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Palynology

ISSN: 0191-6122 (Print) 1558-9188 (Online) Journal homepage: http://www.tandfonline.com/loi/tpal20

New species from the Sabrina Flora: an earlyPaleogene pollen and spore assemblage from theSabrina Coast, East Antarctica

Catherine Smith, Sophie Warny, Amelia E. Shevenell, Sean P.S. Gulick & AmyLeventer

To cite this article: Catherine Smith, Sophie Warny, Amelia E. Shevenell, Sean P.S.Gulick & Amy Leventer (2018): New species from the Sabrina Flora: an early Paleogenepollen and spore assemblage from the Sabrina Coast, East Antarctica, Palynology, DOI:10.1080/01916122.2018.1471422

To link to this article: https://doi.org/10.1080/01916122.2018.1471422

Published online: 12 Dec 2018.

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New species from the Sabrina Flora: an early Paleogene pollen and sporeassemblage from the Sabrina Coast, East Antarctica

Catherine Smitha, Sophie Warnyb, Amelia E. Shevenella, Sean P.S. Gulickc and Amy Leventerd

aCollege of Marine Science, University of South Florida, St. Petersburg, FL, USA; bDepartment of Geology and Geophysics and Museum ofNatural Science, Louisiana State University, Baton Rouge, LA, USA; cInstitute of Geophysics and Department of Geological Sciences,University of Texas at Austin, Austin, TX, USA; dDepartment of Geology, Colgate University, Hamilton, NY, USA

ABSTRACTPalynological analyses of 13 samples from two sediment cores retrieved from the Sabrina Coast, EastAntarctica provide rare information regarding the paleovegetation within the Aurora Basin, whichtoday is covered by the East Antarctic Ice Sheet. The assemblages, hereafter referred to as the SabrinaFlora, are dominated by angiosperms, with complexes of Gambierina (G.) rudata and G. edwardsii rep-resenting 38–66% of the assemblage and an abundant and diverse Proteaceae component. TheSabrina Flora also includes Battenipollis sectilis, Forcipites sp. and Nothofagidites (N.) spp. (mostlybelonging to the N. cf. rocaensis-cf. flemingii complex), along with a few fern spores, includingLaevigatosporites ovatus, a moderate presence of conifers, and previously undescribed angiospermmorphospecies. Two of these, Battenipollis sabrinae sp. nov. and being Gambierina askiniae sp. nov.,are described herein. A majority of the assemblage is interpreted as deposited contemporaneouslywith sedimentation, including Gambierina spp., which is traditionally assigned a Cretaceous–earliestEocene age range. However, our age diagnosis for the Sabrina Flora, based on key morphospecies,indicates that sediment was most likely deposited between the latest Paleocene to early–middleEocene, and that Gambierina rudata and G. edwardsii extended longer than previously proposed.

KEYWORDSPaleocene; Eocene; AuroraBasin; Sabrina Coast; EastAntarctica; Gambierina;Battenipollis

1. Introduction

The Aurora Subglacial Basin (ASB), one of the three largestsubglacial basins in East Antarctica, is drained by large outletglaciers terminating at the Sabrina Coast (115˚ to 121�E and67�S), East Antarctica (Figures 1 and 2, Ferraccioli et al. 2009;Young et al. 2011; Fretwell et al. 2013; Rignot et al. 2013;Greenbaum et al. 2015; Aitken et al. 2016). The region ispresently sensitive to climate change, as indicated by thethinning and retreat of local outlet glaciers influenced bywarm modified Circumpolar Deep Water driven onto theSabrina Coast continental shelf as westerly winds shift south-ward (Rintoul et al. 2016; Greene et al. 2017). Past regionalclimate sensitivity is also suggested by ice sheet and climatemodels and marine geological observations, which indicatethat ice caps may have nucleated in the GambertsevMountains and first reached the Sabrina Coast and Prydz Bayprior to continental scale Antarctic glaciation in the latestEocene (DeConto and Pollard 2003; Gulick et al. 2017).

In 2014, the first marine seismic and geological investiga-tions of Sabrina Coast continental shelf sediments were con-ducted as part of the United States Antarctic Program RV/IBNathaniel B. Palmer cruise NBP 14-02. From the resulting geo-physical data, Gulick et al. (2017) identified three seismicstratigraphic intervals, termed Megasequence I, II, and III(Figure 3), interpreted to reflect pre-glacial, meltwater-richglacial, and polar glacial environments, respectively. To con-strain the age of the Sabrina Coast shelf sedimentary

sequence, marine sediment cores were collected from out-cropping seismic reflectors in the lower part of the sequenceand surrounding the regional unconformity at the base ofMegasequence III. These data reveal a history of Cenozoic cli-mate and environmental change within the ASB catchment,including a record of ice advance and retreat that suggeststhe EAIS is more sensitive to climate change than tradition-ally thought (Gulick et al. 2017).

Two jumbo piston cores (JPC; NPB 14-02 JPC-54 and JPC-55, see Figures 1–3 for locations) retrieved from the lower-most preglacial Sabrina Coast sediments (Megasequence I)contain an abundant, diverse, and well-preserved terrestrialpalynomorph assemblage, as first reported in Gulick et al.(2017). Here we detail this new terrestrial palynologicalassemblage, termed the Sabrina Flora, and describe two pre-viously undescribed species discovered in the Sabrina Coastsediments. The Sabrina Flora provides a rich paleobotanicalarchive of the ASB catchment before and during ice sheetdevelopment and adds to the available Paleogene EastAntarctic margin terrestrial palynomorph records from PrydzBay (e.g. Macphail and Truswell 2004; Hannah 2006; Truswelland Macphail 2009), the Shackleton Ice Shelf region (Truswell1983, 2012), the Wilkes Land margin (Domack et al. 1980;Truswell 1983; Schrum et al. 2004; Pross et al. 2012;Contreras et al. 2013), and the Ross Sea region, including theMcMurdo Erratics (Askin 2000; Levy and Harwood 2000) andMcMurdo Sound (Truswell 1983; Mildenhall 1989; Hannahet al. 1998; Askin and Raine 2000; Raine and Askin 2001;

CONTACT Sophie Warny swarny@lsu.edu Geology and Geophysics, E235 Howe Russell Geoscience Complex, Baton Rouge 70803, US� 2018 AASP – The Palynological Society

PALYNOLOGYhttps://doi.org/10.1080/01916122.2018.1471422

Published online 12 Dec 2018

Prebble et al. 2006; Warny et al. 2009; Feakins et al., 2012;Griener et al. 2013; Griener and Warny 2015).

2. Stratigraphic context

Cores JPC-54 (121 cm) and JPC-55 (170 cm) were collectedabove and below a prograding clinoform in Megasequence I,

respectively (Figure 3). Both cores recovered 20–40 cm of lateQuaternary greenish gray diatom-rich mud (Unit I) with asharp lower contact separating Unit I from Unit II (Figure 4).In core JPC-54, Unit II consists of sandy mud to diamict withangular igneous clasts interpreted as ice-rafted debris (IRD)(Gulick et al. 2017), while Unit II in JPC-55 consists of mica-rich mud with siderite concretions, including one 10 cm indiameter, and pyrite nodules (Figure 4). The sediments inboth cores were recovered from strata stratigraphicallybelow the first seismic evidence of grounded ice on theSabrina continental shelf (Gulick et al. 2017). Thus, coreJPC-55 sediments record the pre-glacial environment in theAurora Basin prior to regional glaciation, while those in coreJPC-54 reflect a environment where marine terminating gla-ciers were present, but ice had yet to advance ontothe shelf.

3. Methods

3.1. Palynology

To quantify absolute abundance of terrestrial palyno-morphs and assign ages to Unit II in cores JPC-54 and JPC-55, nine and eight samples, respectively, were split andprocessed at Global Geolab Limited (Alberta, Canada) toextract terrestrial palynomorphs. Note that the two topsamples in each core are not discussed in this paper asthese represent modern deposition above an erosional sur-face (Figure 4). For each sample, �5 g of dried sedimentwas processed using standard techniques. Acid solubleminerals (carbonates and silicates) were digested in HCl,HF, followed by controlled oxidation. The residues werethen rinsed to neutrality. Residues were concentrated byfiltration on a 10 lm mesh sieve and spiked with a knownquantity of Lycopodium spores to allow quantitative

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Figure 2. Multibeam bathymetry of Sabrina Coast continental shelf collectedduring NBP14-02 (modified from Gulick et al. 2017; Fernandez et al. 2018).Locations of sediment cores JPC-54 and JPC-55 (black circles) and seismic line17 (black line) are indicated. Inset: Map of the Sabrina Coast shelf with locationand orientation of the NBP14-02 study area indicated by the multibeam dataand sesimic survey lines. MUIS¼Moscow University Ice Shelf. (modified fromFretwell et al. 2013).

2 C. SMITH ET AL.

assessment of terrestrial palynomorph concentrations. Atleast 300 terrestrial palynomorphs were counted per sam-ple using a transect method. All terrestrial palynomorphswere identified using a Zeiss Axio Vert-A1 inverted micro-scope with a 100x oil immersion lens.

3.2. Taxonomy

Taxonomic evaluation of palynomorphs was done via lit-erature review (e.g. Cookson 1950; Cookson and Pike1954; Couper 1960; Stover and Partridge 1973; Truswell1983; Jarzen and Dettmann 1992; Macphail and Truswell2004; Hou et al. 2006; Truswell and Macphail 2009;Raine et al. 2011; Pross et al. 2012; Contreras et al.2013) and using collections curated at the LouisianaState University Center for Excellence in Palynology(CENEX). The slides and residues discussed in this paperare curated at CENEX.

4. Results

The Sabrina Coast sediments yielded abundant, diverse, andwell-preserved palynomorphs. Palynomorph concentrationsranged from 3540 to 6560 grains per gram dry sediment(gdw�1) for core JPC-54 and from 4200 to 8570 gdw�1 forcore JPC-55, with a mean of 4330 gdw�1 and 6390 gdw�1,respectively. These concentrations indicate that SabrinaCoast sediments are rich in palynomorphs relative to otherAntarctic sediment sequences. The Sabrina Coast assemb-lages provide a first glimpse into the terrestrial environmentof the Aurora Basin before the EAIS expanded to its currentcontinental-scale configuration.

Cores JPC-54 and JPC-55 are distinguished from oneanother by differences in their respective palynologicalassemblages. The JPC-55 assemblage contains 16–23%Battenipollis sabrinae sp. nov. (formally described below), apreviously undescribed angiosperm pollen species similar toBattenipollis sectilis. In contrast, only one sample from coreJPC-54 (46–47 cm) contains Battenipollis sabrinae sp. nov. (2%of the total assemblage). Core JPC-54 also contains a highertotal abundance of Nothofagidites spp. (5–12%), compared to1-3% of the JPC-55 assemblage. Core JPC-54 sediments con-tain N. emarcidus and N. cranwelliae, which were notobserved in core JPC-55.

Despite these differences, similarities exist between thetwo assemblages. In both cores, the palynological assem-blage is dominated (38-66%) by Gambierina rudata, G.edwardsii, and related complexes. Proteaceae (7–17%) arediverse, consisting mostly of Proteacidites tenuiexinus. Thisangiosperm-dominated assemblage also includes Battenipollis

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PALYNOLOGY 3

Plate 1. Age diagnostic pollen morphospecies from NBP14-02 JPC-54 and JPC-55. 1-4) Battenipollis sabrinae sp. nov. 5-8) Gambierina askiniae sp. nov. 9-10)Gambierina spp. clusters 11) Forcipites longus 12) Phyllocladidtes mawsonii 13) Laevigatosporites ovatus 14) Battenipollis sectilis 15) Gambierina edwardsii 16)Gambierina rudata 17) Proteacidites tenuiexinus 18) Nothofagidites flemingii-rocaensis complex 19) Nothofagidites emarcidus.

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sectilis, Forcipites spp. and Nothofagidites spp. (mostly the N.cf. rocaensis-cf. flemingii complex). Conifer pollen grains arepresent (3–10%), including Phyllocladidites mawsonii,Microcachryidites antarcticus, and Microalatidites paleogenicus,as are fern spores [e.g. Laevigatosporites ovatus (1–8%)].Because of the similarities between cores JPC-54 and JPC-55,we refer to the palynoflora assemblage as the Sabrina Flora,named after the Sabrina Coast.

5. Systematic palaeontology

Anteturma POLLENITES H. Potoni�e 1893Turma POROSES Naumova 1937-39

Subturma TRICOLPORATES Iversen et Troels Smith 1950

Genus Battenipollis Jarzen & Dettmann 1992

Type species. Triporopollenites sectilis Stover in Stover &Partridge 1973

Battenipollis sabrinae sp. nov.Plate 1, images 1-4; Plate 2, image 1

Holotype. Plate 1, image 1.Type locality. Offshore of the Sabrina Coast, East Antarctica(S66˚20.998 E120˚30.454)Diagnosis. Pollen tricolporate, angulaperturate, amb concavelyto slightly convex triangular between apertures, apertures broadlyrounded to truncate, apices smooth. Exine 2–3 mm thick, vaguelyto moderately well differentiated, sexine thicker than nexine,slightly thicker in interradial areas, with sexine coarsely rugulateon the entire surface of the grain apart from the aperture areasthat are mostly psilate to finely rugulate. This consistently coarsetexture is one of the key features of this species of Battenipollis.

Dimensions. Diameter of 15 specimens from core JPC-55: 23(28) 31 mmThe mean distal exine thickness is 2.5 mm.Remarks. Battenipollis sabrinae sp. nov. is distinguished fromBattenipollis sectilis by a thicker exine (2-3 mm vs <2 mm) andthe highly irregular coarse rugulate sculpturing between aper-tures. Specimens vary in width of apical protuberance.Etymology. Battenipollis sabrinae is named for the SabrinaCoast of East Antarctica where the morphospecies isfirst described.

Anteturma POLLENITES H. Potoni�e 1893Turma POROSES Naumova 1937-39

Subturma TRICOLPORATES Iversen and Troels Smith, 1950

Genus Gambierina Harris 1972 emend. Stover & Partridge(1973); emend. Jarzen & Dettmann 1992

Type species. Gambierina edwardsii Stover in Stover &Partridge (1973)

Gambierina askiniae sp. nov.Plate 1, images 5-8; Plate 2, image 2

Holotype. Plate 1, image 5.Type locality. Offshore of the Sabrina Coast, East Antarctica(S66˚20.998 E120˚30.454)Diagnosis. Pollen tricolporate, amb triangular to concavelytriangular, apertures rounded, apertures smooth. Exine 1–2.5mm thick, vaguely differentiated, sexine thicker than nexine,with sexine smooth at apertures and mostly irregularlyroughened to coarsely rugulate between apertures. Exinemay be slightly thickened at pores, with well-defined nickpoint within the apertures.Dimensions. Diameter of 16 specimens from core JPC-55: 23(26) 33 mm

Plate 2. Scanning electron microscope (SEM) images of new Sabrina Coast species. 1) Battenipollis sabrinae sp. nov 2) Gambierina askiniae sp. nov. The microphoto-graph dimensions indicated are those of the specimens illustrated. Specimens of Battenipollis sabrinae sp. nov range from 23 to 31 microns (lm) and specimens ofGambierina askiniae ranged from 23 to 33lm.

PALYNOLOGY 5

The mean distal exine thickness is 1.5 mm.Remarks. Gambierina askiniae is distinguished fromGambierina rudata by a lack of extreme thickening of thewalls at the aperture level and different wall texture.Gambierina askiniae differs from Gambierina edwardsii byhaving less concave sides, rounder apertures, smaller diame-ters, and an irregular, moderately to coarsely rugulate sculp-tured exine between the apertures. Gambierina askiniaeshould include a specimen described as Gambierina sp. A inJarzen and Dettmann (1992). Truswell (1983) illustrated amorphotype described as Gambierina sp., recovered fromreworked sediments sampled from the West Ice Shelf andShackleton Ice Shelf. These specimens also have an exinethat is rugulate, but much coarser than that of G. askiniae,and the exine is more heavily thickened around the aper-tures. The overall size of Gambierina sp. of Truswell (1983) islarger, ranging between 33 and 41 mm. It is possible thatGambierina sp. of Truswell (1983) and G. askiniae sp. nov. arevariations within this species population.Etymology. Gambierina askiniae is named for Dr. RosemaryAskin, in recognition of her mentoring of Antarctic palynolo-gists and for her contribution to Antarctic palyno-logical research.

6. Age Interpretation and significance

The palynological biostratigraphic zonation of cores JPC-54and JPC-55 is based on the presence of a few key speciesand limited data available from Antarctica and surroundingregions (e.g. Australia and New Zealand). The age assign-ments for these cores are discussed in the SupplementalInformation published in Gulick et al. (2017). A summary ofthe discussion is as follows: Phyllocladidites mawsonii,Dilwynites granulatus and Laevigatosporites ovatus are knownfrom various sources to range at least from Late Cretaceousthrough Eocene and thus, they do not allow narrowing ofthe age range beyond 74 to 34Ma. Gambierina edwardsii andGambierina rudata are known as Cretaceous to Paleocene

species based on various studies. A recent study byContreras et al. (2014) published a robust LAD for these spe-cies at the Paleocene/Eocene boundary at ODP Site 1172, onthe East Tasman Plateau. However, Partridge (1999) notedthat in southeastern Australia, the ranges of the twoGambierina species extend into the earliest Early Eocene.Extended ranges for the Gambierina sp., indicated in Figure 5by dashed-lines, are based on the palynological analysis ofOcean Drilling Program (ODP) Site 1166 in Prydz Bay(Macphail and Truswell 2004; Truswell and Macphail 2009),where the authors postulate that the abundant well-pre-served Gambierina specimens are unlikely recycled and arguethat their range should be extended into the early to middleEocene in Prydz Bay (see additional discussion regardingGambierina in section 7). Microalatidites paleogenicus is listedwith a range of Paleogene to Neogene in a detailed sum-mary by Raine et al. (2011). There is some divergence ofopinion regarding this range; Macphail (in Hill 1994) lists thefirst occurrence of Microalatidites paleogenicus as Senonian inAustralia and New Zealand, but there is no robust evidencesupporting an extended range in Antarctica. However,Microalatidites paleogenicus is listed in Fossilworks (PaleoDBtaxon number: 321781) as having a range from 55.8 to11.608Ma. Nothofagidites lachlaniae has a range fromPaleogene to modern while the Nothofagidites flemingii-rocaensis morphotype has a range from Paleogene toNeogene according to the comprehensive summary by Raineet al. (2011). Truswell (1983) lists the range for N. lachlaniaein New Zealand as Late Cretaceous to present day and notessimilarity to other forms. Regarding the variability found inNothofagidites ranges in the Paleocene and Eocene, some ofthe variation observed is undoubtedly climatically induced.For example, Pocknall (1989) argued that broad regionalchanges in vegetation (e.g. the abundance of Nothofagiditeslachlaniae in western Southland (Ohai, Waiau and Ballenybasins) and its scarcity in other Eocene sections fromWaikato, the Taranaki Basin, and the west coast of NewZealand’s South Island) are related to paleoenvironmentalfactors. The type material is Pliocene (Dettmann et al. 1990),but the distinction of this species from other Fuscospora pol-len (including N. brachyspinulosa and N. waipawaensis) isproblematic. If N. waipawaensis and N. senectus are excluded,then the New Zealand FAD of other Fuscospora pollen wouldbe late Paleocene (Ian Raine, pers. comm.). Regarding N. fle-mingii, Raine (pers. comm.) stated that in Southern Australia,Stover and Partridge (1973) and Stover and Evans (1973) putthe FAD of N. flemingii in the upper part of theirLygistepollenites balmei Zone, which is late Paleocene. Harris(1965) did not report the species in his detailed study ofPaleocene-Eocene transition strata in western Victoria. InNew Zealand, the FAD was reported as middle Eocene inCouper (1960) and Raine (1984). Pocknall (1989) notes that,by the late Eocene (Kaiatan stage) in New Zealand, Casuarinaand Nothofagidites flemingii predominate the assemblage,together with several Proteaceae, including Proteaciditesasperatus, P. incurvatus, and P. reticulatus. But going back tothe FAD, Raine (pers. comm.) recently observed occasionalspecimens throughout the early Eocene from well-dated

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6 C. SMITH ET AL.

outcrop localities in New Zealand. However, these specimensare smaller than the typical N. flemingii and there is anongoing debate as to their taxonomic affiliation. Thus, wefollow early recommendations and place the FADs of bothspecies in the late Paleocene. Proteacidites tenuiexinus has arange from 66.043 to 15.97Ma (PaleoDB taxon number:277519 at fossilworks.org). However, Stover and Partridge(1973) list the Proteacidites tenuiexinus FAD as late Paleocenein southeastern Australia. We follow Stover and Partridge(1973), but acknowledge that the FAD could be as early asearly Paleocene.

Several well-preserved specimens of Forcipites longus andBattenipollis sectilis were also identified. Because of the con-troversial nature of these species LADs, they are not used inthe biostratigraphic zonation. While an extended range tothe Eocene is proposed in Antarctica based on well-pre-served specimens from Prydz Bay, questions remain aboutreworking within the sequence (Macphail and Truswell 2004;Truswell and Macphail 2009). In Australia’s Gippsland Basin,Partridge (2006) places the LAD of F. longus and B. sectilis atthe Cretaceous-Paleogene (K/Pg) boundary. While we do notuse these species in our biostratigraphic zonation, their pres-ence may indicate that the proposed extended range inMacphail and Truswell (2004) is correct.

Thus, based on the pollen assemblage alone, we favor aPaleocene to earliest early Eocene age for core JPC-55. Thepresence of benthic foraminifer species that go extinct in thelatest Paleocene and those that evolve in the Paleocene incore JPC-55 enable us to further narrow the age of JPC-55 tolate Paleocene (Gulick et al. 2017).

Two pollen species were present in core JPC-54 that werenot observed in core JPC-55, Nothofagidites cranwelliae andN. emarcidus. Most verified references for N. cranwelliae andN. emarcidus (e.g. those with specimens properly identified;the Nothofagidites group is diverse, complex, and easily misi-dentified) place the FAD of both of these species in the earlyEocene, at the earliest. For instance, in Australia’s GippslandBasin, Greenwood et al. (2003) observe abundant (50-60% ofthe total assemblage) N. emarcidus at the early-middleEocene boundary. Stover and Partridge (1982) also foundthis species in the Eocene of western Australia. Thus, basedon the pollen assemblage alone, we favor an early to middleEocene age for core JPC-54. The presence of IRD in the samecore is then a critical observation that suggests that glaciershad reached the ocean, at least locally within the AuroraBasin, by the early to middle Eocene. However, the presenceof the pollen denotes the presence of an ecosystem withinthe catchment and, thus, only partial glacial cover.

7. Further discussion on Gambierina spp. andpaleobotanical affinity of abundant species

Gambierina spp., the most abundant (38–58%) pollen incores JPC-54 and JPC-55, present certain issues when deter-mining our age assignment and paleoenvironmental inter-pretation of the Sabrina Coast sediments. Most of theGambierina spp. specimens in cores JPC-54 and JPC-55 arelight in color and well-preserved. Furthermore, there are

clusters of both G. rudata and G. edwardsii species, with upto 40 specimens per cluster, in cores JPC-54 and JPC-55(Plate 1, images 9-10). Both lines of evidence suggest thatthese specimens were deposited close to the angiospermparent plant, indicating most Gambierina specimens are notreworked, and are therefore penecontemporaneous withsedimentation.

Although South Australian and New Zealand reports (ref-erenced above) define the age range of Gambierina spp. asLate Cretaceous–late Paleocene/earliest early Eocene,Truswell and Macphail (2009) suggested that Gambierina spp.likely extended through the late Eocene in Prydz Bay, EastAntarctica. Pross et al. (2012) also suggest that the parentplant for Gambierina edwardsii survived during the Early andmiddle Eocene along the Wilkes Land coast, as observed atIntegrated Ocean Drilling Program (IODP) Site U1356. Prosset al. (2012) argued that the longevity of Gambierina spp. inEast Antarctica may reflect perennially cool to cold climatesin Antarctica since the late Paleocene, while a rapidly warm-ing climate in southern Australia during thePaleocene–Eocene Thermal Maximum could have eliminatedGambierina parent plants there (Macphail et al. 1994;Truswell and Macphail 2009). Because Gambierina spp. werelikely living penecontemporaneously with sediment depos-ition at the sites of cores JPC-54 and JPC-55 on the SabrinaCoast, and because we find at least one morphospecies inour assemblage with a FAD in the early Eocene(Nothofagidites emarcidus) only in JPC-54, we suggest thatGambierina edwardsii and G. rudata could extend into theearly Eocene (based on our data), and possibly to themiddle-late Eocene if Truswell and Macphail (2009) and Prosset al. (2012) are correct. Thus, we extend the potential agerange for JPC-54 into the middle Eocene, in consideration ofthese two studies (Figure 5). Furthermore, extending theranges of Gambierina edwardsii and G. rudata to the middleEocene is consistent with evidence for regional marine termi-nating glaciers (e.g. Scher et al. 2014; Gulick et al., 2017;Passchier et al. 2017).

In the Sabrina Coast assemblage, there are additionalmorphospecies with unknown paleobotanical affinity, includ-ing: Battenipollis sectilis (renamed by Jarzen and Dettmann1992 from Triporopollenites sectilis in Stover and Partridge1973) and Forciptes spp. Specimens of Gambierina spp.,Battenipollis sectilis, and Forcipites spp. have all been foundwithin upper Cretaceous sequences in the Otway Basin(Figure 1), where they are compared to pollen of theNorthern Hemisphere Normapolles type (Jarzen andDettmann 1992). Although there are similar morphologicalcharacteristics with the Normapolles, which are breviaxial,transcolpate and have a triangular amb (Batten 1981; Battenand Christopher 1981), closer analyses revealed that thesegenera evolved separately, and thus any paleobotanical affin-ity is speculative (Jarzen and Dettmann 1992). These threegenera (Gambierina, Battenipollis and Forcipites) likely grewwithin forest communities adjacent to, or fringing, an estuary(Dettmann and Jarzen 1988); however, their parent plantsand affinities are still unknown. Although specimens ofBattenipollis sectilis and Battenipollis sabrinae sp. nov. might

PALYNOLOGY 7

be in situ, a lack of additional in situ evidence, such as clus-ters like those of Gambierina spp., prevents a similar ageextension for Battenipollis spp. at the Sabrina Coast.Additional study is required to define whether Battenipollissabrinae sp. nov. extends to the Eocene. Furthermore, mostForcipites longus specimens are dark in color and often bro-ken. Therefore, we speculate that this species is possiblyreworked from Cretaceous or early Paleocene sources.

8. Conclusions

The terrestrial palynomorphs preserved in cores JPC-54 andJPC-55 collected offshore of the Sabrina Coast are well-pre-served, diverse, and likely deposited contemporaneously withsedimentation from the Aurora Basin catchment (now theAurora Subglacial Basin) deposited on the Sabrina Coast con-tinental shelf. The assemblages found within cores JPC-54and JPC-55, now referred to as the Sabrina Flora, providevaluable insight to the paleoflora, including the descriptionof two undescribed morphospecies, Battenipollis sabrinae sp.nov. and Gambierina askiniae sp. nov. We also report on thepaleoenvironments of this previously unstudied region ofEast Antarctica, with core JPC-55 likely recording a pre-glacialenvironment and core JPC-54 recording an environment withmarine terminating tidewater glaciers, and incomplete gla-cial cover.

Acknowledgements

The authors thank the NBP 14-02 Scientific Party, ASC technical staff,and Edison Chouest Offshore crew. We remember E.W. Domack, whopassed away in November 2017, and acknowledge his contribution. Weextend our thanks to Rosie Askin for her insight on Antarctic palynology.Thanks are extended to Dr. David Pocknall and a second anonymousreviewer for their constructive comments that improved our manuscript.This is UTIG Contribution #3282.

Disclosure statement

No potential conflict of interest was reported by the authors.

Funding

This work was supported by the National Science Foundation underGrants 1143834, 1143836, 1143837, 1143843, 1313826, 1048343, 131382;and Geological Society of America Graduate Student Research Grant.

Notes on contributors

CATHERINE SMITH is currently working as a curatorwith the International Ocean Discovery Program atTexas A&M University. Catherine was born in NewYork and attended Hamilton College in Clinton, NY,where she received a B.A. in Geosciences. Shereceived her M.S. in Marine Science at the Universityof South Florida College of Marine Science in St.Petersburg, Florida and trained in palynology at the

LSU Center for Excellence in Palynology (CENEX) as a visiting researcherin 2016. While at USF she participated in a cruise to the Sabrina Coastaboard the RV/IB Nathaniel B. Palmer where the cores for this project

were collected. She presented her preliminary results at the 2015 AnnualGeological Society of America-American Association of StratigraphicPalynologists (AASP) joint meeting in Baltimore where she received theVaughn Bryant Best Student Poster award and Best Overall Posterby AASP.

SOPHIE WARNY is an Associate Professor and theAASP Chair of palynology in the Department ofGeology and Geophysics, and a curator at theMuseum of Natural Science at Louisiana StateUniversity (LSU) in Baton Rouge, Louisiana, USA.Sophie received her PhD from the UniversitéCatholique de Louvain, in Belgium, working withJean-Pierre Suc; her doctoral dissertation was on

the Messinian Salinity Crisis. Since graduating, she has specialized inAntarctic palynology and worked on Antarctic projects such asANDRILL SMS, SHALDRIL and WISSARD. In 2011, she received theNational Science Foundation CAREER award to support her researchin Antarctica. In addition to her research, Sophie teaches historicalgeology, palaeobotany and micropalaeontology. Since being hired atLSU, Sophie has graduated eighteen master and doctoral students;most are employed either in the oil and gas industry, as instructorsat universities or with the U.S. Department of Homeland Security.

AMELIA SHEVENELL is an Associate Professor atthe University of South Florida in the College ofMarine Science. She has conducted paleoceano-graphic and paleoclimatologic research inAntarctica and the Southern Ocean since 1995.Her research interests include the Cenozoic evolu-tion of Antarctica's ice sheets on million year todecadal timescales. She uses geochemical and

foraminiferal paleoceanographic proxies from continental margin anddeep-sea sediments to investigate the importance of ocean-ice inter-actions to ice sheet development. In 2006, she was awarded the GSAStorrs Cole Memorial Research Award for significant publications ininvertebrate micropaleontology. She began working in the Australo-Antarctic Gulf in 2000, as a sedimentologist on Ocean DrillingProgram Leg 189. She is actively involved as both a scientist and anadvisory committee member in international scientific drilling initia-tives, including the Integrated Ocean Discovery Program (IODP). Sheled the marine geology team for the 2014 expedition to the SabrinaCoast. Shevenell sailed as lead sedimentologist and was a co-propon-ent of IODP Expedition 374 to the Ross Sea.

SEAN GULICK is a Research Professor at theUniversity of Texas at Austin in marine geology andgeophysics. He has sailed on over twenty-fiveresearch cruises and been chief or co-chief scientiston fourteen and authored or co-authored over 80journal articles. He received the Jackson SchoolOutstanding Researcher Award in 2014. His researchincludes tectonic and climate interactions in high-lati-

tude systems such as the East Antarctic margin; geohazards and mar-gin evolution of subduction and transform plate boundaries; and thegeologic processes and environmental effects of the Cretaceous-Paleogene Chicxulub meteor impact. He led the seismic acquisitionand processing team for the 2014 Nathaniel B. Palmer expedition tothe Sabrina Coast.

AMY LEVENTER is a Full Professor of geology atColgate University. She has been working inAntarctica since 1983 and specializes in polar marinediatoms, but has also worked with planktonic fora-minifera from the Gulf of Mexico. She received herBS in Aquatic Biology (1979) from Brown University,an MS in Marine Science (1981) from University ofSouth Carolina and a PhD in Geology (1988) from

Rice University. After finishing her graduate work, she spent severalyears at Byrd Polar Research Institute Ohio State University, followed bythree years at the Limnological Research Center University of Minnesota,prior to her position at Colgate.

8 C. SMITH ET AL.

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