This article was downloaded by: [Memorial University of Newfoundland]On: 08 November 2013, At: 16:59Publisher: Taylor & FrancisInforma Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House,37-41 Mortimer Street, London W1T 3JH, UK

Diatom ResearchPublication details, including instructions for authors and subscription information:http://www.tandfonline.com/loi/tdia20

Morphological observations and emended descriptionof Amphora micrometra from the Bolivian Altiplano,South AmericaÉva Ács a , Luc Ector b , Keve T. Kiss a , Csaba Cserháti c , Eduardo A. Morales d e & ZlatkoLevkov fa Danube Research Institute of the Hungarian Academy of Sciences , Göd , Hungaryb Department of Environment and Agro-Biotechnologies (EVA) , Public Research Centre -Gabriel Lippmann , Belvaux , Luxembourgc Department of Solid State Physics , Debrecen University , Debrecen , Hungaryd Herbario Criptogámico, Universidad Católica Boliviana San Pablo , Cochabamba , Boliviae Patrick Center for Environmental Research, The Academy of Natural Sciences ,Philadelphia , USAf Institute of Biology , Skopje , Republic of MacedoniaPublished online: 07 Oct 2011.

To cite this article: Éva Ács , Luc Ector , Keve T. Kiss , Csaba Cserháti , Eduardo A. Morales & Zlatko Levkov (2011)Morphological observations and emended description of Amphora micrometra from the Bolivian Altiplano, South America,Diatom Research, 26:2, 199-212, DOI: 10.1080/0269249X.2011.597987

To link to this article: http://dx.doi.org/10.1080/0269249X.2011.597987

PLEASE SCROLL DOWN FOR ARTICLE

Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) containedin the publications on our platform. However, Taylor & Francis, our agents, and our licensors make norepresentations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of theContent. Any opinions and views expressed in this publication are the opinions and views of the authors, andare not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon andshould be independently verified with primary sources of information. Taylor and Francis shall not be liable forany losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoeveror howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use ofthe Content.

This article may be used for research, teaching, and private study purposes. Any substantial or systematicreproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in anyform to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/terms-and-conditions

Diatom ResearchVol. 26, No. 2, June 2011, 199–212

Morphological observations and emended description of Amphora micrometra from the BolivianAltiplano, South America

ÉVA ÁCS1∗, LUC ECTOR2, KEVE T. KISS1, CSABA CSERHÁTI3, EDUARDO A. MORALES4,5 & ZLATKOLEVKOV6

1Danube Research Institute of the Hungarian Academy of Sciences, Göd, Hungary2Department of Environment and Agro-Biotechnologies (EVA), Public Research Centre - Gabriel Lippmann, Belvaux, Luxembourg3Department of Solid State Physics, Debrecen University, Debrecen, Hungary4Herbario Criptogámico, Universidad Católica Boliviana San Pablo, Cochabamba, Bolivia5Patrick Center for Environmental Research, The Academy of Natural Sciences, Philadelphia, USA6Institute of Biology, Skopje, Republic of Macedonia

A population of Amphora micrometra Giffen, collected in September 2002 from different habitats in Laguna Blanca in the BolivianAltiplano, South America, has been examined using light transmission and scanning electron microscopy. The original description of thisspecies is incomplete and insufficient to characterize the taxon in the light of the newly collected ultrastructural data. The holotype ofA. micrometra was examined during the present study and compared to Bolivian specimens. An emended diagnosis of A. micrometra usingall available information is provided. A taxonomic discussion based on available literature and the ecology of the taxon is also presentedherein.

Keywords: Bacillariophyceae, Andes, Bolivia, Laguna Blanca, Amphora micrometra, taxonomy

IntroductionAmphora micrometra was originally described by Giffen(1967) from the marine littoral region at Kidd’s Beach nearEast London, Cape Province, South Africa. The originaldescription of the species is incomplete: ‘Frustule 7–8 μmlong, up to 5 μm wide, elliptical with truncate ends. Valves7–8 μm long, 2.5 μm wide, with convex dorsal margin, andslightly protracted rounded ends, ventral margin straightor slightly convex. Raphe almost straight, near the ventralmargin. Striae on both sides of raphe extremely fine andscarcely visible. Type slide 210 in the Giffen collection.Locus typicus: marine littoral region at Kidd’s Beach nearEast London Cape Province South Africa’ (Giffen 1967,p. 253).

According to Giffen, his taxon could belong to the sub-genus Oxyamphora Cleve, but since he lacked electronmicroscopy data and due to the reduced size of the valves,he could not be certain of this association. His decisionwas to maintain it in the subgenus Amphora Ehrenberg exKützing.

Subsequent authors reported A. micrometra from theSundays River in the Eastern Cape Province of SouthAfrica (Archibald 1983), the Caspian Sea in Aserbai-jan (Karayeva & Mukhtarova 1987), the Swedish westcoast (Kuylenstierna 1989–1990), several African lakes

∗Corresponding author. Email: acs@ludens.elte.hu

(Received 2 November 2010; accepted 2 May 2011)

(Gasse et al. 1995) and the Baltic Sea, where it was fairlywidespread, although decreasing in abundance, towards thenorth (Piirsoo 1995). Kuylentierna (1989–1990) studied 75localities in the Nordre Älv Estuary, close to Kattegat inthe Baltic Sea, but she found A. micrometra in only onesite. She provided a transmission electron photograph whichclosely resembles fig. 502 in Archibald (1983). The taxonwas common in periphytic material growing on Cladophoraat 4 m depth. Amphora micrometra has been found morerecently in other localities in the Baltic Sea and Kattegat(Witkowski et al. 2000, pl. 165, figs 8–10), where the speciesis fairly widespread. It is also probable that the report byGibson et al. (2006, as ‘Amphora sp. b’) corresponds to thistaxon occurring in lakes of the Bunger Hills, east Antarc-tica. These latter authors were unable to capture electronmicroscopy images, thus it was not possible to establisha fair relation with A. micrometra based only on lightmicroscopy (LM) data. Additional records of A. microme-tra appearing in the literature are those of Gell (1997) andGell et al. (2002) from Australia, Laslandes (2007) fromBrazil, Trobajo Pujadas (2007) from Spain, Amspoker &McIntire (1986) and Zimba et al. (1990) from the USA, andvan Ee & Houdijk (2006) from the Netherlands. However,none of these latter records were supported with electronmicroscopy.

ISSN 0269-249X print/ISSN 2159-8347 online© 2011 The International Society for Diatom Researchhttp://dx.doi.org/10.1080/0269249X.2011.597987http://www.tandfonline.com

Dow

nloa

ded

by [

Mem

oria

l Uni

vers

ity o

f N

ewfo

undl

and]

at 1

6:59

08

Nov

embe

r 20

13

200 Ács et al.

As a result of an expedition to high altitude ponds inthe South American Altiplano, A. micrometra was foundin Laguna Blanca, Bolivia. A detailed description of thistaxon is provided using combined LM and scanning elec-tron microscopy (SEM) information, also incorporating anultrastructural study of type material. Taxonomical and eco-logical issues are discussed in the light of available literaturefor this taxon.

Material and methodsLaguna Blanca is located in the Andean Altiplano, at thefoot of Licancabur Volcano, 4340 m above sea level, on theborder between Chile and Bolivia (22◦50′S and 67◦53′W).It is a brackish pond (with high dissolved salt content:22.4 g L−1), very shallow (maximum depth <1 m) with asurface area of ∼10.5 km2. High winds increase the tur-bidity making the suspended matter reach values of upto 207 mg L−1, while Secchi disk depth occurs between20 and 40 cm. Most of the suspended matter consists ofdiatom frustules, where dense communities are favouredby high silicon and nutrient concentrations. The LagunaBlanca freezes at approximately −1 to −2◦C, but not tothe bottom despite the high altitude and extremely coldwinter because the water supply influx is composed ofthermal (36◦C) and several cold (17◦C) springs. The phys-ical environment of the pond combines high ultravioletradiation (40% higher than at sea level) enhanced by thetropical latitude of the site, as well as low atmosphericpressure, low oxygen (58% of oxygen pressure at sealevel), high atmospheric thermal amplitude, low humiditydue to the proximity to the Atacama Desert, and low pre-cipitation (<200 mm year−1). The NaCl, SO−2

4 and HCO−3

contents are high; however, the concentrations of Ca and Mgare not outstanding (Table 1). Nitrogen and phosphorusare abundant due to significant inputs from large flocksof flamingos, making the water potentially hypertrophic orpolytrophic. This detailed description of Laguna Blanca andthe methods of measurements of environmental data can befound in Cabrol et al. (2007).

Periphyton samples were collected from different habi-tats (stone, submersed macrophyton, sediment surface)within the pond in September 2002. The samples were fixedwith buffered (pH 7) 4% (v/v) formaldehyde immediatelyafter collection, diatoms were treated with HCl and hotH2O2 according to CEN (2003), and washed five times indistilled water.

For LM analyses, diatom slides from aliquots from sam-ples were mounted with Naphrax® mounting medium andobserved with an Olympus IX70 inverted light microscopeequipped with differential interference contrast (DIC) opticsat 1500× magnification. Images were obtained using anARTRAY digital camera (Model: ARTCAM-500MI).

Portions of samples were filtered through a 3 μm-mesh polycarbonate membrane and fixed on SEM stubs,which were then coated with gold–palladium (105 s, 18 mÅ)

and investigated with Hitachi S-2600N and S-4300-CFEscanning electron microscopes. Subsamples of the filteredtreated material were also used for transmission elec-tron microscope (TEM) analysis, 5 μL subsample wasdropped to a grid (mess size 63 μm and covered by for-mvar) and dried at room temperature. MORGAGNI 268Dtransmission electron microscope was used.

The type slide of A. micrometra, No. KB 210 M.H. Gif-fen 10/10/1963 CSIR Hyrax: 287/5728 and a subsample ofraw type material collected by Giffen (1967, CSIR, GiffenCollection Sample KB 210) were also examined under LM,SEM and TEM. This same material was designated as typefor A. exilissima Giffen by Giffen (1967). The small portionof type material used in this study is now deposited at theDanube Research Institute (DRI/G/1). Terminology followsAnonymous (1975) and Levkov (2009). LM illustrations ofthis taxon from this material are presented below.

ResultsAmphora micrometra Giffen emend. Ács, Kiss & Levkov

External view. Conopeum and stauros are absent, proxi-mal raphe endings are straight with slightly expanded andweakly, dorsally deflected central pores. Distal raphe endsdorsally deflected. Striae are uniseriate, 44–52 in 10 μm(dorsal), 50–68 in 10 μm (ventral), composed of smallround areolae due to recessed position with respected toraised costae. The openings of the portulae are visible assimple round pores in the costae and located at both apiceson the dorsal part of the valve, near the distal raphe ends.

Internal view. Stauros is absent, distal raphe ends termi-nate in poorly developed helictoglossae, the proximal rapheends are fused onto a tongue-like extension (central helic-toglossae). The areolae open to a large through, which isoccluded by a single hymen. This hymen is perforated byminute pores arranged in a random pattern. The portulae arecylindrical structures.

Girdle view. The girdle is composed of numerous openbands bearing two rows of round poroids. Density of girdleband poroids ∼70 in 10 μm.

LM observations (Figs 1–12). Very few morphologicaldetails can be observed in valves of A. micrometra usingLM, except for the valve outline, size and the straight natureof the raphe. Valves are elliptical with broadly rounded ends(Figs 3–5, 7–8), although most valves often lie tilted andappear to have more acute apices (Figs 1–2, 6, 9–11). Valvesare 7–12 μm long and 2.0–2.5 μm wide. Striae are not evi-dent, and the raphe is only faintly seen as a straight lineinterrupted in the middle by teardrop-shaped proximal ends(Figs 2–3, 5, 7). When complete elliptical-shaped frustulesare found in side view, several girdle bands can be seen,but no other characteristics are observable (Fig. 12). AllLM characteristics of A. micrometra from Laguna Blanca

Dow

nloa

ded

by [

Mem

oria

l Uni

vers

ity o

f N

ewfo

undl

and]

at 1

6:59

08

Nov

embe

r 20

13

Morphology of Amphora micrometra Giffen 201

Table 1. Summarization of environmental data of Amphora micrometra in the literature and the present study.

Reference Site Environmental data

Giffen (1967) Type locality: Kidd’s Beach, CapeProvince, South Africa

Salinity 30–36 g L−1

Archibald (1983) Sundays River, Eastern Cape Province,South Africa

All sites were under tidal influence

Amspoker & McIntire (1986) Columbia River Estuary, Baker Bay,USA

Salinity 32

Karayeva & Mukhtarova (1987) Caspian Sea, Aserbaijan No dataKuylenstierna (1989–1990) Rammen, Sweden Salinity 1.5–8.9 g L−1 in the estuary and

19–26 g L−1 at seaNO3-N 25–50 μmol L−1

Total phosphorus (TC) (TP) 0.3–1.2 μmol L−1

Zimba et al. (1990) Graveline Bayou, USA No dataGasse et al. (1995) African lakes Conductivity optimum 4.62 S cm−1

pH optimum 7.56Piirsoo (1995) Baltic Sea Salinity 10–12 g L−1

Gell (1997) Western Victoria, Australia Salinity >0.5 g L−1

Witkowski et al. (2000) Baltic Sea and Kattegat Salinity 10–12 g L−1

Gell et al. (2002) Psyche Bend Lagoon, North WesternVictoria, Australia

Conductivity 1350–57 000 μS cm−1

TP <0.01–0.29 mg L−1

Nitrate <0.10–0.75 mg L−1

pH 8.20–9.51Gibson et al. (2006) Bunger Hills, East Antarctica Salinity 4–77 g L−1

van Ee & Houdijk (2006) The Netherlands PO4-P 0.01–0.90 mg L−1

NO3-N 0.1–0.7 mg L−1

Cl 1000–100 000 mg L−1

Brackish to marine watersLaslandes (2007) Niteroi, Brasil Hyposaline lake

Total dissolved salt (TDS) 5–8 g L−1

Cl 99.39–183.08 mmol L−1

Trobajo Pujadas (2007) Empordà, northeast Spain Mediterranean coastal wetlands with lowproductivity

Total organic carbon (TOC) 3.9–31.4 mg L−1

Salinity 2.1–30.4 g L−1

This study Bolivia TDS 22 400 mg L−1

PO4 1.505 mg L−1

Cl 10 200 mg L−1

pH 7.2SO4 1590 mg L−1

HCO3 780.8 mg L−1

Ion concentration (ppm): Li 13.6, B 287, Na 98.2,Mg 396, Al 0.0519, Si 45.6, K 401, Ca 382, Mn0.00264, Fe 0.593, As 12.1, Rb 2.88, Cs 2.88a

Note: aThe chemical analysis of water samples was performed using inductively coupled mass spectrometry (ICP-MS) and ionchromatography (IC). ICP-MS was used to determine elemental abundances across the periodic table to the parts per million (ppm)level.

(Figs 1–8) are also seen in specimens from type material(Figs 9–12), slide N◦ KB 210 M.H. Giffen 10/10/1963CSIR Hyrax: 287/5728 (Fig. 15). Figures 13 and 14 depictspecimens of A. exilissima found in the same material fromthe Giffen collection at CSRI. This same material servesas type for both A. micrometra and A. exilissima, as des-ignated by Giffen (1967). Although both taxa are verysimilar in valve outline they differ in that A. exilissima hasa well-developed, conspicuous central stauros, this featureis completely absent from A. micrometra. No specimens ofA. exilissima were found using the SEM or TEM.

Electron microscopy observations (Figs 16–39). SEMobservations were made on both the sample from LagunaBlanca and the type material collected by Giffen (1967).However, the specimens in the latter material were poorlypreserved, so the description below is mainly based on therecent sample from Laguna Blanca.

In external view, the valve face is flat to slightly curvedand the raphe ledge (conopeum) is absent (Figs 16–18). Thetransition from the valve face to the valve mantle is gradualto abrupt (Figs 16–18, 20), the marginal ridge is absent, asis the central stauros (Figs 16–21). The axial area appears

Dow

nloa

ded

by [

Mem

oria

l Uni

vers

ity o

f N

ewfo

undl

and]

at 1

6:59

08

Nov

embe

r 20

13

202 Ács et al.

Figs 1–15. Figs 1–8. Amphora micrometra from Laguna Blanca, LM. Figs 9–12. A. micrometra from type slide No. KB 210 M.H.Giffen 10/10/1963 CSIR Hyrax: 287/5728, LM. Figs 13–14. A. exilissima from type slide No. KB 210 M.H. Giffen 10/10/1963 CSIRHyrax: 287/5728, LM. Fig. 15. Type slide of A. micrometra and A. exilissima, CSIR diatom collection, KwaZulu-Natal, regional officein Durban, South Africa. Scale bar = 5 μm.

as a narrow clear space on both sides of the raphe, becom-ing slightly expanded ventrally at the valve central nodule(Figs 16, 18). The raphe is straight with straight externalproximal raphe endings, which are slightly expanded(teardrop-shaped) and weakly deflected toward the dorsalmargin (Figs 16–19, 21). The distal raphe ends are stronglyhooked and curved towards the dorsal margin (Figs 16–19, 21). Dorsal striae are recessed between raised flankingcostae, and are parallel throughout the length of the valve,extending onto the dorsal valve mantle without interrup-tion (Figs 16–21). Ventral striae are shorter and run withoutinterruptions into the valve mantle (Fig. 21). Both dorsal andventral striae are uniseriate, and composed of small roundareolae (Fig. 20). Density of dorsal striae varies between 44and 52 in 10 μm, and that of ventral striae ranging between50 and 68 in 10 μm. The openings of the portulae are visibleas simple round pores on the dorsal part of the valve, nearthe distal raphe ends, at both apices (Fig. 21, arrow).

In internal view, the proximal and distal raphe endsare simple, straight, unexpanded. A poorly developed

helictoglossa can be found at the valve apices (Figs 22,24–25), which sometimes seems to be fused with a thicken-ing in the valve apex (Figs 1–3, 9). The proximal raphe endsare fused onto the flanks of a tongue-like protruding cen-tral helictoglossa (sensu Levkov 2009), oblique to the valvecentral nodule (Figs 22–23, 26, 32). Each stria (ventral anddorsal) is internally occluded by hymenes (Figs 36–39), sothe shape of each individual areola cannot be observed fromthe inside. The portulae are cylindrical structures locateddorsally, just above both of the raphe distal ends (Figs 22,24–25). Each portula is positioned on a costa, thus they arenot associated with areolae.

The girdle is composed of numerous open bands bearingtwo rows of round poroids, each of which appears to be alsooccluded by a hymen (Figs 27–29, 36). The density of thesegirdle band pores is of ∼70 per 10 μm.

All of the above described external and internal char-acteristics of A. micrometra are identical in the typematerial (Figs 30–35). A portula is clearly visible inFig. 33.

Dow

nloa

ded

by [

Mem

oria

l Uni

vers

ity o

f N

ewfo

undl

and]

at 1

6:59

08

Nov

embe

r 20

13

Morphology of Amphora micrometra Giffen 203

Figs 16–21. Amphora micrometra from Laguna Blanca, external views, SEM. Figs 16–17. Whole valves. Fig. 18. Proximal raphe ending.Fig. 19. Distal raphe ending. Fig. 20. Stria structure. Fig. 21. Distal raphe ending with the external opening of the portula (arrow). Scalebars = 2 μm (Figs 16–17); 1 μm (Figs 18, 20–21); 500 nm (Fig. 19).

TEM micrographs additionally show the macroareo-lae (sensu Bukhtiyarova 2006), internally occluded by ahymen, which is perforated by minute pores (Figs 36–37, 39). The valve structure (Figs 36–37) appears similarto valves identified as A. micrometra and depicted alsousing TEM in Archibald (1983, pl. 24, fig. 503; Figs 38–39herein).

Distribution and ecology. As shown in Table 1 andFig. 38, A. micrometra has been recorded from everycontinent (Fig. 40). Environmental data for each local-ity are different (Table 1), e.g., in phosphate content,but all occurrences are connected with high salinity(expressed sometimes in conductivity, chloride contentor TDS). Laguna Blanca can also be characterized as a

Dow

nloa

ded

by [

Mem

oria

l Uni

vers

ity o

f N

ewfo

undl

and]

at 1

6:59

08

Nov

embe

r 20

13

204 Ács et al.

Figs 22–29. Amphora micrometra from Laguna Blanca, internal views (Figs 22–26) and girdle views (Figs 27–29), SEM. Figs 22–23.Whole valve. Figs 24–25. Distal raphe ending, showing the internal opening of the portula (arrow). Fig. 26. Proximal raphe endings.Figs 27, 29. Whole frustules. Note open girdle bands in Fig. 27. Fig. 28. Girdle bands with a double row of poroids. Scale bars = 2.5 μm(Fig. 27); 2 μm (Figs 22–23, 29); 1 μm (Figs 24, 28); 500 nm (Figs 25–26).

Dow

nloa

ded

by [

Mem

oria

l Uni

vers

ity o

f N

ewfo

undl

and]

at 1

6:59

08

Nov

embe

r 20

13

Morphology of Amphora micrometra Giffen 205

Figs 30–35. Giffen’s raw type material of Amphora micrometra from sample KB 210. Figs 30–31. Internal view of the whole valve.Fig. 32. Internal view of proximal raphe endings. Fig. 33. Internal view of distal raphe ending with portula-like structure (arrow). Fig. 34.External view of the whole valve. Fig. 35. External view of proximal raphe endings. Scale bars = 2.5 μm (Fig. 30); 2 μm (Figs 31, 34);500 nm (Figs 32–33, 35).

high-salinity environment as mentioned in the Material andmethods.

DiscussionUsing striae density on the dorsal side of the valvesseems to be an unreliable character for the identification of

A. micrometra, because all studies report a wide variabilityeven for single populations (Table 2). This variability canbe due to the difficulty in counting exactly the number ofstriae in 10 μm under LM. Even at the electron microscopylevel, the estimation of the stria density is difficult due tothe small size of the valves. Schoeman & Archibald (1986)

Dow

nloa

ded

by [

Mem

oria

l Uni

vers

ity o

f N

ewfo

undl

and]

at 1

6:59

08

Nov

embe

r 20

13

206 Ács et al.

Figs 36–39. Amphora micrometra, TEM. Fig. 36. Median part of broken valve. Fig. 37. Detail of striae. Fig. 38. Whole valve showingportula (arrow) from Archibald (1983). Fig. 39. Detail of the central part of the valve from Archibald (1983). Scale bars = 1 μm.

Dow

nloa

ded

by [

Mem

oria

l Uni

vers

ity o

f N

ewfo

undl

and]

at 1

6:59

08

Nov

embe

r 20

13

Morphology of Amphora micrometra Giffen 207

Fig. 40. Worldwide geographic distribution of Amphora micrometra. Dots show occurrences according to the literature and this study.

also found some discrepancies in the striae counts duringthe study on Amphora species in the collection of the BritishMuseum.

Thus far, no species of Amphora sensu lato has beenshown to possess a portula-like opening (Levkov 2009).Among the amphoroid group, the genus Eunophora Vyver-man, Sabbe & D.G. Mann is characterised by two large,elongate, sessile and polar rimoportulae per valve, whichare located at the poles and are labiate, non-cylindricalas in A. micrometra (Levkov 2009). Several araphid (e.g.,Asterionella Hassall, Diatoma Bory, Fragilaria Lyngbye,Meridion C. Agardh, Tabellaria (Kützing) Williams &

Round) and raphid (e.g., Actinella F.W. Lewis, Euno-tia Ehrenberg, Peronia Brébisson) diatom genera haverimoportula, but all of them have internal labia (see theultrastructure of these genera in, for example, Round et al.1990). The opening of the portula in A. micrometra resem-bles a stigma. For example, species in Luticola D.G. Mannhave similar stigmata, but internally they show a curved,lipped slit and externally a simple round pore. Severalother pennate diatoms have one poroid-like stigma (e.g.,Encyonema Kützing, Gomphocymbella O.F. Müller, Gom-phonema Ehrenberg, Reimeria Kociolek & Stoermer) orseveral stigmata (Cymbella C. Agardh, Didymosphenia

Dow

nloa

ded

by [

Mem

oria

l Uni

vers

ity o

f N

ewfo

undl

and]

at 1

6:59

08

Nov

embe

r 20

13

208 Ács et al.

Tab

le2.

Com

pari

son

ofse

lect

edch

arac

ters

ofA

mph

ora

mic

rom

etra

inth

elit

erat

ure

and

pres

ents

tudy

.

Len

gth

Wid

thD

orsa

lstr

iae

Ven

tral

stri

aeB

and

areo

lae

Ref

eren

ces

(μm

)(μ

m)

in10

μm

in10

μm

in10

μm

Dis

trib

utio

n

Giff

en(1

967)

7–8

5(2

.5)

27a

27a

n.d.

Kid

d’s

Bea

chN

earE

astL

ondo

n,C

ape

Prov

ince

,Sou

thA

fric

aA

rchi

bald

(198

3)8–

141.

7–2.

558

66n.

d.Su

nday

sR

iver

Eas

tern

Cap

ePr

ovin

ce,

Sout

hA

fric

aPi

irso

o(1

995)

4.5–

122–

360

–65

65–7

0n.

d.B

altic

Sea

Witk

owsk

iet

al.(

2000

)7–

85

(2.5

)U

pto

60U

pto

60n.

d.B

altic

Sea

Kar

ayev

a&

Muk

htar

ova

(198

7)10

–12

264

b72

bn.

d.C

aspi

anSe

aK

uyle

nstie

rna

(198

9–19

90)

81.

658

72n.

d.N

ordr

eÄ

lvE

stua

ryT

his

stud

y7–

122–

2.5

44–5

250

–68

54–7

0L

agun

aB

lanc

a(B

oliv

ia)

Raw

type

mat

eria

lillu

stra

ted

72

6060

n.d.

inth

epr

esen

tstu

dy

Not

e:a In

the

orig

inal

desc

ript

ion

Giff

en(1

967)

did

notg

ive

stri

aede

nsity

,but

ina

late

rpub

licat

ion

(Giff

en19

73)h

ere

port

edag

ain

this

spec

ies

and

gave

the

anno

tate

dst

ria

dens

ity.

b InK

aray

eva

&M

ukht

arov

a(1

987)

55–6

0st

riae

in10

μm

isw

ritte

n(n

otse

para

ting

the

vent

rala

nddo

rsal

stri

ade

nsity

).n.

d.,n

oda

ta.

M. Schmidt, Gomphoneis Cleve), but the position of thesestructures is near to the proximal raphe endings, never in adistal position (see Round et al. 1990).

Lunella bisecta Snoeijs is another species with smallvalves and high striae density (Snoeijs 1996). However,there are significant differences in almost all ultrastructuralfeatures with A. micrometra. In Lunella Snoeijs, the frus-tules are rectangular in girdle view due to the equal sizeof the dorsal and ventral girdle bands. The valve face inL. bisecta is flat without strongly developed costae. Thedistal raphe ends are slightly deflected towards the ventralside and do not continue onto the valve mantle. Inter-nally, the proximal raphe ends do not terminate in thetongue-like extension at the central nodule, and the striaeare composed of small round areolae as opposed to themacroareolae occluded by a perforated hymen as it happensin A. micrometra.

Amphora micrometra resembles Catenula adherensMereschkowsky, but the latter is characterised by rectan-gular frustules, non-porous girdle bands, flat valve face,filled-in striae composed of occluded areolae in the valveface and open only in the valve mantle (due to the colonialhabit of this diatom). Catenula adherens also has a simpleraphe with distantly spaced proximal fissures, and straightdistal fissures with prominent helictoglossae (Round et al.1990).

Amphora micrometra also appears similar to the taxondepicted by Rumrich et al. (2000, pl. 123, figs 15–18),but the latter has lower striae density and clearly visibledorsal striae. The valve depicted on pl. 123, fig. 15 inRumrich et al. (2000) represents an initial valve withoutvisible striation. Such a feature is typical for species relatedto Halamphora veneta (Kützing) Levkov (Lange-Bertalotet al. 2003, Levkov 2009).

Amphora micrometra clearly belongs to Amphorasensu lato (Kützing 1844) because most of the charac-ters are in agreement with other species currently ascribedto this group. In 1895, Cleve described nine subgenera(Amblyamphora, Amphora, Archiamphora, Calamphora,Cymbamphora, Diplamphora, Halamphora, Oxyamphoraand Psammamphora) based on frustule and valve out-line, girdle band striation, raphe position and striatype. Cleve-Euler (1953) distinguished only seven sub-genera, differentiating them into two large sets basedon presence (Amblyamphora, Diplamphora, Halamphora,Oxyamphora) or absence (Amphora, Cymbamphora andPsammamphora) of copulae. Nagumo (2003) agrees thatthe subgenus Amphora can be distinguished from the othersubgenera by the absence of intercalary bands in the girdle;however, the girdle is not ornamented with puncta, lines ordashes in this subgenus. Later, Levkov (2009), making anextensive revision of several species, stated that Amphorasensu stricto usually has three copulae. Amphora microme-tra has more than three girdle elements and they bear tworows of well-defined areolae. Another important difference

Dow

nloa

ded

by [

Mem

oria

l Uni

vers

ity o

f N

ewfo

undl

and]

at 1

6:59

08

Nov

embe

r 20

13

Morphology

ofAm

phoram

icrometra

Giffen

209

Table 3. Main characteristics of recent subgenera of Amphora genus (according to Cleve 1895, Cleve-Euler 1953 and Levkov 2009) and A. micrometra.

AmphoraAmphora Halamphora Oxyamphora Diplamphora Psammamphora Amblyamphora Cymbamphora Calamphora Colliculoamphora Eunophora micrometra

Valve shape Elliptical,linear, semi-lanceolate

Elliptical tolanceolate

Broadly elliptical,lunate

Linear, semi-lanceolate tosemi-elliptical

Linear, semi-lanceolate tosemi-elliptical

Linear, semi-lanceolate tosemi-elliptical

Narrowelongated,semi-lanceolate

Linear Linear Linear to semi-elliptical

Elliptical

Number ofcopulae

Usually 3 Numerous Numerous Numerous Usually 3 Numerous Usually 3 n/a Shallow, nomore than 3

n/a Numerous

Structure ofcopulae

Absence or singlerow of roundporoids

1 or 2 rows ofround poroids

Punctuated n/a n/a n/a n/a n/a Rows of simplepores

n/a 2 rows of roundporoids

Valve ends Truncate orbroadlyrounded

Rostrate orcapitate

Truncate,frequentlyapiculate

Variable (shortlysubprotracted,narrowly tobroadly roundedand slightlyventrally bent)

Variable (shortlysubprotracted,obliquelyrounded andslightly ventrallybent)

Variable (shortlysubprotracted,obliquelyrounded andslightly ventrallybent)

Acute orsubacute

Rounded Broadlyrounded totruncate

Broadlyrounded totruncate

Broadly rounded

Raphe Biarcuate Straight orslightly curvednear the valvemargin

Straight or slightlycurved near thevalve margin orbiarcuate

Strongly ormoderatebiarcuate

Strongly ormoderatebiarcuate

Strongly ormoderatebiarcuate

Straight Biarcuate Straight Biarcuateor nearlystraight

Straight

Raphe ledge(conopeum)

Present (raisedabove the restof the valveon dorsal andventral side)

Partial conopeum(raised abovethe rest of thevalve on dorsalside)

n/a Present (stronglythickened)

n/a n/a n/a n/a n/a n/a Absent

Stauros Absent (some-timespresent)

Absent (some-timespresent)

Present (sometimesabsent)

Absent Present (sometimesabsent)

Present (sometimesabsent)

n/a n/a Ill defined Present Absent

Striae Uniseriate, roundor elliptical totransversallyelongateareolae

Uniseriate orbiseriate, roundelliptical totransversallyelongatedareolae

Uniseriate, roundto elongateareolae

Uniseriate,coarse roundor elongatedslit-like areolae

Uniseriate, smallcircular poroids

Uniseriate, smallcircular poroids

n/a n/a Uniseriate,regular atmargin,scattered andirregular atcentre

Uniseriate,smallcircularporoids

Uniseriate, smallround areolae

(Continued)

Dow

nloa

ded

by [

Mem

oria

l Uni

vers

ity o

f N

ewfo

undl

and]

at 1

6:59

08

Nov

embe

r 20

13

210Á

csetal.

Table 3. Continued.

AmphoraAmphora Halamphora Oxyamphora Diplamphora Psammamphora Amblyamphora Cymbamphora Calamphora Colliculoamphora Eunophora micrometra

Areolae Occluded byvela

Occluded byhymenes

Not occluded Not occluded Not occluded(or some-timesoccluded byvela)

Not occluded(or sometimesoccluded byvela)

n/a n/a n/a Occluded byvela

Occluded byhymenes

External distalraphe ends

Dorsallydeflected

Dorsallydeflected

Dorsallydeflectedacc. toEdlund et al.(2009) andventrallydeflectedacc. toCleve-Euler(1953)

Dorsallydeflected

Dorsallydeflected

Ventrally deflected Ventrallydeflected

n/a Ventrallydeflected

Dorsallydeflected

Dorsally deflected

Externalproximalraphe ends

Straight orventrallydeflected

Straight orventrallydeflected

n/a Straight orstronglydorsallydeflected

n/a n/a n/a n/a n/a Straight Straight

Internal distalraphe ends

Poorlydevelopedhelictoglossae

Poorlydevelopedhelictoglossae

Fullydevelopedhelictoglossae

Poorlydevelopedhelictoglossae

Fullydevelopedhelictoglossae

Fully developedhelictoglossae

n/a n/a n/a Poorlydevelopedhelictoglossae

Poorly developedhelictoglossae

Internalproximalraphe ends(centralhelictoglossae)

Separately Fused inone solidstructure(tongue-likeextensions),except inA. chilensis(Sala et al.2006)

Lack oftongue-likeextensions

Simple Simple Simple n/a n/a Small Asymmetrical,central helic-toglossaeabsent

Fused in onesolid structure(tongue-likeextensions)

Rimoportula Absent Absent Absent Absent Absent Absent n/a n/a Absent 2 Portula-likeExternal

opening ofrimoportulaor portula-likestructure

n.d. n.d. n.d. n.d. n.d. n.d. n/a n/a n.d. Large,elongate,sessile

Simple roundpores

Internalopening ofrimoportulaor portula-likestructure

n.d. n.d. n.d. n.d. n.d. n.d. n/a n/a n.d. Circular,rimmed orsimple

Cylindrical

Habitat Freshwater tomarine

Freshwater tomarine

Marine Brackish andmarine

Freshwater tomarine

Freshwater tomarine

Marine n/a Marine Freshwater Brackish tomarine

Note: n.d., no data; n/a.

Dow

nloa

ded

by [

Mem

oria

l Uni

vers

ity o

f N

ewfo

undl

and]

at 1

6:59

08

Nov

embe

r 20

13

Morphology of Amphora micrometra Giffen 211

is that Amphora sensu stricto has separated or proximalhelictoglossae, whereas A. micrometra has a single fusedsolid structure (tongue-like extension), which is character-istic of species in Halamphora, but the latter lack portulaeof any kind.

The areolar structure can be seen with SEM only athigh magnifications, although pictures are not always clear,whereas at the TEM level, even the porous hymenes canbe appreciated. The arrangement of the small pores on thehymen is rather haphazard. This characteristic resemblesthat presented by Archibald (1983, pl. 24, figs 497–499as A. coffeaeformis (C. Agardh) Kützing now Halam-phora coffeaeformis (C. Agardh) Levkov). The uniseriatestriae internally seen as a large, elongated areola are some-times present in the genus Halamphora (Cleve) Levkov,e.g., in H. hybrida (Grunow) Levkov, but the latter has asingle longitudinal line near the dorsal valve margin inter-rupting the dorsal striae (Schoeman & Archibald 1984,Levkov 2009).

In relation to the subgenera differentiated by Cleve(1895) as having copulae, A. micrometra resembles morespecies in Oxyamphora and Halamphora. However, repre-sentatives of Oxyamphora bear a dorsal stauros (Levkov2009) structure that is not observed in A. micrometra withSEM. The internal proximal raphe ends of Oxyamphoraare simple, do not have tongue-like extensions, whereasA. micrometra does. The internal distal raphe ends ofOxyamphora have fully developed helictoglossae, whereasA. micrometra has poorly developed ones. Additional dif-ferences among A. micrometra and subgenera of Amphorasensu lato can be seen in Table 3.

As stated before, some characteristics of A. micrometrafit into Halamphora. Levkov (2009) raised Halamphorato the level of genus arguing that species associated toit have a unique combination of characters not present inother groups of Amphora sensu lato. Sar (2010) criticisedthis change arguing that the limits between Halamphora,Amphora sensu stricto and Amphora sensu lato have notbeen established with sufficient precision.

Although the present analysis of A. micrometra expandsthe knowledge of this taxon, its placement at the genus level(following the current classification of Levkov (2009)) can-not be determined satisfactorily. Therefore and until moredata are accumulated on additional taxa with similar char-acteristics, we prefer to leave A. micrometra in its currenttaxonomic position, but to emend its protologue to includethe observations presented herein.

AcknowledgementsThe authors thank Johan van der Molen, Curator of CSIR diatomcollection (KwaZulu-Natal, Regional office in Durban, SouthAfrica), for M.N. Giffen type slide and raw material of theSouth African Diatom Collection, Katarina Caput (Departmentof Molecular Biology, Faculty of Sciences, University of Zagreb,Croatia) for TEM micrographs, Mike Amspoker and an unknownreferee for the correction of the manuscript. The 2002 expedition

to Bolivia was funded by the NASA Ames Research Center (ARC)Directorate Discretionary Funds and supported by the ARC SpaceScience Division. The authors thank Nathalie A. Cabrol (Expe-dition Leader) for the possibility to participate on the expeditionand the use of the chemical data presented herein.

ReferencesAmspoker M.C. & McIntire C.D. 1986. Effects of sed-

imentary processes and salinity on the diatom floraof the Columbia River Estuary. Botanica Marina 29:391–399.

Anonymous. 1975. Proposals for a standardization of diatom ter-minology and diagnoses. Beihefte zur Nova Hedwigia 53:323–354.

Archibald R.E.M. 1983. The diatoms of the Sundays and GreatFish Rivers in the Eastern Cape Province of South Africa.Bibliotheca Diatomologica 1: 1–362.

Bukhtiyarova L.N. 2006. Additional data on the diatom genusKarayevia and a proposal to reject the genus Kolbesia. NovaHedwigia, Beiheft 130: 85–96.

Cabrol N.A., McKay C.P., Grin E.A., Kiss K.T., Ács E., Tóth

B., Grigorszky I., Szabó K.É., Fike D.A., Hock A.N.,Demergasso C., Escudero L., Galleguillos P., Chong G.,Grigsby B.H., Román J.Z. & Tambley C. 2007. Signa-tures of habitats and life in Earth’s high-altitude lakes: cluesto Noachian aqueous environments on Mars. In: The geol-ogy of Mars. Evidence from Earth-based analogs (Ed. byM. Chapman), pp. 349–370. Cambridge University Press,Cambridge.

CEN. 2003. Water quality – guidance standard for the routine sam-pling and pretreatment of benthic diatoms from rivers. EN13946: 2003. Comité Européen de Normalisation, Brussels.14 pp.

Cleve P.T. 1895. Synopsis of the naviculoid diatoms. Part II.Kongliga Svenska-Vetenskaps Akademiens Handlingar 27:1–219.

Cleve-Euler A. 1953. Die Diatomeen von Schweden und Finn-land. Part III, Euraphideae. Kongliga Svenska Vetenskaps-Akademiens Handligar 4: 1–240.

Edlund M.B., Shinneman L.C.A. & Levkov Z. 2009. Diatom bio-diversity in Mongolia: a new amphoroid diatom from salinelakes in western Mongolia, Amphora soninkhishigae sp. nov.Acta Botanica Croatica 68: 251–262.

Gasse F., Juggins S. & Khelifa L.B. 1995. Diatom-based trans-fer functions for inferring past hydrochemical characteris-tics of African lakes. Palaeogeography, Palaeoclimatology,Palaeoecology 117: 31–54.

Gell P.A. 1997. The development of a diatom database forinferring lake salinity, Western Victoria, Australia: towardsa quantitative approach for reconstructing past climates.Australian Journal of Botany 45: 389–423.

Gell P.A., Sluiter I.R. & Fluin J. 2002. Seasonal and inter-annual variations in diatom assemblages in Murray Riverconnected wetlands in north-west Victoria, Australia. Marineand Freshwater Research 53: 981–992.

Gibson J.A.E., Roberts D. & Van de Vijver B. 2006.Salinity control of the distribution of diatoms in lakesof the Bunger Hills, East Antarctica. Polar Biology 29:694–704.

Dow

nloa

ded

by [

Mem

oria

l Uni

vers

ity o

f N

ewfo

undl

and]

at 1

6:59

08

Nov

embe

r 20

13

212 Ács et al.

Giffen M.N. 1967. Contributions of the diatom flora of SouthAfrica. III. Diatoms of the marine littoral regions at Kidd’sBeach near East London, Cape Province, South Africa. NovaHedwigia 13: 245–293.

Giffen M.N. 1973. Diatoms of the marine littoral of Steen-berg’s Cove in St. Helena Bay Cape Provence, South Africa.Botanica Marina 16: 32–48.

Karayeva N.I. & Mukhtarova S.H.J. 1987. Redkie dlia SSSR inovye vidy pennatnykh diatomovykh vodoroslei (Bacillario-phyta) iz Azerbaidzhana [Rare for the USSR and new speciesof the pennate diatoms (Bacillariophyta) from Azerbaijan].Botanicheskii Zhurnal 72: 943–947.

Kützing F.T. 1844. Die Kieselschaligen. Bacillarien oderDiatomeen. W. Khöne, Nordhausen. 152 pp.

Kuylenstierna M. 1989–1990. Benthic algal vegetation in theNorde Älv estuary (Swedish west coast). Doctoral Thesis,University of Göteborg. 244 pp., 76 pls.

Lange-Bertalot H., Cavacini P., Tagliaventi N. & Alfinito

S. 2003. Diatoms of Sardinia. Rare and 76 new speciesin rock pools and other ephemeral waters. IconographiaDiatomologica 12: 1–438.

Laslandes B. 2007. Reconstitution de la variabilité climatiquedu littoral Fluminense (Rio de Janeiro, Brésil) au coursde l’Holocène par l’étude de bio-indicateurs (Diatomées,Coccolithophoridés). PhD Thesis, Université d’Angers. 251pp.

Levkov Z. 2009. Amphora sensu lato. In: Diatoms of Europe (Ed.by H. Lange-Bertalot), Volume 5. A.R.G. Gantner VerlagK.G., Ruggell. 916 pp.

Nagumo T. 2003. Taxonomic studies of the subgenus AmphoraCleve of the genus Amphora (Bacillariophyceae) in Japan.Bibliotheca Diatomologica 49: 1–265.

Piirsoo K. 1995. Amphora micrometra Giffen. In: Intercalibrationand distribution of diatom species in the Baltic Sea (Ed. by

P. Snoeijs & M. Potapova), Volume 3. Opulus Press, Uppsala.126 pp.

Round F.E., Crawford R.M. & Mann D.G. 1990. The diatoms.Biology and morphology of the genera. Cambridge Univer-sity Press, Cambridge. 747 pp.

Rumrich U., Lange-Bertalot H. & Rumrich M. 2000.Diatomeen der Anden von Venezuela bis Patagonien/

Feuerland und zwei weitere Beiträge. Iconographia Diato-mologica 9: 1–673.

Sala S.E., Sar E.A., Hinz F. & Sunesen I. 2006. Studieson Amphora subgenus Halamphora (Bacillariophyta): therevision of some species described by Hustedt using typematerial. European Journal of Phycology 41: 155–167.

Sar E. 2010. Book reviews. Diatom Research 25: 227–228.Schoeman F.R. & Archibald R.E.M. 1984. Amphora castellata

Giffen as observed with the light and electron microscopes.Bacillaria 7: 111–134.

Schoeman F.R. & Archibald R.E.M. 1986. Observation onAmphora species (Bacillariophyceae) in the British Museum(Natural History). Nova Hedwigia 43: 113–127.

Snoeijs P. 1996. The establishment of Lunella gen. nov. (Bacil-lariophyta). Diatom Research 11: 143–154.

Trobajo Pujadas R. 2007. Ecological analysis of periphyticdiatoms in Mediterranean coastal wetlands (Empordà wet-lands, NE Spain). Diatom Monographs 7: 1–210.

van Ee G. & Houdijk A. 2006. Referentiewaarden voor Aquatis-che Systemen in Noord-Holland. Provincie Noord-Holland,Haarlem. 180 pp.

Witkowski A., Lange-Bertalot H. & Metzeltin D. 2000.Diatom flora of marine coasts I. Iconographia Diatomologica7: 1–925.

Zimba P.V., Sullivan M.J. & Glover H.E. 1990. Carbon fixationin cultured marine benthic diatoms. Journal of Phycology 26:306–311.

Dow

nloa

ded

by [

Mem

oria

l Uni

vers

ity o

f N

ewfo

undl

and]

at 1

6:59

08

Nov

embe

r 20

13