J. Mar. Biol. Ass. U.K. (2002), 82, 4144/1^5
Printed in the United Kingdom
Polychaetes from the Irving, Meteor and Plato Seamounts,
North Atlantic Ocean: origin and geographical relationships
Patrick Gillet* and Jean-Claude DauvinO
*Institut d'Ecologie Appliquëe, Universitë Catholique de l'Ouest, B.P. 808, F-49008 Angers Cedex 01, France. E-mail: pgillet@uco.fr
O
Station Marine de Wimereux, Universitë de Lille 1, UMR 8013 ELICO, BP 80, F-62093 Wimereux, France.
E-mail: dauvin@pop.univ-lille1.fr
Data came from the Irving, Meteor and Plato seamounts and, were obtained during the Seamount 2
Expedition on board the R.V.`Le Suro|ª t' in 1993. On the three seamounts, polychaetes were sampled on 44
sites from 260 to 1800 m: 8 sites on Irving, 27 on Meteor and 9 on Plato. In all ¢ve seamounts, 1753
individuals were collected: 403 on Atlantis, 346 on Hyeres, 523 on Irving, 387 on Meteor and 94 on
Plato. The species richness from the ¢ve seamounts is 53: 31 on Atlantis, 24 on Hyeres, 20 on Irving, 28
on Meteor and 21 species on Plato. Only nine species are present on all ¢ve seamounts. Three families
Onuphidae, Amphinomidae and Eunicidae are dominant. Two groups of seamounts were identi¢ed by
cluster analysis: Atlantis and Hyeres and, Irving, Meteor and, Plato. The distribution of the polychaetes
collected on these ¢ve seamounts are compared with the polychaete fauna from the north Atlantic ocean.
INTRODUCTION
The polychaete fauna of south Azores seamounts was
studied during the Seamount 2 Expedition to evaluate
their faunal composition and to compare the origin and
the geographical distribution of the collected species with
the surrounding North Atlantic areas.
This paper is the second part of an earlier one (Gillet &
Dauvin, 2000), its objectives are i) to give the species
composition of the fauna found on three other seamounts
of the south Azores, Irving, Meteor and Plato, ii) to
compare the recorded species with those of two other
seamounts explored during the same cruise, Atlantis and
Hyeres (Gillet & Dauvin, 2000), and iii) to discuss the
geographical distribution of the species collected on these
seamounts with the polychaete fauna from the north
Atlantic ocean according to the geographical regions
de¢ned by Morton & Britton (2000a,b) and the colonisation of such isolated sites.
MATERIALS AND METHODS
The Seamount 2 Expedition in January ^ February 1993
with the RV `Le Suro|ª t' studied ¢ve south Azores seamounts: Atlantis, Hyeres, Irving, Meteor and Plato. The
main characteristics of equipment used and description of
the substrates were given in Gofas (1993). Samples were
collected using the Waren and Epibenthic dredges (mesh
size of 2 mm in the net) and a Beam Trawl (mesh size of
5 mm in the net) (Gillet & Dauvin, 2000). The mean
speed of the ship, during each 10 min samples, was 1.5 knot.
About 200 L of bioclastic sand was collected on the top
of the seamounts, a more variable quantity (25^100 L) of
hard substratum and/or organisms (basalt, sponges,
gorgones, coral . . .) was collected on the slope of the
seamount. Sorting and identi¢cation of Polychaetes found
Journal of the Marine Biological Association of the United Kingdom (2002)
on 44 sites (8 on Irving at 260^785 m, 27 on Meteor at
290^1610 m and, 9 on Plato at 520^1800 m) were made
as in Gillet & Dauvin (2000).
The faunal composition of the ¢ve seamounts is
compared with the Jaccard index and, cluster analysis is
carried out using the Lance and Williams (1967) algorithm
(b70.25).
RESULTS
Including Atlantis and Hyeres data, a total of 1753 individuals and 53 taxa were collected on 73 sites (66%) on a
total of 110 sites sampled during the Seamount 2 expedition (Table 1): 523 individuals and 20 taxa at Irving, 387
individuals and 28 taxa at Meteor, 94 individuals and 21
taxa on Plato, 403 individuals and 31 taxa at Atlantis and,
346 and 23 taxa at Hyeres. Three families dominate both
in species number and number of individuals per site:
Amphinomidae, Eunicidae and Onuphidae. The abundance is maximum on Irving (523 individuals) with a low
number of sites (8). On the contrary, the abundance is low
on Plato (94 individuals) with a similar number of sites.
Only nine species occurred at all ¢ve seamounts: Eunice
nicidioformis Treadwell, 1906, E. prognatha McIntosh, 1885,
Harmothoe impar (Johnston, 1839), Hyalinoecia tubicola (O.F.
Mu«ller, 1776), Lysidice ninetta Audouin & Milne-Edwards,
1834, Nothria conchylega (Sars, 1835), Notopygos megalops
McIntosh, 1885, Rhamphobrachium brevibrachiatum (Ehlers,
1875) and Sigalion squamosus (Delle Chiaje, 1830). Five
taxa occurred in four seamounts, two in three, 17 in two,
and 20 (38%) in only one seamount (Table 1).
There is a regular decrease in the number of species and
the number of individuals with depth as shown previously
by Gillet & Dauvin (2000). In bathyal depths greater than
1000 m, the number of taxa was less than ¢ve except in
4144.2
P. Gillet and J.-C. Dauvin
Polychaetes from the North Atlantic Ocean: origin and geographical relationships
Table 1. Number of individuals of each species of polychaetes found on the ¢ve North-Eastern Atlantic seamounts during the Seamount
2 expedition: Atlantis, Hyeres, Irving, Meteor and Plato.
Seamount
Species
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
Aglaophamus agilis Langerhans, 1880
Aglaophamus rubella (Michaelsen, 1897)
Amage gallasi Marion, 1875
Anaitides madeirensis (Langerhans, 1879)
Aphrodite aculeata Linnë, 1761
Chone duneri Malmgren, 1865
Chrysopetalum debile (Grube, 1855)
Cirratulidae undeterminated
Dalhousiella carpenteri McIntosh, 1901
Eclysippe vanelli (Fauvel, 1936)
Eulalia bilineata (Johston, 1839)
Eunice nicidioformis Treadwell, 1906
Eunice norvegica (Linnë, 1767)
Eunice pennata O.F. Muller, 1776
Eunice prognatha McIntosh, 1885
Eunice vittata (Delle Chiaje, 1828)
Euphrosine armadillo Sars, 1851
Euphrosine foliosa Audouin & Milne-Edwards, 1834
Glycera capitata Oersted, 1843
Glycera tesselata Grube, 1863
Harmothoe impar (Johnston, 1839)
Hermodice carunculata (Pallas, 1766)
Hyalinoecia tubicola (O.F. Muller, 1776)
Laena gra¤ti Langerhans, 1884
Lagisca extenuata (Grube, 1840)
Leocrates atlanticus (McIntosh, 1885)
Longibrachium n. sp.
Lumbrineriopsis paradoxa (Saint-Joseph, 1888)
Lumbrineris gracilis (Ehlers, 1868)
Lygdamis muratus Allen, 1904
Lysidice ninetta Audouin & Milne-Edwards, 1834
Neanthes kerguelensis McIntosh, 1885
Nereis rava Ehlers, 1868
Nothria conchylega (Sars, 1835)
Notomastus latericeus Sars, 1851
Notopygos megalops McIntosh, 1885
Ophiodromus £exuosus (Delle Chiaje, 1825)
Orbinia cuvierii (Audouin & Milne-Edwards, 1833)
Paradiopatra ¢ordica (Fauchald, 1974)
Paradiopatra quadricuspis (Sars, 1872)
Phalacrostemma elegans Fauvel, 1911
Pholoe sp.
Piromis eruca Clapare©de, 1870
Poecilochaetus serpens Allen, 1904
Pulliela armata Fauvel, 1929
Rhamphobrachium brevibrachiatum (Ehlers, 1875)
Sigalion squamosus (Delle Chiaje, 1830)
Sinonereis sp.
Syllidae undetermined
Tainokia sp.
Terebellidae undetermined
Typosyllis variegata (Grube, 1860)
Websterinereis glauca Clapare©de, 1870
Total number of individuals*
1
Atlantis
Hyeres
Irving
Meteor
Plato
Total
^
12
^
^
^
^
^
1
^
9
^
7
14
64
3
^
4
4
5
11
3
^
20
^
1
2
3
1
^
^
1
8
^
2
1
76
^
^
^
10
^
^
^
1
^
114
1
^
^
^
^
4
5
6
^
^
^
13
1
^
^
^
1
^
3
^
^
7
^
^
^
3
^
3
1
2
^
1
5
2
^
^
^
2
^
6
15
^
10
^
1
^
^
^
^
^
^
^
7
2
^
3
^
^
^
^
7
27
4
18
14
10
1
1
10
10
1
80
14
82
132
21
6
4
8
26
28
2
381
1
46
33
5
1
4
2
31
20
49
82
1
261
1
1
2
40
4
2
3
1
1
187
8
4
3
1
1
5
6
387
94
17533
^
^
2
17
^
8
1
^
1
^
1
38
^
13
37
19
2
^
^
^
3
^
44
1
15
8
^
^
1
^
22
^
24
47
^
29
1
^
2
11
3
2
3
^
1
1
3
^
^
1
^
^
^
^
^
^
4
^
19
16
^
102
^
^
^
17
1
^
^
^
^
2
1
4
^
^
^
^
1
1
15
^
^
^
^
^
^
^
^
^
5
^
1
26
^
^
^
^
15
14
1
312
^
^
^
^
^
3
2
2
12
^
2
^
44
^
^
^
2
^
^
^
^
^
63
1
^
^
^
1
1
^
4031
3462
523
^
^
2
1
1
1
^
^
9
^
^
27
^
4
59
2
^
^
^
^
5
^
3
^
29
18
Including 33 Eunice spp., 8 Onuphidae and 1 Nereidae undetermined due to bad preservation (see Gillet & Dauvin, 2000).
Eunice spp., 1 Onuphidae and 1 Nereidae undetermined due to bad preservation (see Gillet & Dauvin, 2000).
3
Including 60 individuals undetermined due to bad preservation.
*....
2Including 16
Journal of the Marine Biological Association of the United Kingdom (2002)
Polychaetes from the North Atlantic Ocean: origin and geographical relationships
Figure 1. Relationships between species richness (.),
abundance (.) and site numbers North-Eastern Atlantic:
A: Atlantis, H: Hyeres, I: Irving, M: Meteor and P: Plato.
P. Gillet and J.-C. Dauvin
4144.3
two sites (Meteor 6 and, Plato 8) and the number of individuals remained below 20. Between 270 and 1000 m, the
number of taxa and individuals show great variability
between the sites. At these depths, the number of taxa
and individuals appear lower at Hyeres and Meteor than
at Atlantis, Irving and Plato. The maximum number of
taxa at Atlantis is 13 at 540 m, and the maximum
number of individuals is 189 with 163 Hyalinoecia tubicola
at Irving at 270 m.
Figure 1 shows the relationship between species richness,
abundance and site numbers for all ¢ve seamounts. There
is a general increase of the number of species with the
number of sampled sites, but the number of species
appear to be high at Atlantis than at the other sites.
Conversely, there is no trend of abundance with the
number of sampled sites, but the abundance appear
higher at Irving than at the other sites, especially at Plato
where the seamount top is the deepest.
The four dominant species in all sites are Hyalinoecia
tubicola with 84% of the individuals collected at Irving,
Notopygos megalops which dominated at Hyeres (39% of the
individuals), Rhamphobrachium brevibrachiatum which dominated at Meteor (61% of the individuals) and Eunice
prognatha which shows a high number of individuals at
Atlantis, Hyeres and Irving.
The cluster analysis with the 53 taxa collected at all ¢ve
seamounts shows two main groups of seamounts (Figure 2):
a ¢rst group with Atlantis and Hyeres and, a second group
with Irving, Meteor and Plato.
DISCUSSION
Figure 2. Result of the cluster analysis with the 53 taxa
collected during the Seamount 2 expedition on the ¢ve NorthEastern Atlantic Seamounts: Atlantis, Hyeres, Irving, Meteor
and Plato.
Figure 3. Polychaete species of the North-Eastern Atlantic
seamounts from the Atlantis (Hyeres, Irving, Meteor and
Plato), collected during the Seamount 2 expedition, geographically in common with neighbouring regions. BOR,
Boreal Region; nEUR, northern Europe; sEUR, southern
Europe; MED, Mediterranean, nAFR, northwest Africa;
AZO, Azores; NWA, Northwest Atlantic; TWA, Tropical
Western Atlantic.
Journal of the Marine Biological Association of the United Kingdom (2002)
The Seamount 2 Expedition give the ¢rst data on
the Atlantis, Irving and Plato polychaete fauna, and the
second prospecting of the Hyeres polychaete fauna
(Bellan, 1964). The studies on Meteor seamount are more
numerous, especially during the Calypso cruises (Bellan,
1964) and the German expedition (Hinz, 1969; HartmannSchro«der, 1979, 1982).
A total of 53 taxa was identi¢ed, only nine species
occurred at all ¢ve seamounts (Table 1). Hyalinoecia tubicola
was the single species living only on the top of the
seamounts in the bioclastic sand. Other species showed a
large depth range from the top of the seamounts to the
slope and seemed able to colonise a wide range of substratum from bioclastic sand to hard bottoms. Nevertheless,
the families Ampharetidae, Hesionidae, Terebellidae and
Sabellidae were collected only on the deeper part of the
slope of the seamounts.
The genera Sinonereis and Tainokia were previously only
known in the China Sea and Yellow Sea and from the
Paci¢c Ocean around New Zealand respectively and,
were probably new to science. On Atlantis, Laena sp. has
been identi¢ed later as Laena gra¤ii Langerhans, 1984.
Rhamphobrachium identi¢ed as R. atlanticum Day, 1973 in
Gillet & Dauvin (2000) is in fact R. brevibrachiatum (Ehlers,
1875) according to Paxton (1986). Five Longibrachium
collected on Meteor and Plato form a collection of a new
species. This is the ¢rst record of the species Eunice prognatha
previously only known from the Ascension Island, and of the
species Eunice nicidioformis only known from the Paci¢c
Ocean around Hawaii. The sampling of Pulliela armata
Fauvel, 1929 con¢rms its presence in this part of the
4144.4
P. Gillet and J.-C. Dauvin
Polychaetes from the North Atlantic Ocean: origin and geographical relationships
Atlantic Ocean; its was known previously in the Indian
Ocean (Day, 1973), and found along the North African
coasts by Rosenfeldt (1982). Some other taxa are found
for the ¢rst time on the Atlantic seamounts: Hesionidae
[Leocrates atlanticus (McIntosh, 1885)] on Atlantis, Hyeres,
Meteor and Plato, Orbiniidae [Orbinia cuvierii (Audouin
& Milne-Edwards, 1833)] on Plato, Poecilochaetidae
(Poecilochaetus serpens Allen, 1904), Capitellidae (Notomastus
latericeus Sars, 1851) and Sabellariidae (Lygdamis muratus
Allen, 1904) on Meteor.
The four endemic species described by HartmannSchro«der (1979, 1981) for the south Azores seamounts (see
Gillet & Dauvin, 2000) were not found during the 1993
Expedition. Three other species appeared endemic:
Longibrachium n. sp., Sinonereis sp. and Tainokia sp. So, the
endemic species of polychaetes found on the south Azores
seamounts was relatively low (6^7.5%). In other seamounts,
as in the North Paci¢c seamounts (Wilson & Kau¡man,
1987) and Southwest Paci¢c seamounts (Richer de Forges
et al., 2000), about 15% of the invertebrates were considered as potential seamount endemics
The highest species richness of polychaetes was found on
Atlantis (31 species), as for Brachiopoda in the same expedition Seamount 2 (Logan, 1998): 8 species on Atlantis, 6
on Plato, and 3^4 in the other seamounts. Species richness
and number of stations yielding brachiopods (29% of the
total sites) increase from south to north in the northeastern Atlantic seamounts. But, this pattern does not
exist for polychaetes with a higher number of sites yielding
this invertebrate group.
The lower abundance found on Plato is probably due to
the greater depth of the top of this seamount: 520 m at
Plato compared to 260^290 m for the other seamounts.
The di¡erence between the abundance on Meteor and
those of the other seamounts could be explained by the
lower phytoplankton primary production south of the
Azores front (Macedo et al., 2000).
The cluster analysis shows two main groups of seamounts:
Atlantis and Hyeres and, Irving Meteor and Plato. The
pattern of a¤nities between the seamounts is not linked
with depth, type of substrates, distance between the
seamounts, nor to the age of the seamounts: Atlantis
37^48 Ma, Hyeres 75^83 Ma, Irving 69^78 Ma, Meteor,
82^86 Ma and, Plato 49^60 Ma (Verhoef, 1984).
A total of 28 taxa in 27 sites sampled was identi¢ed on
the Meteor seamount during the Seamount 2 Expedition.
However, this number remained lower than the number of
polychaetes found on the Meteor seamount during the
year 1967 by Hartmann-Schro«der (1979) with 48 species
in 22 sites. It was noted that the Dorvilleidae, as Dorvillea
rubrovittata (Grube, 1855) and most of Syllidae [except
Typosyllis variegata (Grube, 1860)] were collected in abundance by Hartmann-Schro«der (1979). The number of individuals was also very di¡erent during both exploration:
1171 in 1967 against 387 in 1993. Some hypotheses had
been proposed to explain such observations (see Gillet &
Dauvin, 2000).
Figure 3 shows the percentage of the seamount polychaete fauna occurring in other North Atlantic regions
according to the zones determined by Morton & Britton
(2000a,b) and data from Britton et al. (in press) and
Gillet & Dauvin (2000). It appears that the seamount
fauna shows a high percentage of species with the Azores,
Journal of the Marine Biological Association of the United Kingdom (2002)
European regions, including Mediterranean region, a
medium percentage with the North Africa Region, and a
very low percentage with the North-West Atlantic and
Tropical West Atlantic regions. This suggests that the colonisation on these seamounts should be linked with the
dominant currents favouring circulation between the
European and African coasts and the open ocean (Morton
& Britton, 2000a,b; Gillet & Dauvin, 2000). These observations are in accordance with the data reviewed by
Wilson & Kaufmann (1987) which concluded that the
seamount fauna tend to be dominated by regional species
with an equal representation of widespread or cosmopolitan species. More, Moron & Britton (2000b) suggest
that several mechanisms of dispersal and introduction of
species occurred in such isolated areas: phoresy, rafting,
larval and/or adult recruitment, and human assisted colonisations. Among the main mechanisms of colonisation of
seamounts species, it appeared that the dispersal of
bentho-pelagic species with a dispersal phase as temporary
members of the meroplankton should be predominant.
The planktonic propagules are transported by oceanic
currents and recruited on seamounts when they have found
adequate habitats (Rogers, 1994; Parker & Tunnicli¡e,
1994). Nevertheless, the planktonic larvae are not the
single dispersal stages of many benthic organisms, adults
can also drift-over a long distance to colonise isolated
sites (Morton & Britton, 2000b).
The authors thank S. Gofas who supervised the `Seamount 2'
international trip (France, Italy, Spain, Portugal and Sweden), L.
Denis and S. Soussi for help with illustrations and, two anonymous referees for their useful comments on the ¢rst version of
the typescript.
REFERENCES
Bellan, G., 1964. Campagne de la `Calypso' dans l'Atlantique. 1.
Annëlides Polyche©tes. I. Annëlides Polyche©tes des Bancs du
`Mëteor' et de la H.M.S. `Hye©res'. Annales de l'Institut
Ocëanographique, Nouvelle Sërie, 41, 301^305.
Britton J.C., Morton, B. & Martins, A.M. de F. (in press). The
marine biodiversity of the Ac°ores: a checklist of species with
notes on their biogeography. Ac° oreana.
Day, J.H., 1973. Polychaeta collected by U.D. Gaikwad at
Ratnagiri, south of Bombay. Journal of the Linnean Society of
London, 52, 337^361.
Gillet, P. & Dauvin J.C., 2000. Polychaetes from the Atlantic
Seamounts of the southern Azores: biogeographical distribution and reproductive patterns. Journal of the Marine Biological
Association of the United Kingdom, 80, 3651^3661.
Gofas, S., 1993. Mission ocëanographique Seamount 2. Compterendu et liste des stations. Rapport du Musëum National d'Histoire
Naturelle.
Hartmann-Schro«der, G., 1979. Die Polychaeten der `Atlantischen
Kuppenfahrt' von F.S. Meteor (Fahrt 9 c, 1967) 1. Proben aus
Schleppgera«ten. Meteor Forschungsergebnisse, D, 31, 63^90.
Hartmann-Schro«der, G., 1981. Die Polychaeten der Fuhrten 11, 19
und 26 (1967^1972) von F.S. `Meteor' in das Gebiet zwischen
dem Golf von Biscaya und dem Auftriebsgebiet von Westafrika.
Meteor Forschungsergebnisse, D, 33, 23^36.
Hartmann-Schro«der, G., 1982. Die Polychaeten der Fahrt 36
(1975) von F.S. `Meteor' in das Auftriebsgebiet vor Nord
Westafrika. Meteor Forschungsergebnisse, D, 35, 1^20.
Polychaetes from the North Atlantic Ocean: origin and geographical relationships
Hinz, K., 1969. The Great Meteor Seamount. Result of seismic
re£ection measurements with a pneumatic sound source and
their geological interpretation. Meteor Forschungsergebnisse, D, 2,
63^77.
Lance, G.N. & Williams, W.T., 1967. A general theory of classi¢cation sorting strategies. I. Hierarchical System Computing Journal,
9, 373^380.
Logan, A., 1998. Recent Brachipoda from the oceanographic
expedition Seamount 2 to the north-eastern Atlantic in 1993.
Zoosystema, 20, 549^562.
Macedo, M.F., Duarte, P., Ferreira, J.G., Alves, M. & Costa, V.,
2000. Analysis of the deep chlorophyll maximum across the
Azores Front. Hydrobiologia, 441, 155^172.
Morton, B. & Britton, J.C., 2000a. Origins of the Azorean intertidal biota: the signi¢cance of introduced species, survivors of
chance events. Arquipëlago, Life and Marine Sciences, supplement
2, 29^51.
Morton, B. & Britton, J.C., 2000b. The origins of the coastal and
marine £ora and fauna of the Azores. Oceanography and Marine
Biology: an Annual Review, 38, 13^84.
Parker, T. & Tunnicli¡e, V., 1994. Dispersal strategies of the biota
on an oceanic Seamount: implications for ecology and biogeography. Biological Bulletin, 187, 336^345.
Journal of the Marine Biological Association of the United Kingdom (2002)
P. Gillet and J.-C. Dauvin
4144.5
Paxton, H., 1986. Revision of the Rhamphobrachium complex
(Polychaeta: Onuphidae). Records of the Australian Museum, 38,
75^104.
Richer de Forges, B., Koslow, J.A. & Poore G.C.B., 2000.
Diversity and endemism of the benthic seamount fauna in the
southwest Paci¢c. Nature, 405, 944^947.
Rosenfeldt, P., 1982. Die polychaeten der Fahrt 44 (1977) von F.S.
`Meteor' in das Auftriebs gebiet vor Nordwest Afrika. Meteor
Forschungsergebnisse D, 35, 43^53.
Rogers, A. D., 1994. The biology of the seamounts. Advances in
Marine Biology, 30, 305^340.
Verhoef, J., 1984. A geophysical study of the Atlantis-Meteor
Seamount complex. Geologica Ultraiectina, 38, 1^151.
Wilson, R.R. & Kaufmann, R.S., 1987. Seamount biota and
biogeography. In Seamounts, Islands and Atolls (ed. B.H. Keating
et al.), pp. 319^334. Geophysical Monograph 43. American
Geophysical Union, Washington.
Received .... Accepted ....
Patrick Gillet