of morphological features, or if the northern and southern forms (herein
Arctic and Nordic Seas (
Sediments, at shelf to slope depths (
Irminger Basin, SW of Iceland, North Atlantic Ocean, 63° 0.46'N, 28° 4'W, 1593 m.
Body ellipsoid, flattened dorsoventrally. Body unpigmented (fixed specimen). Head appendages smooth and digitiform. Tentacular cirri smaller than prostomial appendages. Dorsum with four longitudinal rows of large, sessile and pear-shaped macrotubercles in a single transverse row per segment, from segment 2. Additional papillae on dorsum and ventrum. Acicular lobe from segment 1. Parapodia with four papillae. Ventral cirri digitiform reaching tip of acicular lobe. Approximately eight compound chaetae with medium length blades (7–9 times as long as wide); unidentate.
Paratypes 1–2 mm long, 0.3 mm wide, 15–17 segments. Epithelial parapodial papillae are more evident in paratypes, and ventral papillae include of ca. 20 rounded and sub-equal papillae, arranged in four irregular transverse rows per segment (Fig.
This new species is dedicated to Joan Pons, a researcher from the Mediterranean Institute of Advanced Studies (IMEDEA), Balearic Islands, colleague, and friend.
Only known from type locality, the Irminger Basin in the North East Atlantic.
Sediments at ca. 1600 m.
Banc le Danois, Bay of Biscay,
(28 specs)
Body ellipsoid, flattened dorsoventrally, up to 5 mm long. Head appendages smooth, lacking spurs or basal papillae. Antenniform papillae present. Four longitudinal rows of macrotubercles, in a single transverse row per segment, from segment two. Macrotubercles sessile, pear-shaped or with terminal papilla. Small spherical papillae scattered on dorsal (four irregular transverse rows with ca. 30 papillae per segment) and on ventral surfaces (four irregular transverse rows per segment). Parapodia with acicular lobe from segment 1, with 16–19 rounded sub-equal papillae, apparently randomly arranged. Approximately 20–25 compound chaetae with long blades (9–13 times as long as wide).
Size range of material examined: 2–5 mm long; 0.8–1.5 mm wide; with 17–31 chaetigers. Sexual dimorphism or reproductive features not observed in paratypes or additional material examined. Everted pharynx bare (Fig.
The species was originally considered as belonging to
Newly recorded in southern Iceland (present study). Previously reported in Bay of Biscay and NW Iberian Peninsula (
Sediments at 1400–2000 m (
Capbreton Canyon, Bay of Biscay,
Body ellipsoid, flattened dorsoventrally, up to 3.2 mm long. Head appendages digitiform, lacking spurs. Median antenna shorter than palps and lateral antennae. Antenniform papillae present. Dorsum with four longitudinal rows of macrotubercles, in a single transverse row per segment, from segment 2. Macrotubercles sessile pear-shaped. Additional small spherical papillae on dorsum, arranged in 3–4 transverse rows per segment, each with ca. ten papillae. Ventrum with papillae, in 3–4 transverse rows per segment. Parapodia conical, with 7–10 sub-equal papillae uniformly distributed. Ventral cirri digitiform not surpassing acicular lobe tip. Approximately 6–12 compound chaetae with medium length blades (near six times their width), showing small gradation within fascicles; unidentate and subtle spinulation along its cutting margin.
According to the original description, the range of variation of material examined is 18–20 chaetigers, 1.7–3.1 mm long and 0.6–0.8 mm wide.
A combination of features may allow distinguishing
Capbreton Canyon, Bay of Biscay (
Soft bottoms at depths of between 990–1040 m.
Body ellipsoid, flattened dorsoventrally, up to 3 mm long. Body unpigmented; macrotubercles in live specimens orange, or brownish in fixed material. Head appendages smooth, digitiform. Tentacular cirri smaller than prostomial appendages. Dorsum with four longitudinal rows of large, spherical, or pear-shaped sessile macrotubercles in a single transverse row per segment, from segment 2. Additional papillae on dorsum. First parapodia short and digitiform, with two rounded papillae on dorsal surface. Acicular lobe from segment 1. Eight to ten parapodial papillae. Ventral cirri digitiform shorter than acicular lobe tip. Approximately eight compound chaetae with medium length blades (ca. ten times as long as wide); unidentate.
(5 specs)
These specimens were initially identified as
Iceland Sea, Svalbard, Barents Sea, and Skagerrak.
Continental shelf sediments (100–350 m).
Body short and ovoid, some forms slender. Prostomial appendages short, spherical or digitiform; median antenna shorter or as long as lateral antennae; antenniform papillae absent or present. Macrotubercles sessile or stalked; smooth, without terminal papilla, arranged in more or less clear longitudinal rows, one transverse row per segment, with at least seven macrotubercles each. Microtubercles absent. Additional papillae over body surface and parapodia. Parapodia with compound chaetae; stout hooks in anterior chaetigers absent.
In the present study, a clade was recovered containing species previously assembled under
The type species of the genus
The diagnosis of the genus
Species currently considered within
Type locality: Laptev Sea, 3–6.5 m.
Type locality: Capbreton Canyon, Bay of Biscay, 984–1029 m.
Type locality: Off Phi Phi Island, Andaman Sea, Thailand, 29 m.
Type locality: Yonge Reef, Great Barrier Reef, Australia, 4–12 m.
Type locality: Kiel, Baltic Sea, 6–8 m.
Type locality: Porto Novo, Madras, India, 1.5 m.
Type locality: Off eastern coast of South Africa, 172 m.
Type locality: Peru Basin, Pacific Ocean, 4163 m.
Type locality: Dieppe, English Channel, France.
Type locality: Barents Sea, 226 m.
Type locality: North of Iceland, 97 m.
Type locality: North of Iceland, 600 m.
Type locality: Alaska, USA, 10 m.
Type locality: Barents Sea, 290 m.
Type locality: Canada Basin, 1004 m.
Type locality: Sea of Japan, 33–62 m.
Type locality: E Florida, Gulf of Mexico, 34 m.
Type locality: Off New England, USA, shelf depths.
Type locality: Off Galera, Chile, 260 m.
Type locality: King George Island, Antarctica, 263 m.
Type locality: Monterey Bay, California, USA.
Type locality: Alaska, USA, 3 m.
Capbreton Canyon, Bay of Biscay, 984–1029 m.
(1 spec)
Body short and cylindrical, less than 3.5 mm long. Palps, lateral antennae, and tentacular cirri, with spurs or basal papillae (lateral antennae 6–8). Median antenna smooth, shorter than other head appendages. Antenniform papillae present. Dorsal macrotubercles sessile, almost spherical, arranged in eight longitudinal rows in a single transverse row per segment, from segment 3. Dorsum with additional large spherical papillae, arranged between macrotubercles in more or less clear transverse rows, 25–30 papilla per segment. Ventrum with ca. 20 small spherical papillae per segment in midbody, arranged in 3–4 transverse rows per segment. Parapodia with three papillae; two sub-equal spherical papillae on ventral and anterior surfaces, and one postchaetal terminal papilla. Acicular lobe from segment 3. Approximately 6–8 compound chaetae with medium blades (up to seven times as long as wide), showing slight intra-fascicle variation in size.
This species has been described in detail (
Stylized drawings of selected dorsal and ventral segments of species of
Capbreton Canyon, Bay of Biscay (
Soft bottoms between 100–1030 m (
Kiel, Baltic Sea, 6–8 m.
(16 specs)
Body short and ellipsoid. Prostomial appendages digitiform, smooth, longer than wide. Palps and lateral antennae with basal spurs or basal papillae, the later with 3–4 spurs. Median antenna as long as or slightly shorter than other head appendages. Antenniform papillae absent. Eight to nine longitudinal rows of spherical and sessile macrotubercles in one transverse row per segment. Additional spherical papillae arranged in three transverse rows per segment, in dorsum and ventrum. Parapodia with acicular lobe from chaetiger 3, digitiform; ventral cirri digitiform, projecting well beyond acicular lobe; four spherical parapodial papillae. Compound chaetae with medium length blades (6–7 times as long as wide), showing little dorso-ventral gradation; unidentate, finely serrated.
This species has been widely recorded across the North and Baltic seas (
New records for the Barents Sea, Norwegian Sea, and Kattegat. Reported in the North and Baltic seas (
Sandy and muddy sediments, 6–200 m (
NW Iceland,
Type series:
(17 specs)
Body ellipsoid with strongly convex dorsum and flat ventrum, up to 6 mm long. Median antenna and head appendages digitiform, elongated. Median antenna smooth, shorter than other head appendages. Lateral antennae and palps similar, with 4–10 papillae (spurs) on proximal half. Antenniform papillae absent. Tentacular cirri digitiform, with 2–3 elongated papillae on proximal third. Dorsal macrotubercles stalked, without terminal papilla, arranged in 10–12 longitudinal rows in mid-body chaetigers; stalk half as long as tubercle, with 0–1 small papilla on proximal half. Dorsum with up to additional 50–60 spherical-oval papillae with short stalk, in front of each row of macrotubercles, somewhat arranged in 3–4 irregular transverse rows roughly following a zig-zag pattern. Ventrum with ca. 20 papillae per segment in mid-body, arranged in at least four more or less defined transverse rows in a zig-zag pattern. Parapodia with digitiform acicular lobe from chaetiger 3; large ventral cirri, not surpassing the length of acicular lobe; mid-body parapodia with 7–8 papillae. Chaetae blades showing slight gradation in length between chaetigers, slightly shorter in posterior chaetigers; ca. 8–9 times longer than maximum width.
Photographs of live specimens, dorsal view.
Paratypes measuring 1.1–6.0 mm long, 0.4–0.9 mm wide, with 16–30 chaetigers. Most specimens measuring ca. 2–4 mm in length, 0.4–0.7 mm in width with 20–25 chaetigers. Two dark dorsal eyes behind lateral antennae observed in many paratypes. Some variation occurring in number of papillae and spurs on head appendages: lateral antennae and palps with at least four spurs and tentacular cirri with two short papillae near base. Macrotubercles numbering 7–11 on first chaetiger and usually 10–12 in mid-body. Small papilla at base of macrotubercle stalk not distinguished in all specimens, not related to size or degree of contraction of stalks or body. Short stalk of body papillae (dorsum and ventrum) not always distinguished. Variation in number and distribution of body, ventrum, and parapodial papillae similar to holotype. Pharynx extending over 3–4 chaetigers. Sexual dimorphism not observed in paratypes or additional material examined; several females with oocytes observed.
The three species recently described from Arctic waters (
This new species is dedicated to Celia Moreira, in regard of her support and friendship to her brother, JM.
Around Iceland and coastal Norwegian waters from the Skagerrak in the south to Finnmark in the north.
Soft bottoms, from gravelly sand to silt, at depths of 120–2074 m.
Dieppe, France, English Channel.
(3 specs).
Body ellipsoid. Prostomial appendages digitiform, elongated. Median antenna smooth, shorter than lateral antennae. Lateral antennae similar in length to palps, with 3–4 basal papillae (spurs). Tentacular cirri digitiform, smooth, slightly shorter than lateral appendages. Dorsal macrotubercles stalked, smooth, arranged in eight longitudinal rows in mid-body chaetigers; stalk as long as or shorter than tubercle. Dorsum with additional 10–12 rounded papillae between transverse rows of macrotubercles somewhat arranged in a zig-zag pattern. Ventrum with 3–4 transverse rows of papillae per segment. Parapodia with digitiform, large ventral cirri, and acicular lobe; parapodia without papillae, or with a spherical papilla in anterior surface. Approximately six chaetae per parapodium, with short blades (ca. four times as long as wide).
The species was described as bearing six rows of longitudinal and stalked macrotubercles (Fig.
This species has only been reported twice, from Dieppe, France (
English Channel and western coast UK. ? Atlantic coast of Iberian Peninsula, ? Mediterranean, ? Red Sea (
Among algae and shallow sediments (1–5 m). Also collected in planktonic samples (Southern, 1914).
Northwest Iceland,
(11 specs)
Body short and ellipsoid, less than 2 mm long. Prostomial appendages smooth, lacking spurs. Median antenna as long or slightly shorter than other prostomial appendages. Lateral antennae, palps, and tentacular cirri of similar shape and length. Antenniform papillae absent. 8–12 longitudinal rows of large spherical and sessile macrotubercles in one transverse row per mid-body segment. Dorsum without papillae; ventrum with seven (♂) or 9 (♀) spherical papillae per segment. Parapodia with 1–4 papillae. Acicular lobe from chaetigers 3–4, digitiform. Ventral cirri digitiform, projecting well beyond acicular lobe. Compound chaetae with short blades (less than five times its maximum width), showing little dorso-ventral gradation; unidentate and fine spinulation along its cutting margin.
This is the first report of this species from southern Greenland. Specimens show some minor variations to original description. The species was described with 20–25 chaetigers but specimens with less segments have been found (16–19, Fig.
Differences between this species and other congeners are the large, sessile, and spherical macrotubercles, arranged in one single transversal row of up to 12 per segment, and absence of any other dorsal papillae (Fig.
From East Iceland to South Greenland, Norwegian Sea (
Silty sand, at depths of 88–400 m (
Northern Iceland,
(51 specs)
Body ellipsoid, up to 8 mm long. Median antenna and prostomial appendages digitiform, elongated. Median antenna smooth, near half of length of lateral antennae. Lateral antennae longer than palps, with 6–10 basal papillae (spurs). Antenniform papillae absent. Tentacular cirri digitiform, with two elongated papillae on proximal third. Dorsal macrotubercles stalked, without terminal papilla, arranged in 11–12 longitudinal rows in mid-body chaetigers; stalk as long as or slightly longer than tubercle, with 1–3 small papillae along proximal half. Dorsum with additional 10–16 hemispherical spherical papillae in front of each row of macrotubercles, somewhat arranged in two irregular transverse rows following a zig-zag pattern. Ventrum with 10–18 papillae per chaetiger, arranged in three more or less defined transverse rows. Parapodia with digitiform acicular lobe from chaetiger 3; large ventral cirri, not surpassing the length of acicular lobe; midbody parapodia with 5–6 papillae. Chaetae blades showing gradation in length within and between chaetigers, slightly shorter in mid-body to posterior chaetigers; ca. six times longer than maximum width.
The description of this species is complete and
First record of the species in Svalbard and Norwegian Waters. Already reported around Iceland (
Mostly in muddy sediments (sandy silt and silt), 49–1253 m depth (
Off Maine, United States, North Atlantic Ocean, shelf depths.
(13 specs)
Body short and ellipsoid. Prostomial appendages digitiform, smooth, lacking spurs; median antenna as long as or slightly shorter than other head appendages. Antenniform papillae absent. Ten to twelve longitudinal rows of spherical and stalked macrotubercles in one transverse row per segment, in mid-body segments. Additional spherical papillae arranged in three transverse rows per segment, in dorsum and ventrum. Parapodia with acicular lobe from chaetiger 3, digitiform; ventral cirri digitiform, projecting well beyond acicular lobe; four spherical parapodial papillae. Compound chaetae with medium length blades (6–7 times as long as wide), showing little dorso-ventral gradation.
Reported as a common species in the North Atlantic and Arctic. However, some records should be reviewed as they could be misidentifications (e.g.,
Shelf or slope depths (
1 | Body elongate, with somewhat parallel sides (except for blunt anterior and tapering posterior ends). Two longitudinal rows of dorsal macrotubercles (large tubercles) with terminal papilla (one pair per segment) |
|
– | Body ellipsoid (sometimes elongate). Dorsal tubercles different |
|
2 | Parapodia with only simple chaetae |
|
– | Parapodia with only compound chaetae (except of, sometimes chaetiger 1) |
|
– | Parapodia with both compound and simple chaetae |
|
3 | Dorsum with four longitudinal rows of sessile macrotubercles, in a single transverse row per segment |
|
– | Dorsum with more than four longitudinal rows of tubercles |
|
4 | All chaetae simple, unidentate, enlarged subdistally. Macrotubercles and dorsal papillae small, most of dorsal surface smooth |
|
– | All chaetae compound. Large macrotubercles, covering most of dorsal surface. Additional papillae often present… |
|
5 | Dorsal macrotubercles stalked, without terminal papilla, arranged in up to six longitudinal rows, one transverse row per segment…. |
|
– | Dorsal macrotubercles (sometimes not clearly larger than other dorsal papillae) stalked or sessile, arranged in more than six longitudinal rows or in more than one transverse row per segment |
|
6 | Dorsum with additional 10–12 papillae per segment, in two irregular transverse rows, following a zig-zag pattern. One or two parapodial papillae |
|
– | Dorsum with additional epithelial papillae other than the six longitudinal rows of macrotubercles absent. Three parapodial papillae |
|
7 | Dorsal tubercles small and of similar size (difference in size between them less than twice), in several transverse rows per segment. All chaetae simple unidentate, enlarged subdistally… |
|
– | Dorsal tubercles include macrotubercles and papillae (less than half of the size of macrotubercles) |
|
8 | Dorsal tubercles in four irregular transverse rows per segment. Parapodia with a large dorsal papilla |
|
– | Dorsal tubercles in three irregular transverse rows per segment. Parapodia without papilla |
|
9 | Tubercles sessile, arranged in two transverse rows per segment |
|
– | Tubercles sessile or stalked, arranged in one single transverse row per segment |
|
10 | Dorsal macrotubercles sessile, hemispherical, arranged in two transverse rows per segment, with five and six macrotubercles each, from segment 2 |
|
– | Dorsal macrotubercles sessile, almost spherical, arranged in two transverse rows per segment, with six and seven macrotubercles each, from segment 3 |
|
11 | Dorsum with 4–6 additional papillae per segment in mid-body. Parapodia without papillae |
|
– | Dorsum with additional five papillae per segment in mid-body. Parapodia with one papilla on anterior surface |
|
12 | Dorsal macrotubercles hemispherical, clearly wider than high |
|
– | Dorsal macrotubercles spherical, pear-shaped or with a terminal papilla |
|
13 | ?Dorsal papillae star-shaped |
|
– | Dorsal papillae rounded (spherical, hemispherical, ellipsoid) |
|
14 | Parapodia with more than 10 papillae |
|
– | Parapodia with less than 10 papillae |
|
15 | Parapodia with ca. 12–14 papillae. Compound chaetae, 10–15, with medium length blades (ca. 6–8 times as long as wide) |
|
– | Parapodia with 20–40 spherical papillae. Compound chaetae, up to 40, with medium length blades (3–8 times as long as wide) |
|
– | Parapodia with ca. 16–19 papillae. Chaetae, 20–25, with long blades (9–13 times as long as wide) |
|
16 | Parapodia with more than five papillae |
|
– | Parapodia with less than five papillae |
|
17 | Parapodia with 7–8 papillae, larger papilla in dorso-distal position. Approximately 20–25 compound chaetae with long blades (ca. 8–12 times as long as wide) |
|
– | Eight to ten parapodial papillae. Approximately eight compound chaetae with medium length blades (ca. ten times as long as wide) |
|
18 | Parapodia with 3–4 sub-equal papillae. Compound chaetae with long blades (8–20 times as long as wide) |
|
– | Parapodia with four papillae. Ventral cirri digitiform reaching tip of acicular lobe. About eight compound chaetae with medium length blades (ca. 7–9 times as long as wide); unidentate |
|
19 | Dorsal macrotubercles sessile |
|
– | Dorsal macrotubercles stalked |
|
20 | Dorsum with additional papillae between transverse rows of macrotubercles |
|
– | No additional papillae covering dorsum |
|
21 | Lateral antennae with 6–8 spurs |
|
– | Lateral antennae with 3–4 spurs |
|
22 | Eight macrotubercles in mid-body segments |
|
– | Ten to 12 macrotubercles in mid-body segments |
|
23 | Lateral antennae and palps with spurs. Dorsal macrotubercles with stalk about half as long as tubercle, with 0–1 small papilla on proximal half. Parapodia with 7–8 papillae. Chaetae with blades about 8–9 times longer than wide |
|
– | Lateral antennae and palps with spurs. Dorsal macrotubercles with stalk as long as or slightly longer than tubercle, with 1–3 small papillae along proximal half. Parapodia with 5–6 papillae. Chaetae with blades ca. six times longer than wide |
|
– | Prostomial appendages lacking spurs. Dorsal macrotubercles with stalked shorther than tubercle, without basal papillae. Parapodia with four spherical parapodial papillae. Chaetae with blades 6–7 times as long as wide |
|
The North East Atlantic holds a large diversity of species belonging to the family
The present integrative taxonomic study, including morphological examination and DNA analyses of specimens, has allowed us to assess the presence of 25 species of short-bodied sphaerodorids including four new species:
Some of the most revealing outcomes of the present study are the results obtained after analyses of the DNA sequences of selected specimens. After some recent papers, the family
The phylogenetic hypothesis presented herein, is congruent with that presented by Capa et
The newly proposed classification suggests that the main feature characterising genera is the number of longitudinal and transverse rows of dorsal macrotubercles, and not so much the shape of these macrotubercles (as per
This study would have been unfeasible without the access to the material hosted by different institutions and the colleagues who collected, processed, and curated those samples. In this regards, we would like to thank collection managers and curators from NTNU University Museum, Norwegian University of Science and Technology, Trondheim, Natural History Collections, University of Bergen; Akvaplan-Niva, Tromsø; Museo Nacional de Ciencias Naturales, Madrid; Museo de Historia Natural, Universidade de Santiago de Compostela; Museum National d’Histoire Naturelle, Paris; Zoological Museum Hamburg, Hamburg; Deutsches Zentrum für Marine Biodiversitätsforschung (
Not reported in NEA waters