HELIOLITHUS BUKRYIA NEW UPPER PALEOCENE CALCAREOUS NANNOFOSSIL
Wuchang Wei
Department of Geology, Florida State University,Tallahassee, FL32306, USA
INTRODUCTION
A new species of Heliolithus was found during a detailed
nannofossil study of the Paleogene core samples from the Rio
Grande Rise in the southwest Atlantic Ocean. Most species ofthis genus described previously have biostratigraphic utility,i.e., H. kleinpellii is used in the zonations of both Martini(1971) and Okada and Bukry (1980); ~. riedelii is used inMartini's (1971) zonation; and g. university is used in Wise's(1983)
zonation.
The new species, describedbelow
asHeliolithus bukryi, has been found in two closely spaced
samples from DSDP Site 516 on the Rio Grande Rise in the upper
Paleocene sediments and has been figured by Bukry (1971) from aupper Paleocene sample from the northwest Atlantic Ocean.
Itwas also found in one upper Paleocene sample (LB 821, see Hayand Mohler, 1967) from Pont Labau (France) when the present
author reexamined these middle to upper Paleocene samples. The
erection of the new species will facilitate the correct
applicationof
other index species ofHeliolithus
tostratigraphy and may be useful for refining stratigraphy andproviding paleoenvironmental information.
SAMPLES AND METHODS
Samples were taken from DSDP Hole 516F in the southwest
Atlantic Ocean (30.16.59'S, 35°17.10'W). Detailed informationon the geologic setting, stratigraphic framework, lithology andpaleoenvironment of the site can be found in Barker and Johnson(1983).
In addition to the conventional method of examination, thenew species has been studied using a slightly
modifiedtechnique of Moshkovitz (1978). This technique facilitates theobservation of the same nannofossil specimens under the lightmicroscope and in the SEM, and is the best among all those
proposed to date for the light microscope-SEM correlation studyof the same nannofossil specimens (see Shafik, 1983 and thereferences cited there).
SYSTEMATIC PALEONTOLOGY
Genus HELIOLITHUS Bramlette and Sullivan 1961
Heliolithus bukryi Wei, n. sp.
Plate 1, Figures 1,3-11.
Heliolithus sp. Bukry, 1971, p. 1002, pl. 8, fig. 5.
Diagnosis: Relatively large .. and compressed heliolithidwith a small and low cycle.
Description: This species has two cycles of elements. Thelarger cycle (presumably the distal cycle, see Romein, 1979)has 23-36 elements (most commonly around 30). The smaller cycle

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(presumably the proximal cycle) is about one third the size ofthelarger cycle. Under cross nicols, both cycles
arebirefringent.
Remarks: A morphometric study of 22 random specimens of
Heliolithus bukryi from DSDP sample 516F-85-2, 35-36 cm showedthat the diameter of the distal cycle ranges from 10 to 17 ~m(mean-14,
standard deviation-1.86),
the diameter oftheproximal cycle ranges from 4 to 6 ~m (mean-5.1,standarddeviation-0.8), and the number of elements in the distal cycle
varies from 23 to 36 (mean•31.2, standard deviation-3.3).
Heliolithus bukryi differs from H· kleinpellii by that theformer has a smaller cycle and has fewer elements and thelatter (see Plate 1, Figure 12) has a proximal cycle which isover 1/2 the diameter of the distal cycle and usually has morethan 40 elements (the holotype showing 45). No transitional
form between the two species has been observed. The new species
can be distinguished easily from H. cantabriae, H. riedelii, or~· universus by its compressed cycles and the large
differencein the diameters between the two cycles. The latter species all
have thick columns, and the proximal and distal cycles have
similar diameters. Though the outline of Heliolithus bukryi
resembles that of Biantholithus conicus, the distal cycle ofthe latter species does not birefringe under cross-polarized
lightandthus it is easy to differentiate
itfromheliolithids. Similarly, the distal side of Heliolithus bukryi
looks identical to Discoaster multiradiatus in SEM micrographs(see Plate 1, Figures 3 and 4), but the former species
birefringes under cross-polarized light whereas the latter doesnot.
Occurrence: Few to rare near the bottom of Heliolithus
kleinpellii Zone (Zone CP5 of Okada and Bukry, 1980) in Rio
Grande Rise upper Paleocene sediments. It was reported from thebottom of Heliolithus kleinpellii zone (Zone CP5)in thenorthwest Pacific sediment at DSDP Site 47 (Bukry, 1971, p.
1002). The present author also found it common in one sample(LB 821)from Discoater mohleri zone (CP6)in Pant Labau(France) section.
Size: Holotype: 13 ~m in diameter; isotypes: 10-15 ~m indiameters.
Holotype: Plate 1, Figures 1, 5, 6 (Negatives FSU PN8831788319).
Isotypes: Plate 1, Figures 3, 4, 7-11 (Negatives FSU
PN88320-88326).
~locality: Deep Sea Drilling Project Site 516 ( RioGrande Rise, southwest Atlantic Ocean), Sample 516F-85-2,3536cm.
ACKNOWLEDGEMENTS
The samples examined in this study were provided by theDeep Sea Drilling Project. Shimon Moshkovitz (Geological Surveyof Israel) kindly provided the gridded glass forlightmicroscope-SEM correlation study .. Kim Riddle is thanked forhelp in the SEM photography. I also wish to thank John Firthfor helpful discussion on the species. Laboratory facilities
were provided in part by NSF grant DPP 8414268 to s. w. Wise.

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REFERENCESBARKER, P. F. AND JOHNSON, D. A., 1983. Initial Reports of theDeep Sea Drilling Project, 72:1-1024. UnitedState
Government
Printing Office, Washington D. C ..
BUKRY, D., 1971. Coccolith stratigraphy Leg 6, Deep Sea
Drilling
Project. In: Fischer, A. G., Bruce, B. C., etal.,
InitialReports of the Deep Sea Drilling Project,
6: 965-1004. United
State
Government Printing Office,Washington D. c ..
HAY, W. W., AND MOHLER, H. P., 1976. Calcareous nannoplankton
from early Tertiary rocks at Pont Labau, France, andPaleocene-Eocene correlations. Journal of Paleontology,
41: 1505-1541.
MARTINI, E., 1971. Standard Tertiary and Quaternary calcareous
nannoplankton zonation. In: Farinacci, A. ED., ProceedingsII Planktonic Conference, Roma, 1970, 2: 739-785.
MOSHKOVITZ, s., 1978. New types of cover-slip and mountingslidewith a graticule for examination of the samesmall object both by
the light microscope and thescanning · electron microscope.
MicroscopicaActa:80{2): 161-166.
OKADA, Hand BUKRY, D., 1980. Supplementary modification andintroduction of code numbers to the low-latitude coccolith
biostratigraphic zonation {Bukry, 1973,; 1975). Marine
micropaleontology: 5(3), 321-325.
ROMEIN, A. J. T., 1979. Lineages in early Paleogene calcareous
nannoplankton. Utrecht Micropaleontological Bulletins, 22:
1-231.
SHAFIK, S., 1983. A procedure for both the optical and scanningelectronmicroscope studyof individual
calcareous
nannofossils.
Journal of Paleontology, 57: 1135-1140.
WISE,
s. w., 1983. Mesozoic and Cenozoic calcareous
nannofossils
recovered by Deep Sea Drilling Project
Leg 71 in the Falkland
Plateau region, Southwest
Atlantic Ocean. In: Lugwig, w. J.,
Krasheninnikov, V.
A., et al.
Initial Reports of DSDP, 71:
481500.
Washington(U.S. Government Printing Office), p.
481550.
PLATE 1Figures
1,3-11 Heliolithus bukryi Wei, n. sp.
DSDP Sample 516F-85-2, 35-36 cm. 1, 5, 6, Holotype. 1,SEM, proximal view, X4,000; 5, same specimen as 1, phasecontrast light, proximal view, X1,770; 6, same specimen as
1, cross-polarized light,proximal view~ X1,770; 3, 4,711, isotypes. 3, SEM, distal view, X4,000; 4, SEM, distalview, X3,300; 7, 8, 11, cross-polarized light, X1,770;9,same specimen as 3, phase-contrast light, distal view,Xl,770; 10, same specimen as 3, cross-polarized light,distal view, Xl,770.
2, 12Heliolithus kleinpellij Sullivan
DSDP Sample 516F-85-2, 35-36 cm; 2, SEM, oblique view,
X4,000; 12, phase-contrast light, distal view, X1,350.

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