282
I. Di Geronimo et al.
markedly abundant, due to the presence of
pumices.
On the basis of faunal affinities, stations were
grouped into three bathymetric belts: "AY> (248 to
505 m,3 stns), "Bn (696 to 1,096 m, 12 stns) and
"C" (1,139 to 1,536 m, 13 stns) (Tables 2-4).
Several species were notably abundant
and/or frequent all through the investigated
depth range, such as the molluscs Alvania elegantissima, Microgloma tum idu la, Thyasira
cTOulinensis, 1: ferruginea. 1: subovata, Abra
longicallus, Graptacme agilis and Entalina
tetragona, the bryozoans Crisia tenella longinodata, Anguisia verrucosa, Entalophoroecia gracilis (deep-water morphotype) and the serpulid
Hyalopomatus variorugosus. These species have a
wide bathymetric distribution, starting from ca.
200 m. Other common species, Bathyarca pectunculoides, Kelliella abyssicola and Xylophaga dorsalis. displayed an even wider distribution, being
also known from the mid-outer shelf. All these
species can generally be regarded as eurybathic.
The molluscs Alvania cimicoides, A. testae,
Ringicula leptocheila, Ennucula aegeensis,
Yoldiella philippiana and Verticordia trapezoidea
are only (or mostly, see E. aegeensis) present in
the shallowest belt (A). They are actually known
from the outer shelf to the upper bathyal. becoming less and less common with depth (e.g.
Bouchet and Waren 1993; Salas 1996). Also the
bryozoan Tessaradoma boreale (mostly found in
the A belt) shared a similar distribution,
although in the Atlantic it is much deeper (Rosso
and Di Geronimo 1998). It is also worth noting
the occurrence of some species, i.e. the molluscs
Nueula sulcata. Saccella commutata, Nassarius
lima and Trophonopsis muricata, typical of circalittoral communities and extending beyond
the shelf break. Other molluscan species were
restricted to the shallowest belt, or they partially
extended to the deeper ones, but they were too
scarce (or their distribution is poorly known) to
be further commented upon.
Many species were abundant and/or frequent
from 600-700 m to the deepest stations (belts B
and C): the molluscs Alvania subsoluta,
Benthonella ten ella, Benthomangelia maera,
Ennucula corbuloides, Ledella messanensis,
Yoldiella micrometrica, Katadesmia cuneata,
Notolimea crassa, the bryozoans Tubulipora sp. 1.
Setosella folini, Reteporella sparteli and the serpulids Filogranula stellata and Filograna sp. 1. For
Reteporella sparteli, a shallower range not exceeding 500-700 m in the Atlantic-Mediterranean area,
was previously known (Hayward 1979; Harmelin
and d'Hondt 1992). Differences between belts B
and C are mainly due to a remarkable increase in
abundance of Benthonella tenella, Ennueula eorbuloides, Yoldiella micrometrica, Katadesmia
cuneata, Tubulipora sp. 1 and Filogranula stellata.
The nuculoid Katademia cuneata is one of the
deepest species, its shallowest record being from
station 29 (897 m) and becoming more and more
common below 1,000 m.
A major faunal change occurred at ca. 500600 m depth, where several·species add to or
replace the eurybathic ones. This change was
more evident within molluscs. Some common
species listed from belts B and C most probably
define the typical deep bathyal assemblage
througq. the Mediterranean, including the
Eastern Basin (Janssen 1989). The gastropod
Benthonella tenella is one of the most common
species in 500-4,000 m in Mediterranean and
Northeast Atlantic (Bouchet and Waren 1993). Di
Geronimo (1974) recognised a "Cithna
(=Benthonella) tenella" assemblage below 2,300
m in the Ionian Sea". Ennucula corbuloides is a
common protobranch in Atlantic-Mediterranean
bathyal bottoms below 500-700 m (Rhind and
Allen 1992; Salas 1996, as E. bushae). Ledella messanensis is another widespread AtlanticMediterranean protobranch. common below 500
m (Waren 1989; Salas 1996). Katadesmia cuneata
has an almost world-wide distribution, below
800-1,000 m (Knudsen 1970; Sanders and Allen
1985; Salas 1996). Among these common molluscan species, Yoldiella micrometrica deserves a
special mention. It is probably present also in the
Northeast Atlantic (Jeffreys 1879), where this
species must be markedly rare as it was neither
included by Allen et al. (1995) in their revision of
Atlantic species of Yoldiella, nor reported by
Salas (1996) from the Ibero-Moroccan Gulf. This
species is present in other Tyrrhenian areas (Di
Geronimo and Li Gioi 1981; Di Geronimo and
Bellagamba 1985) and in the Eastern Basin
(Janssen 1989), but it is unrecorded from the
westernmost Mediterranean {Salas 1996}. Other
molluscan species from the "B" and/or "C"
assemblages, such as Copulabyssia corrugata,
Adeuomphalus ammoniformis. Alvania subsoluta, Graphis gracilis, Benthomangelia maera,
Yoldiella seguenzae, Delectopecten vitreus,
Cyclopecten hoskynsi, Allogramma formosa,
Polycordia gemma, Pholadomya loveni, are also
I. Di Geronimo et al.
markedly abundant, due to the presence of
pumices.
On the basis of faunal affinities, stations were
grouped into three bathymetric belts: "AY> (248 to
505 m,3 stns), "Bn (696 to 1,096 m, 12 stns) and
"C" (1,139 to 1,536 m, 13 stns) (Tables 2-4).
Several species were notably abundant
and/or frequent all through the investigated
depth range, such as the molluscs Alvania elegantissima, Microgloma tum idu la, Thyasira
cTOulinensis, 1: ferruginea. 1: subovata, Abra
longicallus, Graptacme agilis and Entalina
tetragona, the bryozoans Crisia tenella longinodata, Anguisia verrucosa, Entalophoroecia gracilis (deep-water morphotype) and the serpulid
Hyalopomatus variorugosus. These species have a
wide bathymetric distribution, starting from ca.
200 m. Other common species, Bathyarca pectunculoides, Kelliella abyssicola and Xylophaga dorsalis. displayed an even wider distribution, being
also known from the mid-outer shelf. All these
species can generally be regarded as eurybathic.
The molluscs Alvania cimicoides, A. testae,
Ringicula leptocheila, Ennucula aegeensis,
Yoldiella philippiana and Verticordia trapezoidea
are only (or mostly, see E. aegeensis) present in
the shallowest belt (A). They are actually known
from the outer shelf to the upper bathyal. becoming less and less common with depth (e.g.
Bouchet and Waren 1993; Salas 1996). Also the
bryozoan Tessaradoma boreale (mostly found in
the A belt) shared a similar distribution,
although in the Atlantic it is much deeper (Rosso
and Di Geronimo 1998). It is also worth noting
the occurrence of some species, i.e. the molluscs
Nueula sulcata. Saccella commutata, Nassarius
lima and Trophonopsis muricata, typical of circalittoral communities and extending beyond
the shelf break. Other molluscan species were
restricted to the shallowest belt, or they partially
extended to the deeper ones, but they were too
scarce (or their distribution is poorly known) to
be further commented upon.
Many species were abundant and/or frequent
from 600-700 m to the deepest stations (belts B
and C): the molluscs Alvania subsoluta,
Benthonella ten ella, Benthomangelia maera,
Ennucula corbuloides, Ledella messanensis,
Yoldiella micrometrica, Katadesmia cuneata,
Notolimea crassa, the bryozoans Tubulipora sp. 1.
Setosella folini, Reteporella sparteli and the serpulids Filogranula stellata and Filograna sp. 1. For
Reteporella sparteli, a shallower range not exceeding 500-700 m in the Atlantic-Mediterranean area,
was previously known (Hayward 1979; Harmelin
and d'Hondt 1992). Differences between belts B
and C are mainly due to a remarkable increase in
abundance of Benthonella tenella, Ennueula eorbuloides, Yoldiella micrometrica, Katadesmia
cuneata, Tubulipora sp. 1 and Filogranula stellata.
The nuculoid Katademia cuneata is one of the
deepest species, its shallowest record being from
station 29 (897 m) and becoming more and more
common below 1,000 m.
A major faunal change occurred at ca. 500600 m depth, where several·species add to or
replace the eurybathic ones. This change was
more evident within molluscs. Some common
species listed from belts B and C most probably
define the typical deep bathyal assemblage
througq. the Mediterranean, including the
Eastern Basin (Janssen 1989). The gastropod
Benthonella tenella is one of the most common
species in 500-4,000 m in Mediterranean and
Northeast Atlantic (Bouchet and Waren 1993). Di
Geronimo (1974) recognised a "Cithna
(=Benthonella) tenella" assemblage below 2,300
m in the Ionian Sea". Ennucula corbuloides is a
common protobranch in Atlantic-Mediterranean
bathyal bottoms below 500-700 m (Rhind and
Allen 1992; Salas 1996, as E. bushae). Ledella messanensis is another widespread AtlanticMediterranean protobranch. common below 500
m (Waren 1989; Salas 1996). Katadesmia cuneata
has an almost world-wide distribution, below
800-1,000 m (Knudsen 1970; Sanders and Allen
1985; Salas 1996). Among these common molluscan species, Yoldiella micrometrica deserves a
special mention. It is probably present also in the
Northeast Atlantic (Jeffreys 1879), where this
species must be markedly rare as it was neither
included by Allen et al. (1995) in their revision of
Atlantic species of Yoldiella, nor reported by
Salas (1996) from the Ibero-Moroccan Gulf. This
species is present in other Tyrrhenian areas (Di
Geronimo and Li Gioi 1981; Di Geronimo and
Bellagamba 1985) and in the Eastern Basin
(Janssen 1989), but it is unrecorded from the
westernmost Mediterranean {Salas 1996}. Other
molluscan species from the "B" and/or "C"
assemblages, such as Copulabyssia corrugata,
Adeuomphalus ammoniformis. Alvania subsoluta, Graphis gracilis, Benthomangelia maera,
Yoldiella seguenzae, Delectopecten vitreus,
Cyclopecten hoskynsi, Allogramma formosa,
Polycordia gemma, Pholadomya loveni, are also