A certain number of criteria are here applied to the taxonomy of silicoflagellates, with the main purpose of simplifying an otherwise profuse and complicated assignment of morphotypes to different taxa by different authors. This effort to try and unify the criteria used is of vital importance in the application of silicoflagellates to both stratigraphy and paleoecology. Difficulties in comparing previous silicoflagellate studies by various authors arise when ranges are examined. On one hand, lumping of morphotypes that have different stratigraphic ranges into one taxon (as in much of the older literature) precludes the stratigraphic value of silicoflagellates reaching its full potential. On the other hand, oversplitting of one taxon into a myriad of taxa (most of which are rare varieties that appear within the range of the regular morphotype) serves no purpose, either stratigraphic or paleoecological. In addition, assignment of the same taxon to different genera by different authors complicates matters when trying to assess the paleoecological signature of an assemblage.
For these reasons, when encountering a morphotype that deviates from an established taxon, its range and abundance were evaluated before taxonomic assignment. If it appears to be just a variety of a named taxon, it has been counted and tabulated separately for future reference. Such a morphotype, however, has been included within the taxon to avoid the creation of unnecessary taxa that increase the complexity of silicoflagellate systematics. In such cases, these varieties are described in the remarks section of the taxon, and their abundance and stratigraphic distribution can be observed in Table 1 and Table 2 (e.g., Dictyocha fibula [regular], D. fibula [five-sided], and D. fibula [three-sided]). When morphotypes that cannot be assigned to any known taxon were encountered, they were considered new taxa only if they were at least relatively common within the assemblage and maintained their distinctive morphology throughout their range. A considerable effort was put into avoiding the establishment of new taxa in this study. As a result, only one new taxon is described herein, Distephanus crux lockerii, with a regular, four-sided morphology and three- and five-sided varieties. Other morphotypes (which, though distinctive, were rare) were described and illustrated but were only assigned to a genus and listed as such (e.g., Dictyocha sp. 1, Dictyocha sp. 2, etc.).
The unfortunate results of using different taxonomic criteria for silicoflagellates in the past can be evidenced clearly in the previous studies of silicoflagellates in the same realm considered here, the Norwegian-Greenland Sea. Locker and Martini (1989) and Ciesielski et al. (1989) both studied Vųring Plateau sections from Leg 104 and provided different lists of taxa encountered and a different zonal scheme. In addition, because of differences of generic assignment of taxa, their paleoecological interpretations do not coincide entirely. To avoid such complications, the taxonomic assignments herein result from a compromise between these two "schools" and purport to clarify previous and future assignments by providing a short but adequate synonymy. The first major generic criterion is the grouping of all silicoflagellates consisting solely of a basal ring into the genus Bachmannocena (Locker), avoiding the criteria followed by Locker and Martini (1986), which separate such morphotypes into the genera Septamesocena, Mesocena, and Paramesocena. The second major criterion is the use of the genus Caryocha Bukry and Monechi for morphotypes with a spherical subdivided apical apparatus and downpointing basal spines, and the retention of all morphotypes with a nonspherical subdivided apical apparatus and a distephanid morphology in the genus Distephanus Stöhr (Locker and Martini, 1989, include all morphotypes with a subdivided apical apparatus in the genus Cannopilus, which is dropped herein). Minor criteria are described within the taxonomic listing.
In addition to the remarks, a mention of the abundance and stratigraphic range of most taxa within the sections studied is given under the heading occurrence. Taxa that are stratigraphically valuable and do not figure extensively in the literature are shown in Plate 1, Plate 2, and Plate 3.
Kingdom PROTISTA
Subkingdom PROTOPHYTA
Class CHRYSOPHYCEAE
Order SILICOFLAGELLATA Borgert, 1891
Genus BACHMANNOCENA (Locker, 1974) Bukry, 1987
Bachmannocena apiculata apiculata (Schulz, 1928) Bukry, 1987
Occurrence: Restricted to the middle Miocene in Holes 982B and 907B.
Bachmannocena apiculata curvata (Bukry, 1976b) Bukry, 1987
Occurrence: Restricted to the middle Miocene in Holes 982B and 907B.
Bachmannocena
circulus apiculata (Lemmermann, 1901) nov. comb.
(Pl. 3, figs. 17-20)
Remarks: This taxon was elevated to subspecies rank by Locker and Martini (1989) but placed within their genus Paramesocena Locker and Martini (1986). It is here transferred to the genus Bachmannocena (Locker), which is more widely used and accepted for silicoflagellate morphotypes that consist solely of a basal ring and lack an apical apparatus.
This taxon is characterized by having two sets of spines in different planes but is otherwise quite variable, as illustrated in Plate 3. The basal ring varies in size (small to large), thickness, and shape (circular to elliptical), while the spines themselves vary in number and shape (pointed to rounded). Future studies on high-resolution intervals such as those herein might elucidate the stratigraphic and ecological significance of these variations.
Occurrence: Common to abundant throughout its range in both Holes 907B and 982B.
Bachmannocena
circulus circulus (Ehrenberg, 1841) nov. comb.
(Pl. 2, fig. 17)
Remarks: This morphotype consists of a generally round basal ring, with many small spines extending within the plane of the basal ring. Locker and Martini (1989) elevated it to a subspecies rank, within their genus Paramesocena (Locker and Martini, 1986). It is herein retained at this rank but kept within the genus Bachmannocena (Locker) following the usage of most silicoflagellate specialists.
Occurrence: Rare in both Holes 907B and 982B.
Bachmannocena
diodon borderlandensis (Bukry, 1981a) Bukry, 1987
(Pl. 3, fig. 13)
Occurrence: Abundant in the Bachmannocena diodon Zone in Hole 982B.
Bachmannocena
diodon diodon (Ehrenberg, 1844) Bukry, 1987
(Pl. 3, fig. 16)
Remarks: It is important to distinguish between this subspecies and B. d. nodosa (Bukry), since its first occurrence predates the latter's first occurrence by a considerable amount of time (see Table 1). Its first occurrence marks an important bioevent recognizable in all latitudes. A few unspined specimens were observed in Sample 162-982B-55X-1, 99-100 cm (see Table 1).
Occurrence: Common throughout most of the Miocene section of Hole 982B, less common in that of Hole 907B.
Bachmannocena
diodon nodosa (Bukry, 1978b) Bukry, 1987
(Pl. 3, fig. 14)
Remarks: A very complete synonymy can be found in Bukry, 1978b. Its first occurrence marks an important bioevent during the latest middle Miocene, approximately coincident with the disappearance of the genera Corbisema Hanna and Caryocha Bukry and Monechi at high-latitude sites such as those studied herein (see Table 1, Table 2).
Occurrence: Abundant throughout the Miocene as from its first occurrence in both Holes 907B and 982B.
Bachmannocena
diodon triodon (Bukry, 1973) McCartney, Churchill and
Woestendiek, 1995
(Pl. 2, fig. 18)
Occurrence: This taxon is of extremely good stratigraphic value since its total range lies within the Distephanus crux stradneri Subzone (Amigo, this chapter) in both Holes 907B and 982B.
Bachmannocena dumitricae (Perch-Nielsen, 1975) Bukry, 1987
Occurrence: Few specimens, restricted to the Distephanus crux stradneri Subzone of Hole 907B.
Bachmannocena
elliptica elliptica (Ehrenberg, 1841) Bukry, 1987
(Pl. 1, figs. 18-21)
Remarks: Bukry (1978c) argued against the necessity to subdivide elliptical to rhomboid bachmannocenid morphotypes with four spines according to size, as proposed by Bachmann and Papp, 1967. However, the stratigraphic range of small morphotypes is different from that of large morphotypes (see Table 1), and Bachmann and Papp's (1967) criterion is followed here. In this way, large morphotypes, which resemble in shape and size B. d. diodon (Ehrenberg) except for the presence of four spines instead of two, are placed within this taxon, while small morphotypes are placed within B. e. miniformis (Bachmann and Papp; see below).
Occurrence: Common in middle Miocene samples from Hole 982B.
Bachmannocena
elliptica miniformis (Bachmann and Papp, 1967) Bukry,
1987
(Pl. 1, fig. 17)
Remarks: See discussion under B. e. elliptica (Ehrenberg) above.
Occurrence: Restricted to the uppermost upper Corbisema triacantha Zone in both Holes 907B and 982B.
Bachmannocena
hexalitha (Bukry, 1981a) Bukry, 1987
(Pl. 2, fig. 16)
Remarks: Locker and Martini (1986) erected a new forma (M. hexalitha f. heptalitha) for morphotypes with seven (instead of the regular six) spines. Their new form seems unnecessary since only one specimen with that morphology was found. Such specimens are herein considered aberrant, following Bukry's (1981a) description (p. 548), and not separated from the six-spined taxon.
Occurrence: Only two specimens were found, both in the early late Miocene of Hole 907B.
Bachmannocena
quadrangula (Ehrenberg ex Haeckel, 1887) Bukry, 1987
(Pl. 3, fig. 1)
Occurrence: Rare, restricted to uppermost upper Miocene samples in both Holes 907B and 982B.
Bachmannocena
triangula (Ehrenberg, 1840) Locker, 1974
(Pl. 2, fig. 12)
Occurrence: Rare, scattered throughout upper middle and upper Miocene samples in both Holes 907B and 982B.
Bachmannocena
sp. cf. B. diodon borderlandensis
(Pl. 3, fig. 15)
Remarks: This morphotype is similar to B. d. borderlandensis (Bukry) but is about half its size and has therefore been tabulated separately (see Table 1). In addition, its range is quite older than that of B. d. borderlandensis (Bukry).
Occurrence: Restricted to Samples 40X-3, 99-100 cm, and 41X-1, 99-100 cm, in Hole 982B (middle part of the Distephanus crux stradneri Subzone).
Genus CARYOCHA Bukry and Monechi, 1985
Caryocha depressa (Ehrenberg, 1854) Bukry and Monechi, 1985
Remarks: Locker and Martini (1989) include morphotypes traditionally assigned to Caryocha ernestinae (or, according to them, Cannopilus ernestinae) within this species. However, they illustrate C. ernestinae separately (in their pl. 1, fig. 6) but do not include this illustration within their listing of figures for C. depressus.
Occurrence: Common throughout the upper C. triacantha Zone and Caryocha spp. Subzone in Hole 982B, less common in the same interval for Hole 907B, but present (though rare) in younger sediments in the latter.
Caryocha ernestinae (Bachmann, 1962) Bukry and Monechi, 1985
Occurrence: Common throughout the Caryocha spp. Subzone in Hole 907B but rare in Hole 982B (only two specimens were found, in Sample 162-982B-47X-4, 99-100 cm).
Caryocha jouseae
(Bachmann in Ichikawa et al., 1964) Bukry and Monechi,
1985
Occurrence: Only two specimens were found, both within the Caryocha spp. Subzone of Hole 907B.
Caryocha picassoi (Stradner, 1961) Bukry and Monechi, 1985
Occurrence: Rare, found mostly within the Caryocha spp. Subzone of Hole 982B.
Genus CORBISEMA Hanna, 1931
Corbisema hastata hastata (Lemmermann, 1901) Amigo, 1995
Remarks: Many subspecies have been erected since Bukry's (1976b) transfer of the species, in such a way that all the morphotypes he included are no longer within it. In his study of Paleogene sections, Amigo (1995) revised this taxon to restrict it to the morphotypes that do not belong in any of those subspecies (Corbisema hastata alta Ciesielski, C. h. cunicula Bukry, C. h. georgia Amigo, C. h. globulata Bukry, and C. h. miranda Bukry).
Occurrence: Rare, scattered throughout the Miocene of Hole 907B as reworked specimens.
Corbisema inermis inermis (Lemmermann, 1901) Amigo, 1995
Remarks: Amigo (1995) gives a thorough discussion on the revision of this taxon and includes only unspined, piked trilobate basal-ringed morphotypes, with rounded portals and only slightly indented junctures.
Occurrence: One (reworked) specimen was found in Sample 162-907B-17H-5, 109-110 cm.
Corbisema
triacantha (Ehrenberg, 1844) Hanna, 1931
(Pl. 1, fig. 22)
Occurrence: Rare but present (though scattered) until the top of the Caryocha spp. Subzone in Hole 982B. In Hole 907B, the distribution is similar but the taxon is even rarer, although some specimens were recorded in samples younger than the top of the above-mentioned subzone.
Genus DICTYOCHA Ehrenberg, 1837
Dictyocha arcuata
Curto, 1990
(Pl. 1, fig. 16)
Remarks: This taxon was described for the first time by Curto (1990) from the Betic ranges of southern Spain, where it ranges from the late early Miocene to the early middle Miocene. As pointed out by Curto (1990), his new taxon has affinities to Dictyocha rhombica (Schulz). For this reason, this taxon may have been included within the latter in previous studies of high-latitude sections of the Atlantic Ocean and the Norwegian-Greenland Sea.
Occurrence: Restricted to the upper and lower C. triacantha Zones in Hole 982B.
Dictyocha
brevispina ausonia (Deflandre, 1950) Bukry, 1978a
(Pl. 3, fig. 6)
Occurrence: Common in upper Miocene samples from Hole 982B.
Dictyocha fibula Ehrenberg,
1840
(Pl. 1, figs. 8-10)
Remarks: This taxon was observed in three-sided and five-sided varieties during peak abundances of the regular, four-sided variety (see Pl. 1, figs. 9, 10; Table 2, lower Bachmannocena circulus apiculata Zone).
Occurrence: Abundant in the middle part of the Caryocha spp. Subzone in Hole 907B, scattered throughout the rest of the zone. Present in the upper C. triacantha Zone of both Holes 907B and 982B.
Dictyocha
messanensis stapedia f. stapedia (Haeckel, 1887) Locker and
Martini, 1986
Occurrence: Rare, only in the upper upper Miocene samples from Hole 982B.
Dictyocha
subclinata Bukry, 1981a
(Pl. 2, figs. 8, 9)
Occurrence: Scattered throughout the Miocene of both Holes 907B and 982B.
Dictyocha varia Locker, 1975
Occurrence: Scattered throughout the Miocene of both Holes 907B and 982B.
Dictyocha
sp. cf. D. rhombica (Schulz, 1928) Deflandre, 1941
(Pl. 1, fig. 11)
Remarks: This morphotype is similar in all aspects to Dictyocha rhombica (Schulz) but differs in having longer spines, particularly those aligned with the major axis of the basal ring.
Occurrence: This morphotype was found to be markedly abundant in Sample 162-907B-21H-6, 109-110 cm, where it made up more than 90% of the assemblage (see Table 2) but was absent in all other samples from the same hole. This horizon was not found at Hole 982B, where only a few specimens were observed (see Table 1).
Dictyocha
sp. 1
(Pl. 1, fig. 2)
Remarks: This morphotype is similar in most aspects to the medusoid Dictyocha medusa Haeckel, but the presence of an apical bar (though small) precludes assignment to this taxon.
Occurrence: Found almost exclusively in the Caryocha spp. Subzone of Hole 982B.
Dictyocha
sp. 2
(Pl. 2, fig. 13)
Remarks: This morphotype is characterized by a circular basal ring with relatively long and equant spines and a short apical bar. In addition, all elements are conspicuously thin.
Occurrence: Restricted to the Distephanus crux stradneri Subzone of Hole 907B.
Dictyocha
sp. 3
(Pl. 2, figs. 14, 15)
Remarks: This morphotype is characterized by a highly elevated apical apparatus with curved elements.
Occurrence: Restricted to the Distephanus crux stradneri Subzone of Hole 907B.
Dictyocha sp.
4
(Pl. 1, figs. 6, 7)
Remarks: This morphotype is characterized by a slightly medusoid apical apparatus consisting of thin and flattened elements. A similar morphotype was found in lower Miocene sediments from Deep Sea Drilling Project Site 278 by Perch-Nielsen (1975).
Occurrence: Restricted to the lower part of the Caryocha spp. Subzone of Hole 907B.
Genus DISTEPHANUS Stöhr, 1880
Distephanus
boliviensis binoculus (Frenguelli, 1940) Amigo and Ciesielski,
in press
Remarks: Locker and Martini, 1986 (table 5), place all morphotypes with a subdivided apical window in their forma D. aculeatus f. binoculus. The synonymy given here includes only those in which the apical window is subdivided into two. Morphotypes with more than two subdivisions are included in D. boliviensis major (Frenguelli) Bukry, 1975a.
Distephanus boliviensis boliviensis (Frenguelli, 1940) Bukry, 1975a
Remarks: This subspecies is restricted to morphotypes with an undivided apical window. Ciesielski et al. (1989, p. 512) did not formally use a subspecies rank to accommodate the variation in the morphology of the apical window, choosing to separate the varieties as "cannopilean" (multiwindowed, including two, three, or four or more windows), "cannopilean-irregular," and "hemisphaericoid." Locker and Martini (1989) restrict those with an undi-vided apical window in D. aculeatus f. aculeatus, placing all morphotypes with a subdivided apical window in D. a. f. binoculus (Ehrenberg) Locker and Martini, 1986.
Distephanus boliviensis major (Frenguelli, 1940) Bukry, 1975a
Remarks: All varieties of this species that have its apical window subdivided into more than two are placed in this subspecies (see discussion above under D. b. binoculus (Frenguelli)).
Distephanus crux
crux (Ehrenberg, 1840) Haeckel, 1887
(Pl. 1, fig. 1)
Remarks: Distephanus crux (Ehrenberg) counts with many subspecies of widely accepted usage, which have specific morphologies and stratigraphic ranges. Only small and square morphotypes with small and equant spines are included within the subspecies with the species' epithet herein. A few specimens with a rounded rather than square basal ring were found in samples from Hole 982B (see Pl. 1, fig. 1), where they have been tabulated separately.
Distephanus crux hannai Bukry, 1975b
Occurrence: Rare, only in upper Miocene samples from Hole 982B.
Distephanus crux
lockerii n. ssp.
(Pl. 1, figs. 12-15)
Diagnosis: Large quadrate basal ring with moderate and equant spines and a square apical window supported by four rods that leave the basal ring at the midpoint between vertices. Three- and five-sided varieties are included within this new taxon.
Etymology: This new taxon is named in honor of Dr. Sigurd Locker of the Geologisch-Palaontologisches Institut der Universität in Kiel, Germany.
Remarks: This new subspecies resembles Distephanus crux crux (Ehrenberg) in most ways, except for its size, which is considerably larger (see measurements below) and curiously similar to Dictyocha fibula Ehrenberg, with which it also shares basal ring shape (see Pl. 1, figs. 8, 13). Basal ring shape and size of its three- and five-sided varieties (Pl. 1, figs. 12, 14, 15) are also almost identical to the three- and five-sided varieties of D. fibula Ehrenberg (Pl. 1, figs. 9, 10). Because of their shared stratigraphic ranges, this new subspecies could be more related to D. fibula Ehrenberg than it is to D. crux crux (Ehrenberg).
Measurements: basal ring diameter 55(60)65 µm, spine length 16(20)24 µm; holotype: basal ring diameter 62 µm, spine length 21 µm.
Holotype: Florida Museum of Natural History #UF84989 (Pl. 1, fig. 13).
Type locality: Iceland Plateau, Hole 907B.
Occurrence: Restricted to the middle Miocene in both Holes 907B and 982B; more common in the former.
Distephanus crux
longispinus (Schulz, 1928) Locker and Martini, 1989
(Pl. 2, figs. 1, 6, 7)
Remarks: A variety with equant spines was encountered in Hole 907B and tabulated separately (see Table 2).
Occurrence: Middle to early late Miocene in both Holes 907B and 982B.
Distephanus crux
parvus (Bachmann in Ichikawa et al., 1967) Bukry, 1982
(Pl. 2, fig. 2)
Occurrence: Middle to early late Miocene in both Holes 907B and 982B.
Distephanus crux
scutulatus Bukry, 1982
(Pl. 2, fig. 3)
Occurrence: Middle to early late Miocene in both Holes 907B and 982B.
Distephanus crux
stradneri (Jerkovic, 1965) Locker and Martini, 1989
(Pl. 2, figs. 4, 5)
Occurrence: Middle to early late Miocene in both Holes 907B and 982B.
Distephanus polyactis (Ehrenberg, 1840) Deflandre, 1932
Occurrence: Rare, restricted to the middle part of the Distephanus crux stradneri Subzone in Hole 982B.
Distephanus
quinarius Locker and Martini, 1989
(Pl. 2, figs. 10, 11, 19-22)
Remarks: The importance of distinguishing between this taxon and Distephanus speculum pentagonus is evidenced in its stratigraphic distribution (see Table 1, Table 2).
Occurrence: In the uppermost Distephanus crux stradneri Subzone of Hole 907B this taxon dominates the assemblage, constituting a true horizon (see Table 2). This horizon was not detected in Hole 982B, but low preservation for that interval might be responsible for this. However, an older lesser acme for this taxon was found in this hole, in the upper C. triacantha Zone (see Table 1), which is unfortunately a barren interval in Hole 907B.
Distephanus
schulzii (Deflandre in Bachmann and Ichikawa, 1962)
Ciesielski et al., 1989
Distephanus speculum binoculus (Ehrenberg, 1844) Bukry, 1975b
Distephanus speculum hemisphaericus (Ehrenberg, 1844) Bukry, 1975b
Occurrence: Most common in the upper and lower C. triacantha Zones of Hole 982B.
Distephanus
speculum minutus (Bachmann in Ichikawa et al., 1967)
Bukry,1976a
(Pl. 3, figs. 7-12)
Remarks: A variety of this subspecies with equant spines (Pl. 3, figs. 9, 10) was tabulated separately, since its first occurrence is much younger than the regular variety (see Table 1, Table 2). This equant-spined variety was observed to occasionally have five (Pl. 3, fig. 11) or seven sides (Pl. 3, fig. 12) instead of the usual six.
Occurrence: This taxon is common in the B. diodon nodosa Subzone and younger intervals of both Holes 907B and 982B, but its range extends to slightly below the bottom of the Distephanus crux stradneri Subzone in Hole 907B (see Table 2).
Distephanus speculum pentagonus (Lemmermann, 1901) Bukry, 1976a
Distephanus
speculum speculum (Ehrenberg, 1840) Haeckel, 1887
(Pl. 3, figs. 2-4)
Remarks: Some upper Miocene samples from Hole 907B contained a variety of this subspecies with a thickened apical apparatus, causing a reduction in the size of the apical window. These morphotypes were tabulated sepa-rately.
Occurrence: This taxon is abundant throughout the Miocene of both Holes 907B and 982B.
Distephanus
speculum speculum f. notabilis (Locker and Martini, 1987)
McCartney and Wise, 1990
Occurrence: Rare, scattered throughout the late Miocene of Hole 907B.
Distephanus
speculum speculum f. pseudofibula (Schulz, 1928)
Locker and Martini, 1986
Occurrence: Only two specimens of this conspicuous taxon were found in upper Miocene samples from Hole 907B.
Distephanus
speculum speculum f. septenarius (Ehrenberg, 1845)
Locker and Martini, 1986
Distephanus speculum triommata (Ehrenberg, 1845) Bukry, 1976a
Distephanus
stauracanthus (Ehrenberg, 1845) Haeckel, 1887
(Pl. 1, figs. 3-5)
Remarks: Two varieties are recognized within this species: those with an apical ring (like f. stauracanthus [see Pl. 1, figs. 4, 5]) and those with an apical bar (like f. octagonus [see Pl. 1, fig. 3]).
Occurrence: Rare, restricted to the Caryocha spp. Subzone of Hole 982B.
Distephanus xenus
Bukry, 1985
(Pl. 3, fig. 5)
Occurrence: Rare, only in upper Miocene samples from Hole 982B.
Distephanus sp. aff. D. slavincii (Jerkovic, 1965) Bukry, 1973
Remarks: This morphotype differs from D. slavincii (Jerkovic) in having longer spines.
Occurrence: Relatively common only in the middle Miocene of Hole 982B.
Genus LYRAMULA Hanna, 1928
Lyramula furcula Hanna, 1928
Remarks: Present only as reworked specimens.
Occurrence: Rare, scattered throughout Miocene samples from Hole 907B.
Genus NAVICULOPSIS Frenguelli, 1940
Naviculopsis
constricta (Schulz, 1928) Bukry in Barron, Bukry, and Poore,
1984
Remarks: Present only as reworked specimens.
Occurrence: Rare, scattered throughout Miocene samples from Hole 907B.
Naviculopsis eobioapiculata Bukry, 1978c
Remarks: Present only as reworked specimens.
Occurrence: Rare, restricted to the middle Miocene of Hole 982B.
Naviculopsis lata (Deflandre, 1932) Frenguelli, 1940
Remarks: Present only as a reworked specimen.
Occurrence: Only one specimen was found, in Sample 162-982B-51X-3, 99-100 cm.
Naviculopsis minor (Schulz, 1928) Bukry in Barron, Bukry, and Poore, 1984
Remarks: Present only as a reworked specimen.
Occurrence: Only one specimen was found, in Sample 162-907B-11H-5, 109-110 cm.
Naviculopsis transitoria Deflandre nov. comb.
Remarks: Given its morphology, this species is herein transferred to the genus Naviculopsis Frenguelli. Present only as reworked specimens in this study. This is only the second mention of this taxon in the Norwegian-Greenland Sea basins, the first being from Cores 151-908A-27X through 34X (Fram Strait), as recorded by Locker, 1996.
Occurrence: Two reworked specimens were found within the B. diodon nodosa Subzone of Hole 907B.