A new Prunum species from Saba (Netherlands Antilles) (Gastropoda; Marginellidae)

3 Pages·1991·1.3 MB·English

R.G.Moolenbeek& MJ.Faber AnewPrunumfrom Saba APEX 6(1): 25-27, avril 1991
A new Prunum species from Saba (Netherlands Antilles)
(Gastropoda; Marginellidae)
R.G. Moolenbeek & M.J. Faber
Zoologisch Muséum Amsterdam,P.O.Box4766,NL-1009 ATAmsterdam,
TheNetherlands
ABSTRACT. In shallow watersatthe islandofSaba (Dutch Leeward Islands, WestIndies),an
unknown marginellid was collected by SCUBA diving. It is referred to the genus Prunum, but
generic assignation on the basis ofconchological characters only appeared to be difficult. The
new taxon {Prunum hoffi n.sp.) shows characters in between thoseofseveral wellknown margi-
nellid gênera.
RESUME. Dans leseauxpeuprofondesde l'îledeSaba (PetitesAntilles, Ilessous le Vent), une
espèce inconnue de marginellidesaété récoltéeen plongée. ElleestassignéeaugenrePrunum.
Cependant, définir l'appartenance à un genre sur seule base de caractères conchyliologiques est
trèsdifficile. Lenouveautaxon,(Prunumhoffin.sp.)présentedescaractèresintermédiairesentre
ceuxde différentsgenresbien connusdemarginellides.
KEYWORDS: Gastropoda, Marginellidae,Prunum,WestIndies,Caribbean, Saba.
INTRODUCTION Prunum hoffi n.sp.
Figs 1-2
InFebruaryandMarch 1987duringatriponboard
of the M.V. "Plancius", the first author had the TYPE MATERIAL. Holotype (figs 1-2) in
opportunity to collect marine molluscs on several Zoologisch Muséum Amsterdam (ZMA Moll.
islands of the Lesser Antilles. Amongst them the 3.90.014)and4paratypes(3inZMAMoll.3.90.015,
"Unspoiled Queen of the Caribbean", the island of onetoDayton Muséum ofNatural History, USA).
Saba, of which hardly anything is known of the
marinemalaco-fauna(Coomans, 1958).Duringour TYPE LOCALITY. West Indies, SABA, Ladder
samplingactivities,Dr.Tom van 'tHoff,initiatorof Bay, Ladder Labyrinth, 10-15 m, 11 March 1987,
theSTINAPAunderwaterparcproject"SABA"was leg. R.G. Moolenbeek.
so kind to show us the best localities for sédiment
sampling. Molluscs and sédiment samples were DESCRIPTION OF HOLOTYPE. Shell minute
taken atfour localities, in depthranging from 10 to (length 3.6mm, width 1.9 mm), thick, low biconic,
30m. InasamplefromLadderLabyrinth inLadder oblong, semi-opaque, smooth, shiny, shoulder
Bay, an unknown marginellid was found. It is de- smooth. SpireblunL Aperturenarrow,roundedand
scribed as: broaderanteriorly,length2.8 mm.
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APEX 6(1): 25-27, avril 1991 AnewPrunumfrom Saba R.G.Moolenbeek& MJ.Faber
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Figs. 1-2. Prunumhoffi n.sp., Saba, holotype (ZMA Moll. 3.90.014), length 3.6 mm.
Nucleus of 1 1/2 semi-translucent whorls, with a upper dark brown spots are more or less arranged
finebrownsuturaiUne.Twopale-whitepost-nuclear intoaspiral band.
whorls with irregular (zigzag) axial brown stripes,
and in between some more or less triangular pale- ETYMOLOGY. This new marginellid is named
white markings. Suture filled with a pale opaque after Dr. Tom van 't Hoff, to express our gratitude
callus. On centre of body whorl a band of 8 dark for his stimulating activities in nature conservation
brown spots. On shoulder and anterior part also a in the Carribean, and in particular in initiating the
few irregular brown spots. Pariétal callus white, protection of underwater parcs in the Netherlands
with 4 plications ofequal size, occupying half the Antilles.
innerlip. At theheightoftheuppercolumellarplica
averyfinefasciolargroove. Outerlipopaquewhite, REMARKS. The genericplacement in the family
thickened,curvedinmedially,with8smalldenticles Marginellidae is still in a state of confusion. The
onthelowerhalf. Edgeofouterlipwhite,onborder gêneraPrunum Hermannsen, 1852, Hyalina Schu-
tothepartwithbrownpattern,aminuteaxialgroove macher, 1817andVolvarinaHinds, 1844areclosely
(butnotreally formingan extemal varix). related (Coovert, 1987, 1988; Coan & Roth,
1976) and especially the latter two are difficult to
VARIABILITY. The fourparatypes measure 3.8 separateonconchological characteristicsonly. Due
X 2.0 mm (Dayton Muséum), 3.7 X 1.9 mm, 3.1 X tothemoresolidshell,itsrelativelynarrowaperture,
1.7 mm, 3.0X 1.6 mm. The two smallerspécimens its thicker outer lip with denticles inside, we place
are subadult with a thinner outer lip, and lacking our new taxon in the genus Prunum. We do not
denticles. In the smallest spécimen the lower and know anyspecieswhichshowsacloseresemblance
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R.G.Moolenbeek& MJ.Faber AnewPrunumfrom Saba APEX 6(1): 25-27, avril 1991
to the new species. The new taxa in the genus REFERENCES
Volvarina, described by De Jong & Coomans Coan, E. & B. Roth, 1966. The West American
(1988)differailbybeingmoreelongateanduniform Marginellidae. Veliger, 8: 276-299.
in colour (Volvarinapauli, V. abbotti) or having a Coan, E. & B. Roth, 1976. Status ofthe genus
banded pattem (V. vokesi). Also Coan & Roth HyalinaSchumacher, 1817(Mollusca;Gastropoda).
(1966)didnotfigureanyspecieswiththesamekind J. Moll. Stud.,42: 217-222.
ofcolourpattern. We do not know aWestAtlantic Coomans, H.E., 1958. A Survey of the littoral
Prunum specieswithacolourpatternofaxialstripes Gastropoda of the Netherlands Antilles and other
andwith the small sizeofournew taxon. CaribbeanIslands.Stud.FaunaCuraçao,8:42-111.
Coovert, G.A., 1987. Proper useage of the
generic namesHaloginella,Hyalina,and Volvarina
withdiagnosisofthegenusHaloginella.Marginella
ACKNOWLEDGEMENTS
marginalia, 3: 1-7.
ThanksareduetotheownersandcrewoftheM.V. Coovert, G.A., 1988. Marginellidae ofFlorida,
"Plancius"forfacilitiesduringthevoyage. Tomvan part II: Prunumsuccinea with adiscussion ofPru-
't Hoff assisted during SCUBA diving activities num and Volvarina. Marginella marginalia,4: 35-
around Saba. Gary Coovert (Dayton Muséum) was 42.
so kind to send us a complète set of "Marginella DeJong, K.M. & H.E. Coomans, 1988. Marine
marginalia",ajournalentirelydevotedtotheMargi- gastropodsfromCuraçao, Arubaand Bonaire.Stud.
nellidaepublishedby the DaytonMuséumofNatu- FaunaCuraçao,69: 1-261.
ral History, USA. Dr. Henry E. Coomans and an
unknown reviewer gave advice concerning the ms.
The photographs were made by L.A. van der Laan *STUDIES ONWESTINDIANMARINEMOL-
(ZMA). LUSCS: 20
AEBX
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