Lower Cretaceous agglutinated Foraminifera from the Superfamilies Verneuilinacea and Ataxophragmiacea; southern Dobrogea, Romania

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Annales Societatis Geologorum Poloniae (1997), vol. 67: 307-323.

LOWER CRETACEOUS AGGLUTINATED FORAMINIFERA FROM THE SUPERFAMILIES VERNEUILINACEA AND

ATAXOPHRAGMIACEA; SOUTHERN DOBROGEA, ROMANIA

T h eo d o r A. N E A G U

U niversity o f Bucharest, L aboratory o f Paleontology, B -d u lN . B alcescu I, 70111 Bucharest, R om ania

Neagu, T. A., 1997. Lower Cretaceous agglutinated foraminifera from the Superfamilies V erneuilinacea and Ataxophragmiacea: Southern Dobrogea. Romania. Ann. Soc. Geol. Polon.. 67: 307-323.

A b stra c t: The present paper starts the study o f the upper Berriasian-low er A ptian agglutinated foram inifera from southern Dobrogea. The following taxa are presented: l'erneuilionoides faraonica, V. polonicus, V. danubiensis n.sp., I', pumilionis n.sp., (" fastigatus. Gaudryina cf. ectypa. G. dacica, Verneuilina angularis. V. dobrogiaca n.sp., Arenobulimina venasta n.sp.. A. melitaeformis n.sp., A. melitae, A. corniculum, A. cochleata. A. gibberosa n.sp., A. pfenderinae n.sp., A. moessiana n.sp., A. acervata n.sp., //. dissoluta n.sp.. A. corrugata n.sp.. A.

cuculifonnis n.sp. Two new genera, Danubina n.gen. and Gerochella n.gen. are also described. Palaeoecological and pnlaeogeographical considerations, using the morpho-structural characters o f the wall are also discussed.

A b stra k t: Prezentowana praca rozpoczyna cykl badań nad otwornicami aglutynującymi z utworów od górnego beriasu do dolnego aptu, w ystępujących w rejonie Dobrudży. Przedstawiono opis system atyczny następujących gatunków: l ’erneuilionoides faraonica, V. polonicus, V. danubiensis n.sp., V. pumilionis n.sp., V. fastigatus.

Gaudryina cf. ectypa, G. dacica, lerneuilina angularis, V. dobrogiaca n.sp., Arenobulimina venusta n.sp., A.

melitaeformis n.sp., A. melitae. A. corniculum. A. cochleata, A. gibberosa n.sp., A. pfenderinae n.sp., /!. moessiana n.sp., A. acervata n.sp., A. dissoluta n.sp.. A. corrugata n.sp., A. cuculifonnis n.sp. W yróżniono oraz opisano dwa nowe rodzaje w śród otwornic aglutynujących: Danubina i Gerochella. Zawarto także uwagi dotyczące paleo- ekologii i paleogeografii w oparciu o analizę morfostruktury ścian opisanych taksonów.

Key w ords: Lower Cretaceous foraminifera, V erneuilinacea and A taxophragm iacea groups, new species and new genera, Dobrogea, Romania.

Manuscript received 4 September 1996, accepted 17 July 1997

INTRODUCTION

T h e L o w e r C re ta c e o u s fo ra m in ife ra l fau n a o f so u th ern D o b ro g e a are situ a te d in th e first p la n e re g a rd in g th e ta x a a n d sp e c im e n s ric h n e ss, to g e th e r w ith m o llu sc s (G a stro p o d a a n d B iv a lv ia ). A m o n g th e s e fo ra m in ife ra l asse m b la g e s, a c h a ra c te ris tic featu re is th e p re d o m in a n c e o f ag g lu tin a te d sp e c ie s, w ith a sim p le o r c o m p le x w a ll stru c tu re . T h e n e x t g ro u p in te rm s o f d iv e rsity g ro u p is c o m p rise d o f m ilio lid s an d in v o lu tin id s . W ith a s u b o rd in a te an d re d u c e d fre q u e n c y o c c u r th e c a lc a re o u s b e n th ic sp e c ie s, re p re se n te d by ra re n o - d o sa rin id s , p o ly m o rp h in id s , sp irillin id s, d isco rb id s, ep is- to m in id s a n d c o n o rb o in id s. F ro m th e se v ery rich an d w ell p re s e rv e d a ss e m b la g e s, th e p fe n d e rin id s, m ilio lid s, an d in v o lu tin id s h a v e a lre a d y b e e n stu d ie d a n d d e sc rib e d (N eag u , 1975).

T h e p re s e n t p a p e r b e g in s a d e ta ile d stu d y o f th e a g g lu ti

n a te d g ro u p w ith sim p le w all stru c tu re w h ic h a p p e a r w ith p a rtic u la r fre q u e n c y in th e u p p e r B e rria s ia n -lo w e r A p tia n d ep o sits.

S o m e ta x a fro m the s u p e rfa m ily V e rn e u ilin a c e a : G ero

chella cylindrica n .g en et n .sp ., D an u b in a obtusa n .g en . et n .sp ., Verneulinoides fa ra o n ica S a id & B arak at, 1961, V.

polonicus (C u sh m an & G la z e w sk i), 1949, V. danubiensis n.sp ., V. fa stig a tu s M a g n e z -Ja n n in e , 1973, V. pum ilio n is n.sp ., G audryina cf. ectypa A m a u d -V an n e a u , 1980, G.

dacica N eag u , 1975, Verneuilina angularis G o rb a tc h ik , 1971, V. dobrogiaca n.sp., an d fro m th e su p e rfa m ily A ta x o  p h ra g m ia c e a : A renobulim ina venusta n .sp ., A. m elitaefor

mis n. sp., A. m elitae K o v a tc h e v a , 1969, A. corniculum A r- n a u d -V a n n e a u , 1980, A. cochleata A rn a u d -V a n n e a u , 1980, A. m oesiana n .sp ., A. acervata n .sp ., A. p fe n d erin a e n .sp ., A dissoluta n.sp., A. corrugata n .sp ., A. cu cu lifo n n is n .sp . w ill be p re s e n te d first.

T h e V e rn e u ilin a c e a g ro u p is w ell k n o w n fro m Ju ra ssic an d L o w e r C re ta c e o u s d e p o sits, b u t th e A ta x o p h ra g m ia c e a gro u p is c o m p le te ly n ew in th e u p p e r B e rria sia n -V a la n g - inian d ep o sits, a n d is s p o ra d ic a lly re p re s e n te d by th re e spe-

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cies (A renobulim ina melitae, A. corniculum and A. co- chleatd) in th e B a rre m ia n -A p tia n d e p o sits (K o v a tc h e v a , 1969; A rn a u d -V a n n e a u , 1980). T h e m a jo r d e v e lo p m e n t o f th is g ro u p is c o n sid e re d to b eg in in the early A p tia n (A n g lo - P a risia n B asin ), a n d it is la te r w ell re p re se n te d in all U p p er C re ta c e o u s d e p o sits fro m E u ro p e (B a rn a rd & B a n n e r, 1980;

P ric e , 1977; F rie g & P ric e , 1982; V o lo sh in o v a , 1972). T h e L o w e r C re ta c e o u s d e p o sits (u p p e r B e rria s ia n -lo w e r A p tia n ) in s o u th e rn D o b ro g e a o ffe r v e ry in te re stin g d a ta w h ic h c o m p le te th e k n o w n stra tig ra p h ic a l d is trib u tio n o f th is group.

T h e g e n u s A renobulim ina is p re s e n t even in th e u p p er B e rria sia n in C e rn a v o d a , a n d la te r u n d e rw e n t a larg e m o r

p h o s tru c tu ra l e v o lu tio n d u rin g th e B a rre m ia n -A p tia n . T h is m o rp h o stru c tu ra l e v o lu tio n a n d im p re ssiv e d e v e lo p m e n t o f p o p u la tio n s m a d e it p o s s ib le to fin d 9 n e w sp e c ie s a d d e d to th e o n e s a lre a d y d e sc rib e d .

T w o n ew g e n e ra , D anubina n .g en . an d G erochella n .g en . w h ic h b y th e ir w a ll stru c tu re an d a p e rtu re can be a s

sig n e d to the V e m e u ilin a c e a g ro u p , are also a d d e d to the g e n e ra l in v e n to ry o f th e fo ra m in ife ra .

T h e ric h n e ss a n d g o o d p re s e rv a tio n o f th e a v a ila b le m a te ria l o ffe re d th e p o s s ib ility to m a rk th e lim its o f th e a llie d g e n e ra Verneuilina a n d Verneuilinoides a c co rd in g to L o e  b lic h a n d T a p p a n (1 9 8 8 ). W e a v o id th e c o n fu s io n c a u se d A rn a u d -V a n n e a u (1 9 8 0 ) w h o c o n sid e re d th a t th e re w e re n o n o tic e a b le d iffe re n c e s b e tw e e n th e s e g en era.

SYSTEMATIC PALEONTOLOGY

S u b o rd e r T E X T U L A R IIN A D e la g e an d H e ro u a rd , 1896 S u p e rfa m ily V E R N E U IL rN A C E A C u sh m a n , 1911 F a m ily P R O L IX O P L E C T ID A E L o e b lic h an d T a p p a n ,

1985

G e n u s G erochella n.gen.

D escription: Test with a trochospiral early stage, pyramidally square-rounded in transversal section, with 4 chambers per whoii;

an interm ediate short stage w ith 2-3 chambers irregularly unise- i'ial. The adult stage is well developed, uniserial, cylindrical, with low chambers, weakly inflated and straight depressed sutures. The aperture in the early stage is represented by a virgulate interiomarginal slit, becoming in the last uniserial stage multiple with many circular or elongated pores. Chambers simple, w ithout inner ele

ments. Wall compact, finely agglutinated, with calcareous cement.

Etym ology: This genus is dedicated to the memory o f Professor Stanislaw Geroch, Jagiellonian University. Kraków in profound homage.

R e m a rk s: The general shape o f the test is similar with that o f Pseudoliluonella, but the total absence of inner structure o f the chambers, and the nature o f the early stage indicate a clear differ

ence. It is noteworthy that the early stage o f this genus is similar in its cham ber arrangement, to Riyadhella Redmond, 1965, described in M iddle to Upper Jurassic. The simple inner structure, the tro

chospiral chamber disposition and the virgulate aperture o f the early stage are the features that indicate this genus belongs to the family Prolixoplectidae.

S tra tig ra p h ie d istrib u tio n : Lower Valanginian.

Gerochella cylindrica gen. et sp. nov.

Fig. 1 ( 1 - 4 1 )

Etym ology: This form is named from the shape o f the last stage o f the test; latin cylindricus-i = cylinder.

Type-locality: Cernavoda Pod, right bank o f the D anube River.

Type-level: ISPH drillings C4-H inog - 47.20 m; lower Valang

inian.

Diagnosis: Gracile test, with the early stage trochospiral with a pyramidal shape with 4 chambers per whorl; an interm ediate stage with 2-3 chambers irregularly uniserial; the adult stage uniserial;

well developed with a cylindrical shape; weakly inflated cham bers, and straight sutures. Inner part o f the cham bers w ithout any kind o f secondary elements; wall compact, finely agglutinated with calcareous cement. Aperture in the early stage a virgulate interiomarginal slit, becoming m ultiple in the adult, represented by many circular or elliptical pores on the apertural face.

M easu rem en ts (m m ): Holotype length - 1.24; thickness - 0.26.

Paratypes length - 0.48-136; thickness - 0.24-0.29 (figured speci

mens).

D eposition o f types: H olotype = L.P.B.IV .l 1.190. Paratype = L.P.B.IV.l 1.191.

S tra tig ra p h ie d istrib u tio n : U ppermost Berriasian to lower Valanginian.

G en u s D anubina n.gen.

Etym ology: This form is named from the latin name o f the Danube River.

D escription: Conical-obtuse trochospiral test, early stage with 2-3 whorls with 5-6 chambers per w hoii, last stage with 4 or 4 1/2 chambers per whorl; arcuate weakly depressed sutures, apertural face flat or weakly to moderately concave. Interiomarginal aper

ture, simple, as low virgulate slit in the early stage, becoming textularoid with a large valvular tooth in the adult stage. Wall finely agglutinated, compact, with calcareous cement.

R em ark s: The material from the lower V alanginian o f Cernavoda possesses an early trochospiral stage similar to that o f Orienlalia Bykova, 1947 and Eomarssonella Levina, 1972. It clearly differs from Eomarssonella by its trochospiral last stage, and from Orien- talia by the absence of a quadriserial chambers arrangement in the adult stage. In addition a clear difference from the above men

tioned two genera is the presence o f an aperture with a valvular tooth. From Riyadhella whose chamber disposition is also trochos

piral with 4 chambers per whorl, Danubina n.gen. differs by the presence o f the valvular tooth.

S tra tig ra fic d istrib u tio n : Lower Valanginian.

D anubina obtusa gen. et sp. nov.

F ig. 2 ( 3 5 - 5 1 )

E tym ology: This form is named from shape o f the test; latin obtusus-a-um = obtuse, blunted, not sharpor pointed.

T ype-locality: Cernavoda Pod, right bank o f the Danube River.

T ype-level: Lower Valanginian.

D iagnosis: Free test, conical-obtuse with trochospiral chamber arrangement, 4 to 4 1/2 per whorl. Sutures oblique-arcuate, weakly depressed. Apertural face made by the chambers o f the last whoii has a flat to weakly concave shape, and contains an interiom argi

nal aperture as a simple, arcuate slit in the early stage becoming textularoid in the last stage with a well developed valvular tooth.

R em ark s: From Orientalia norris Hedinger, 1993, D. obtusa dif

fers by the adult chambers arrangem ent (trochospiral not quadris

erial) and structure o f the aperture.

M easurem ents (m m ): Holotype length - 0.62; thickness - 0.39.

Paratypes length -0 .3 1 -0 .5 5 ; thickness - 0.31-0.39 (figured speci

mens).

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309

Fig. 1. Low er Cretaceous agglutinated foraminifera from southern Dobrogea. 1-41 - Gerochella cylindrica N eagu n.gen. n.sp.: (1 -3 9

1

paratypcs, L.P.B.IV.l 1.191; (40. 41) holotype, L .P .B .I V !1.190; lower Valanginian. Cernavoda Pod. right bank o f the Danube River 42-53 - Gaudiyina dacica Neagu, 1975. hipotypcs L.P.B.IV. 11.192; lower Aptian, Fetesti, ISPH Drilling F.135. 138 m. 54-56 - Arenobulimina cochleata A rnaud-Vanneau, 1980, hipotypes. L.P.B.IV. 170; lower Aptian. Alimanu-Adâncata. Scale bar = 300 (.im

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Fig. 2. Lower Cretaceous agglutinated foraminifera from southern Dobrogea. 1-3 - Verneuilina angularis Gorbatchik, 1971. liypo- ivpes, L.P.B.IV. 11.154; lower Valanginian, Alimanu. left bank o f Lake Vederoasa. 4-13 - Arenobulimina dissolura Neagu n.sp..

paratypes, L.P.B.IV. 11.176: lower Aptian. Oltina ISPH Drilling Bala I. 32 m. 14-26 - Arenobulimina pfenderinae Neagu n.sp.: (14-19.

23-26) paratypes. L .P .B .IV .11.166: (20-22) holotype, L.P.B.IV .l 1,165; lower Aptian. Oltina ISPH Drilling Bala I. 32.1 m. 27-34 - Arenobuliinina acervata Neagu n.sp.: (27-32) paratypes, L.P.B.IV. 11.180: (33-34) holotype, L.P.B.IV. 11.179; lower Aptian. O ltina ISPH Drilling Bala I, 32.1 m. 35-51 - Danubina obtusa Neagu n.gen. n.sp.: (35-43. 46-51) paratypes. L.P.B.IV .l 1.153: (44-45) holotype, L.P.B.IV. 11.152: lower Valanginian. Cernavoda Pod. right bank o f the Danube River. 52-55 - Arenobulimina melilae Kovatchcva. 1968, hypotypes. L.P.B.IV. 11.188; upper Barremian, Ostrov-Gâiiitza, southern bank o f the Lake Bugeac. 56-58 - Arenobulim ina corniciilum Arnaud-Vanneau, 1980, hypotypes. L.P.B.IV. 11.185; lower Barremian. Alimanu quarry. Scale bar = 300 pm

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311

Fig. 3. Lower Cretaceous agglutinated foraminifera from southern Dobrogea. 1-15 - Arenobulimina venusta Neagu n.sp.: (1-3, 5-15) paratypes. L.P.B.IV. 11.162: (4) liolotype. L.P.B.IV. 11.161: lower Valanginian. Cem avoda Pod, right bank o f the Danube River. 16-25 - Arenobulimina melitaeformis Neagu n.sp.: (16-17) holotvpe, L.P.B.IV. 11.163.; (18-25) paratypes, L.P.B.IV. 1 1.164; lower Valanginian.

Cernavoda Pod, light bank ol the Danube River. 26-42 - Verneuilina dobrogiacea Neagu n.sp.: (26-39) paratypes, L.P.B.IV. 155, lower Valanginian, Cernavoda Pod. right bank o f the Danube River; (40-42) paratypes, L.P.B.IV. 11,159. lower Aptian Oltina. 1SPH Drilling Bala I. 36 m. 43-50 - I'erneuiHnoides faraonica Said & Barakat. 1961, hololypcs. L.P.B.IV. 11.140: lower Valanginian, Alimanu. Scale bar = 300 pm

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Fig. 4. Lower Cretaceous agglutinated ['oiamiiiifeia from southern Dobrogea. 1-12 - Verneuilinoides faraonica (Said & Barakat.

1961), hipolypes, L.P.B .IV .l 1.140: lower Valanginian, Alimanu, left bank o f Lake Vederoasa. 13-19 - Verneuilinoides polonicus (Cushman & Glazewski. 1949), hipotypes, L.P.B.IV. 11.141; lower Valanginian, Cernavoda Pod, right bank o f the D anube River. 20-26 -A ren o b u lim in a corniculum Arnaud-Vanncau. 1980, hipotypes, L.P.B.IV.l 1.185; lower Aptian, A lim anu-Adâncata. 27-31 -A r e n o b u  limina gihberosa N eagu n.sp.: (27-29) paratypes. L .P.B .IV .11.183; (30,31) holotype. L.P.B.IV.11.182: lower Aptian, Oltina, ISPH Drilling Bala 1.36 m. 32, 33 - Arenobulim inapfenderinae Neagu n.sp.. paratypes, L.P.B.IV. 11.166; lower Aptian, Oltina, ISPH Drilling Bala I, 36 m. 34-44 - Arenobulimina cochleata Arnaud-Vanneau, 1980, hipotypes, L.P.B.IV. 11.170; lower Barremian. Alimanu quarry.

Seale bar = 300 pm

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LOW ER CRETACEOUS AGGLUTINATED FORAMINIFERA FROM SOUTHERN DOBROGEA

313

S tra tig ra p h ie d is trib u tio n : Lower Valanginian.

D eposition o f types: Holotype = L.P.B.IV.11.152. Paratype = L.P.B.IV. 11.153.

F a m ily V E R N E U IL IN ID E C u sh m a n , 1911 S u b fa m ily V E R N E U IL IN O ID IN A E S u le y m a n o v , 1973

G e n u s V em euilinoides L o eb lich & T ap p a n , 1949 R e m a rk s: In the reference literature (Arnaud-Vanneau, 1980;

Gorbatchik. 1971) there are different opinions regarding the defi

nition and individuality o f the genus Vemeuilinoides. I took into consideration Loeblich and Tappan (1988) to differentiate Verne- uilinoides from the morphologically similar genus Verneuilina.

V em euilinoides fa ra o n ic a (S a id & B arak at, 1961) Fig. 3 ( 4 3 - 5 0 ) , F ig. 4 (1 - 1 2 )

1958. Vemeuilinoides minuta Said & Barakat: Said & Barakat, p. 242, pi. 4. fig. 5.

1961. V erneuilina faraonica Said & Barakat: Said, p. 148.

non 1980. Verneuilina aff. faraonica Said & Barakat: Arnaud- Vanneau, p. 399, text-fig. 148, pi. 6. figs. 15-16.

M easu rem en ts (m m): Length -0 .3 4 -0 .4 6 ; breadth 0.29-0.40 mm (figured specimens).

O cc u rre n c e : Alimanu, left bank o f Lake Vederoasa.

D eposition o f types: Hipotypc = L.P.B.IV. 11.140.

V em euilinoides polo n icu s (C u sh m a n & G lazew sk i, 1949) Fig. 4 ( 1 3 - 1 9 ) , Fig. 5 (3 9 ^ 1 9 )

1949. Verneuilina polonica Cushman & Glazewski: Cushman &

Glazewski, p. 7, pl. 1, figs. 14-15.

R em ark s: As already m entioned by Cushman and Glazewski (1949), this species presents a large to very large size (> 1 mm). In our material, a very rich assemblage made it possible to follow the progressive developm ent o f the test from small specimens (0.40 mm length) to the largest ones (over 1.10 mm length). The small specimens are similar to Verneuilina subminuta Gorbatchik, 1971.

It is possible that G orbatchik’s species from the Berriasian o f the Crim ea represents a junior synonym o f V. polonicus.

M easu rem en ts (m m ): Length - 0.60-1.08; breadth 0.40-0.48.

O cc u rre n c e : Cernavoda Pod, right bank o f the Danube River.

D eposition o f types: Hipotype = L.P.B.IV. 11.141.

V em euilinoides danubiensis n.sp.

F ig. 5 (2 1 - 2 6 )

Etym ology: This form is named from the latin name o f the Danube River = Danubius-i.

Type-Iocality: Cernavoda Pod, right bank o f the Danube River, Ilie B arza’s quarry.

T ype-level: ISPH drillings FD VIII - 68.10 m; uppermost Berri

asian to lower Valanginian.

D iagnosis: T est free, finely agglutinated, smooth, triserial with globular cham bers increasing rapidly in dimensions. The last three cham bers are strongly inflated. Sutures weakly oblique and deeply depressed. Apertural face low, with a crescentic shape, with an interiomarginal aperture present as a low slit with a thick lip.

R e m a rk s: This species differs from V. polonicus (small speci

mens) and V. faraonica by its smooth agglutinated test and the globular shape o f the chambers.

M easu rem en ts (m m ): Holotype length - 0.68, breadth - 0.49.

Paratypes length - 0.42-0.68; breadth - 0.34-0.49 (figured speci

mens).

S tra tig ra p h ie d istrib u tio n : Upperm ost Berriasian to lower Valanginian.

D eposition o f types: Holotype = L.P.B.IV. 11.142. Paratypes = L.P.B.IV .l 1.143-11.145.

V em euilinoides fa stig a tu s M a g n ie z -Ja n n in , 1973 Fig. 5 (2 7 - 3 5 )

1973. Vemeuilinoides fastigatus M agniez-Jannin: M agniez-Jan

nin, p. 23, pi. 3, figs. 1-8.

R em ark s: This species differs from V. danubiensis by its gracile- elongate test and its interiomarginal-arcuate aperture. It differs from V. schizea (Cushman & Alexander) by the shape and position o f the apertural face, and by the form o f the aperture.

M easu rem en ts (m m ): Length - 0.48-0.96; breadth - 0.24-0.39 (figured specimens).

O ccu rren ce: Ostrov-Gârlitza, southern bank o f Lake Bugeac, Olt- ina ISPH drillings Bala I - 36 m.

S tra tig ra p h ie d istrib u tio n : U pper Barrem ian to low er Aptian.

D eposition o f types: Hipotypes = L.P.B.IV .l 1.146-11.148.

V em euilinoides p u m ilio n is n.sp.

F ig. 5 ( 9 - 2 0 )

Etym ology: This form is named from the reduced dimensions o f the test; Iatin pumilio-oni = dw arf (regarding plants and animals).

T ype-Iocality: Ostrov-Gârlitza, southern bank o f Lake Bugeac.

Type-level: Fetesti ISPH Drilling F. 135, 138 m; upper Barremian to lower Aptian.

D iagnosis: Small sized triserial test (rarely more than 0.5 mm length); globulose chambers with straight and depressed sutures.

Wall medium agglutinated with a large quantity o f calcareous cement. Test with a rough aspect. A perture interiomarginal. virgulate with a fine lip. In robust specimens the test can take a twisted shape.

R em ark s: By the small size and the globulose shape o f the cham bers and the virgulate aperture, this species differs from V fcisli- gatus to which it is frequently associated.

M easu rem en ts (m m ): Holotype length - 0.51; breadth - 0.25.

Paratypes length - 0.34-0.51: breadth 0.22-0.29 (figured speci

mens).

S tra tig ra p h ie d istrib u tio n : U pper Barrem ian to lower Aptian.

D eposition o f types: Holotype = L .P.B .IV .l 1.149. Paratypes = L.P.B.IV .l 1.150-11.151.

S u b fa m ily V E R N E U IL IN IN A E C u sh m a n , 1911

G e n u s G audryina d ’O rb ig n y , 1839

G audryina cf. ectypa A rn au d -'V an n eau , 1980 Fig. 6 ( 4 5 - 4 8 )

D iagnosis: Test very large (up to 1,68 mm length). Early triserial stage not tricarinate, with globulose cham bers representing up to h alf o f the total length: terminal stage biserial also w ith globulose chambers. Sutures straight, depressed. Wall coarsely agglutinated with calcareous cement. A perture interiomarginal, textularoid with a large valvular tooth.

R em ark s: O ur material differs from G. ectypa Arnaud-Vanneau, 1980 by its early triserial rounded stage (Vemeuilinoides shape) and by the presence o f a valvular apertural tooth.

M easu rem en ts (m m ): Length 1.65-1.68; thickness 0.72 (figured specimens).

O ccu rren ce: Ostrov-Gârlitza, southern bank o f Lake Bugeac.

S tra tig ra p h ie d is trib u tio n : Upper Barrem ian

i 3 — A n n a le s...

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D eposition o f types: H ipotype = L.P.B.IV .l 1.160.

G audryina dacica N eag u , 1975 Fig. 1 (4 2 - 5 3 )

1975. Gaudryina dacica Neagu: Neagu, p. 33, pi. 26, figs. 21-28;

pi. 27, figs. 1-9; pi. 28, figs. 1-15; pi.29, figs. 1-2.

M easu rem en ts (m m ): Length - 0.26-0.60; breadth - 0.25-0.43.

O c c u rre n c e : Fetesti, ISPH drillings F 135-138 m.

S tra tig ra p h ie d is trib u tio n : Lower Aptian.

D eposition o f types: H ipotype = L.P.B.IV. 11.

G e n u s Verneuilina d ’O rb ig n y , 1839

Verneuilina angularis G o rb a tc h ik , 1971 F ig . 2 ( 1 - 3 )

1971. Verneuilina angularis Gorbatchik: Gorbatchik, p. 131, pi. 2, fig. 6.

1975. Verneuilina angularis Gorbatchik: Neagu, p. 31, pi. 25, figs.

14-15.

R e m a rk s: This species differs from V. dobrogiaca by the truncate, carinate shape o f the cham bers in the last stage.

M easu rem en ts (m m ): Length - 0.55-0.86; breadth - 0.34-0.43 (figured specimens).

O cc u rre n c e : Alim anu, left bank o f Lake Vederoasa, Cernavoda Pod, right bank o f the D anube River, Hie B arza’s quarry.

D eposition o f types: H ipotypes = L.P.B.IV. 11.154-11.156.

V erneuilina dobrogiaca n.sp.

Fig. 3 (2 6 - 4 2 ), Fig. 5 (1 - 8 )

Etym ology: from Dobrogea, the historical name o f the territory between the Black Sea and the Danube River.

T ype-locality: O strov-Gârlitza, southern bank o f Lake Bugeac;

Cernavoda Pod, right bank o f the Danube River.

T ype-level: Oltina ISPH Drilling Bala I - 36 in; Fetesti ISPH Drilling F. 135, 138 m; upper Barremian.

D iagnosis: Test ordinarily small sized, rarely exceeding 0.8 mm in length, triserial, tricarinate in the early stage with acute keels, becomes later weakly rounded, with the last 2 -3 chambers weakly inflated with straight depressed sutures. Wall medium agglutinated with calcareous cement. Interiom arginal aperture, as a virgulate slit.

R e m a rk s: This species differ from V. angularis Gorbatchik, 1971 by its small size and the absence o f the truncate carinated last chambers.

M easu rem en ts (m m ): H olotype length - 0.54; breadth - 0.34.

Paratypes length - 0.34-0.84; breadth - 0.27-0.46 (figured speci

mens).

S tra tig ra p h ie d istrib u tio n : Lower Valanginian, Barrem ian to lower Aptian.

D eposition o f types: H olotype = L.P.B.IV. 11.157. Paratypes = L .P.B .IV .l 1.156-11.158, 11.159.

S u p e rfa m ily A T A X O P H R A G M IA C E A S ch w ag er, 1877 F a m ily A T A X O P H R A G M IID A E S ch w ag er, 1877 S u b fa m ily A T A X O P H R A G M IIN A E S c h w a g e r, 1877

G en u s A renobulim ina C u sh m an , 1927

A renobulim ina venusta n.sp.

F ig. 3 ( 1 - 1 5 )

Etym ology: This form is named from the general shape o f the test;

latin venustus-a-um = elegant.

T ype-locality: Cernavoda Pod, right bank o f the D anube River.

Type-level: Lower Valanginian.

Diagnosis: Small sized test, typical trochospiral with 4 -6 cham

bers per whorl. Chambers o f the last part globulous with falcate- depressed sutures. Wall compact, finely agglutinated, sm ooth with calcareous cement; the virgulate aperture may or may not have a small valvular tooth and a peripheral lip.

Paratypes length - 0.29-0.46; thickness - 0.31-0.58 (figured speci

mens).

S tra tig ra p h ie d istrib u tio n : Upperm ost Berriasian to lower Valanginian.

D eposition o f types: Holotype = L.P.B.IV .l 1.161. Paratype = L.P.B.IV.l 1.162.

A renobulim ina m elitaeform is n.sp.

Fig. 3 (1 6 - 2 5 )

Etym ology: This form is named from the resemblance o f the test with that o f Arenobulimina melitae Kovatcheva, 1969.

T ype-locality: Cernavoda Pod, right bank o f the D anube River.

Type-level: Lower Valanginian.

Diagnosis: Medium-sized trochospiral test w ith a low whorl; 4 -5 globulose chambers in the last whorl increasing rapidly in size, sutures arcuate, deeply depresed. Wall finely agglutinated with calcareous cement. Aperture interiomarginal, a large virgulate slit in the middle o f the apertural face o f the last chamber.

R em ark s: This species differs from A. melitae Kovatcheva, 1969 from the B arrem ian-A ptian by the shape o f test and the aperture position.

M easu rem en ts (m m ): H olotype length - 0.46; thickness - 0.50.

Paratypes length - 0.36-0.53; thickness 0.36-0.53 (figured speci

mens).

D eposition o f types: H olotype = L.P.B.IV .l 1.163. Paratypes = L .P.B.IV .l 1.164.

A renobulim ina m elitae K o v a tc h e v a 1969 F ig. 2 (5 2 - 5 5 )

1969. Arenobulimina melitae Kovatcheva: K ovatcheva, p. 37, pi.

1, figs. 1-3.

1971. Arenobulimina melitae Kovatcheva: Bartenstein, Betten- staedt & Kovatcheva, p. 133, pl. 1. figs. 9-11.

1975. Eggerellina melitae (K ovatcheva): Neagu, p. 41, pi. 23, figs.

1-24; pi. 24, figs. 1-37.

M easu rem en ts (m m ): D iam eter-0 .3 6 -0 .4 3 ; h e ig h t-0 .2 4 -0 .3 6 . O ccu rren ce: Ostro v-Gârlitza, southern bank o f Lake Bugeac, Fetesti, ISPH drillings F. 135, 138 m.

D eposition o f types: Hipotype = L .P.B .IV .l 1.188.

A renobulim ina cochleata A m a u d -V a n n e a u , 1980 F ig. 1 (5 4 - 5 6 ), Fig. 4 (3 4 - 4 4 ) , Fig. 7 ( 4 3 - 5 2 )

1980.Arenobulimina cochleata Arnaud-Vanneau: Arnaud-Van- neau, p. 446, pi. 53, figs. 4-10; pi. 81, figs. 9-21, text-figs.

166-167.

M easu rem en ts (m m ): Length - 0.46-0.67; thickness - 0.48-0.58 (figured specimens).

O ccu rren ce: Alimanu quarry. A lim anu-Adanceata.

S tra tig ra p h ie d istrib u tio n : Lower Barremian to Aptian.

D eposition o f types: Hipotype = L.P.B .IV .l 1.170.

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315

Fig. 5. Lower Cretaceous agglutinated foraminifera from southern Dobrogea. 1-8 - I'erneuilina dobrogicica Neagu n.sp.: (1-6) paratypes. L.P.B.IV. 11.158; (7-8) holotype, L.P.B.IV. 11.157; upper Barremian, Ostrov-Gârlitza, southern bank o f the Lake Bugeac. 9-20 - Verneuilinoides pum ilionis N eagu n’sp: (9-18) paratypes, L .P .B .IV .II. 150; (19-20) holotype, L.P.B..IV. 11.149; upper Barremian.

Ostrov-Gârlitza. southern bank o f the Lake Bugeac. 21-26 - Verneuilinoides danubiensis Neagu n.sp.: (21-23, 25-26) paratypes.

L.P.B.IV .l 1.143: (24) holotype. L.P.B.IV .l 1.142; upper Barremian, Ostrov-Gârlitza. southern bank o f the Lake Bugeac. 27-38 - Verneuilinoides fastigatus Magniez-Jannin, 1973, hipotypes, L.P.B.IV .l 1.146-11.147: upper Barremian, O strov-Gârlitza, southern bank o f the Lake Bugeac. 39-49 - Verneuilinoides polonicus (Cushman & Glazewski, 1949), hipotypes L.P.B.IV. 11.141; lower Valanginian, Cernavoda Pod. right bank o f the Danube River. Scale bar = 300 um

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Fig. 6. Lower Cretaceous agglutinated foraminifera from southern Dobrogea. 1-17 - Arenobulimina corrugata N eagu n.sp.: (1-9.

11-15) paratypes, L.P.B .IV .l 1.173, upper Barremian, Ostro v-Gârlitza, southern bank o f the Lake Bugeac; (10) holotype.

L.P.B.IV. 11.174, upper Barremian, Ostrov-Gârlitza, southern bank o f the Lake Bugeac; (1-17) paratypes, L.P.B.IV. 11.173, lower Aptian, Oltina, ISPH Drilling Bala I, 32-32.1 m. 18-35 - Arenobulimina cucullaeformis Neagu n.sp.: (18-32) paratypes, L.P.B.IV. 11.168; (33-35) holotype, L.P.B.IV .l 1.168; upper Barremian, Ostrov-Gârlitza, southern bank o f the Lake Bugeac. 36-44 - Arenobulimina pfenderinae Neagu n.sp.. paratypes, L .P.B .IV .l 1. 166; lower Aptian, Oltina, ISPH Drilling Bala I, 36 in. 45-48 - Gaudryina cf. ectypa Amaud-Van- neau, 1980, hipotypes L.P.B.IV. 11.160; upper Barremian, Ostrov-Gârlitza, southern bank o f the Lake Bugeac. Scale bar = 300 (.im

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L O W KR C R E T A C E O U S A G G L U T I N A T E D F O R A M IN IF E R A F R O M S O U T H E R N D O B R O G E A

317

Kig. 7. L o w e r C r e t a c e o u s a g g l u t i n a t e d I'o ra m inif er a fro m s o u t h e r n D o b r o g e a . 1-17 - Arenobulimina acervata N e a g u n .s p .. p a r a t y p e s . L . P . B . I V . 11.180: l o w e r A p t i a n , O l t i n a . I S P H D r i l li n g B a l a I, 3 6 m. 18-25 - Arenobulimina sp. cl'. A. acervata N e a g u n.sp..

L . P . B . I V . 11.180: l o w e r A p t i a n . O l t i n a I S P H D r i l li n g B a l a I. 36 in. 26-33 Arenobulimina dissoluta N e a g u n .sp., p a r a t y p e s . L . P . B . I V . 11. 1 7 6 : l o w e r A p t i a n . O ltin a , I S P H D r i l li n g B a la I. 36 m. 34-42, 55-57 - Arenobulimina moesiana N e a g u n.sp.: ( 3 4 - 3 7 , 4 0 - 4 2 . 5 5 - 5 7 ) p a r a t y p e s . L . P . B . I V . 11.1 8 7 : (38. 3 9 ) h o lo ty p e , L . P . B . I V . 11.186: l o w e r A p t i a n , O ltin a . I S P H D r i l li n g B a l a I. 3 6 m. 43-52 - Arenobulimina cochleata A r n a u d - V a n n e a u , 19 80 . h i p o t y p e s L . P . B . IV . 11 . 170: l o w e r A p t i a n , A l i m a n u - A d â n c a t a . 53, 54 - Arenobulimina gibberosa N e a g u n.sp.. p a r a t y p e s , L . P . B . I V . l 1.183: lo w e r A p t i a n . O l t i n a I S P H D r i l li n g B a l a I. 3 6 m. 58 - Arenobulimina sp.; l o w e r

A p t i a n . O ltin a . I S P H D r i l l i n g B a l a I. 32.1 m. S c a l e b a r = 3 0 0 ^un

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Fig. 8. Lower Cretaceous agglutinated foraminifera from southern Dobrogea. 1-14 - Arenobulimina gibberosa Neagu n.sp., paratypes.

L.P.B.IV .l 1.184; upper Barrem ian, Ostrov-Gârlitza. southern bank o f the Lake Bugeac. 15-51 - Arenobulimina dissoluta Neagu n.sp.:

(15-45, 49-51) paratypes, L .P.B .IV .l 1.175; (46-48) holotype, L.P.B.IV .l 1.175; lower Aptian, Oltina, ISPH D rilling Bala I, 36 m. 52-57 -Arenobulim ina gibberosa Neagu n.sp.. paratypes, L.P.B.IV .l 1.183; lower Aptian. Oltina, ISPH D rilling Bala I, 36 m. Scale bar = 300

|.im

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319

A renobulim ina corniculum A m a u d -V a n n e a u , 1980 Fig. 2 ( 5 6 - 5 8 ) , F ig. 4 (2 0 - 2 6 )

1980. Arenobulimina corniculum Amaud-Vanneau: Arnaud-Van- neau, p. 441. pi. 53, figs. 1-3; pi. 81, figs. 1-8, text-figs.

164-165.

M easu rem en ts (m m ): Length - 0.48-0.77; thickness - 0.34-0.46 (figured specimens).

O c c u rre n c e : Alimanu - quarry, Alimanu-Adancata.

S tra tig ra p h ie d istrib u tio n : Low er Barremian to lower Aptian.

D eposition o f types: H ipotype = L.P.B.IV. 11.185.

A ren o b u lim in a p fe n d erin a e n.sp.

Fig. 2 (1 4 - 2 6 ) , Fig. 6 (3 6 - 4 4 )

E tym ology: This form is named from the resemblance o f the test to that o f Pfenderina globosci Foury, 1964.

T ype-locality: Ostrov-Gârlitza, southern bank o f Lake Bugeac.

T ype-level: Oltina. ISPH D rilling Bala I - 32.10-36 m; upper Barrem ian to lower Aptian.

D iagnosis: Test trochospiral, globulose with 4 -5 crescentic cham

bers in the last whorl (with breadth sm aller than length). Sutures arcuate weakly depressed. Apertural face truncate and weakly concave, in the middle position. Aperture is a simple virgulate slit, rarely with an “ Y”- shape tooth. The globulose spheroidal test can rarely becom e elongate. Wall finely agglutinated with calcareous cement.

R em ark s: This species is characterised by the pfenderiniform shape o f its test.

M easu rem en ts (m m ): H olotype length - 0.46; thicknes - 0.34.

mens).

S tra tig ra p h ie d istrib u tio n : Upper Barremian to lower Aptian.

D eposition o f types: H olotype = L.P.B.IN .l 1.165. Paratypes = L.P.B.IV .l 1.166-11.167.

A renobulim ina cucullaeform is n.sp.

Fig. 6 ( 1 8 - 3 5 )

Etym ology: This form is named from its hood shaped test; latin cucuius-i = hood, and forma-ae = form, shape.

T ype-level: U pper Barremian.

D iagnosis: Conical tapering test (as a hood shape), trochospiral with 4 -5 chambers in the last whorl; chambers are narrow w ith a falcate-arculate, weakly depressed sutures. The pateUiform (form o f a flattened cone) apertural face and concave, supports in a median position, the large virgulate slit-aperture with a thin lip.

Test surface is smooth; wall finely agglutinated with calcareous cement.

mens).

S tra tig ra p h ie d is trib u tio n : U pper Barremian.

D eposition o f types: H olotype = L.P.B.IV .l 1,168. Paratype = L .P .B .IV .11.169.

A renobulim ina corrugata n.sp.

F ig . 6 (1 - 1 7 )

Etym ology: This form is named from the shape o f the chambers;

latin corrugo-are = to wrinkle.

T ype-locality: Ostrov-Gârlitza. southern bank o f Lake Bugeac.

T ype-level: O ltina ISPH D rilling B ala I - 32,10-36 m; Fetesti ISPH D rilling F. 135,138 m; upper Barremian.

D iagnosis: T est elongate, gracile, and trochospirally coiled com

prised o f 4 -7 whorls with globulose-truncate chambers, three per whorl. Sutures arcuate-depressed, marked by the keel formed by the truncated chambers. Apertural face concave, supports, in me

dian position, a virgulate slit aperture with a thin lip. Test smooth, finely agglutinated, with calcareous cement.

R em ark s: This species is distinguished by the truncate-carinate aspect o f its chambers.

M easurem ents (m m ): Holotype length - 0.72; thickness - 0.34.

Paratypes length -0 .4 0 -0 .7 2 , thickness-0 .2 1 -0 .3 6 (figured speci

mens).

S tra tig ra p h ie d istrib u tio n : U pper Barrem ian to low er Aptian.

D eposition o f types: Holotype = L.P.B.IV .l 1.171. Paratypes = L.P.B.IV.l 1.172-11.174.

A renobulim ina dissoluta n.sp.

F ig. 2 ( 4 - 1 3 ) , F ig. 8 ( 1 5 - 5 1 )

E tym ology: This form is named from the uncoiled shape o f the last part o f the test; latin dissolutus-a-um = unwound.

T ype-locality: O strov-Gârlitza southern bank o f Lake Bugeac.

Type-level: O ltina ISPH D rilling Bala I - 32,10-36 m; Fetesti ISPH Drilling F. 135, 138 m, A lim anu-A dâncata; upper Barremian to lower Aptian.

D iagnosis: Test elongate with a gracile aspect, trochospiral (nar

rower than broad) with 3 -6 chambers per whorl. Cham bers in the early stage weakly globular with arcuate depressed sutures, with a tendency to become uncoiled in the terminal stage, 2 or 2'A cham

bers in the last whorls. Apertural face truncate and concave, sup

ports in median position, the aperture, a simple virgulate slit sometime with an '‘Y” shape; wall medium agglutinated with calcareous cement.

R em ark s: This species is well defined by the tendency o f the last two whorls to uncoil.

Paratypes length - 0.26-0.67; thickness - 0.24-0.36 (figured speci

mens).

D eposition o f types: Holotype = L .P.B .IV .l 1.175. Paratypes = L.P.B.IV .l 1.176-11.178.

A renobulim ina acervata n.sp.

F ig. 2 (2 7 - 3 4 ), F ig. 7 ( 1 - 1 7 )

Etym ology: This form is named from the shape o f the chambers disposition; latin acervatus-a-um participle o f the verb acervo-are

= to pile up, to assemble, to gather.

Type-level: O ltina ISPH D rilling B ala I - 32.10-36 m; lower Aptian.

Diagnosis: Small conical-trochospiral test with a tapering shape o f the early stage; 3 -4 globulose chambers in the last whorl. Sutures arcuate, depressed. Wall finely to moderately agglutinated, with calcareous cement. A perture a virgulate slit with a w eak lip.

R em ark s: This species differs from A. moesiana n.sp. by its globular chambers o f the last whorl.

Paratypes length - 0.29-0.53; thickness 0.24-0.40.

D eposition o f types: Holotype = L .P .B .IV .II. 179. Paratypes = L.P.B.IV .l 1.180-11.181.

A renobulim ina g ib b ero sa n.sp.

Fig. 4 (2 7 - 3 1 ) , Fig. 7 ( 5 3 - 5 4 ) , Fig. 8 ( 1 - 1 4 ) Etym ology: This form is named from the general shape o f the test;

latin gibberosus-a-um = humped.

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Fig. 9. Stratigraphie distribution o f agglutinated foraminifera from the Superfamilies V erneuilinacea and A taxophragm iacea; southern Dobrogea, Romania

T ype-locality: O strov-Gârlitza, southern bank o f Lake Bugeac. the early stage; 3—4 chambers in the last whorl. Chambers weakly T ype-level: O ltina ISPH Drillings Bala I - 10-36 m; lower Aptian. to moderately inflated. Sutures arcuate-falcate w eakly depressed.

D iagnosis: Test small to moderate size (0.30-0.60 mm in length) Wall moderately agglutinated, compact, w ith calcareous cement, humped shaped in the last stage, trochospiral with blunt shape o f Aperture a large interiomarginal slit with a thin lip on the concave

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LOWER CRETACEOUS AGGLUTINATED FORAM INIFERA FROM SOUTHERN DOBROGEA

321

apertural face.

R em ark s: This species differs from A. moesiana by the blunt shape o f its early stage: from A. corniculum Amaud-V anneau, 1980 by the generally sm aller size and the arrangement o f cham

bers in the last two whorls.

M easu rem en ts (m m ): H olotype length - 0.48, thickness - 0.34.

Paratypes length - 0.36-0.53, thickness - 0.29-0.40 (figured speci

mens).

S tra tig ra p h ie d istrib u tio n : U pper Barremian to lower Aptian.

D eposition o f types: H olotype = L.P.B.IV.l 1.182. Paratypes = L.P.B.IV .l 1.183-11.184.

A renobulim ina m oesiana n.sp.

Fig. 7 ( 3 4 - 4 2 , 5 5 -5 7 )

Etym ology: This form is named from the latin name o f present- day Dobrogea = Moesia-ae.

T ype-Iocality: Ostrov-Gârlitza. southern bank o f Lake Bugeac.

T ype-level: Oltina, ISPH Drilling Bala I - 32.10-36 m; lower Aptian.

D iagnosis: Test small, trochospiral (smaller than 0.5 mm length) with a conical shape (with a tapered early stage): 3 -4 globulose cham bers on the last two whorls. Sutures arcuate depressed. Plano

concave apertural face support the aperture, which is a slit with a thin lip. Wall moderately to finely agglutinated with calcareous cement.

R e m a rk s: This species differs from A. gibberosa by the tapered- conical shape o f its early stage.

M e asu rem en ts (m m ): H olotype length - 0.50; thickness - 0.39.

Paratypes length - 0.3 1-0.46; thickness - 0.24-0.36.

S tra tig ra p h ie d istrib u tio n : U pper Barremian to lower Aptian.

D eposition o f types: Holotype = L.P.B.IV. 11.186. Paratypes = L.P.B.IV .l 1.187.

PALAEOECOLOGICAL AND PALAEOGEOGRAPHICAL

CONSIDERATIONS

B y c o n s id e rin g th e a re a l d is trib u tio n o f th e s tu d ie d ta x a a n d th e ir stru c tu re , it is p o s s ib le to c a rry o u t so m e p a la e o e - c o lo g ic a l a n d g e o g ra p h ic a l in te rp re ta tio n s. T h e g en u s V em euilinoides in clu d es sp e c ie s d e sc rib e d fro m th e U p p er J u ra ssic th a t e x te n d , w ith a c o n sta n t fre q u e n c y , into th e L o w e r C re ta c e o u s, b o th in th e T e th y a n a n d B o real re a lm s.

V em euilinoides neocom iensis M jatliu k , 1939 w ith a c o a rs e ly a g g lu tin a te d te s t a n d m o d e ra te size is fre q u e n t in th e B o re a l fa c ie s ( o f n o rth e rn G e rm a n y , P o la n d an d R u ssia).

W ith th e sa m e m o rp h o lo g ic a l fe a tu re s o f the test, th is tax o n is also p re s e n t in the L o w e r C re ta c e o u s fly sc h d ep o sits o f th e C a rp a th ia n s (P o la n d , th e U k ra in e a n d R o m an ia). O th e r s p e c ie s o f V em euilinoides (V. polo n icu s) th a t p o sse se s a fin e ly a n d sm o o th a g g lu tin a te d te s t a n d larg e d im e n sio n s d e v e lo p to g e th e r w ith th e p re v io u s V. neocom iensis g ro u p d u r

ing th e L a te B e rra s ia n -V a la n g in ia n in th e T e th y a n realm an d th e ir m o rp h o stiic tu ra l c h a ra c te r w as p re s e rv e d u n til th e e a rly A p tia n . It is p o ss ib le to d ra w th e c o n c lu s io n th a t e n v i

ro n m e n ta l c o n d itio n s h a d a d e c is iv e in flu e n c e on th e m o r

p h o s tru c tu ra l c h a ra c te ristic s o f th e test. S p e c ie s fro m the B o re a l re a lm , liv in g in co ld w a te r b a sin s w ith co a rse s e d i

m e n ts m a d e an a d e q u a te te s t stru c tu re , w h ile th o se fro m th e in n e r c a rb o n a te p la tfo rm se d im e n ta ry fa c ie s o f th e T e th y a n a re a (w ith a re d u c e d a m o u n t o f c la s tic s) m a d e a fin e, sm o o th

a g g lu tin a te d test. T h is ex p la in s th e a b se n c e o f th e c o n te m p o ra n e o u s sp e c ie s V. neocom iensis in th e asse m b la g e s in so u th e rn D o b ro g e a .

T h e g e n u s A renobulim ina, w ith its larg e sp e c ific and su b g e n e ric v a ria b ility , w as also d e sc rib e d fro m th e A lb ia n an d U p p e r C re ta c e o u s d e p o sits o f th e A n g lo -P a risia n B asin . U p to n o w , th is g e n u s is k n o w n to h a v e o n ly th re e sp e c ie s in d e p o sits o ld e r th a n A lb ia n (i.e. B a rre m ia n a n d A p tia n ) in the ca rb o n a tic p la tfo rm s o f F ra n c e an d B u lg a ria . In so u th ern D o b ro g e a A renobulim ina, is p re s e n t in sed im e n ts as o ld as late B e rria sia n (F ig . 9), w ith sc a rc e p o p u la tio n s , a n d is re p re s e n te d by tw o sp ecies. In th e B a rre m ia n to A p tia n o n e can n o tic e a s p e c ta c u la r d e v e lo p m e n t o f th is g e n u s, re p re se n te d by ten sp e c ie s w ith larg e p o p u la tio n s . T h e L o w e r C re ta ceo u s a ss e m b la g e fro m th e s o u th e rn D o b ro g e a d e m o n s tra te s th a t th e p ro v e n a n c e o f th is g e n u s m a y h a v e b een lo c a te d in th e so u th T e th y a n a re a fro m w h e re it p ro b a b ly m ig ra te d n o rth w a rd s d u rin g the A lb ian . In th e c a se o f th is g e n u s also, th e c o rre la tio n b e tw e e n th e m o rp h o stru c tu ra l c h a ra c te ristic s a n d th e e n v iro n m e n ta l c o n d itio n s c le a rly a p p e a r. D iffe re n t p o p u la tio n s o f th is g e n u s h av e, as c o n s ta n t fe a tu re , a sm o o th a n d fin ely a g g lu tin a te d te s t stru c tu re s in c e th e b e g in n in g o f th e late B erriasia n . T h e u p p e r B a rre m ia n to lo w e r A p tian p o p u la tio n s w ith sm o o th an d fin e ly a g g lu tin a te d te s ts a p p ear, to g e th e r w ith o n es h a v in g a m e d iu m to ro u g h ly a g g lu tin ated w all stru c tu re . T h e se fe a tu re s la te r c h a ra c te ris e th e A lb ia n - U p p e r C re ta c e o u s sp e c ie s as w ell.

In b o th cases it is p o ss ib le to re a c h a g e n e ra l c o n c lu sio n . T h e in tim a te c o rre la tio n b e tw e e n th e te s t m o rp h o lo g y , th e n a tu re o f th e b o tto m se d im e n t, a n d th e w a te r te m p e ra tu re are d e c isiv e facto rs. T h e B o re a l fa c ie s a re c h a ra c te ris e d by c o a rs e ly a g g lu tin a te d tests, w h ile s y n c h ro n o u s te s ts fro m th e T e th y a n re a lm h a v e fin e ly , sm o o th to m o d e ra te ly a g g lu tin a te d o nes. T h e stro n g in flu e n c e o f lim itin g e n v iro n m e n ta l facto rs on th e a g g lu tin a te d fo ra m in ife ra is o n c e m o re d e m o n strated .

Acknowledgements

The author wants to express his total gratitude to Dr. M. A.

Kaminski and to the Geological Society o f Poland for inviting him to participate in this volum e dedicated to the m em ory o f the one of the best Carpathians m icropaleontologists, Prof. Stanislaw Geroch.

For the author is a profound honor and a duty to render, in this manner, homage to more than 35 years o f friendship with Prof. S.

Geroch.

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S tr e s z c z e n i e

DOLNOKREDOW E OTW ORNICE AGLUTYNUJĄCE Z NADRODZINY VERNEUILINACEA I ATAXOPHRAGM IACEA;

POŁUDNIOWA DOBROGEA, RUMUNIA

Theodor A. N eagu

Bogaty zespól makrofauny (Bivalvia, G astropoda) oraz m ik

rofauny (Foraminiferida) zaw ierają osady dolnej kredy w rejonie południowej Dobrogei (Rumunia). Wśród mikrofauny dom inują otwornice aglutynujące, których przedstawiciele z nadrodziny Verneuilinacea oraz Ataxophragm iacea są przedm iotem niniej

szych badań autora.

Otwornice z nadrodziny V erneuilinacea są znane z osadów' jury oraz dolnej kredy, natom iast ataxophragmidy były opisywane z osadów znacznie młodszych (barem -apt: Arenobulimina meli

tae, A. corniculum, A. cochleata; K ovatcheva. 1969, Arnaud-Van- neau, 1980). W osadach południowej Dobrogei występuje zespół starszy od znanych dotychczas otwornic z tej grupy, reprezen

tujący górny berias-dolny apt.

A utor opisał dziewięć nowych gatunków z rodzaju Arenobu

limina (Figs. 2.-A. 6-8): Arenobulimina venusta n.sp., A. melitae- formis n.sp.. A. gibberosa n.sp., A. pfenderinae n.sp., A. moessiana n.sp., A. acen’ata n.sp., A. dissoluta n.sp.. A. corrugata n.sp., A.

cuculifonnis n.sp. Rodzaj ten pojawia się po raz pierwszy w badanych osadach (Cernavoda Pod) od górnego beriasu (Fig. 9).

Opisano ponadto dwa nowe rodzaje Danubina n.gen. i Gero- chella n.gen., a wśród nich 2 gatunki: Danubina obtusa n.sp. (Fig.

2) i Gerochella cylindrica (Fig. 1). Rodzaje te włączono do nad- rodziny Verneuilinacea.

Dobry stopień zachow ania otw om ic z tej nadrodziny pozwo

li! na szczegółową analizę m ikropaleontologiczną w obrębie dwóch rodzajów: Verneuilina i Verneuilinoides (Figs. 2-5).

Szczegółowy opis systematyczny kilku gatunków (Verneuilionoi- des faraonica, V. polonicus, V. danubiensis n.sp., V pumilionis n.sp., V. fastigatus, Verneuilina angularis, V. dobrogiaca n.sp.) dał podstawę do postawienia wyraźnych granic taksonomicznych po-między tymi rodzajami.

Biorąc pod uwagę rozprzestrzenienie geograficzne opisanych taksonów oraz różnice w ich strukturze wewnętrznej można prze

prowadzić pewne interpetacje paleoekologiczne i paleogeogra- ficzne. Rodzaj Verneuilinoides został opisany z osadów od górnej jury i był znajdowany licznie w osadach dolnej kredy prowincji tetydzkiej i borealnej. Verneuilinoides neocomiensis Mjatliuk, 1939, który posiada skorupkę średnich rozmiarów, aglutynowaną z grubych ziarn jest liczny w osadach prowincji borealnej (pół

nocne N iemcy, Polska i Rosja). Takie same cechy m orfologiczne skorupki tego taksonu charakteryzują osobniki występujące w osa

dach K arpat fliszowych (Polska, U kraina i Rumunia). Inny z ga

tunków tego rodzaju - V. polonicus - który ma skorupkę dużych rozmiarów, aglutynowaną z bardzo drobnych ziaren, w'spólwystę-

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323

powal z opisanym wyżej taksonem w czasie od późnego beriasu do walanżynu w prowincji tetydzkiej, zachowując charakter morfostruktury ścian skorupki do wczesnego aptu. W edług autora, wa

runki środowiska sedym entacji były głów ną przyczyną różnic m orfostrukturalnych u obu gatunków. Osobniki z prowincji borealnej, żyjące w wodzie chłodnej, w warunkach dostawy grubo- klastycznego materiału miały adekw atną do tego strukturę i roz

miary skorupki. Otwornice żyjące w obrębie wewnętrznej części platform y węglanowej prowincji tetydzkiej, w warunkach zredu

kowanej dostawy materiału klastycznego charakteryzuje bardzo drobnoziarnista struktura ścian skorupki. Te przyczyny m ogą tłu

maczyć fakt nieobecności gatunku Verneuilinoides neocomiensis w osadach w południowej Dobrogei.

W obrębie rodzaju Arenobulimina opisano tylko trzy gatunki z osadów starszych od albu (platform a w ęglanowa z rejonu Francji i Bułgarii). W południowej Dobrogei pojedyncze otwornice tego

taksonu w ystępują w osadach ju ż od górnego beriasu, reprezento

wane tam przez dwa gatunki. W czasie od barem u do aptu nastąpił rozkwit tej grupy, która w ystępuje tam reprezentow ana przez 10 gatunków w bardzo licznych zespołach. Fakt ten wskazuje na to, że migracja otwornic z rodzaju Arenobulimina miała miejsce z tego właśnie obszaru w kierunku północnym , od albu.

W obrębie tej grupy otw ornic widoczne są rów nież zmiany morfostruktury związane ze zmianami w arunków paleośrodo- wiska. Zm ieniała się mianowicie w ielkość aglutynowanego ziarna w skorupkach. N ajstarsze zespoły (góm y berias-hoteryw ) charak

teryzuje skorupka aglutynowana z bardzo drobnych ziarn. W osa

dach od górnego barem u do dolnego aptu populacje z rodzaju Arenobulimina charakteryzuje podobny typ morfostruktury ścian skorupki. Jednak w spólw ystępująone z osobnikami o skorupkach zbudowanych ze średnich i grubych ziarn. Ten ostatni typ prze

waża u gatunków znanych od albu i żyjących w późnej kredzie.