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Globorotalia menardii neoflexuosa new subspecies from the northern Indian Ocean
Deep-SeaResearch, 1974, Vol. 21, pp. 321 to 324. Pergamon Press. Printedin Great Britain.
NOTE
Globorotalia menardii neoflexuosa new subspecies from the northern Indian Ocean* M. S. SRINIVASAN,'~ J. P. KENNETTt and ALLAN W. H. Bfi+ + (Received27 July 1973;accepted in revisedform 1 October 1973)
Abstract--Globorotalia menardii neoflexuosa new subspecies is proposed for Globorotalia menardii flexuosa figured by B]~ and MCINT~J~ (1970), (non Pulvinulina tumida var. flexuosa KOCH, 1923) from the northern Indian Ocean. It is suggested that the name G. tumidaflexuosa (Koch) be restricted to the flexuose forms of G. tumida and that the name G. menardii neoflexuosa be limited to the flexuose
forms of G. menardii(s.s.). G. tumidaflexuosa (Koch) is an extinct species, making its last appearance during the last interglacial (Zone X), while G, menardiineoflexuosa new subspecies, which became extinct in the Atlantic near the end of the X climatic episode (approximately 80,000 years ago), is still a member of the living planktonic fauna in the northern Indian Ocean. INTRODUCTION
THE FORM of Globorotalia tumida (Brady) with the last chamber twisted towards the umbilical side was first described by KOCH (1923) from the Late Cenozoic of Java as Pulvinulina tumida Brady var. flexuosa. Since then, numerous workers (BOLLI, 1966; HAYS, SAITO, OPDYKE and Bt~CKLE, 1969; BEARD, in press; LAMB and BEARD, 1972; SRINIVASAN and SRIVASTAVA, 1972) have observed the flexuose form in G. tumida (Brady) and referred to it as Globorotalia tumidaflexuosa (Koch). ERICSON and WOLLIN (1956) considered that intergradation occurs between G. menardii (s.s.) and G. tumida and that this inter-relationship is below the species level. Since G. menardii has priority, they proposed G. menardii menardii the nominate subspecies, reducing G. tumida to the rank of subspecies as G. menardii tumida. ERICSON and WOLLIN (1956) also noted the occurrence of flexuose forms of G. menardii tumida identical to Koch's variety of G. tumidaflexuosa during studies of equatorial Atlantic and Caribbean cores. They considered Koch's variety (G. tumida var. flexuosa Koch) as a subspecies of G. menardii and referred it to G. menardiiflexuosa (Koch). Following ERICSON and WOLLIN(1956), subsequent workers such as ERICSON, EWlNG and WOLLIN (1964), LIDZ (1966), and KENNETT and HUDDLESTUN(1972) found flexuose forms of G. tumida at certain Quaternary levels of tropical and subtropical north Atlantic deep-sea cores, and referred to them as G. menardiiflexuosa (Koch). ERICSON, EWlNG and WOLLIN (1964) considered G. menardiiflexuosa [ = G. tumida flexuosa (Koch)] an extinct species, after having flourished during the last two interglacial episodes (Zones V and X). *Contribution No. 2043 from Lamont-Doherty Geological Observatory. tGraduate School of Oceanography, University of Rhode Island, Kingston, R.I. 02881, U.S.A.
**Lamont-Doherty Geological Observatory, Palisades, New York 10964, U.S.A.
321
322
M.S. SRIN1VASAN,J. P. K[NNETTand A. W. H. B~
B~ and MCINTYRE (1970) illustrated specimens of G. menardii (s.s.) with their last chambers twisted towards the umbilical side, collected alive in plankton samples from the northern Indian Ocean. They believed these Recent flexuose forms to be the same as G. menardiiflexuosa of ERICSON, EWING and WOLLIN(1964), which became extinct about 80,000 years ago in the Atlantic. Therefore, B~ and MclNrVRE (1970) considered the northern Indian Ocean form to be a living relict of an 'extinct' species. From an examination of specimens from the Gulf of Mexico and the Nicobar Islands (northern Indian Ocean), and by an analysis of published work, we consider that the flexuose forms of G. tumida [= G. tumidaflexuosa (Koch)] are found only as fossils. G. tumida flexuosa makes its initial appearance in the early Pliocene (Java, Nicobar Islands) and its last at the X-Y climatic episode boundary, near the end of the Pleistocene. On the other hand, the flexuose form of G. menardii first appears in the interglacial episode V, and after having flourished in the last two interglacial episodes apparently became extinct in the Atlantic, but it is still a member of the living planktonic fauna in the northern Indian Ocean. The flexuose forms of G. menardii in Atlantic cores are, however, elongate in periphery and broader and hence tend toward G. tumida, compared with the Recent Indian Ocean form which is flatter and clearly related to G. menardii. It is suggested that G. tumida with flexuose development alone should be referred to as G. tumida flexuosa (Koch). Hence, a new subspecies name Globorotalia menardii neoflexuosa is here proposed for the Recent forms illustrated by B~ and MclNTYRE (1970). The specimen illustrated as Fig. 1, f (B~ and MclNa'YRE, 1970) is designated the holotype and the specimens illustrated as 1 a-e are designated as the paratypes.
Globorotalia menardii d'Orbigny neoflexuosa new subspecies (Plate 1, Figs. 1 and 2) Description of the holotype Test fairly large, rounded in peripheral view, rather compressed, consists of about three whorls of fairly rapidly enlarging chambers arranged in a very low trochospire. There are about eight chambers present in the last whorl. In dorsal aspect the chambers are weakly inflated and are little, if at all, embracing; the chambers are nearly as broad radially as they are long circumferentially; the final and penultimate chambers are strongly twisted toward the umbilical side. The dorsal sutures are gently depressed and are thickened, the thickening appearing to be continuous with the imperforate peripheral keel. In ventral aspect the chambers are sub-triangular and are slightly inflated. The ventral sutures are depressed and nearly radial. Umbilicus small, open and deep. The primary aperture extends the full length of the ventral base of the final chamber and is bordered by a broad lip. The wall is finely perforated, except on the dorsal sutures and the peripheral keel. The surface of the test is smooth except for the weakly pustulose areas on the ventral side surrounding the umbilical shoulder. Maximum length of the holotype : 1290/~m. Remarks. G. menardii neoflexuosa new subspecies differs from G. menardii menardii by the characteristically twisted last chamber towards the umbilical side. G. tumida flexuosa (Koch), which also exhibits the flexuose character, differs from G. menardii
Plate 1. Fig. 1. Globorotalia menardii neoflexuosa new subspecies. Collected alive in 0-275 m plankton sample, Anton Bruun Cruise 6-335 A-7201 (04°02'N, 65°03'E), Holotype (×42). USNM No. 189935. Fig. 2. Globorotalia menardii neoflexuosa new subspecies. Collected alive in 0-1000 m plankton sample, Anton Bruun Cruise 1-60-306 Bay of Bengal (17°54'N, 86°31'E), Paratype (x38). USNM No. 189936. Figs. 3-7. Globorotalia tumida flexuosa (Koch). Early Pliocene (Zone N. 19), Car Nicobar Island, Bay of Bengal, Hypotypes (3 and 5, x45; 4, x55; 6, x43; 7, x47). Fig. 8. Globorotalia menardii neoflexuosa new subspecies. Pleistocene (Zone N. 22); Leg 21, Site 209; 213---49--51 cm. Southwest Pacific, Hypotype (× 38); morphology intermediate between G. menardii neoflexuosa and G. tumida flexuosa. Figs. 9 and I0. Globorotalia menardii neoflexuosa new subspecies. Late Pleistocene; TR/126; 838~40 cm. S.W. Gulf of Mexico, Hypotypes (9, ×39; I0, x42); morphology intermediate between G. menardii neoflexuosa and G. tumida flexuosa. Figs. 11-13. Globorotalia menardii menardii (d'Orbigny) Recent, Indian Ocean. (8°07'N, 73°15'E) (11, x41; 12, x40; 13, x35). [facing p. 322]
Globorotalia menardiineoflexuosa new subspecies from the northern Indian Ocean
323
neoflexuosa in typically possessing the tumid test and by the presence of a massive keel and calcite crust in the early part of the test. Distribution. G. menardii neoflexuosa new subspecies first appears in the late Pleistocene interglacial periods (V and X episodes) in the Atlantic and in the Gulf of Mexico. It is also known from the Recent northern Indian Ocean, and appears to be the latest offshoot from the virile Globorotalia menardii-Globorotalia tumida stock. The subspecies may have developed in isolation in the northern Indian Ocean. On the other hand, as suggested by B/~ and MCINTYRE(1970), the flexuose northern Indian Ocean form may also be a phenotypic variant of G. menardii related to distinct oceanographic conditions in that area. A biostratigraphic study of cores from the northern Indian Ocean is required to determine the nature of its origin in this region. Location of types Holotype: Collected alive in 0-275 m plankton sample, Anton Bruun Cruise 6-335A-7201 (04°02'N, 65°03'E) northern Indian Ocean, Plate 1, Fig. f of Bf~and MCINTYRE (1970). Paratypes: 3 paratypes, Plate 1, Figs. a-c of Bi] and MCINTYRE(1970): were collected afive in 0--1000 m plankton sample, Anton Bruun Cruise 1-60-306 (17°54'N, 86°31'E), northern Indian Ocean. 2 paratypes, Plate 1, Figs. d and e of B~ and MCINTYRE(1970): collected at same location as the holotype. Repository of types U.S. National Museum, Washington, D.C. Holotyp¢ is USNM No. 189935 Paratypes are USNM Nos. 189936-189940. GloborotaIia tumida flexuosa (Koch) PARKER (1967) considered flexuose forms of G. tumida to be gradational with the typical form and hence, did not record the stratigraphic range of G. tumida flexuosa (Koch) as distinct from G. tumida tumida (Brady). The writers, however, have found G. tumida flexuosa (Koch) to have stratigraphic utility in characterizing the early Pliocene in the Nicobar Islands (northern Indian Ocean), Java (BOLLI, 1966) and in the Late Pleistocene interglacial periods of the Atlantic and Gulf of Mexico areas (ERICSON, EWING and WOLLIN,1964; LAMBand BEARD, 1972). The earliest occurrence of G. tumida flexuosa (Koch) is within the Globorotalia margaritae zone of Java (BOLLI,1966) and in the G. tumidaflexuosa zone of the Nicobar Islands (SRINIVASANand SRIVASTAVA,1972). Both these zones are now considered to be of early Pliocene age because of the association of G. margaritae and S. dehiscens. More than 95 ~o of the specimens of G. tumida flexuosa (Koch) examined from the G. tumida flexuosa zone (Nicobar Islands) show preference to the dextral coiling. HAYS,SAITO,OPDYKEand BURCKLE(1969) record a coiling change from right to left in G. tumida flexuosa at the top of the Gilbert 'a' event (3-7 million years B.P. in the equatorial Pacific). The last occurrence of G. tumidaflexuosa is at certain Pleistocene interglacial levels in the tropical and subtropical Atlantic, where it is recorded as G. menardiiflexuosa by several workers (ERICSONand WOLLIN,1956; ERICSON,EWING and WOLLIN, 1964; LIDZ, 1966; KENNETTand HUDDLESTUN, 1972).
324
M.S. SRINIVASAN,J. P. KENNETTand A. W. H. B~
Acknowledgements--The scanning electron microscope facility at the University of Rhode Island was established with the assistance of a grant from the National Science Foundation (Oceanography Division; GA-28905). This work was supported by U.S. National Science Foundation Grant GA-35252 (U.R.I.) and GA-32, 129 (L.D.G.O.). REFERENCES B~ A. W. H. and A. MCINTYRE (1970) Globorotalia menardiiflexuosa (Koch): An 'extinct' foraminiferal subspecies living in the northern Indian Ocean. Deep-Sea Research, 17, 595-601. BEARD J. H. (in press) The Pleistocene-Holocene boundary and Wisconsinan climatic substages, Gulf of Mexico. Memoirs. Geological Society of America, 136. BOLLI H. M. (1966) The planktonic Foraminifera in Well Bodjonegoro-1 of Java. Eclogae Geologicae Helvetiae, 59(1), 499-465. ERICSON D. B. and G. WOLLrN (1956) Correlation of six cores from the equatorial Atlantic and the Caribbean. Deep-Sea Research, 3(2), 104-125. EgICSOND. B., M. EWINO and G. WOLLIN(1964) The Pleistocene epoch in deep-sea sediments. Science, 146(3645), 723-732. HAYSJ. D., T. SAtTO, N. D. OPDYKEand L. H. B URCKLE(1969) Pliocene-Pleistocene sediments of the equatorial Pacific--their paleomagnetic, biostratigraphic and climatic record. Bulletin of the GeologicalSociety of America, 80(8), 1481-1514. KENNETT J. P. and P. HUDDLESTUN (1972) Late Pleistocene paleoecology, foraminiferal biostratigraphy and tephrochronology, western Gulf of Mexico. Quaternary Research, 2(1), 38-69. KOCH R. (1923) Die jungtertiare Foraminiferenfauna von Kabu (Res. Surabaja, Java). Eclogae Geologicae Helvetiae, 18(2), 342-357. LAMB J. L. and J. H. BEARD (1972) Late Neogene planktonic foraminifera in the Caribbean, Gulf of Mexico, and Italian stratotypes. University of Kansas Paleontogical Contributions Article 57 (Protozoa 8), pp. 1-67, pls. 1-36. Lxoz L. (1966) Deep-sea Pleistocene biostratigraphy. Science, 154(3755), 1448-1452. PARKER F. L. (1967) Late Tertiary biostratigraphy (planktonic Foraminifera) of tropical Indo-Pacific deep-sea cores. Bulletins of American Paleontology, 52(235), 111-208. SR~NIVASANM. S. and S. S. SRIVASTAVA(1972) Late Neogene biostratigraphy and planktonic foraminifera of Andaman-Nicobar Islands, Bay of Bengal. 24th International Geological Congress, Montreal, Symposium, 109, 540, Abstract.
NOTE
Globorotalia menardii neoflexuosa new subspecies from the northern Indian Ocean* M. S. SRINIVASAN,'~ J. P. KENNETTt and ALLAN W. H. Bfi+ + (Received27 July 1973;accepted in revisedform 1 October 1973)
Abstract--Globorotalia menardii neoflexuosa new subspecies is proposed for Globorotalia menardii flexuosa figured by B]~ and MCINT~J~ (1970), (non Pulvinulina tumida var. flexuosa KOCH, 1923) from the northern Indian Ocean. It is suggested that the name G. tumidaflexuosa (Koch) be restricted to the flexuose forms of G. tumida and that the name G. menardii neoflexuosa be limited to the flexuose
forms of G. menardii(s.s.). G. tumidaflexuosa (Koch) is an extinct species, making its last appearance during the last interglacial (Zone X), while G, menardiineoflexuosa new subspecies, which became extinct in the Atlantic near the end of the X climatic episode (approximately 80,000 years ago), is still a member of the living planktonic fauna in the northern Indian Ocean. INTRODUCTION
THE FORM of Globorotalia tumida (Brady) with the last chamber twisted towards the umbilical side was first described by KOCH (1923) from the Late Cenozoic of Java as Pulvinulina tumida Brady var. flexuosa. Since then, numerous workers (BOLLI, 1966; HAYS, SAITO, OPDYKE and Bt~CKLE, 1969; BEARD, in press; LAMB and BEARD, 1972; SRINIVASAN and SRIVASTAVA, 1972) have observed the flexuose form in G. tumida (Brady) and referred to it as Globorotalia tumidaflexuosa (Koch). ERICSON and WOLLIN (1956) considered that intergradation occurs between G. menardii (s.s.) and G. tumida and that this inter-relationship is below the species level. Since G. menardii has priority, they proposed G. menardii menardii the nominate subspecies, reducing G. tumida to the rank of subspecies as G. menardii tumida. ERICSON and WOLLIN (1956) also noted the occurrence of flexuose forms of G. menardii tumida identical to Koch's variety of G. tumidaflexuosa during studies of equatorial Atlantic and Caribbean cores. They considered Koch's variety (G. tumida var. flexuosa Koch) as a subspecies of G. menardii and referred it to G. menardiiflexuosa (Koch). Following ERICSON and WOLLIN(1956), subsequent workers such as ERICSON, EWlNG and WOLLIN (1964), LIDZ (1966), and KENNETT and HUDDLESTUN(1972) found flexuose forms of G. tumida at certain Quaternary levels of tropical and subtropical north Atlantic deep-sea cores, and referred to them as G. menardiiflexuosa (Koch). ERICSON, EWlNG and WOLLIN (1964) considered G. menardiiflexuosa [ = G. tumida flexuosa (Koch)] an extinct species, after having flourished during the last two interglacial episodes (Zones V and X). *Contribution No. 2043 from Lamont-Doherty Geological Observatory. tGraduate School of Oceanography, University of Rhode Island, Kingston, R.I. 02881, U.S.A.
**Lamont-Doherty Geological Observatory, Palisades, New York 10964, U.S.A.
321
322
M.S. SRIN1VASAN,J. P. K[NNETTand A. W. H. B~
B~ and MCINTYRE (1970) illustrated specimens of G. menardii (s.s.) with their last chambers twisted towards the umbilical side, collected alive in plankton samples from the northern Indian Ocean. They believed these Recent flexuose forms to be the same as G. menardiiflexuosa of ERICSON, EWING and WOLLIN(1964), which became extinct about 80,000 years ago in the Atlantic. Therefore, B~ and MclNrVRE (1970) considered the northern Indian Ocean form to be a living relict of an 'extinct' species. From an examination of specimens from the Gulf of Mexico and the Nicobar Islands (northern Indian Ocean), and by an analysis of published work, we consider that the flexuose forms of G. tumida [= G. tumidaflexuosa (Koch)] are found only as fossils. G. tumida flexuosa makes its initial appearance in the early Pliocene (Java, Nicobar Islands) and its last at the X-Y climatic episode boundary, near the end of the Pleistocene. On the other hand, the flexuose form of G. menardii first appears in the interglacial episode V, and after having flourished in the last two interglacial episodes apparently became extinct in the Atlantic, but it is still a member of the living planktonic fauna in the northern Indian Ocean. The flexuose forms of G. menardii in Atlantic cores are, however, elongate in periphery and broader and hence tend toward G. tumida, compared with the Recent Indian Ocean form which is flatter and clearly related to G. menardii. It is suggested that G. tumida with flexuose development alone should be referred to as G. tumida flexuosa (Koch). Hence, a new subspecies name Globorotalia menardii neoflexuosa is here proposed for the Recent forms illustrated by B~ and MclNTYRE (1970). The specimen illustrated as Fig. 1, f (B~ and MclNa'YRE, 1970) is designated the holotype and the specimens illustrated as 1 a-e are designated as the paratypes.
Globorotalia menardii d'Orbigny neoflexuosa new subspecies (Plate 1, Figs. 1 and 2) Description of the holotype Test fairly large, rounded in peripheral view, rather compressed, consists of about three whorls of fairly rapidly enlarging chambers arranged in a very low trochospire. There are about eight chambers present in the last whorl. In dorsal aspect the chambers are weakly inflated and are little, if at all, embracing; the chambers are nearly as broad radially as they are long circumferentially; the final and penultimate chambers are strongly twisted toward the umbilical side. The dorsal sutures are gently depressed and are thickened, the thickening appearing to be continuous with the imperforate peripheral keel. In ventral aspect the chambers are sub-triangular and are slightly inflated. The ventral sutures are depressed and nearly radial. Umbilicus small, open and deep. The primary aperture extends the full length of the ventral base of the final chamber and is bordered by a broad lip. The wall is finely perforated, except on the dorsal sutures and the peripheral keel. The surface of the test is smooth except for the weakly pustulose areas on the ventral side surrounding the umbilical shoulder. Maximum length of the holotype : 1290/~m. Remarks. G. menardii neoflexuosa new subspecies differs from G. menardii menardii by the characteristically twisted last chamber towards the umbilical side. G. tumida flexuosa (Koch), which also exhibits the flexuose character, differs from G. menardii
Plate 1. Fig. 1. Globorotalia menardii neoflexuosa new subspecies. Collected alive in 0-275 m plankton sample, Anton Bruun Cruise 6-335 A-7201 (04°02'N, 65°03'E), Holotype (×42). USNM No. 189935. Fig. 2. Globorotalia menardii neoflexuosa new subspecies. Collected alive in 0-1000 m plankton sample, Anton Bruun Cruise 1-60-306 Bay of Bengal (17°54'N, 86°31'E), Paratype (x38). USNM No. 189936. Figs. 3-7. Globorotalia tumida flexuosa (Koch). Early Pliocene (Zone N. 19), Car Nicobar Island, Bay of Bengal, Hypotypes (3 and 5, x45; 4, x55; 6, x43; 7, x47). Fig. 8. Globorotalia menardii neoflexuosa new subspecies. Pleistocene (Zone N. 22); Leg 21, Site 209; 213---49--51 cm. Southwest Pacific, Hypotype (× 38); morphology intermediate between G. menardii neoflexuosa and G. tumida flexuosa. Figs. 9 and I0. Globorotalia menardii neoflexuosa new subspecies. Late Pleistocene; TR/126; 838~40 cm. S.W. Gulf of Mexico, Hypotypes (9, ×39; I0, x42); morphology intermediate between G. menardii neoflexuosa and G. tumida flexuosa. Figs. 11-13. Globorotalia menardii menardii (d'Orbigny) Recent, Indian Ocean. (8°07'N, 73°15'E) (11, x41; 12, x40; 13, x35). [facing p. 322]
Globorotalia menardiineoflexuosa new subspecies from the northern Indian Ocean
323
neoflexuosa in typically possessing the tumid test and by the presence of a massive keel and calcite crust in the early part of the test. Distribution. G. menardii neoflexuosa new subspecies first appears in the late Pleistocene interglacial periods (V and X episodes) in the Atlantic and in the Gulf of Mexico. It is also known from the Recent northern Indian Ocean, and appears to be the latest offshoot from the virile Globorotalia menardii-Globorotalia tumida stock. The subspecies may have developed in isolation in the northern Indian Ocean. On the other hand, as suggested by B/~ and MCINTYRE(1970), the flexuose northern Indian Ocean form may also be a phenotypic variant of G. menardii related to distinct oceanographic conditions in that area. A biostratigraphic study of cores from the northern Indian Ocean is required to determine the nature of its origin in this region. Location of types Holotype: Collected alive in 0-275 m plankton sample, Anton Bruun Cruise 6-335A-7201 (04°02'N, 65°03'E) northern Indian Ocean, Plate 1, Fig. f of Bf~and MCINTYRE (1970). Paratypes: 3 paratypes, Plate 1, Figs. a-c of Bi] and MCINTYRE(1970): were collected afive in 0--1000 m plankton sample, Anton Bruun Cruise 1-60-306 (17°54'N, 86°31'E), northern Indian Ocean. 2 paratypes, Plate 1, Figs. d and e of B~ and MCINTYRE(1970): collected at same location as the holotype. Repository of types U.S. National Museum, Washington, D.C. Holotyp¢ is USNM No. 189935 Paratypes are USNM Nos. 189936-189940. GloborotaIia tumida flexuosa (Koch) PARKER (1967) considered flexuose forms of G. tumida to be gradational with the typical form and hence, did not record the stratigraphic range of G. tumida flexuosa (Koch) as distinct from G. tumida tumida (Brady). The writers, however, have found G. tumida flexuosa (Koch) to have stratigraphic utility in characterizing the early Pliocene in the Nicobar Islands (northern Indian Ocean), Java (BOLLI, 1966) and in the Late Pleistocene interglacial periods of the Atlantic and Gulf of Mexico areas (ERICSON, EWING and WOLLIN,1964; LAMBand BEARD, 1972). The earliest occurrence of G. tumida flexuosa (Koch) is within the Globorotalia margaritae zone of Java (BOLLI,1966) and in the G. tumidaflexuosa zone of the Nicobar Islands (SRINIVASANand SRIVASTAVA,1972). Both these zones are now considered to be of early Pliocene age because of the association of G. margaritae and S. dehiscens. More than 95 ~o of the specimens of G. tumida flexuosa (Koch) examined from the G. tumida flexuosa zone (Nicobar Islands) show preference to the dextral coiling. HAYS,SAITO,OPDYKEand BURCKLE(1969) record a coiling change from right to left in G. tumida flexuosa at the top of the Gilbert 'a' event (3-7 million years B.P. in the equatorial Pacific). The last occurrence of G. tumidaflexuosa is at certain Pleistocene interglacial levels in the tropical and subtropical Atlantic, where it is recorded as G. menardiiflexuosa by several workers (ERICSONand WOLLIN,1956; ERICSON,EWING and WOLLIN, 1964; LIDZ, 1966; KENNETTand HUDDLESTUN, 1972).
324
M.S. SRINIVASAN,J. P. KENNETTand A. W. H. B~
Acknowledgements--The scanning electron microscope facility at the University of Rhode Island was established with the assistance of a grant from the National Science Foundation (Oceanography Division; GA-28905). This work was supported by U.S. National Science Foundation Grant GA-35252 (U.R.I.) and GA-32, 129 (L.D.G.O.). REFERENCES B~ A. W. H. and A. MCINTYRE (1970) Globorotalia menardiiflexuosa (Koch): An 'extinct' foraminiferal subspecies living in the northern Indian Ocean. Deep-Sea Research, 17, 595-601. BEARD J. H. (in press) The Pleistocene-Holocene boundary and Wisconsinan climatic substages, Gulf of Mexico. Memoirs. Geological Society of America, 136. BOLLI H. M. (1966) The planktonic Foraminifera in Well Bodjonegoro-1 of Java. Eclogae Geologicae Helvetiae, 59(1), 499-465. ERICSON D. B. and G. WOLLrN (1956) Correlation of six cores from the equatorial Atlantic and the Caribbean. Deep-Sea Research, 3(2), 104-125. EgICSOND. B., M. EWINO and G. WOLLIN(1964) The Pleistocene epoch in deep-sea sediments. Science, 146(3645), 723-732. HAYSJ. D., T. SAtTO, N. D. OPDYKEand L. H. B URCKLE(1969) Pliocene-Pleistocene sediments of the equatorial Pacific--their paleomagnetic, biostratigraphic and climatic record. Bulletin of the GeologicalSociety of America, 80(8), 1481-1514. KENNETT J. P. and P. HUDDLESTUN (1972) Late Pleistocene paleoecology, foraminiferal biostratigraphy and tephrochronology, western Gulf of Mexico. Quaternary Research, 2(1), 38-69. KOCH R. (1923) Die jungtertiare Foraminiferenfauna von Kabu (Res. Surabaja, Java). Eclogae Geologicae Helvetiae, 18(2), 342-357. LAMB J. L. and J. H. BEARD (1972) Late Neogene planktonic foraminifera in the Caribbean, Gulf of Mexico, and Italian stratotypes. University of Kansas Paleontogical Contributions Article 57 (Protozoa 8), pp. 1-67, pls. 1-36. Lxoz L. (1966) Deep-sea Pleistocene biostratigraphy. Science, 154(3755), 1448-1452. PARKER F. L. (1967) Late Tertiary biostratigraphy (planktonic Foraminifera) of tropical Indo-Pacific deep-sea cores. Bulletins of American Paleontology, 52(235), 111-208. SR~NIVASANM. S. and S. S. SRIVASTAVA(1972) Late Neogene biostratigraphy and planktonic foraminifera of Andaman-Nicobar Islands, Bay of Bengal. 24th International Geological Congress, Montreal, Symposium, 109, 540, Abstract.