Notes on the systematics, morphology and biostratigraphy of fossil holoplanktonic Mollusca, 14. A new species of Vaginella (Gastropoda, Euthecosomata, Cavoliniidae) from the Late Oligocene of the North Sea Basin and its bearing on Chattian biostratigraphy

2005·0.68 MB·English

by  Janssen, Arie W

BASTERIA, 69: 73-80,2005
Notes onthe systematics, morphology and biostratigraphy of fossil holoplank-
tonic Mollusca, 14. Anewspecies ofVaginella (Gastropoda, Euthecosomata,
Cavoliniidae)from theLateOligocene oftheNorth Sea Basinand its bearing on
Chattianbiostratigraphy
Arie+W. Janssen
Nationaal Natuurhistorisch Museum Naturalis,PalaeontologyDepartment, P.O.Box9517,2300 RA
Leiden,theNetherlands;currently: 12,Triq tal'Hamrija,XewkijaVCT110,Gozo,Malta;
[email protected].
Anewpteropod species,Vaginellabasitruncata,is erected onthe basisofmaterial fromthe
Late Oligocene (ChattianA) ’Kasseler Meeressand’ in Hessen (Germany). Itis the oldest
representative ofthis genus known from the North Sea Basin, and is characterised by
sheddingofthe larval shell,a straight ventral aperturalmargin and bythe absence ofa
preapertural constriction and aperturalfolds.
Some notes onthe biostratigraphical implication of pteropod distributions duringthe
Late OligocenewithintheNorthSea Basinareadded,and itis concluded onthisevidence
thatthe’Kasseler Meeressand’ is coevalwith thebasal portionoftheGrafenbergSands in
theLower Rhine area (Germany). Asubdivision ofpteropodzone 16intothree subzones
covering the Eochattian appears tobe feasible. The so-called ’SternbergerGestein’ is of
middle and late Eochattian age (ChattianA/B,pteropodsubzones 16b-c).
Key words: Gastropoda, Euthecosomata, Vaginella, systematics, biostratigraphy, new
species,Oligocene,Chattian,NorthSea Basin.
INTRODUCTION
Among pteropods (Gastropoda, Euthecosomata:holoplanktonic molluscsknown
since the Late Paleocene), thegenus Vaginella Daudin, 1800(type species: V. depressa
Daudin, 1800; Early Miocene) demonstrates a surprisingly rapid development. The
earliest representative (just a single, specifically unassigned specimen) is known
from Oligocene (Rupelian) sediments in SW France. During the Late Oligocene
(Chattian) severalspecies occurred,but itwas during the Early andMiddleMiocene
that the genus reached full development, only to go extinct suddenly around the
boundary betweenMiddleand Late Miocene(Serravallian-Tortonian), meaning that
the complete 'riseand fall'of the genuslasted a mere 20-25 Ma. From this interval,
numerous occurrences havebeen describedas species of Vaginella, severalof which
are currently assigned to other genera (e.g., Edithinella Janssen, 1995, or Ireneia
Janssen, 1995).Yetotherspecies are insufficiently knownto be certainof theirgener-
ic placement. Species of Vaginella occur worldwide: SW France (Aquitaine),
Mediterranean, Paratethys, North Sea, Caribbean, Japan, southernAustralia and
New Zealand. Foradditionalnotes on the genus Vaginella and onother species that
mightbelong there, reference is madeto Janssen(1995: 133).
1)Forno.13inthisseries seeCainozoic Research,2(1-2): 163.
74 BASTERIA, Vol. 69,No. 1-3,2005
Abbreviations, for collections: RGM, Nationaal Natuurhistorisch Museum
Naturalis, Palaeontology Department, Leiden(The Netherlands), formerly Rijksmuseum
van Geologie en Mineralogie; SMF, Senckenberg Museum, Frankfurt am Main,
Germany. For shellcharacters: D, diameter(dorso-ventral diameter); DS, diameterof
septum (measured in ventral view); H, height; W, width.
VAGINELLAIN THE NORTH SEABASIN
From the NorthSea Basin, Janssen & King (1988) listed sevenVaginella species,
occurring in theirpteropod zones 16 to 19(Late Oligocene to MiddleMiocene):
NNaammeeiinnJJaannsssseenn&&KKiinngg,, 11998888 pptteerrooppooddzzoonnee rreevviisseedd nnaammee((tthhiissppaappeerr))
VVaaggiinneellllaaaauussttrriiaaccaa 1188--1199 VVaaggiinneellllaaaauussttrriiaaccaa KKiittttll,,11888866
VVaaggiinneeilllaasspp.. vveell CClliioo sspp..nnoovv.. 1188 VVaaggiinneellllaaaauussttrriiaaccaa KKiittttll,,11888866
VVaaggiinneellllaaaafitf.. llaappuuggyyeennssiiss 1IK8 VVaaggiinneellllaallaappuuggyyeennssiissKKiittttll,,11888866
VVaaggiinneellllaaddeepprreessssaa 1177 VVaaggiinneellllaaddeepprreessssaaDDaauuddiinn,,11880000
VVaaggiinneellllaacchhaattttiiccaa ttoopp1166 VVaaggiinneellllaacchhaattttiiccaaRR.. JJaannsssseenn,,11997799
‘'VVaaggiinneellllaa’'tteennuuiissttrriiaattaa 1166 IIrreenneeiiaa tteennuuiissttrriiaattaa((SSeemmppeerr,,11886611))
VVaaggiinneellllaasspp.. bbaassee 1166 VVaaggiinneellllaabbaassiittrruunnccaattaa ssppeecc..nnoovv..
Table1. NorthSea Basinspeciesof‘Vaginella’
Theso-called ‘Vaginella sp. vel Cliosp. nov.' was recognised as the juvenile, pre-
metamorphosis stage of Vaginella austriaca (compare Janssen, 1984: figs 8 and 10).
‘Vaginella’ tenuistriata subsequently became the type species of the genus Ireneia
Janssen, 1995, characterised by the lack of lateralcarinae, the presenceof longitudi-
nalmicro-ornamentanda differentlyshaped aperture(Janssen, 1995:48,pi. 4,fig. 3a-
c). Ireneiais consideredto belong to the Cuvierinidae.
Theoldestvaginellid, anundescribedspecies, in the North SeaBasin was recog-
nisedby Janssen& King (1988);thiswas already referredtoandillustratedby Gorges
(1952: 118, pi.3, fig. 10),but incorrectly identifiedas Vaginella lanceolata (Boll, 1846).
Thelatternameis anolder(but preoccupied) synonymof V. chatticaR. Janssen, 1979.
In his monograph of German Chattianmolluscs, R. Janssen (1979b: 351) didnot
distinguish the new species from ‘Vaginella’ tenuistriata, although he did note the
presenceof lateralcarinae andthe absenceof micro-ornamentin partof hismaterial.
Interestingly, the new species differs in various respects from other species of the
genus.
SYSTEMATIC PART
Vaginella basitruncataspec. nov.(figs 1a-c,2a-d)
VaginelladepressaDaudin;Semper,1861:274 (pars,nonDaudin;only thetwospecimensfrom 'Cassel').
Vaginellalanceolata (Boll1846);Gorges,1952:118,pi. 3fig. 101(nonBoll).
Vaginellatenuistriata Semper, 1861; R. Janssen, 1979b: 351 (pars, non Semper; specimens from
Niederkaufungenand Ahnetalonly).
Janssen: A newspecies ofVaginella 75
Holotype. - RGM 515.284 (fig. la-c), leg. M. van den Bosch, June 1973. Measure-
ments,seeTable2.
Locus typicus. - Ahnetal (Germany, Hessen), Brandkopf outcrop at co-ordinatesr
26.400h88.980,topographical mapsheet4622.
Stratumtypicum. - 'Kasseler Meeressand, Schill2/3'; Oligocene, Chattian A.
Derivationominis.- fromL.- basis (noun),base, andL.- truncare (verb), totruncate:
afterthetruncatedbasalpartoftheshell, causedbyshedding ofthelarvalshell.
Diagnosis. - Species ofVaginella withastraight ventralapertural marginand amuch
higher, semicircular dorsal apertural margin. Preapertural constriction and apertural
foldsabsent.Larvalshellshed, theopening closedby anoblique, ratherflatseptum.
Description. - Theshelliselongated triangular,dorso-ventrally flattenedtowardsthe
proximal aperture, especially ventrally. Theapical partof theshellproduces an angle of
approximately 35°inventralview,and25°inlateralview. Towardstheaperture, thesides
becomenearparallel, butlack thepreapertural constriction whichis seenin manyother
speciesof Vaginella.Thegreatestwidthissituatedattheaperture.Theventralsideisclear-
ly more convex (lateral view)than the dorsalside, withits maximum convexity at half
height.
The larvalshellis shed, anda septumcloses theapical partof theshell.Theseptum
is slighty convex toalmostflatandis situatedabitobliquely, higherontheventralsideof
theshell.
The ventral apertural margin is straight, sometimes slightly reinforced (bent out-
wards). Thedorsal margin is semicircular, considerably higher thantheventral one,and
consequently the aperture is very oblique, and narrow in adapical view (Fig. 2d).
Apertural folds,as seeninmanyotherspecies ofVaginella, areabsent.Weakgrowth lines
are only observablein specimens in shellpreservation. They are curvedadaperturallyon
thedorsalside,andalmoststraight ontheventralside.In somespecimens in shellpreser-
vation aweak andirregularlongitudinal striationis seen, especially so onthedorsalside.
Lateralcarinae,typical ofthegenusVaginella,arepresentin theapicalhalfofthe shell.The
larvalshellwithprotoconch is not yetknown.
Measurements:
sample H W D DS
RGM 515.284(holotype) 7.20 2.40 1.84 0.64
RGM515.574 7.44+ 2.56 1.92 0.72
6.80+ 2.48 1.76 0.72
6.32+ 2.48 1.84 -
SMF 251355 6.16+ 2.64 1.84 -
SMF251358 6.08+ 2.16 1.84 0.64
SMF 251661 6.32+ 2.64 1.60 -
SMF 251356 6.64 2.24 1.68 0.64
6.08+ 2.24 1.52
6.00+ 2.48 1.68 0.64
5.84+ 2.08 1.44 0.48
6.40+ 2.32 1.76 0.80
5.92+ 2.16 1.60 0.48
4.88+ 2.00 1.76 -
meanvalues 6.29+ (n=14) 2.35(n=14) 1.72 (n=14) 0.64(n=9)
Table 2.Measurements of Vaginella basitruncata spec. nov.(in specimensmarked + theapertureis
incomplete)
76 BASTERIA,Vol. 69, No. 1-3,2005
Figs1-2.Vaginellabasitruncata spec. nov., holotypeand paratype.1,holotype,RGM515.284;2,paratype,
SMF 251355.a=ventral,b=lateral,c=dorsal, d=aperturalview.
Paratypes: All specimensarefromthe'Kasseler Meeressand',Oligocene, Eochattian (Chattian
A).
From the typelocality (RGM515.574/3),leg.M.vanden Bosch,June1973.
Ahnetal nearKassel (Germany, Hessen),(SMF251356/13;SMF251357/10;SMF251358/4;SMF
251661/1);all J.GorgesCollection.
Ahnetal(Germany, Hessen),Brandkopfoutcrop,'Schurf' (SMF327957/50;SMF327958/16;SMF
327959/3);'Schurf,Schicht9'(SMF327960/1;SMF 327961/1);all leg.T. Schellmann.
Ahnetal (Germany, Hessen),Brandkopfoutcrop, 'Schurf , Schicht 3' (SMF327962/1?),leg. R.
Janssen,10June1973;'Schurf,Schicht 6'(SMF327963/1),leg.R. Janssen,1972-1973;'Schurf,Schicht
9'(SMF327964/1),leg.R. Janssen, 10 June1973.
Niederkaufungen,GelberBerg(SMF251355/1),specimenillustrated in Gorges, 1952,pi. 3fig.
101;herefig.2a-d); J.GorgesCollection;'Hangfufia.S-Seite'(SMF327965/1),leg.R. Janssen,1973-
1976.
Janssen:Anewspecies ofVaginella 77
Discussion: Thepresentspecies, theearliestmemberofVaginella inthe NorthSea
Basin, differsin severalrespects from latervaginellids. Larvalshellshedding, inpar-
ticular, is remarkable,since such isknownonly from fewotherspecies inthe genus,
e.g. V.chipolana Dall (1893: 431,pi. 23figs 4-5) andV.floridana Collins, 1934(compare
Collins, 1934: 214, 216, pi. 13 figs 16-19, 22-23), both from the Early Miocene of
Florida, USA. Also conspicuous is the straight ventral apertural margin; in other
vaginellids both dorsaland ventral apertural margins arecurved, usually the dorsal
oneprotrudingbeyond the ventral.
BIOSTRATIGRAPHY
Withinthe North Sea Basin the Late Oligocene ChattianStage usually iseither
subdivided into substages A, B and C, or into the Eochattian and Neochattian
(Eochattian = ChattianAand B, Neochattian=ChattianC). Underlying criteria for
these subdivisions are of a palaeontological nature. Especially the development of
species of thebivalve family Pectinidaehasbeen applied in thisrespect (Anderson,
1958;revised in R. Janssen, 1979b).The 'KasselerMeeressand', from which the new
species originates, is of unequivocal 'ChattianA' age (Anderson, 1961;Welle, 1993:
385).
Forthe so-called'Sternberger Gestein', referring toreworked fossiliferous sand-
stone boulders found in fluvio-glacial deposits of Mecklenburg and Schleswig-
Holstein(Germany), in particular, differentageinterpretations arefoundin the liter-
ature. R. Janssen (1979a:11) suggested 'ChattianA,?B'. Gaemers (1988: 373),in con-
trast,basedonfish otoliths, interpreted the 'Sternberger Gestein'as 'Late Oligocene,
Neochattian (late part)'. Welle (1993: 386), however, again accepted a 'vermutlich
Chatt A und B' age. To obtaina more reliable age assignment of the 'Sternberger
Gestein',the fossilcontents of separate bouldersshouldbe analysed andcompared.
Mostboulders,however,yield thepectinid Palliolumdecussatum(von Miinster, 1833),
whichis restrictedto (the laterpartof?) ChattianA(R. Janssen, 1979a:fig. 1).
Eight pteropod species are known from the Sternberg boulders (Table 4), of
which atleast Heliconoideshospes, Ireneiatenuistriataand Vaginella chattica havebeen
recorded from a single boulder (from Segrahner Berg, RGM collections, leg. K.
Eichbaum, don.F. Weinbrecht).
TheChattian Grafenberg SandMember, in Nordrhein-Westfalen(Germany), has
yielded quite a numberof pteropods in materialrecovered fromboreholes or mine
shaftexcavations (RGM collections), most ofwhich remain unpublished to this date.
Themost important sectionof the Grafenberg Sands is the Sophia Jacoba8mine
shaft(Erkelenz, Nordrhein-Westfalen, sunk 1985-1988).Welle(1993)analysed acom-
plete seriesof samples fromthisshaft,butfoundjustasingle pteropod species inthe
Late Oligocene portion, Vaginella chattica. Aset of samples fromthis section is also
availablein the RGM collections, but remains to be studied. Aparallel section from
the K-3borehole, sunkearlierthanthe actualshaftconstruction, was analysed by Mr
A.C. Janse,Brielle(RGM collection) and has yielded several morepteropod species.
The Grafenberg Sands occur in this section between approximately 402 and 165 m
belowsurface. Welle(1993: 43,408) doubtedthevalueof Pectinidaeinthissectionfor
asubdivision oftheChattian, butdidrecordPalliolumdecussatumfrombetween339.5
and205m belowsurface, considering it tobe alaterdevelopment of P. aquaetranquil-
lae(Hubach, 1952), whichwas foundin this sectionbetween367.5and339.5 m. Both
species are alsoknownfromthe'KasselerMeeressand'(R. Janssen, 1979a:54). Ranges
78 BASTERIA, Vol. 69, No. 1-3, 2005
of pteropod species recorded from the Sophia Jacoba8 (K-3 borehole) section are
given inTable3.
ddeepptthhiinnmmbbeellooww ssuurrffaaccee
440000 339900338800 337700336600335500 334400333300 332200331100330000229900228800227700226600225500224400 223300222200221100220000 119900 118800
I1 EEoocchhaattttiiaann ((AA)) I1 EEoocchhaattttiiaann ((BB)) I1 NNeeoocchhaattttiiaann ((CC)) I1
HHeelliiccoontiooiiddeess hhoossppeess
++++++
LLiimmaacciinnaavvaallvvaattiinnaa
IIrreenneeiiaa tteennuuiissttrriiaattaa
SSttyylliioollaassuubbuullaa
++++++++++++
VVaaggiinneellllaacchhaattttiiccaa
Table 3.Pteropoddistribution intheGrafenbergSandsofthe Erkelenz- SophiaJacoba8(K-3)bore-
hole section.
The basal 50m and the uppermost 70 m of this section didnot yieldanyptero-
pod. In theinterval250-350m,fivepteropod species occur. In theupperportion, the
absence of pteropods is presumably caused by decalcificationof the sediment, but
the basal part contains excellently preserved molluscan faunas, and the absence of
pteropods is difficulttoexplain.
Theco-occurrence of Heliconoides hospes, Ireneiatenuistriataand Vaginella chattica,
as seen in one of the Sternberg boulders (see above), is found in the Sophia Jacoba
section exclusively in the Chatt B part. Spoelia torquayensis was not found in the
Sophia Jacoba section, but is known from another Grafenberg Sands locality
(Rheinberg, RGM collections).
Classic assemblages known from the Kassel area ('Kasseler Meeressand') are
supposed tohaveoriginated in arather isolatedbasin (Anderson, 1961:131,map 1),
whereas both 'Sternberger Gestein' and Grafenberg Sands represent more open
marine settings. Interms of holoplanktonic organisms, such as pteropods, onemight
expect thatopen sea assemblages contain more species than thosefrom shelteredor
coastal areas, whereonly the mostfrequent open-seaspecies can beexpected. Table
4lists pteropod species onrecord fromthese threelithological units.
Six out of eight species known from the 'Sternberger Gestein' are also recorded
from theGrafenberg Sands,andinclosely comparable frequencies. Justtwovery rare
species fromthe Sternberg bouldersare stillunknown fromtheGrafenberg Sands.
None of theseeight species, however, isknown fromthe 'Kasseler Meeressand',
in whichVaginella basitruncatasp.n.is the solepteropod, collectedin theAhnetalout-
crop from threedifferentlevels ('Schicht 3, 6, 9'), whichaccording to R. Janssen (in
litt., 2005)covers some 7 m of sediment.This species is absentfrombothotherlitho-
logical units.
Someof these eight species also occur in younger (Miocene) deposits (Limacina
valvatina, Styliola subula, Spoelia torquayensis), and a single (Heliconoides hospes) is
foundin pre-Chattian strata. On this basis, I assume the Kasseler Meeressand to be
coevalwith thelowermostpartofthe Grafenberg Sands,thusrepresenting theoldest
Chattianin the NorthSea Basin.
]anssen:A newspecies ofVaginella 79
ssppeecciieess KKaasssseelieerr SStteerrnnbbeerrggeerr GGrraaffeennbbeerrgg
MMeeeerreessssaanndd GGeesstteeiinn SSaanndd MMeemmbbeerr
HHeelliiccoonnooiiddeess hhoossppeess ((RRoollllee,,11886622)) . cc cc
LLiimmaacciinnaa vvaallvvaattiinnaa((RReeuussss,, 11886677)) - rr rr
LLiimmaacciinnaa ssppeecc..nnoovv..?? - rrrr -
SSttyylliioollaassuubbuullaa ((QQuuooyy&&GGaaiimmaarrdd,,11882277)) - rr rr
IIrreenneeiiaa tteennuuiissttrriiaattaa ((SSeemmppeerr,,11886611)) - cccc cc
SSppooeelliiaattoorrqquuaayyeennssiissAA..WW..JJaannsssseenn,,11999955 - rrrr rrrr
VVaaggiinneellllaabbaassiittrruunnccaattaa ssppeecc..nnoovv.. cc - -
VVaaggiinneellllaacchhaattttiiccaa RR..JJaannsssseenn,, 11997799 - cc cc
VVaaggiinneellllaa ttrriiccuussppiiddaattaaZZoorrnn&& JJaannsssseenn,,11999933 - rrrr -
Table4.Occurrence ofpteropodspecies inthree lithologicalunits ofLate Oligocene(Chattian)age;
rr - veryrare, r- rare, c- common,cc- verycommon.
Data presented above also allow to subdividepteropod zone 16into three sub-
zones, viz. 16a, 16band 16c,characterised by the FODs (firstoccurrence datums) of
Vaginella basitruncata, Ireneiatenuistriataand Vaginella chattica, respectively. Subzones
16a-ctogether cover the Eochattian.The Neochattianhas so far yielded barely any
pteropods. The only species known withcertainty to continueinto thebasal part of
the Neochattianis Vaginella chattica. Most probably, V. chattica is the precursor of
Vaginella depressa Daudin, 1800,whichisrestrictedtothe EarlyMiocene (Burdigalian,
pteropod zone 17).
ACKNOWLEDGEMENTS
The author is grateful to Dr Karl Gurs (Landesamt fur Natur und Umwelt
Schleswig-Holstein, Flintbek, Germany), Dr Jochen Welle (Geologisch-Palaontolo-
gisches Institut der Universitat Miinster, Germany) and Dr Ronald Janssen
(Senckenberg Museum,FrankfurtamMain, Germany) fordiscussionson(bio-)strati-
graphicalimplications. Thelast-namedisalso thanked forallowing along-term loan
of samples in his care. Mr AntonC. Janse (Brielle, the Netherlands) analysed along
series of samples from the K-3 borehole. Mr Friedrich Weinbrecht (Gliicksburg,
Germany) donatedpteropod materialfrom the 'Sternberger Gestein'. Dr JohnW.M.
Jagt (Venlo, theNetherlands), asalways, improved theEnglish.
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