First Mediterranean record of Diaphana marshalli (Sykes, 1904) (Gastropoda, Diaphanidae) - a rare bathyal species

2011·2.2 MB·English

by  Enzo Campani

© SociedadEspañoladeMalacología Iberus, 29 (1); 35-38, 2011
First Mediterranean record ofDiaphana marshalli (Sykes,
1904) (Gastropoda, Diaphanidae) - a rare bathyal species
Primera cita para el Mediterráneo de Diaphana marshalli (Sykes,
1904) (Gastropoda, Diaphanidae) - una especie rara del batial
Enzo CAMPANI*, Cesare BOGI** and Bella S. GALIL***
Recibidoel4-II-2011.Aceptadoel20-III-2011
ABSTRACT
The rare bathyal gastropod Diaphana marshalli (Sykes, 1904), previously known only for
the Atlantic, ¡s reported for the firsttime in the Mediterranean. The specimens, collected off
Hadera, Israel, are photographed and compared with its Mediterranean congener, D. jón-
ica Di Gerónimo, 1974
RESUMEN
Se cita por primera vez en el Mediterráneo el gasterópodo Diaphana marshalli (Sykes,
1904), una especie rara del batial, previamente conocida solamente en el Atlántico. La
cita se basa en ejemplares recogidos frente a Hadera, Israel, que se ilustran y se compa-
ran con su congénere del Mediterráneo, D. jónica Di Gerónimo, 1974
INTRODUCTION
The bathyal molluscs of the Levan- the northern coast of Israel (Bogi and
tine Sea are scarcely known. Nearly a Galil, 2004). Of these, five species con-
century passed from Stuarny's (1896) stituted new records for the eastern
publication of the specimens collected Mediterranean, and 8 were newly
during the voyages of the "POLA" recorded from the Levantine Sea. Two
(1890-1893), Janssen's (1989) report of specimens, earlier considered juveniles
those collected by "METEOR" [cruise 5] of an unidentified gastropod, have been
(1987) and Bogi's account of the few recently re-examined and recognized as
specimens collected by "POSEIDON" Dipahana marshalli(Sykes, 1904).
[cruise 201/2] (1994) from Eratosthenes
Seamount (Galil and Zibrowius,
1998). A total 42 species were identified MATERIALSAND METHODS
from material collected during a series
of cruises conducted between 1994 and The area investigated is located off
1999 as part of pollution monitoring the coast of Israel, at depths between
surveys by the Israel Oceanographic 1227 and 1454 m. The material was col-
and Limnological Research (IOLR) off lected during monitoring surveys of a
*CorsoG. Mazzini299, 57126Livorno, Italy,[email protected]
**ViadelleViole7, 57124Livorno, Italy, [email protected]
***IsraelOceanographicandLimnologicalResearch,NationalInstituteofOceanography,P.O.B. 8030, Haifa
31080,[email protected]
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Iberus, 29 (1), 2011
deepwater coal fly ash disposal site off the samples were washed and sieved
Hadera (between32° 38' N34° 02' E and through a 250 jum mesh, preserved in
32° 36' N 34° 16' E). The samples were 70% alcohol, stained inRose Bengal and
collected aboard the R/V Shikmona, sorted. Two specimens (with soft parts)
m
using a 45 ft Marinovich type deep were collected at a depth of 1400 in
watemrmtrawl (codend mesh 6 mm)with a Septembemrm1997 [1,5 x 0,91 mm (fig. 2);
0.5 plankton net secured atop. The 1,3 x 0,8 (figs. 3 - 5)]. The smaller
sampleswerepreservedin10% buffered specimen was damaged, the larger one
formalin aboard ship. In the laboratory. ispreservedintheBogicollection.
TAXONOMY
Opisthobranchia Milne-Edwards, 1848
Cephalaspidea P. Fischer, 1883
Diaphanidae Odhner, 1914
Diaphana Brown, 1827
Diaphana marshalli (Sykes, 1904)
Discussion: Diaphana marshalli is an the shell and referred to it as "holotype"
exceedingly rare species. Aside from the (there, fig. 18i), thoughthatshell, at2.45
type series collected off Portugal, only mm, wasratherlargerthatthe specimen
two additional specimens are known: a measured by Sykes. These authors
shell collected by the "THALASSA" declared 'Retusa' marshalli "probably a
Expedition (station Z 447, 48° 47', 11° Diaphana" (there, p. 237). Schiotte (1999)
12', 1450 - 1500 m) and cited as Retusa reportedthatthetypematerialconsisted
mm
(?) marshalli by Bouchet (1975), and a of a "holotype" 2.45 high
mm
2.1 high specimen with soft parts, (BMNH1922122) and "pieces of 4 or 5
collected by the "INCAL" Expedition additional specimens, labelled as syntypes,
1976 (station CP08, 50° 15' N, 13° 14' W, alldryshells" (there, p. 87).
2644m) (SCHI0TTE, 1999). Few species of Diaphana Brown,
Retusa marshalli was described and 1827 have been recorded from the
illustrated (Sykes, 1904: 31, figs. 5, 6, 6a, Mediterranean Sea, but the only one
b) from specimens collected by the resembling D. marhalli is D. jónica Di
"PORCUPINE" Expedition of 1870, off Gerónimo, 1974. The latter has been
Portugal, at station 17, at 600-1095 considered ajúnior synonym ofD. ladea
fathoms. Only a single specimen was (Jeffreys, 1877)by BouchetandWarén
measured ("Alt. 2, diam. max. 1.1 mm", (1979) who examined the type.
there, p. 32), though the author refers to Schiotte (1999: 124) who compared
another, larger specimen ("one specimen, illustrations ofbothspecies declared "...
broken, is larger than the type", there, p. thereisa verygoodresemblancebetween the
32). Sykes' illustration (1904, fig. 6) is shellsofD. ladea and D.jónica.".
reproduced (fig. 1). Bouchet and Warén (1979: 237)
Bouchet (1975: 334) expressed separated 'Retusa'marshalli from its con-
doubtonthe species' genericplacement: gener D. ladea as the former has "... a
"Des caracteres tels que la présence d'un whitish unsculptured shell with an umbili-
ombilic ou la conformation du sommet sem- cal chink, but the larval shell is white, not
blent tres originaux pour une Retusa et il brown as in ladea, and the broadest part of
est vraisemblable que lorsque l'animal sera theaperture is at the lower thirdoftheshell,
connu, une séparation générique deviendra instead of the middle of the shell. In 'R'.
nécessaire". Bouchet and Warén (1979) marshalli the larval shell is completely
examined Sykes' material, illustrated visible even in adult specimens when seen
36
CampaniETAL FirstMediterranean record ofDiaphana marshalli, a rare bathyal species
.:
Figures 1-5. Diaphanamarshalli(Sykes, 1904). 1: Sykes’ illustration, reproduced, height2.45 mm;
2: Scanningelectrón micrograph ofthe larger Levantine specimen, height 1.5 mm; 3: adapertural
viewofsmallerLevantinespecimen, height 1.3 mm; 4: sideviewofthesamespecimen; 5: detailof
theapexofthesamespecimen.
Figuras 1-5. Diaphanamarshalli (Sykes, 1904). 1:ReproduccióndelailustracióndeSykes, altura2,45
mm;2:Micrografíaelectrónicadebarridodelmayorejemplarlevantino, altura 1,5mm, 3: Vistaada-
perturaldelmenorejemplarlevantino, altura 1,3 mm, 4: vista lateraldelmismo ejemplar; 5: detalle
delápicedelmismoejemplar.
37
. .
Iberus, 29 (1), 2011
from the adapertural side, while in lactea 1979: 231). Schiotte (1999: 133) agrees
only the topmostpartofthe larval shellpro- "... interestingly, deep-waterspecies usually
trudes above the top ofthe body whorl. 'RL seem to have planktotrophic development"
marshalli is smaller, being only 2.45 mm Thismayexplaintheoccurrenceofarare
zuhenadult" Atlanticbathyal diaphanid gastropod in
On comparingDiGerónimo's (1974) theLevantineSea.Thecommonmollusks
description and SEM image of the holo- at depths greater than 1000 m off the
type of D. jónica with the Levantine Israeli coast are eurybathic Atlanto-
specimens of D. marshalli it was appar- Mediterranean and Boreal species with
ent that the shell of the former is more an upper bathymetric range enabling
cylindrical and slender than the shell of them to overeóme thebarriers posedby
the latter species, its height-to-width the shallow Gibraltar Straits and the
ratio being 1,84 compared with 1,6-1,65 Siculo-Tunisian sill (< 400 m), or steno-
in marshalli; the columella differently set bathic species with epipelagic larvae.
and the umbilicus narrower; the apex of Indeed, thepresentrecord ofD. marshalli
D. jónica is described as "piú o meno agrees with the distribution patterns of
sporgente", but is similar to that of D. the Levantine deep water benthos
lactea as figured in Bouchet and (Galil,2004).
Warén (1979) with only the topmost
part ofthe larval shell protruding above
thebodywhorl. ACKNOWLEDGEMENTS
The reproductivebiology of D. mar-
shalliisunknown,butthesizeofitslarval We thank Dr. A. Warén, for the SEM
shell indicates planktotrophic larval images and Mr. S. Bartolini for the
development (Bouchet and Warén, digitalphotographs.
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38