Corresponding author: Hiroshi Yamasaki (
Academic editor: P. Stoev
Kinorhynchs rarely show a wide distribution pattern, due to their putatively low dispersal capabilities and/or limited sampling efforts. In this study, a new kinorhynch species is described,
Yamasaki H, Grzelak K, Sørensen MV, Neuhaus B, George KH (2018)
The meiofauna, defined as the assemblage of microscopic benthic organisms passing through a 1 mm-sieve mesh and collected on a 40–63 µm-sieve mesh, is composed of various taxonomic groups, and occurs in diverse habitats including extreme environments such as polar regions, the deep sea, and seamounts (
In the present study, we describe a new kinorhynch species with a geographically and bathymetrically wide distribution, ranging from the Arctic Ocean to the Mediterranean Sea and from upper bathyal to lower abyssal depths. The interpopulational morphological variation of the new species is also discussed.
Kinorhynchs were obtained from meiofauna samples collected from the central mount of the Karasik Seamount, Langseth Ridge in the Arctic Ocean (by the R/V
Map of the sampling localities.
Data on sampling stations.
Sampling region | Station | Cruise | Date | Depth [m] | Latitude | Longitude | Gear |
---|---|---|---|---|---|---|---|
Langseth Ridge, central mount on Karasik Seamount | 152-1 | PS101 | 28.09.2016 | 903 |
|
multicorer | |
North of Svalbard | 31 | PS92 | 04.06.2015 | 1,656 |
|
box corer | |
North of Svalbard | 43 | PS92 | 15.06.2015 | 790 |
|
box corer | |
Sedlo Seamount | 717 | M60/1 | 24.11.2003 | 2,721 |
|
box corer | |
Mediterranean deep sea | 24 | M71/2 | 04.01.2007 | 2,789 |
|
multicorer | |
Mediterranean deep sea | 51 | M71/2 | 07.01.2007 | 4,323 |
|
multicorer | |
Mediterranean deep sea | 52 | M71/2 | 07.01.2007 | 4,326 |
|
multicorer | |
Mediterranean deep sea | 55 | M71/2 | 07.01.2007 | 4,332 |
|
multicorer | |
Mediterranean deep sea | 56 | M71/2 | 08.01.2007 | 4,327 |
|
multicorer | |
Mediterranean deep sea | 62 | M71/2 | 08.01.2007 | 4,396 |
|
multicorer | |
Mediterranean deep sea | 63 | M71/2 | 08.01.2007 | 4,395 |
|
multicorer | |
Mediterranean deep sea | 64 | M71/2 | 08.01.2007 | 4,399 |
|
multicorer | |
Mediterranean deep sea | 65 | M71/2 | 09.01.2007 | 4,403 |
|
multicorer | |
Mediterranean deep sea | 66 | M71/2 | 09.01.2007 | 4,401 |
|
multicorer | |
Mediterranean deep sea | 94 | M71/2 | 12.01.2007 | 4,147 |
|
multicorer | |
Mediterranean deep sea | 1167.1 | MSM14/1 | 11.01.2010 | 4,353 |
|
multicorer | |
Mediterranean deep sea | 1169.1 | MSM14/1 | 12.01.2010 | 4,344 |
|
multicorer | |
Anaximenes Seamount | 918 | M71/1 | 17.12.2006 | 2,043 |
|
multicorer | |
Anaximenes Seamount | 930 | M71/1 | 19.12.2006 | 675 |
|
multicorer |
Specimens for light microscopy (
Five specimens from the Karasik Seamount and 23 specimens from the Mediterranean deep sea were used for scanning electron microscopy (
The terminology follows
The species name is derived from the Latinized Greek
Holotype: Adult male (
Paratypes: Adults, collected in the Mediterranean Sea off Crete; four males and one female, collected at station 24 (
Additional material for
Additional material for
Deep-sea trench off Crete, Mediterranean Sea, (
Adult with head, neck, and eleven trunk segments (Figs
Measurements of adult
Total | Anaximenes Seamount | Mediterranean deep-sea off Crete | Sedlo Seamount | North of Svalbard | Karasik Seamount | |||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Range | Mean | SD |
|
Range | Mean | SD |
|
Range | Mean | SD |
|
|
Range | Mean | SD |
|
Range | Mean | SD | ||
tl | 56 | 186–253 | 219.3 | 15.5 | 3 | 205–234 | 215.4 | 15.9 | 30 | 186–253 | 217.8 | 16.5 | 0 | n.a. | 4 | 208–241 | 224.5 | 14.0 | 19 | 196–250 | 221.2 | 15.0 |
msw-5/6 | 30 | 42–59 | 50.2 | 4.3 | 2 | 48–48 | 47.9 | 0.3 | 13 | 42–54 | 48.0 | 3.5 | 1 | 49 | 4 | 56–59 | 58.0 | 1.4 | 10 | 46–56 | 50.5 | 2.5 |
msw/tl | 29 | 19–28% | 22.9% | 2.2% | 2 | 21–23% | 21.9% | 1.9% | 13 | 19–26% | 21.9% | 1.7% | 0 | n.a. | 4 | 23–28% | 25.9% | 2.1% | 10 | 21–26% | 23.2% | 1.7% |
sw-10 | 38 | 35–50 | 42.8 | 4.0 | 2 | 41–41 | 41.0 | 0.3 | 19 | 35–49 | 40.8 | 4.2 | 1 | 41 | 4 | 48–50 | 49.0 | 0.8 | 12 | 41–45 | 44.2 | 1.3 |
sw/tl | 37 | 16–24% | 19.7% | 1.6% | 2 | 18–20% | 18.7% | 1.6% | 19 | 16–22% | 19.2% | 1.6% | 0 | n.a. | 4 | 21–24% | 21.9% | 1.2% | 12 | 18–22% | 19.9% | 1.3% |
s1 | 46 | 25–38 | 31.8 | 2.9 | 2 | 29–31 | 29.9 | 1.0 | 25 | 25–37 | 31.6 | 3.1 | 1 | 30 | 4 | 27–29 | 28.3 | 1.0 | 14 | 31–38 | 33.6 | 1.6 |
s2 | 45 | 16–31 | 25.2 | 3.2 | 2 | 21–25 | 22.9 | 2.9 | 25 | 16–31 | 24.6 | 3.1 | 0 | n.a. | 4 | 19–23 | 21.3 | 1.7 | 14 | 23–29 | 27.6 | 1.7 |
s3 | 44 | 20–26 | 23.3 | 1.4 | 2 | 22–23 | 22.5 | 0.3 | 24 | 20–25 | 22.6 | 1.4 | 0 | n.a. | 4 | 23–26 | 24.5 | 1.3 | 14 | 23–26 | 24.1 | 1.1 |
s4 | 45 | 20–30 | 24.7 | 1.9 | 2 | 24–25 | 24.1 | 0.7 | 25 | 20–26 | 23.8 | 1.4 | 0 | n.a. | 4 | 27–30 | 28.0 | 1.4 | 14 | 24–27 | 25.7 | 1.1 |
s5 | 46 | 22–33 | 25.8 | 2.5 | 2 | 24–25 | 24.5 | 0.7 | 25 | 22–27 | 24.4 | 1.1 | 1 | 24 | 4 | 30–33 | 31.3 | 1.3 | 14 | 25–31 | 27.3 | 1.5 |
s6 | 46 | 25–36 | 28.7 | 2.5 | 2 | 25–28 | 26.6 | 2.3 | 25 | 25–32 | 27.4 | 1.7 | 1 | 27 | 4 | 32–36 | 33.8 | 1.7 | 14 | 27–32 | 29.9 | 1.4 |
s7 | 46 | 25–38 | 30.5 | 2.7 | 2 | 29–30 | 29.2 | 0.7 | 25 | 25–32 | 28.9 | 1.5 | 1 | 30 | 4 | 36–38 | 36.8 | 1.0 | 14 | 30–33 | 31.8 | 1.3 |
s8 | 46 | 29–43 | 33.8 | 3.0 | 2 | 30–34 | 31.9 | 2.6 | 25 | 29–37 | 32.5 | 2.0 | 1 | 30 | 4 | 40–43 | 41.3 | 1.3 | 14 | 32–36 | 34.4 | 1.3 |
s9 | 46 | 31–40 | 34.8 | 2.2 | 2 | 32–34 | 33.3 | 1.3 | 25 | 31–37 | 34.0 | 1.5 | 1 | 31 | 4 | 39–40 | 39.8 | 0.5 | 14 | 33–38 | 35.2 | 1.5 |
s10 | 46 | 32–50 | 39.3 | 4.8 | 2 | 32–37 | 34.5 | 2.9 | 25 | 34–39 | 36.4 | 1.4 | 1 | 36 | 4 | 36–41 | 38.3 | 2.2 | 14 | 40–50 | 45.8 | 3.1 |
s11 | 45 | 19–27 | 22.8 | 2.2 | 2 | 19–21 | 19.9 | 2.0 | 24 | 19–27 | 23.3 | 1.9 | 1 | 19 | 4 | 20–25 | 22.8 | 2.2 | 14 | 19–26 | 22.6 | 2.2 |
mds4 | 53 | 25–44 | 33.1 | 5.0 | 3 | 27–29 | 28.2 | 0.9 | 28 | 25–36 | 30.1 | 3.3 | 1 | 35 | 4 | 33–36 | 34.8 | 1.3 | 17 | 33–44 | 38.5 | 3.0 |
mds5 | 53 | 34–60 | 44.5 | 6.6 | 3 | 38–42 | 39.5 | 1.9 | 28 | 34–47 | 39.8 | 3.1 | 1 | 50 | 4 | 44–50 | 47.8 | 2.6 | 17 | 45–60 | 52.1 | 3.9 |
mds6 | 52 | 44–69 | 54.0 | 7.0 | 3 | 51–52 | 51.5 | 0.8 | 27 | 44–57 | 48.8 | 3.4 | 0 | n.a. | 4 | 48–60 | 55.0 | 5.6 | 18 | 56–69 | 62.0 | 3.6 |
mds7 | 53 | 56–92 | 71.4 | 11.5 | 3 | 60–69 | 63.7 | 4.6 | 29 | 56–69 | 63.0 | 3.4 | 1 | 68 | 3 | 75–76 | 75.3 | 0.6 | 17 | 79–92 | 86.6 | 4.4 |
mds8 | 48 | 71–108 | 88.0 | 11.2 | 2 | 84–85 | 84.5 | 0.3 | 27 | 71–88 | 79.5 | 4.6 | 1 | 101 | 4 | 89–99 | 95.5 | 4.7 | 14 | 95–108 | 101.9 | 4.2 |
ldt10 | 31 | 5–13 | 9.5 | 2.3 | 0 | n.a. | n.a. | n.a. | 12 | 5–9 | 7.2 | 1.3 | 0 | n.a. | 0 | n.a. | n.a. | n.a. | 19 | 8–13 | 10.9 | 1.2 |
lvt5 | 49 | 6–15 | 9.3 | 1.8 | 1 | 10–10 | 10.2 | n.a. | 28 | 6–15 | 9.7 | 2.1 | 0 | n.a. | 1 | 12–12 | n.a. | n.a. | 19 | 7–11 | 8.5 | 1.0 |
lvs6 | 51 | 22–43 | 31.7 | 5.4 | 3 | 27–32 | 29.6 | 2.3 | 27 | 22–38 | 28.0 | 3.6 | 1 | 35 | 4 | 30–35 | 33.5 | 2.4 | 16 | 32–43 | 37.7 | 3.0 |
lvs7 | 55 | 30–49 | 38.0 | 4.7 | 2 | 32–37 | 34.5 | 3.6 | 29 | 30–41 | 34.8 | 2.9 | 1 | 42 | 4 | 37–41 | 39.0 | 1.8 | 19 | 38–49 | 42.8 | 3.0 |
lvs8 | 56 | 37–65 | 48.4 | 7.0 | 3 | 42–46 | 43.7 | 2.1 | 29 | 37–50 | 43.9 | 3.7 | 1 | 45 | 4 | 47–61 | 54.5 | 7.0 | 19 | 46–65 | 55.0 | 5.2 |
lvs9 | 57 | 49–90 | 61.9 | 11.4 | 3 | 50–57 | 54.5 | 3.6 | 30 | 49–64 | 55.9 | 3.8 | 1 | 83 | 4 | 58–88 | 72.8 | 15.9 | 19 | 55–90 | 69.1 | 12.8 |
lvs9 (m) | 25 | 50–90 | 66.2 | 14.9 | 1 | 56–56 | n.a. | n.a. | 15 | 50–62 | 55.5 | 3.1 | 1 | 83 | 2 | 85–88 | 86.5 | 2.1 | 7 | 80–90 | 84.9 | 3.9 |
lvs9 (f) | 32 | 49–83 | 58.6 | 6.1 | 2 | 50–57 | 53.9 | 4.9 | 15 | 49–64 | 56.4 | 4.4 | 0 | n.a. | 2 | 58–60 | 59.0 | 1.4 | 12 | 55–64 | 59.9 | 3.2 |
lts | 56 | 114–184 | 154.4 | 14.5 | 3 | 153–155 | 153.4 | 1.4 | 29 | 114–176 | 155.8 | 17.1 | 1 | 184 | 4 | 138–161 | 147.0 | 9.8 | 19 | 129–165 | 152.6 | 10.4 |
ltas | 25 | 44–61 | 54.7 | 4.4 | 2 | 57–61 | 59.1 | 2.8 | 10 | 44–60 | 52.4 | 5.1 | 0 | n.a. | 2 | 51–52 | 51.5 | 0.7 | 11 | 52–61 | 56.7 | 2.5 |
lts/tl | 55 | 52–86% | 70.5% | 7.2% | 3 | 65–75% | 71.5% | 5.3% | 29 | 57–86% | 71.9% | 8.2% | 0 | n.a. | 4 | 63–69% | 65.5% | 3.1% | 19 | 52–78% | 69.3% | 5.9% |
ltas/tl | 25 | 20–29% | 25.2% | 2.5% | 2 | 28–29% | 28.7% | 1.1% | 10 | 20–28% | 23.9% | 2.4% | 0 | n.a. | 2 | 22–25% | 23.6% | 1.9% | 11 | 22–29% | 26.0% | 2.1% |
Summary of locations of cuticular structures and appendages in
Position | md | pd | sd | ld | ml | sl | la | lv | vl | vm |
---|---|---|---|---|---|---|---|---|---|---|
segment | ||||||||||
1 | gco1, gco1 | ss | ss | gco1 | ||||||
2 | gco1, ss | ss | gco1, ss | |||||||
3 | gco1 | gco1 | ||||||||
4 | ac | gco1 | gco1 | |||||||
5 | ac | gco1 | tu | gco1 | ||||||
6 | ac | gco1, ss | ss | ac | ss, gco1 | |||||
7 | ac | gco1 | ac | |||||||
8 | ac | gco1, ss | ac | gco1 | ||||||
9 | gco1 | ss | si | ac | ss | gco1 | ||||
10 | gco1, gco1 | ss | tu | ss | gco1 | |||||
11 | gco1, gco1 | ss | pe×3 (m), ltas (f) | lts |
Head consisting of retractable mouth cone and introvert (Fig.
Neck with 16 placids (Figs
Segment 1 consisting of complete cuticular ring. Sensory spots located in subdorsal and laterodorsal position (Figs
Polar-coordinate diagram of mouth cone, introvert, and placids in
Segment 2 with complete cuticular ring as segment 1. This and following eight segments with thick pachycyclus at anterior margin of each segment (Figs
Segment 3 and following eight segments consisting of one tergal and two sternal plates (Fig.
Segment 4 with middorsal acicular spine (Figs
Segment 5 with middorsal acicular spine and lateroventral tubes (Figs
Segment 6 with middorsal and lateroventral acicular spines (Figs
Segment 7 with middorsal and lateroventral acicular spines (Figs
Segment 8 with middorsal and lateroventral acicular spines (Figs
Segment 9 with lateroventral acicular spines (Figs
Segment 10 with laterodorsal tubes (Figs
Segment 11 with lateral terminal spines (Figs
With respect to other characters, the spine/tube pattern of
The head morphology of
There are few other kinorhynchs which have been reported to show either a geographically or a bathymetrically wide distribution. Species with a geographically wide distribution are e.g.,
The morphological comparison between populations of
Box plot for the spine-lengths comparison among populations of
Considering the geographically and bathymetrically wide distribution of
Whichever hypothesis is correct, all populations in this study are undoubtedly closely related to each other. They have expanded their habitat range with or without speciation, however, their distribution process is open to question: did they distribute from the Arctic Ocean via the Atlantic Ocean to the Mediterranean, from the Mediterranean via the Atlantic Ocean to the Arctic Ocean, or from the Atlantic Ocean to both the Arctic Ocean and the Mediterranean? Indeed the species represents interesting material for studying the “meiofauna paradox” or the “everything is everywhere hypothesis”. We cannot provide a strongly-supported answer based on our current data. Further data about the species distribution range and population connectivity would also enable us to approach the question in future studies.
We greatly appreciate Prof. Pedro Martínez Arbizu (Senckenberg am Meer, Abt. Deutsches Zentrum für Marine Biodiversitätsforschung DZMB) for providing the specimens collected during the expedition M71/2 by R/V