FRESH and BRACKISH WATER OSTRACODA from the NEOGENE of NORTHERN VENEZUELA CONTENTS Page 141 ...141 I. ABSTRACT II. INTRODUCTI
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FRESH AND BRACKISH WATER OSTRACODA FROM THE NEOGENE OF NORTHERN VENEZUELA W. A. VAl\ DF:l\ BOLD LOUIS/AN!\ ST\TE L \'IVERS/TY RATOI\i' ROL'GF: CONTENTS Page I. ABSTRACT 141 II. INTRODUCTION ..... 141 Ill. ACKNOWLEDGMENTS ... 142 TV. MATERIAL STUDIED 142 V. DISCUSSION 146 VI. SYSTEMATIC DESCRIPTIONS 146 VII. LITERATURE CITED. 156 ILLUSTRATIONS TEXT FIGURE I . 14:l TEXT FIGURE 2 146 TEXT FIGURE :) . 147 TABLE 1 . 145 PLATE 1 . 149 PLATE 2 . 151 PLATE 3 153 I. ABSTRACT bro argiiloso Caparo de la formacioii Tal Twenty-four species of ostracodes are paro de Trinidad (Piioceno). La parte recorded from the Siqwre, Tuy and supenor de la formaci6n Siquire se cor Cumaca formations of the State of Mir· nda relaciona con la parte superior de la forma and from the Guiria Formation of the State ciOn Talparo; Ia formaci6n Tuy y la Unidad of Sucre. Three new species are dt· E de Ia formaciOn Guiria superior se ponen scribed: Cytheridea? purperae. Callzs con reserva en el Pleistocene. tocythe1·e? macsotayi and Xestoleberis be mudezi. The lower Siquire Formation C" II. INTRODUCTION correlated with the lowermost unit (Unit J I One of the fruslralmg problems for a of the Guiria Formation and with the Cap paleontologist is the dating of Cenozoic aro clay member of the Talparo Formatim fresh or brackish water deposits. They of Trinidad (Pliocene). The upper Siquire often contain only endemic, and special Formation is correlated with the upper ized. environmentally controlled faunas. Talparo Formation, and the Tuy Forma They are usually not overlain by datable tion and UnitE of the Guiria Formation are younger sediments and often overlie much tentatively assigned to the Pleistocene. older deposits unconformably. Withm the Caribbean Region there are several exam RESUMEN ples, including in Venezuela, the Siquire, En las formaciones Siquire, Tuy y Cumaca and Tuy Formations of Miranda Cumaca del Eslado de Miranda yen Ia f01- (Picard and Pimentel, 1968), and the maci6n Guiria del Estado Sucre se regis Guiria Formation of Sucre (Macsotay. tran veinticuatro especies de ostnicodos. 1976); and in Hispaniola, the Jimani For Aqui se describen tres especies nuevas· mation of the Hoya de Enriquillo and its Cytheridea? purperae. Callistocythere"' equivalents in the Cul-de-Sac continuation macsowyi y Xestoleberis bennudezi. La (Bold. 1975). In Brasil, Ivone Purper (1977, p arte inferior de la formaci6n Siquire se 1979) encountered a similar situation with correlaciona con Ia parte inferior (Unidad the Pebas Formation of the upper Amazon J ) de Ia Formacion Guiria y con el miem· basin. as did Sheppard and Bale (1980) m EDITORIAL COMMITTEE FOR THIS PAPER: RICH ARD M. FORESTER. United Statl'S Gcolog1cal Surve~·- Den\·er. Colorado JOSEPH E. HAZEL. Amoco Production and Research. Tulsa. Oklahoma MERVIN KONTROVITZ. No1·theastern Louisiana Uni\·ersity,l\1onroe. Louisiana 141 142 Tulane Studies in Geology and Paleo11tology Vol. 19 Colombia and Peru. In Colombia I have conformity (Picard and Pimentel, 1968). found the dating of the so-called '·Cham Dr. C. Beck (University of Lille, France) zone" in the upper Magdalena Valley of sent me samples of the Siquire Formation, the department of Huila equally difficult. which were taken along a section about 2 Additional problems may occur when km long, running from aboutl km south of foraminifer and ostracode-rich unconsoli Sta. Teresa to the north-northwest (Text dated sediments are reworked into lacus Fig. 1). From the late Dr. P. J. Bermudez trine environment. where the fauna con I received a sample from the Tuy Forma sists of very thin-shelled and fragile tion (Picard and Pimentel, 1968. p. 284). species, which are destroyed in sample Dr. Bermttdez also furnished a sample of preparation. I recently encountered this in the Cumaca Formation, which is the sup the Neogene of the Camp Perrin Basin of posed equivalent of the Siquire Formation southern Haiti, where the fresh water in the Lower Tuy-Barlovento basin ostsracodes disintegrate completely on (Picard and Pimentel, 1968). washing so that the residue contains only In the Siquire Formation (Table I) the well preserved (but reworked) marine most common ostracodes are species of forms. A similar situation is present in the Darwinula and Limnocythere, usually Llanos region of Ecuador where Cretace characteristic of ephemeral or permanent ous planktonic foraminifera have been re lakes. Many of the freshwater ostracodes deposited in Tertiary fresh and brackish are represented only by casts with occa water sediments (Tschopp, 1953). The re sionally adherent parts of shell material; sult of all this is that specialists on different thus, generic determinations are some groups of fossils will inevitably come to to what uncertain and specific determina tally different conclusions about the age tions unreliable. Only two samples show a and environment of such sediments. more diverse fauna which, in addition to The purpose of this paper is to discuss fresh water forms, also contains some the biostratigraphic distribution of the os (probably) brackish water CythNacea. It is tracodes of the Siquire, Cumaca, Tuy and especially in these samples that shell male Guiria formations and their relations to rial is slightly thicker and, therefore. partly faunas from Trinidad and Hispaniola. The or even completely preserved. results of the study are at variance with In the lower part of the Siquire Forma previous paleontological interpretations. tion (Samples 858-886) the fauna is domi nated by LimnocytheTe sp. I and 3. Sample III. ACKNOWLEDGMENTS 885 yielded Danninula sp. aff. D. oiivencae I am indebted to Christian Beck (Univer Purper, Pseudocandona? sp. and Lim sity of Lille, France) and Oliver Macsolay nocythere sp. 3, as well as Cyrheridea? (Universidad de Oriente, Cumana, Ven TohTi (Bold, 1963). which is known from the ezuela) for providing the samples on which Talparo Formation of Trinidad and the this study is based. I dedicate this paper to Guiria Formation of the Paria peninsula the late Pedro BermUdez, who also con (Bold in Macsolay, 1968, p. 64: Bold. 1972, tributed material. I wish to thank R. M. Table 2). The uppe r part of the Siquire Formation Forester for the numerous notations made (samples 890-952) is characterized by Lim in reviewing the manuscript; I have fol nocythere sp. 2. Sample 898 contains. in ad lowed many of his suggestions. dition to Stenocyphs? sp. and Heterocyp ris? sp .. also Cy1.heridella boldi Pw·per. IV. MATERIAL STUDIED Cythehclea? rohri (Bolcli and Cyrhericlea:' ptn·perae n. sp. Conspicuous in this sample BASIN OF SANTA LUCIA - OCUMARE is the absence of Darwin ulo. and Lim DELTUY HOCythere. which suggests an inte n-uption In this basin (Estado Miranda) two for of lacustrine deposition by a brackish mations are present, which have yielded a water invasion. Cytheridella boldi is living small number of fresh and brackish water in Lago d e Valencia (T ext-fig. 1). and has ostracodes. The Siquire Formation uncon been found as a fossil In the Jimani Forma formably overlies metamorphic rocks and tion of Hispaniola (Bold. 1975) and in the underlies the Tuy Formation with local un- upper part of the Talparo Formation of No.3 Venezuelan Neogene Ostracoda 143 Trinidad (M. Dempsey, Texaco Trinidad, Gutentag and Benson (1962), originally de letter and material, 1972. scribed from the Pleistocene of Kansas Bermudez' sample (VB-2) from the and subsequently reported from the upper Cumaca Formation (Bold, 1972, p. 1012) Las Salinas Formation and the Jimani For only contains Limnocythere staplini mation of Hispaniola (Bold, 1975), late kilometer~ I ' I \ ' I \ ' ' I \ ' \ ' I \ ' ' I \ ' ' I \ ' ' I ' ' 0 10 '---'-------' kilometers CPO, Carlo. Sect lSU Text-fig. 1. Map of the study area. Vol. 144 Tulane Studies in Geology and Paleontology 19 Pliocene or Pleistocene in age. In North (Bold), Perissocytheridea subrugosa America this species is found in lakes in (Brady), P. cytheridellaformis Forester, which the water is enriched in Na, Mg, Ca, Cativella pulleyi Teeter, Bassle>·ites S02, and Cl, and depleted in HC03 (Fores minutus Bold, Loxoconcha levis Brady, ter , 1983), which suggests that similar con Callistocythere? macsotayi n. sp., and Xes ditions may have been present in the tolebe,·is bemtudezi n. sp. The Cativella Cumaca lake(s). and Bnsslerites species are marine for ms The Bermudez sample from the Tuy with a fairly long stratigraphic range in the Formation (VB-1, Bermudez, 1966, p. 344; Neogene. Cytheridea? 'rohri occurs in the Bold, 1972, p. 1012) contains Darwinula sp. Caparo and Chin-Chin clay members of aff. D. olivencae Purper, Pseudocandona? the Talparo Formation. Perissocytheridea sp., Ostracode sp., Limnocythere sp. 4, and subntgosa is known from Pliocene to Re Cytheridea? purpem n. sp. , the latter also cent in the Greater Antilles and Trinidad, occurring in the Siquire and Guiria Forma whereas the other brackish water species tions. P. cythericlellafonnis has been found so far The fauna of the lower "brackish water" only in the upper Las Salinas Formation of intercalation of the Siquire Formation (885) Hispaniola (Cyp,·ideis salebrosa zone, late correlates well with the brackish-marine Pliocene - Recent). Cyp1·ideis similis has lower part of the Guiria Formation (Unit J the same range as C. salebTosa. of Macsotay, 1968, p. 55) and the brackish Loxoconcha levis is known from Pliocene water parts of the Talparo Formation to Recent brackish water deposits in the (Table 1). The upper "brackish water" in Caribbean; it occurs throughout the Tal tercalation (898) is somewhat similar in para Formation, except the Sum-Sum fauna to the upper part of the Guiria For sand member (Table 1). mation (Unit E of Macsotay, 1968, p. 56), In the Caribbean the brackish water which lacks, however, Cytheridea rohri, Pliocene can be subdivided into a late and and to the fresh water upper part of the early division on the basis of the presence Talparo Formation.