Search

During a survey of diatoms present in tidal pools on the coasts of Livingston Island (South Shetland Islands), we found several populations, belonging presumably to the Antarctic endemic Craspedostauros laevissimus. Further analyses using light microscopy revealed that the populations show differences in stria density. Following scanning electron microscopy observations, only part of the investigated populations could be assigned to C. laevissimus, whereas the others are sufficiently morphologically different based on stria density and their cribrate areolae structure to be described as a new species: Craspedostauros confusus sp. nov. The new taxon is compared with known, morphologically similar, Craspedostauros taxa. The paper presents morphological and ecological data for both taxa discussed in the study. A detailed survey of the early Antarctic literature showed that the Craspedostauros taxa in Antarctica have convoluted taxonomic histories and that the new taxon has likely been hidden for long within the variability of C. laevissimus.

Craspedostauros laevissimus (West & G.S.West 9: 8) Sabbe (00: 5) (Figs – 8, 7, 9– 7, 80–85) LM observations (Figs – 8, 7, 80–85):— Frustules rectangular, lanceolate in girdle view with weakly convex margins (Figs 7, 8), constricted in the middle (i.e. biarcuate), with numerous copulae (Fig. 18). Longest valves linear (Figs 80, 83, 85), linear-lanceolate, smaller valves becoming elliptic-lanceolate (Figs 4, 13, 15, 27). Apices broadly rounded (Figs 4, 15, 27), to almost cuneate (Figs 2, 3, 13). Valve margins in the middle ranging from occasionally almost straight (Fig. 83) to, usually, weakly (Figs 3, 5) to moderately (Figs 4, 9) convex. Valve dimensions (n = 26): valve length 20–42 µm, valve width 4.5–7.0 µm. Occasionally, weakly silicified valves, probably in state of formation, and easily “squashed” on the slides, appear to have a larger valve width (see for instance Figs 81, 82, 84). Axial area very narrow, linear. Central area variable in size, from very narrow (Figs 9, 11), almost rectangular (Figs 3, 16) to bow-tie-shaped fascia, widening towards the margin (Figs 2, 4, 5, 27). Raphe filiform, slightly curved to straight, with enlarged central raphe endings, and elongated, unilaterally bent, terminal raphe fissures. Striae fine, parallel, occasionally very weakly radiate in the middle, 28–30(32) in 10 µm. Areolae not or occasionally slightly individually discernible in LM. SEM observations (Figs 9– 7, 86–87):— Externally, valve face curving into a deep mantle (Figs 29, 38). Raphe almost straight (Figs 29, 32, 36, 39) or sometimes weakly undulating (Fig. 35). Central raphe endings weakly curved and enlarged (Figs 29–30, 32–33, 35, 37), occasionally straight and only weakly expanded (Figs 39–40). At the apices, axial area triangularly widening, forming a silica flap (Figs 38, 41) on one side covering the terminal raphe fissures. Fissures continuing shortly onto the mantle (Figs 31, 34, 35, 38, 39, 41), clearly unilaterally bent (Figs 35, 36) to weakly hooked (Fig. 38). Striae uniseriate, composed of cribrate areolae of almost equal size (Figs 30, 35, 39, 40, 45) to slightly larger near the axial area (Figs 37, 40, 41). Larger areolae, apparently formed by merging two adjacent areolae occasionally present near the axial area (Figs 31, 87, arrows). Areolae continuing around the apices (Figs 31, 34, 38). Cribra composed of usually four (Figs 34, 37, 40, 42), rarely five (Figs 33, 34, 40) peripheral pores, although very rarely, up to 6–7 very small peripheral pores were observed (Fig. 41), or very occasionally only 1–3 (Fig. 45). In general, areolae near the axial area more complex, with more peripheral pores, whereas areolae on the rest of the valve face simplified having a lower number of peripheral pores (Figs 40, 45). Central cribrum pores usually single or absent (Figs 30, 37, 40), occasionally 2–3 (Figs 31, 33, 34, 41). Areolae uniformly distributed over the valve face, ca. 40 in 10 µm. Internally, areolar openings square to rectangular (Figs 46, 47), to almost rounded (Figs 43, 45). Internal raphe branches straight, located on a distinctly raised sternum. Central raphe endings terminating onto double helictoglossae (Figs 43, 45, 46). Stauros narrow, located on a wider hyaline fascia (Figs 43–46). Terminal raphe endings finish onto broad helictoglossae (Figs 46, 47). Ecology and associated diatom flora:— The species was often found in the epilithon of tidal pools at Hannah Point (samples 11 and 13, and LT10), having variable salinity levels between 11.5 and 33.7 (Table 2), but it was most abundant in sample 13. The diatom flora of this sample included Melosira spp. and several unidentified Navicula taxa in larger numbers., Published as part of Zidarova, Ralitsa, Haan, Myriam De, Ivanov, Plamen, Hineva, Elitsa & Vijver, Bart Van De, 2022, The genus Craspedostauros E. J. Cox (Bacillariophyta) on the coasts of Livingston Island, Maritime Antarctica, pp. 1-24 in Phytotaxa 572 (1) on pages 4-7, DOI: 10.11646/phytotaxa.572.1.1, http://zenodo.org/record/7305672

Craspedostauros confusus Zidarova, M.de Haan, P.Ivanov, Hineva & Van de Vijver sp. nov. (Figs 9– 6, 8, 8–56) Description LM observations (Figs 9– 6, 8):— Frustules lanceolate in girdle view with convex, rarely weakly constricted (and hence biarcuate) margins, bearing numerous copulae. Longer valves linear with broadly rounded apices (Fig. 19), becoming narrowly lanceolate to elliptic-lanceolate in smaller valves with more cuneately rounded (Figs 21, 22), sometimes almost subrostrate apices (Fig. 23). Valve margins weakly convex (Fig. 21) to almost straight in the middle (Figs 20, 22, 24), lacking any constriction. Valve dimensions (n = 16): length 22.0–49.5 µm, width 4.5–6.5 µm. [Valves (n = 27) observed in other populations on Livingston Island during the study (Figs 60–77, 79) had a valve length of 18–50 µm and a valve width of 4.0–6.5 µm]. Axial area very narrow, linear (Figs 19–24, 28). Central area narrow, forming an almost rectangular (Fig. 19) to bow-tie-shaped fascia (Figs 20–24, 28), widening towards the valve margins. Raphe filiform, straight (Fig. 19) to weakly undulating, with expanded central raphe endings, and elongated terminal raphe fissures, unilaterally weakly bent (Figs 21, 24, 28). Striae rather coarse, parallel to occasionally very weakly radiate in the middle (Fig. 22), parallel to very weakly convergent near the apices (Figs 19, 24), 22–24 in 10 µm. Areolae, at least the larger ones bordering the axial area, weakly discernible in LM (Fig. 19). SEM observations (Figs 8–56):— Valve face weakly domed, with a deep mantle (Figs 48–51). External raphe branches straight with weakly undulating (Fig. 49) to straight (Fig. 51) central raphe endings, terminating in drop-like expanded pores (Figs 49, 51). Terminal raphe fissures continuing shortly onto the mantle, unilaterally hooked (Figs 48, 51). Axial area triangularly expanded at the apices, bearing a silica flap on one side, covering the terminal raphe fissures (Fig. 50). Striae uniseriate, composed of cribrate, rounded to elliptic areolae. Near the raphe areolae clearly larger (Figs 49, 50 and Figs 88–90). Cribrum structure of the areolae bordering the axial area possessing four to seven peripheral pores, and two to three central pores. All other areolae with cribra composed of 2–5 peripheral pores, lacking central pores (Figs 49, 50). Areolae continuing around the apices (Figs 48, 50), ca. 25–30 in 10 µm. Internal areolar openings rounded to elliptic (Figs 53–56). Internal raphe straight, located on a distinct sternum (Figs 52, 53). Central raphe endings terminating onto double helictoglossae (Figs 53, 55). Terminal raphe endings finish onto broad helictoglossae. Stauros narrow, located on a wider hyaline fascia (Figs 52, 53, 55). Type:— ANTARCTICA. South Shetland Islands: Livingston Island, Hannah Point, sample 14 (62° 39’13” S, 60° 36’ 41” W), marine epilithon, R. Zidarova, 16th December 2018 (holotype BR-4760! = Fig. 28, isotype Slide 417! (University of Antwerp, Belgium)). Etymology:— The species epithet, confusus, Latin for confusing, reflects the complex taxonomic history of the genus Craspedostauros in the Antarctic Region, and the possible long-term inclusion of this species within the more common Antarctic species C. laevissimus. Ecology and associated diatom flora:— Craspedostauros confusus sp. nov. was found as abundant in the epilithon of several tidal pools at Hannah Point (sample 14, type), Mongolian (Reserve) Port (samples DNA5 and MO’), and Caleta Argentina (sample LT6). The salinity level in the pools (when measured) ranged between 33 and 35 PSU (Table 1), and their diatom flora was dominated by various species, including Navicula spp., Melosira spp., Parlibellus sp., Tabulariopsis australis (Peragallo 1921: 67) D.M. Williams (1988: 249) and Tripterion margaritae (Frenguelli & Orlando 1958: 98) L.F. Fernandes & Sar (2009: 67).

Luticola ivetana Chattová & Van de Vijver sp. nov. Figs 27‒43 Etymology The new species was named after Mrs. Iveta Chattová, mother of the first author, on the occasion of her 50th birthday. Type ILE AMSTERDAM: Entrecasteaux, TAAF, sub-Antarctica, 37°51′18.6″ S, 77°31′23.5″ W, 21 Dec. 2016, B. Van de Vijver sample W030 (holo-: slide no. BR‒4495, Fig. 27; iso-: slide PLP ‒330; University of Antwerp, Belgium). Description Light microscopy (Figs 27–36) Valves elliptic-lanceolate with convex margins and broadly rounded, non-protracted apices. Valve dimensions (n = 50): length 11.0‒25.5 µm, valve width 6.0‒7.5 µm. Axial area narrow, linear, almost not widening towards the apices and central area. Central area forming a bow-tie shaped stauros. One isolated pore present in the central area, positioned close to the valve centre. Raphe filiform, straight with weakly deflected simple proximal raphe endings and elongated terminal raphe fissures. Striae radiate throughout the entire valve, 16‒18 in 10 µm. Scanning electron microscopy (Figs 37–43) Striae composed of 2–4 round to elongated areolae, clearly enlarged near the central area and the valve margins (Figs 37, 43). Mantle areolae very large, rounded, never slitlike (Fig. 39). Central area bordered by 1–2 rounded to weakly transapically elongated areolae. Isolated pore elliptic, clearly isolated from the central striae (Fig. 38). Raphe branches straight with short proximal raphe endings bent towards the side with the isolated pore (Fig. 42). Terminal raphe fissures hooked, continuing onto the valve mantle (Fig. 41). Internally, poroids of valve face occluded by hymens forming a continuous strip on each stria. Distinct stauros visible. Internal proximal raphe endings straight, terminating on the edge of the stauros. Distal raphe endings terminating onto small helictoglossae (Fig. 40). Ecology and distribution So far, L. ivetana sp. nov. was observed on Ile Amsterdam only. The type locality where a large population of this new species was observed, was a small crack in a rock face at Entrecasteaux, clearly under the permanent influence of seaspray. A very thin film of water was present in the crack together with wet mud. The sample was taken by scraping off the mud and the water from the crack. Another large population where L. ivetana sp. nov. was found is a lava cavern in the partly collapsed Grand Tunnel, running from the Cratères Vénus to the northern coast. The sample was taken from wet mosses (F-value IV-V), growing on the wall of the cavern, close to the entrance, in a population of Blechnum australe L. The sample was dominated by Ferocia setosa (Greville) Van de Vijver & Houk (Van de Vijver et al. 2017), Orthoseira verleyenii Van de Vijver (Lowe et al. 2013), Sellaphora barae Van de Vijver & E.J.Cox (Van de Vijver & Cox 2013) and various Humidophila species.

Luticola beyensii Van de Vijver, Ledeganck & Lebouvier Figs 1���12 Diatom Research 17: 235���241 (Van de Vijver et al. 2002b). Type ILE SAINT PAUL: TAAF, sub-Antarctica, 16 Dec. 1999, B. Van de Vijver sample A9 (holo-: CAS 220051, California Academy of Science; iso-: slide no. BR ���4045, University of Antwerp, Belgium). Description Light microscopy (Figs 1���10) Valves rhombic-lanceolate with clearly convex margins. Larger individuals with more or less rostrate apices, in smaller specimens apices more broadly rounded. Valve dimensions (n = 25): length 14.5��� 22.0 ��m, width 6.0���8.5 ��m. Axial area relatively narrow, linear. Central area with a large fascia, rarely reaching the valve margins, due to a series of small areolae bordering the central area near the margins. Isolated pore solitary, round, located close to the valve margin, never connected to a stria. Raphe filiform, straight, with simple, bent proximal raphe endings, away from the isolated pore. Terminal raphe fissures clearly hooked. Striae weakly radiate near the central area, becoming more radiate towards the apices, 22���24 in 10 ��m. Areolae well visible in LM. Scanning electron microscopy (Figs 11���12) Striae composed of 2���4 rounded areolae (Figs 11���12). Occasionally areolae fused within one stria forming transapically enlarged areolae (Fig. 11). Terminal raphe fissures clearly hooked, first deflected towards the side opposite the isolated pore, then hooked into the other side, weakly continuing onto the valve mantle (Fig. 12). Ecology and associated diatom flora Luticola beyensii was found in relatively dry, bare soils and on dry mosses (F-value VII-VIII) on both islands. The samples with L. beyensii were dominated by several taxa of the genus Humidophila R.L.Lowe et al. [Humidophila contenta (Grunow) R.L. Lowe et al. (Lowe et al. 2014), Humidophila brekkaensis (J.B.Petersen) R. L. Lowe et al. (Lowe et al. 2014)], and Pinnularia borealis Ehrenb. (Ehrenberg 1843) and Hantzschia amphioxys (Ehrenb.) Grunow (Cleve & Grunow 1880)., Published as part of Chattov��, Barbora, Lebouvier, Marc, Haan, Myriam De & Vijver, Bart Van De, 2017, The genus Luticola (Bacillariophyta) on Ile Amsterdam and Ile Saint-Paul (Southern Indian Ocean) with the description of two new species, pp. 1-17 in European Journal of Taxonomy 387 on pages 3-5, DOI: 10.5852/ejt.2017.387, http://zenodo.org/record/1133653, {"references":["Van de Vijver B., Ledeganck P. & Lebouvier M. 2002 b. Luticola beyensii sp. nov., a new aerophilous diatom from ile Saint Paul (Indian Ocean, TAAF). Diatom Research 17: 235 - 241. https: // doi. org / 10.1080 / 0269249 X. 2002.9705541","Lowe R. L., Kociolek J. P., Johansen J. R., Van de Vijver B., Lange-Bertalot H. & Kopalova K. 2014. Humidophila gen. nov., a new genus for a group of diatoms (Bacillariophyta) formerly within the genus Diadesmis: species from Hawai'i, including one new species. Diatom Research 29: 351 - 360. https: // doi. org / 10.1080 / 0269249 X. 2014.889039","Ehrenberg C. G. 1843. Verbreitung und Einfluss des mikroskopischen Lebens in Sud-und Nord-Amerika. Abhandlungen der Koniglichen Akademie der Wissenschaften zu Berlin 1841: 291 - 466.","Cleve P. T. & Grunow A. 1880. Beitrage zur Kenntniss der arctischen Diatomeen. Kongliga Svenska Vetenskaps-Akademiens Handlingar ser. 4 17 (2): 1 - 121."]}

Luticola vancampiana Chattov�� & Van de Vijver sp. nov. Figs 44���71 Etymology The species is named after Prof. Dr. Karel Van Camp (University of Antwerp, Belgium), to thank him for his efforts in conserving the Van Heurck Collection and his broad interest in diatom research. Type ILE SAINT-PAUL: Conserverie, TAAF, sub-Antarctica, 38��42���52.0��� S, 77��31���55.5��� W, 24 Nov. 2016, B. Van de Vijver sample S029 (holo-: slide no. BR���4496, Fig. 47; iso-: slide PLP���331; University of Antwerp, Belgium). Description Light microscopy (Figs 44���67) Valves linear-lanceolate to elliptic-lanceolate, elliptic in the smallest specimens, with protracted, subcapitate to rostrate apices. In smaller specimens, valve ends not as protracted, only subrostrate or obtusely rounded. Initial cells rhombic-lanceolate. Valve dimensions (n = 35): length 10.0���26.0 ��m, width 5.0���8.5 ��m. Axial area linear, narrow. Single, rounded isolated pore present in the central area, located halfway between the valve centre and margin, sometimes attached to a stria. Central area wide, bow���tie shaped, bordered on both sides with a series of 3���5 round areolae. Raphe branches straight, Figs 44���71. Luticola vancampiana Chattov�� & Van de Vijver sp. nov. Light (LM) and scanning electron micrographs (SEM) from the type population from Conserverie on Ile Saint-Paul, B. Van de Vijver sample S029. 44���67. LM showing the variation in size and shape of the valve apices. 68���69. SEM of valve exterior. 70. SEM of valve interior. 71. SEM girdle view. Scale bars: 44���67 10 ��m; 68���71 = 5 ��m. deflected away from the isolated pore at both proximal and distal ends. Transapical striae radiate throughout, 16���19 in 10 ��m. Scanning electron microscopy (Figs 68���71) Valve mantle with a single row of round areolae (Fig. 71), interrupted at the apices. Striae composed of 3���4 areolae, 1���2 areolae at the apices. Areolae round to elongated, clearly enlarged and prolonged close to the valve margins (Fig. 68). Internally, areolae occluded by hymens, forming a continuous strip across the valve (Fig. 70). Isolated pore showing an elliptic external opening. Internally, central nodule thickened, expanding into stauros. Isolated pore with semi-lunar opening formed by tonguelike structure. Raphe branches straight. Proximal raphe endings short, deflected to side opposite to the isolated pore. Terminal raphe fissures deflected to the same side as the proximal endings, not extending onto the mantle (Fig. 69). Internally, proximal raphe endings straight, while distally, raphe branches terminating on small helictoglossae. Ecology and distribution So far L. vancampiana sp. nov. was found on both IleAmsterdam and Ile Saint-Paul.The largest population was found in a wet soil covered by green algae close to the ocean on Ile Saint-Paul. The sampling site is frequently visited by fur seals and penguins, as was visible in the macroremains (feathers, excrements). The sample was almost entirely dominated by the new Luticola species. Other (smaller) populations were found in soil samples collected near penguin rookeries where similar conditions (considerable biotic influence, considerable salinity input) prevailed., Published as part of Chattov��, Barbora, Lebouvier, Marc, Haan, Myriam De & Vijver, Bart Van De, 2017, The genus Luticola (Bacillariophyta) on Ile Amsterdam and Ile Saint-Paul (Southern Indian Ocean) with the description of two new species, pp. 1-17 in European Journal of Taxonomy 387 on pages 8-10, DOI: 10.5852/ejt.2017.387, http://zenodo.org/record/1133653

Luticola sp. Figs 72‒82 Description Light microscopy (Figs 72–82) Valves linear-lanceolate to elliptic-lanceolate in smaller specimens, with rounded, non-protracted apices. Valve dimensions (n = 12): length 10.7‒20.5 µm, width 4.5‒6.5 µm. Axial area narrow, linear. Central area wide, bow-tie shaped, clearly asymmetrical with the side bearing the isolated pore markedly wider. Isolated pore present in the central area, located halfway between the valve centre and margin. Raphe branches straight, deflected away from the isolated pore at both proximal and distal ends. Transapical striae punctate, radiate throughout the entire valve, 20‒24 in 10 µm. Remarks So far, this species has only been observed with light microscopy. Further studies and SEM observations will be necessary to determine its correct taxonomic position. The species was so far found in only two soil samples (A6 and A7) taken from Ile Saint-Paul. Both samples are dominated by L. beyensii, Humidophila brekkaensis, Pinnularia acidicola Van de Vijver & Le Cohu (Van de Vijver et al. 2002 a) and Hantzschia amphioxys.

Luticola vancampiana Chattová & Van de Vijver sp. nov. Figs 44‒71 Etymology The species is named after Prof. Dr. Karel Van Camp (University of Antwerp, Belgium), to thank him for his efforts in conserving the Van Heurck Collection and his broad interest in diatom research. Type ILE SAINT-PAUL: Conserverie, TAAF, sub-Antarctica, 38°42′52.0″ S, 77°31′55.5″ W, 24 Nov. 2016, B. Van de Vijver sample S029 (holo-: slide no. BR‒4496, Fig. 47; iso-: slide PLP‒331; University of Antwerp, Belgium). Description Light microscopy (Figs 44–67) Valves linear-lanceolate to elliptic-lanceolate, elliptic in the smallest specimens, with protracted, subcapitate to rostrate apices. In smaller specimens, valve ends not as protracted, only subrostrate or obtusely rounded. Initial cells rhombic-lanceolate. Valve dimensions (n = 35): length 10.0‒26.0 μm, width 5.0‒8.5 μm. Axial area linear, narrow. Single, rounded isolated pore present in the central area, located halfway between the valve centre and margin, sometimes attached to a stria. Central area wide, bow–tie shaped, bordered on both sides with a series of 3–5 round areolae. Raphe branches straight, Figs 44–71. Luticola vancampiana Chattová & Van de Vijver sp. nov. Light (LM) and scanning electron micrographs (SEM) from the type population from Conserverie on Ile Saint-Paul, B. Van de Vijver sample S029. 44–67. LM showing the variation in size and shape of the valve apices. 68–69. SEM of valve exterior. 70. SEM of valve interior. 71. SEM girdle view. Scale bars: 44–67 10 µm; 68‒71 = 5 µm. deflected away from the isolated pore at both proximal and distal ends. Transapical striae radiate throughout, 16‒19 in 10 µm. Scanning electron microscopy (Figs 68–71) Valve mantle with a single row of round areolae (Fig. 71), interrupted at the apices. Striae composed of 3–4 areolae, 1–2 areolae at the apices. Areolae round to elongated, clearly enlarged and prolonged close to the valve margins (Fig. 68). Internally, areolae occluded by hymens, forming a continuous strip across the valve (Fig. 70). Isolated pore showing an elliptic external opening. Internally, central nodule thickened, expanding into stauros. Isolated pore with semi-lunar opening formed by tonguelike structure. Raphe branches straight. Proximal raphe endings short, deflected to side opposite to the isolated pore. Terminal raphe fissures deflected to the same side as the proximal endings, not extending onto the mantle (Fig. 69). Internally, proximal raphe endings straight, while distally, raphe branches terminating on small helictoglossae. Ecology and distribution So far L. vancampiana sp. nov. was found on both IleAmsterdam and Ile Saint-Paul.The largest population was found in a wet soil covered by green algae close to the ocean on Ile Saint-Paul. The sampling site is frequently visited by fur seals and penguins, as was visible in the macroremains (feathers, excrements). The sample was almost entirely dominated by the new Luticola species. Other (smaller) populations were found in soil samples collected near penguin rookeries where similar conditions (considerable biotic influence, considerable salinity input) prevailed.

Luticola ivetana Chattov�� & Van de Vijver sp. nov. Figs 27���43 Etymology The new species was named after Mrs. Iveta Chattov��, mother of the first author, on the occasion of her 50th birthday. Type ILE AMSTERDAM: Entrecasteaux, TAAF, sub-Antarctica, 37��51���18.6��� S, 77��31���23.5��� W, 21 Dec. 2016, B. Van de Vijver sample W030 (holo-: slide no. BR���4495, Fig. 27; iso-: slide PLP ���330; University of Antwerp, Belgium). Description Light microscopy (Figs 27���36) Valves elliptic-lanceolate with convex margins and broadly rounded, non-protracted apices. Valve dimensions (n = 50): length 11.0���25.5 ��m, valve width 6.0���7.5 ��m. Axial area narrow, linear, almost not widening towards the apices and central area. Central area forming a bow-tie shaped stauros. One isolated pore present in the central area, positioned close to the valve centre. Raphe filiform, straight with weakly deflected simple proximal raphe endings and elongated terminal raphe fissures. Striae radiate throughout the entire valve, 16���18 in 10 ��m. Scanning electron microscopy (Figs 37���43) Striae composed of 2���4 round to elongated areolae, clearly enlarged near the central area and the valve margins (Figs 37, 43). Mantle areolae very large, rounded, never slitlike (Fig. 39). Central area bordered by 1���2 rounded to weakly transapically elongated areolae. Isolated pore elliptic, clearly isolated from the central striae (Fig. 38). Raphe branches straight with short proximal raphe endings bent towards the side with the isolated pore (Fig. 42). Terminal raphe fissures hooked, continuing onto the valve mantle (Fig. 41). Internally, poroids of valve face occluded by hymens forming a continuous strip on each stria. Distinct stauros visible. Internal proximal raphe endings straight, terminating on the edge of the stauros. Distal raphe endings terminating onto small helictoglossae (Fig. 40). Ecology and distribution So far, L. ivetana sp. nov. was observed on Ile Amsterdam only. The type locality where a large population of this new species was observed, was a small crack in a rock face at Entrecasteaux, clearly under the permanent influence of seaspray. A very thin film of water was present in the crack together with wet mud. The sample was taken by scraping off the mud and the water from the crack. Another large population where L. ivetana sp. nov. was found is a lava cavern in the partly collapsed Grand Tunnel, running from the Crat��res V��nus to the northern coast. The sample was taken from wet mosses (F-value IV-V), growing on the wall of the cavern, close to the entrance, in a population of Blechnum australe L. The sample was dominated by Ferocia setosa (Greville) Van de Vijver & Houk (Van de Vijver et al. 2017), Orthoseira verleyenii Van de Vijver (Lowe et al. 2013), Sellaphora barae Van de Vijver & E.J.Cox (Van de Vijver & Cox 2013) and various Humidophila species., Published as part of Chattov��, Barbora, Lebouvier, Marc, Haan, Myriam De & Vijver, Bart Van De, 2017, The genus Luticola (Bacillariophyta) on Ile Amsterdam and Ile Saint-Paul (Southern Indian Ocean) with the description of two new species, pp. 1-17 in European Journal of Taxonomy 387 on pages 6-8, DOI: 10.5852/ejt.2017.387, http://zenodo.org/record/1133653, {"references":["Chattova B., Lebouvier M. & Van de Vijver B. 2017. Morphological and taxonomical analysis of the terrestrial diatom genus Humidophila (Bacillariophyta) on Ile Amsterdam and Ile Saint-Paul (Southern Indian Ocean). Phytotaxa (in press).","Lowe R. L., Kociolek J. P. & Van de Vijver B. 2013. Two new Orthoseira species (Bacillariophyceae) from lava tubes on Ile Amsterdam and Big Island (Hawaii). Phytotaxa 111: 39 - 52. https: // doi. org / 10.11646 / phytotaxa. 111.1.3"]}

Luticola sp. Figs 72���82 Description Light microscopy (Figs 72���82) Valves linear-lanceolate to elliptic-lanceolate in smaller specimens, with rounded, non-protracted apices. Valve dimensions (n = 12): length 10.7���20.5 ��m, width 4.5���6.5 ��m. Axial area narrow, linear. Central area wide, bow-tie shaped, clearly asymmetrical with the side bearing the isolated pore markedly wider. Isolated pore present in the central area, located halfway between the valve centre and margin. Raphe branches straight, deflected away from the isolated pore at both proximal and distal ends. Transapical striae punctate, radiate throughout the entire valve, 20���24 in 10 ��m. Remarks So far, this species has only been observed with light microscopy. Further studies and SEM observations will be necessary to determine its correct taxonomic position. The species was so far found in only two soil samples (A6 and A7) taken from Ile Saint-Paul. Both samples are dominated by L. beyensii, Humidophila brekkaensis, Pinnularia acidicola Van de Vijver & Le Cohu (Van de Vijver et al. 2002 a) and Hantzschia amphioxys., Published as part of Chattov��, Barbora, Lebouvier, Marc, Haan, Myriam De & Vijver, Bart Van De, 2017, The genus Luticola (Bacillariophyta) on Ile Amsterdam and Ile Saint-Paul (Southern Indian Ocean) with the description of two new species, pp. 1-17 in European Journal of Taxonomy 387 on pages 10-11, DOI: 10.5852/ejt.2017.387, http://zenodo.org/record/1133653, {"references":["Van de Vijver B., Frenot Y. & Beyens L. 2002 a. Freshwater diatoms from Ile de la Possession (Crozet Archipelago, Subantarctica). Bibliotheca Diatomologica 46: 1 - 412."]}

Luticola subcrozetensis Van de Vijver, Kopalov��, Zidarova & Levkov Figs 13���26 Diatoms of Europe: Diatoms of the European Inland Waters and Comparable Habitats 7: 228, pl. 46 figs 15���31, pl. 47 figs 4���6 (Levkov et al. 2013). Type ILE DE LA POSSESSION: Crozet Archipelago, sub-Antarctica, 5 Dec. 1999, B. Van de Vijver (holo-: slide no. BR ���4290; iso-: slides BRMZU 9 /25, MKNDC 006278 / B). Description Light microscopy (Figs 13���22) Valves rhombic-lanceolate to elliptic-lanceolate and even elliptic in smaller specimens with clearly convex margins and broadly rounded, non-protracted apices. Valve dimensions (n = 25): length 12��� 29 ��m, width 7.0���8.5 ��m. Axial area linear, slightly widening towards apices and central area. Central area bow-tie shaped, wider opposite the isolated pore, bordered by shortened striae on both sides. An isolated pore present in the central area, located halfway between the valve centre and the valve margin. Raphe branches straight, bent away from the isolated pore at both proximal and distal ends. Striae radiate throughout the entire valve, 15���17 in 10 ��m. Scanning electron microscopy (Figs 23���26) Striae composed of 3���5 small, rounded to slightly elongated areolae at the apices, only 1���2 rounded areolae per stria, extending past the terminal raphe fissures on the valve face (Fig. 23). A single row of rounded areolae present along entire valve mantle, interrupted at apices (Fig. 26). Isolated pore rounded, slightly elongated, not associated with a stria. Central area usually bordered by one, rarely two, series of small, rounded areolae. Raphe branches straight to slightly curved. Proximal raphe endings bent to the side opposite the isolated pore, terminating into weakly developed pores. Terminal raphe fissures bent to the same side as the proximal endings terminating on the valve face, not extending onto the mantle (Fig. 24). Ecology and distribution Luticola subcrozetensis is a typical sub-Antarctic and Maritime Antarctic species. Originally described from Ile de la Possession (Crozet archipelago), the species was also reported from Livingston Island (Zidarova et al. 2016), one of the major South Shetland Islands, located in the southern Atlantic Ocean. The species was recently found in moss samples from Gough Island (Vin��ov��, unpubl. res.). It was present in samples from both Ile Saint-Paul and Ile Amsterdam. The largest population was observed in a soil sample collected near the rockhopper penguin rookery of Ile Saint-Paul, at an altitude of 110 m, hidden in cracks in the rocks that border the penguin rookery., Published as part of Chattov��, Barbora, Lebouvier, Marc, Haan, Myriam De & Vijver, Bart Van De, 2017, The genus Luticola (Bacillariophyta) on Ile Amsterdam and Ile Saint-Paul (Southern Indian Ocean) with the description of two new species, pp. 1-17 in European Journal of Taxonomy 387 on pages 5-6, DOI: 10.5852/ejt.2017.387, http://zenodo.org/record/1133653, {"references":["Levkov Z., Metzeltin D. & Pavlov A. 2013. Diatoms of Europe: Diatoms of the European Inland Waters and Comparable Habitats. Vol. 7. Koeltz Scientific Books, Koningstein.","Zidarova R., Kopalova K. & Van der Vijver B. 2016. Diatoms from the Antarctic region: maritime Antarctica. Iconographia Diatomologica 24: 1 - 504."]}

Sterrenburg, Frithjof A. S., Haan, Myriam De, Herwig, Wulf E., Hargraves, Paul E. (2014): Typification and taxonomy of Gyrosigma tenuissimum (W. Sm.) J.W. Griffith & Henfr., comparison with Gyrosigma coelophilum N. Okamoto & Nagumo and description of two new taxa: Gyrosigma tenuissimum var. gundulae var. nov. and Gyrosigma baculum sp. nov. (Pleurosigmataceae, Bacillariophyta). Phytotaxa 172 (2): 71-80, DOI: 10.11646/phytotaxa.172.2.2, URL: http://dx.doi.org/10.11646/phytotaxa.172.2.2

Gyrosigma baculum Herwig & Sterrenburg, sp. nov. (Figs 24–27) Valve linear, 82–92 µm long, 5.5–6.0 µ wide, transverse striae circa 18–19 in 10 µm, longitudinal striae circa 35–37 in 10 µm, raphe sternum staff-shaped in its apical portion. Type:— ITALY, Cala Gonone, Sardinia (BRM ZU 8 /35!, holotype, coordinates 7.4 East, 4.6 South = Fig. 24; Fig 25 is another specimen from the same slide, isotype; collection Herwig, isotype; collection Sterrenburg # 712, isotype). Valves very delicate, 82–92 µm long, 5.5–6.0 µm wide, practically parallel-sided and straight for most of their length, becoming sigmoid near acute apex. Raphe sternum straight except near apices, where it first curves to dorsal side and then recurves on a strongly eccentric and sigmoid course. Striation (Fig. 26): transverse striae circa 18–19 in 10 µm, longitudinal striae circa 35–37 in 10 µm, becoming irregular at the apices (Fig. 27). No hyaline central area visible, central raphe node minute and elongated. Etymology: —The specific epithet baculum (“staff”) is chosen to describe the typical reversed curvature of the raphe sternum at the apices. Habitat:—Littoral-marine, benthic. Distribution:— Type locality only. Observations:— Gyrosigma baculum differs from G. tenuissimum in two independent characters: the different course of the raphe sternum and stria density. Gyrosigma baculum somewhat resembles Gyrosigma uncinatum Ricard (1975: 209, fig. 3) in valve contour and raphe sternum course but G. uncinatum has much coarser (15 in 10 µm) transverse striae, a value incompatible with the stria density of G. baculum. No type specimens for Gyrosigma uncinatum have been deposited in PC. No specimens have been isolated for G. baculum for SEM examination as it is very rare in the type material, but the LM findings of raphe sternum course and stria densities already permit separation from the described species., Published as part of Sterrenburg, Frithjof A. S., Haan, Myriam De, Herwig, Wulf E. & Hargraves, Paul E., 2014, Typification and taxonomy of Gyrosigma tenuissimum (W. Sm.) J. W. Griffith & Henfr., comparison with Gyrosigma coelophilum N. Okamoto & Nagumo and description of two new taxa: Gyrosigma tenuissimum var. gundulae var. nov. and Gyrosigma baculum sp. nov. (Pleurosigmataceae, Bacillariophyta), pp. 71-80 in Phytotaxa 172 (2) on page 76, DOI: 10.11646/phytotaxa.172.2.2, http://zenodo.org/record/5142351, {"references":["Ricard, M. (1975) Quelques diatomees nouvelles de Tahiti decrites en microscopie photonique et electronique a balayage. Bulletin du Museum National d'Histoire Naturelle, Botanique, 3 e ser., no 326, 23: 201 - 229."]}

Luticola desmetii Kopalov�� & Van de Vijver, sp. nov. (Figs 2���13) Valvae rhombicae at rhombicae-elloticae marginibus distincte convexis, apicibusque protractis, rostratis. Longitudo 22��� 42.5 ��m, latitudo 11.3���16.8 ��m. Area axialis angustissima, paene linearis ad linearis-lanceolata, leviter dilatata in aream centralem. Sternum lineare adest marginatum depressionibus longitudinalibus. Area centralis irregularis, formans staurum rectangularem asymmetricum, marginatum serie una areolarum rotundatarum ad leviter transapicaliter elongatarum. Stigma solitaria magna rimiformis inter mediam partem valvae marginesque. Depressiones plures in area centrali, visibiles in microscopio photonico. Raphe filiformis, recta, terminationibus proximalibus indistinctis, fissurisque distalibus elongatis, deflexis. Striae transapicales radiatae in centro valvae, fortiter radiatae ad apices, 12���16 in 10 ��m. Type:��� ANTARCTICA. James Ross Island, Ulu Peninsula, Blue-Green Lake, sample D51, leg. L. Nedbalov��, coll. date 27/01/2009, slide no. BR-4241 (holotype BR, Fig. 7 is the encircled holotype specimen), slide PLP-189 (isotype University of Antwerp, Belgium), BRM-ZU8/06 (isotype BRM). Valves rhombic to rhombic-elliptical with inflated, distinctly convex margins (Figs 2���8). Apices typically protracted, rostrate. Valve length 22���42.5 ��m, valve width 11.3���16.8 ��m (n=37). Axial area quite narrow, almost linear to linear-lanceolate, slightly widening towards the central area, formed by a raised, almost straight, linear sternum; bordered by longitudinal depressions (Fig. 9). Central area irregular, forming a rectangular, asymmetrical stauros, bordered by one series of rounded to very weakly transapically elongated areolae. One large, slit-like isolated stigma present, located halfway between valve margin and valve centre (Figs 9, 11). Multiple irregular, shallow depressions present in central area, visible in LM (Figs 9, 11). External raphe branches usually straight, with inconspicuous straight proximal raphe endings (Figs 9, 11). Distal raphe endings elongated, deflected towards stigma-bearing side (Figs 9, 12). Transapical striae radiate near valve centre, becoming strongly radiate towards poles, 12���16 in 10 �� m. Pattern of areolae rather irregular. Striae usually composed of 2���3 small, rounded areolae and one slit-like areola close to valve margin (Fig. 9). Towards apices, striae composed of 1���2 strictly rounded areolae (Fig. 12). Internally, poroids of valve face occluded by hymenes (Figs 10, 13). Internal expression of stigma absent (Fig. 13). Distinct stauros visible (Fig. 13). Longitudinal canal covered by siliceous outgrowth (Figs 10, 13). Internal proximal raphe endings terminate on edge of stauros (Fig. 13). Distal raphe endings terminate on small helictoglossae (Fig. 10). Habitat, Ecology and Distribution:��� To date, L. desmetii has been found only in one small kettle lake (Blue-Green Lake) on James Ross Island close to the Whisky Glacier. The largest population was found in an epilithon sample. The lake had a pH of 7.8, a low specific conductance (91 ��S/cm) and was relatively species rich with 32 species observed, dominated by Nitzschia taxa belonging to the complex around Nitzschia perminuta (Grunow in Van Heurck 1881: pl.68. Fig. 31) Peragallo (1903: 672) and Psammothidium metakryophilum (Lange-Bertalot & Schmidt in Schmidt et al. 1990: 64) Sabbe (in Sabbe et al. 2003: 242). A record from the South Shetland Islands (H��kansson & Jones 1994) has not be verified. Etymology:��� Luticola desmetii is named after our dear friend and colleague Prof. Dr. Willem De Smet (University of Antwerp, Belgium) in honour of his Arctic and Antarctic limnological work. Observations: ��� At present, no Luticola taxa have a similar valve shape to L. desmetii. Luticola higleri and L. katkae Van de Vijver & Zidarova (in Van de Vijver, Zidarova & de Haan 2011: 143) have a similar irregular pattern of longitudinal depressions, raised sternum and shallow depressions in the axial and central area (Van de Vijver et al. 2006, 2011). However, both taxa have a different valve outline with clearly capitate apices (L. katkae) and broadly rounded valves (L. katkae and L. higleri). Moreover, L. higleri shows a distinct marginal rim on the valve face/mantle margin, which is absent in L. desmetii. Both have short distal raphe fissures in contrast to the elongated, deflected distal raphe endings in L. desmetii. At present, no taxon of Luticola has a similar valve outline. Luticola heufleriana (Grunow 1863: 155) D.G.Mann (in Round, Crawford & Mann 1990: 671) has weakly rhombic valves with clearly capitate apices, whereas L. lagerheimii (Cleve 1894: Taf. 7:11) D.G.Mann (in Round, Crawford & Mann 1990: 671) has a comparable outline but forms long chains, has deflected proximal raphe endings and short marginal spines. Bj��rck et al. (1996) reported L. heufleriana from sediment cores taken in three lakes on Ulu Peninsula, close to Blue-Green Lake. Although this record could not be verified, due to the lack of samples and illustrations, it is highly likely that this taxon should be attributed to L. desmetii., Published as part of Kopalov��, Kate��ina, Nedbalov��, Linda, Haan, Myriam De & Vijver, Bart Van De, 2011, Description of five new species of the diatom genus Luticola (Bacillariophyta, Diadesmidaceae) found in lakes of James Ross Island (Maritime Antarctic Region), pp. 44-60 in Phytotaxa 27 on pages 47-49, DOI: 10.11646/phytotaxa.27.1.5, http://zenodo.org/record/4894204, {"references":["Van Heurck, H. (1881) Synopsis des Diatomees de Belgique. Atlas. Ducaju & Cie., Anvers. pls 31 - 77.","Peragallo, M. (1903) Le Catalogue General des Diatomees. Clermont-Ferrand. 2: 472 - 973.","Schmidt, R., Mausbacher, R. and Muller, J. (1990) Holocene diatom flora and stratigraphy from sediment cores of two Antarctic lakes (King George Island). Journal of Paleolimnology 3 (1): 55 - 74.","Sabbe, K., Verleyen, E., Hodgson, D. A., Vanhoutte, K. and Vyverman, W. (2003) Benthic diatom flora of freshwater and saline lakes in the Larsemann Hills and Rauer Islands, East Antarctica. Antarctic Science 15: 227 - 248.","Hakansson, H. & Jones, V. J. (1994) The compiled freshwater diatom taxa list for the maritime region of the South Shetland and South Orkney Islands. In: Hamilton, P. B. (ed.), Proceedings of the Fourth Arctic-Antarctic Diatom Symposium Workshop, Canadian Technical report of Fisheries and Aquatic Sciences 157: 77 - 83.","Van de Vijver, B., Zidarova, R. & de Haan, M. (2011) Four new Luticola taxa (Bacillariophyta) from the South Shetland Islands and James Ross Island (Maritime Antarctic Region). Nova Hedwigia 92: 137 - 158.","Van de Vijver, B., Van Dam, H. & Beyens, L. (2006) Luticola higleri sp. nov. A new diatom species from King George Island (South Shetland Island, Antarctica). Nova Hedwigia 83: 69 - 79.","Grunow, A. (1863) Ueber einige neue und ungenugend bekannte Arten und Gattungen von Diatomaceen. Verhandlungen der Kaiserlich-Koniglichen Zoologisch-Botanischen Gesellschaft in Wien 13: 137 - 162.","Round, F. E., Crawford, R. M. & Mann, D. G. (1990) The diatoms: Biology and Morphology of the genera. Cambridge, Cambridge University Press, 747 pp.","Cleve, P. T. (1894) Synopsis of the Naviculoid Diatoms, Part I. Kongliga Svenska-Vetenskaps Akademiens Handlingar 26: 1 - 194.","Bjorck, S., Olson, S., Ellis-Evans, C., Hakansson, H., Humlum, O. & Manuel de Lirio, J. (1996) Late Holocene palaeoclimatic records from lake sediments on James Ross Island, Antarctica. Palaeogeography, Palaeoclimatology, Palaeoecology 121: 195 - 220."]}

Luticola tomsui Kopalov��, sp. nov. (Figs 73���87) Valvae lineares ad lineares-ellipticae apicibus late rotundatis. Margines clare sed asymmetrice constrictae in media parte valvae. Longitudo 18.5���23 ��m, latitudo 6.5���8.1 ��m. Area axialis lata, lanceolata, clare dilatata ad apices areamque centralem. Area centralis formans staurum rectangularem ad paene ellipticum, marginatum serie una areolarum parvarum rotundatarum ad leviter transapicaliter elongatarum. Stigma rimiformis solitaria adest, inter mediam partem valvae marginesque. Raphe filiformis, terminationibus proximalibus recta unilateraliter deflexis opposite stigma poris centralibus indistinctis. Fissurae distales curtae, leviter deflexae. Striae transapicales radiatae omnino, positae prope margines valvae, 16���18 in 10 ��m. Areolae 1���2 rimiformes. Ad margines, areola expansa adest. Type:��� ANTARCTICA. James Ross Island, Ulu Peninsula, Vondra II Lake, sample D39, leg. L. Nedbalova, coll. date 19/01/2009, slide no. BR-4244 (holotype BR, Fig. 78 is the encircled holotype specimen), slide PLP-192 (isotype University of Antwerp, Belgium), BRM-ZU8/10 (isotype BRM). Valves linear to linear-elliptic with broadly rounded, capitate apices (Figs 73���83). Stigma-bearing side almost straight with opposite side more convex. Valve margins clearly convex but asymmetrically constricted near valve middle. Valve length 18.5���23 ��m, valve width 6.5���8.1 ��m (n=15). Axial area broad, lanceolate, widening towards apices and central area, (Fig. 84). Central area forming rectangular to almost elliptical stauros, bordered by one series of small rounded to very weakly transapically elongated areolae (Figs 84, 85). One small slit-like solitary stigma present, halfway between valve centre and margin (Fig. 85). External raphe branches straight to weakly curved with unilaterally deflected proximal raphe endings, away from the stigma, terminating in almost unexpanded central pores (Fig. 85). Distal raphe fissures short, weakly deflected (Fig. 86). Transapical striae radiate throughout entire valve, positioned close to valve margin, 16���18 in 10 ��m (Fig. 84). Striae composed of 1���2 small, slitlike areolae and one enlarged areola close to valve margin (Fig. 84). Towards apices, striae composed only one areola. Internally, poroids of valve face occluded by hymens, forming continuous strip on each stria. Internal stigma opening consisting of small, rounded lipped slit. Stauros clearly developed (Fig. 87). Internal proximal raphe endings straight, terminating on stauros edge. Distal raphe endings terminating on small helictoglossae (Fig. 87). Habitat, Ecology and Distribution:��� Luticola tomsui has been found in only two samples from one lake on James Ross Island. The largest population was found in the epilithon of the shallow Vondra II Lake located on the Lagoons Mesa plateau near the ice-free area close to Croft Bay. The lake had a pH of 7.7, a low specific conductance value (53��S/cm) and was dominated by Nitzschia species including Nitzschia perminuta, N. paleacea and Nitzschia gracilis. Etymology:��� Luticola tomsui is named after my dear friend Jan Tom�� ů (Prague, Czech Republic). Observations: ��� The number of Luticola taxa with constricted valves is low thus confusion with L. tomsui is unlikely. Recently, L. adelae was described from White Lake on James Ross Island (Van de Vijver et al. 2011) and L. binodis (Hustedt 1922: 239) Edlund (in Edlund et al. 2001: 85) was reported from the nearby Livingston Island (South Shetland Islands) (Van de Vijver et al. 2011). Both are species with constricted valves. The valve size ranges of L. tomsui (L 18���23 ��m, W 6,5 ���8.0 ��m) is in between those of L. adelae and and L. binodis: L. adelae is smaller (L 16���20 ��m, W 5���6 ��m), L. binodis is larger (L �� 24 ��m, W �� 7,5 ��m). L. adelae and L. binodis both differ from L. tomsui in having a more slender valve outline and less inflated valve centre. Additionally, the number of areolae per stria in L. binodis is higher than L. tomsui and the axial area is smaller compared to the rather broad axial area in L. tomsui. Other species with constricted valves, such as L. mollis Lange-Bertalot & Rumrich (in Rumrich et al. 2000: 149) and L. incoacta (Hustedt 1966: 619) D.G.Mann (in Round et al. 1990: 670), have a higher number of areolae per stria, a narrower axial area and deeper constrictions. Finally, when L. tomsui is compared to L. nivalis, the latter has a valve outline with more undulations., Published as part of Kopalov��, Kate��ina, Nedbalov��, Linda, Haan, Myriam De & Vijver, Bart Van De, 2011, Description of five new species of the diatom genus Luticola (Bacillariophyta, Diadesmidaceae) found in lakes of James Ross Island (Maritime Antarctic Region), pp. 44-60 in Phytotaxa 27 on pages 56-58, DOI: 10.11646/phytotaxa.27.1.5, http://zenodo.org/record/4894204, {"references":["Van de Vijver, B., Zidarova, R. & de Haan, M. (2011) Four new Luticola taxa (Bacillariophyta) from the South Shetland Islands and James Ross Island (Maritime Antarctic Region). Nova Hedwigia 92: 137 - 158.","Hustedt, F. (1922) Die Bacillariaceen-Vegetation des Lunzer Seengebietes (Nieder-Osterreich). Internationale Revue der gesamten Hydrobiologie und Hydrographie 10: 40 - 74.","Edlund, M. B., Soninkhishsig, N., Williams, R. M. & Stoermer, E. F. (2001) Biodiversity of Mongolia: Checklist of diatoms, including new distributional reports of 31 taxa. Nova Hedwigia 72: 59 - 90.","Rumrich, U., Lange-Bertalot, H. and Rumrich, M. (2000) Diatoms of the Andes. From Venezuela to Patagonia / Tierra del Fuego and two additional contributions. Iconographia Diatomologica 9: 1 - 673.","Hustedt, F. (1966) Die Kieselalgen Deutschlands, Osterreichs und der Schweiz unter Berucksichtigung der ubrigen Lander Europas sowie der angrenzenden Meeresgebiete. In:. Rabenhorst, L. (Ed.), Kryptogamen Flora von Deutschland, Osterreich und der Schweiz. Akademische Verlagsgesellschaft m. b. h. Leipzig 7 (Teil 3, Lief. 4): 557 - 816.","Round, F. E., Crawford, R. M. & Mann, D. G. (1990) The diatoms: Biology and Morphology of the genera. Cambridge, Cambridge University Press, 747 pp."]}

Luticola evkae Kopalov��, sp. nov. (Figs 35���50) Valvae ellipticae-lanceolatae marginibus clare convexis apicibusque capitatis, late rotundatis. Valvae minores paene ellipticae. Longitudo 14���22 ��m, latitudo 5.4���8.2 ��m. Area axialis latissima, lanceolata, leviter dilata in aream centralem. Ad apices, area axialis clare dilata. Area centralis formans staurum paene rectangularem, leviter dilatatum ad margines, marginatumque serie una areolarum minutissimarum. Stigma rotundata, punctiformis solitaria adest inter mediam partem valvae marginesque. Raphe filiformis, recta terminationibus proximalibus unilateraliter deflexis opposita stigma poris centralibus leviter expansis. Fissurae distales curtae, leviter deflexis. Striae transapicales radiatae in parte centrali valvae ad fortiter radiatae ad apices, 16���20 in 10 ��m. Areolae rotundae 1���2 per striam terminans in areolam transapicaliter elongatam ad marginem. Type:��� ANTARCTICA. James Ross Island, Ulu Peninsula, Vondra II Lake, sample D39, leg. L. Nedbalov��, coll. date 19/01/2009, slide no. BR-4242 (holotype BR, Fig. 46 is the encircled holotype specimen), slide PLP-190 (isotype University of Antwerp, Belgium), BRM-ZU8/08 (isotype BRM). Valves elliptic-lanceolate with clearly convex margins and broadly rounded, capitate apices (Figs 35���46). Smaller valves almost elliptical (Fig. 47). Valve length 14���22 ��m, valve width 5,4���8,2 ��m (n=32). Axial area very broad, lanceolate, slightly widening towards central area (Fig. 48). Towards apices, axial area clearly widened (Fig. 49). Central area forming almost rectangular stauros, slightly widening towards margins, bordered by one series of very small rounded areolae (Fig. 50). One small, solitary, rounded stigma present, halfway between valve centre and margin (Figs 48, 50). Raphe branches filiform, straight with unilaterally deflected proximal endings away from stigma, terminating in weakly expanded central pores (Figs 48, 50). Distal fissures short, slightly deflected (Fig. 49). Transapical striae radiate near valve centre to strongly radiate towards poles, 16���20 in 10 ��m, composed of two (occasionally 1) small rounded areolae terminating in one clearly transapically elongated areola in middle part of valve near margin (Fig. 50). Areolae always rounded near apices (Fig. 49). Internal structure not observed. Habitat, Ecology and Distribution:��� Luticola evkae was described from the epilithon of a small, stable, shallow lake on Lagoons Mesa in the ice-free area close to Croft Bay. The lake had a pH of 7.7, a low specific conductance of 53 ��S/cm and was dominated by several Nitzschia species such as Nitzschia perminuta, Nitzschia paleacea Grunow (in Van Heurck 1881: pl. 68, Figs 9���10) and Nitzschia gracilis Hantzsch (1860:40). Etymology:���Named after my dear friend, Eva (Evka) Volemanov�� (Prague, Czech Republic). Observations: ��� Based on valve dimensions and the shape of the axial and central area of the valves, Luticola evkae may at first appear similar to Luticola dolia and L. doliiformis. These three species can, however, be clearly distinguished based on their contrasting valve outlines. Luticola evkae has a typical elliptical central part of the valve whereas both L. doliiformis and L. dolia always have more elongated valves with, in most cases, almost parallel margins (Esposito et al. 2008). The apices in L. evkae are always broader and more capitate than in L. dolia, which has more rostrate to weakly capitate apices. This can be appreciated by the differences in valve width/apex ratio, which is 1.70��0.18 (n=13) in L. evkae and 2.36��0.22 (n=13) in L. dolia; L. doliiformis has wider apices. Additionally, the shoulders just below the apices are more oblique in both L. dolia and L. doliiformis. In L. evkae, the outer row of areolae is always composed of transapically elongated areolae clearly visible in LM, whereas in L. doliiformis these areolae are always strictly rounded. Luticola austroatlantica is similar but distinguished by a different striation pattern with larger, usually elongated areolae. Moreover, L. austroatlantica lacks the broad axial area and has a more elongated valve outline. Smaller valves of L. austroatlantica with comparable valve dimensions as L. evkae always have rostrate apices contrary to the capitate apices in L. evkae. Other species that might be considered morphologically similar include L. muticopsis (and its smaller forms) and L. palearctica (Hustedt 1966: 613) D.G.Mann (in Round et al. 1990: 671). The former has a different valve outline, with one straight and one convex margin, clearly deflected proximal and distal raphe endings, rostrate apices and a narrower axial area (Van de Vijver & Mataloni 2008), whereas the latter is larger with more expanded apices and a higher areola density (Hustedt 1966). Finally, L. truncata has more areolae per stria (3���4 vs. 1���2 in L. evkae) with a more elliptical outline and truncated, non-capitate apices (Kopalov�� et al. 2009)., Published as part of Kopalov��, Kate��ina, Nedbalov��, Linda, Haan, Myriam De & Vijver, Bart Van De, 2011, Description of five new species of the diatom genus Luticola (Bacillariophyta, Diadesmidaceae) found in lakes of James Ross Island (Maritime Antarctic Region), pp. 44-60 in Phytotaxa 27 on pages 51-52, DOI: 10.11646/phytotaxa.27.1.5, http://zenodo.org/record/4894204, {"references":["Van Heurck, H. (1881) Synopsis des Diatomees de Belgique. Atlas. Ducaju & Cie., Anvers. pls 31 - 77.","Hantzsch, C. A. (1860) Neue Bacillarien: Nitzschia vivax var. elongata, Cymatopleura nobilis. Hedwigia 2 (7): 40.","Esposito, R. M. M., Spaulding, S. A., McKnight, D. M., Van de Vijver, B., Kopalova, K., Lubinski, D., Hall, B. & Whittaker, T. (2008) Inland diatoms from the McMurdo Dry Valleys and James Ross Island, Antarctica. Botany 86: 1378 - 1392.","Hustedt, F. (1966) Die Kieselalgen Deutschlands, Osterreichs und der Schweiz unter Berucksichtigung der ubrigen Lander Europas sowie der angrenzenden Meeresgebiete. In:. Rabenhorst, L. (Ed.), Kryptogamen Flora von Deutschland, Osterreich und der Schweiz. Akademische Verlagsgesellschaft m. b. h. Leipzig 7 (Teil 3, Lief. 4): 557 - 816.","Round, F. E., Crawford, R. M. & Mann, D. G. (1990) The diatoms: Biology and Morphology of the genera. Cambridge, Cambridge University Press, 747 pp.","Van de Vijver, B. & Mataloni, G. (2008) New and interesting species in the genus Luticola D. G. Mann (Bacillariophyta) from Deception Island (South Shetland Islands). Phycologia 47: 451 - 467.","Kopalova, K., Elster, J., Nedbalova, L. & Van de Vijver, B. (2009) Three new terrestrial diatom species from seepage area on James Ross Island (Antarctic Peninsula Region). Diatom Research 24: 113 - 122."]}

Luticola doliiformis Kopalov�� & Van de Vijver, sp. nov. (Figs 14���28) Valvae lanceolatae marginibus convexis, apicibusque capitatis. Longitudo 17���22 ��m, latitudo 7���8 ��m. Area axialis lata, lanceolata, clare dilatata in aream centralem, leviterque dilatata in apices. Area centralis formans staurum rectangularem, marginatum serie una areolarum rotundatatrum. Stigma solitaria rotundata prope marginem valvae adest. Raphe filiformis, clare curvata, terminationibus proximalibus unilateraliter deflexis, fissurisque distalibus curtis, rectis. Striae transapicales radiatae in centro valvae, convergentes ad apices, 18���20 in 10 ��m. Areolae parvae, semper rotundae, 2-3 per striam. Type: ��� ANTARCTICA. James Ross Island, Ulu Peninsula, Lachman Crags, sample D07, leg. L. Nedbalov��, coll. date 27/01/2008, slide no. BR-4250 (holotype BR, Fig. 20 is the encircled holotype specimen), slide PLP-195 (isotype University of Antwerp, Belgium), BRM-ZU8/07 (isotype BRM). Valves lanceolate with convex margins and capitate apices (Figs 14���24). Valve length 17���22 ��m, valve width 7���8 ��m (n=15). Axial area broad, lanceolate, clearly widening towards central area, only slightly widening towards apices (Fig. 25). Central area forming a broad, rectangular stauros, bordered by one series of small, rounded areolae (Fig. 27). One small, solitary, rounded stigma present, close to valve margin (Fig. 27). External raphe branches clearly curved, with weakly unilaterally deflected, simple proximal endings away from stigma (Fig. 27). Distal raphe fissures very short, straight (Fig. 28). Transapical striae radiate near valve centre becoming convergent towards apices, 18���20 in 10 ��m (Fig. 25). Striae composed of 2-3 small, always rounded areolae (Fig. 25). Internal structure hardly visible since only one valve was found (Fig. 26). Clearly developed stauros present. Detail of internal stigma opening obscured by debris. Proximal raphe endings terminating on edge of stauros. Habitat, Ecology and Distribution:��� Luticola doliiformis was found in small cracks on wet soil on the table mountain Lachman Crags close to the glacier front. The sample was dominated by Luticola cohnii, Hantzschia amphioxys (Ehrenberg 1843: 413) Grunow (in Cleve & Grunow 1880: 103) and several unidentified species of Diadesmis. Etymology: ��� This specific epithet doliiformis refers to its close resemblance to L. dolia (- formis: Latin for ���resembling���). Observations: ��� The James Ross Island (JRI) specimen of Luticola doliiformis bears a strong resemblance to L. dolia, a taxon described from the McMurdo Dry Valleys on the Antarctic Continent (Esposito et al. 2008). The valve dimensions do not permit discrimination between the two taxa but there are other important differences. Unfortunately, in the original description of Esposito et al. (2008), the ultrastructure of the valves and girdle could not be examined as specimens were rare in the samples. Therefore, isotype material (INSTAAR Collection slide 532, isotype slide for Luticola dolia Spaulding & Esposito, Esposito et al. 2008: 1385) was re-examined using SEM and two valves were found showing some of the morphological features enabling separation between L. dolia and L. doliiformis (Figs 29���34). Based on the description in Esposito et al. (2008) and our observations of the isotype material, several differences can be noted. The distal raphe fissures in the JRI population are very short contrary to L. dolia where slightly elongated fissures were noted (Fig. 33). The valve apices in L. dolia are usually much narrower than in L. doliiformis that have normally broadly rounded, enlarged apices (Figs 29���31). The shape and size of the areolae also differs with transapically elongated, larger areolae in L. dolia, whereas L. doliiformis has small, always rounded areolae (Figs 32, 33). Moreover, the number of striae in 10 ��m is higher in the JRI population contrary to that stated in the original description (18���20 vs 14���18). Although the external stigma opening could not be observed in the isotype material, it is clear that, based on the LM and the internal SEM views of L. dolia (Fig. 34), the stigma opening is positioned more to the valve middle whereas in L. doliiformis, the stigma opening is closer to the valve margin (Fig. 25). Based on these differences, separation of these taxa can be made., Published as part of Kopalov��, Kate��ina, Nedbalov��, Linda, Haan, Myriam De & Vijver, Bart Van De, 2011, Description of five new species of the diatom genus Luticola (Bacillariophyta, Diadesmidaceae) found in lakes of James Ross Island (Maritime Antarctic Region), pp. 44-60 in Phytotaxa 27 on pages 49-50, DOI: 10.11646/phytotaxa.27.1.5, http://zenodo.org/record/4894204, {"references":["Ehrenberg, C. G. (1843) Verbreitung und Einfluss des mikroskopischen Lebens in Sud-und Nord-Amerika. Abhandlungen der Koniglichen Akademie der Wissenschaften zu Berlin 1841: 291 - 445.","Cleve, P. T. & Grunow, A. (1880) Beitrage zur Kenntniss der Arctischen Diatomeen. Kongliga Svenska-Vetenskaps Akademiens Handlingar 17 (2): 1 - 121.","Esposito, R. M. M., Spaulding, S. A., McKnight, D. M., Van de Vijver, B., Kopalova, K., Lubinski, D., Hall, B. & Whittaker, T. (2008) Inland diatoms from the McMurdo Dry Valleys and James Ross Island, Antarctica. Botany 86: 1378 - 1392."]}

Luticola permuticopsis Kopalov�� & Van de Vijver, sp. nov. (Figs 51���72) Valvae lineares-lanceolatae ad lineares-ellipticae marginibus distincte convexis apicibusque late rotundatis, stricte capitatis. Longitudo 18.5���26.0 ��m, latitudo 7.3���9.2 ��m. Area axialis moderate angusta, linearis, paene non dilatata in aream centralem apicesque. Area centralis formans staurum rectangularem ad cuneatum, marginatum serie una areolarum rotundatarum magnarum. Stigma paene rotundata adest in extremo striae curate vel isolata inter mediam partem valvae marginesque. Raphe filiformis, recta, terminationibus proximalibus unilateraliter clare deflexis, poris centralibus leviter expansis. Fissurae distales deflectis, clare expansae. Striae transapicales fortiter radiatae omnino, 18���22 in 10 ��m. Areolae 3���6 per striam, moderate magnae. Type:��� ANTARCTICA. James Ross Island, Ulu Peninsula, Vondra IV Lake, sample D44, leg. L. Nedbalova, coll. date 19/01/2009, slide no. BR-4243 (holotype BR, Fig. 55 is the encircled holotype specimen), slide PLP-191 (isotype University of Antwerp, Belgium), BRM-ZU8/09 (isotype BRM). Valves linear-lanceolate to linear-elliptic with distinctly convex margins and broadly rounded, distinctly capitate apices (Figs 51���66). Valve length 18.5���26.0 �� m, valve width 7.3���9.2 �� m (n=15). Axial area moderately narrow, linear (Figs 67, 68), almost not widening towards apices (Fig. 72) and central area (Fig. 71). Central area forming a rectangular to wedge-shaped stauros, bordered by one series of large, rounded areolae. One solitary, almost rounded stigma present, usually at end of shortened stria, composed of 3 small, rounded areolae (Fig. 67) or isolated halfway between valve centre and margin (Fig. 71). External raphe branches straight with unilaterally clearly deflected, slightly expanded proximal raphe endings. Distal raphe fissures clearly elongated, deflected. Transapical striae rather strongly radiate throughout entire valve, composes of 3���6 moderately large, rounded areolae, 18���22 in 10 ��m. Near central area, areolae close to margin, clearly enlarged (Figs 67, 71) Internally, poroids of valve face occluded by hymens forming continuous strip on each stria (Fig. 69). Internal stigma opening consisting of almost rounded lipped slit (Fig. 70). Stauros clearly developed (Fig. 70). Internal proximal raphe endings straight, terminating on edge of stauros. Distal raphe endings terminating on small helictoglossae (Fig. 69). Habitat, Ecology and Distribution:��� Luticola permuticopsis has been found in a few lakes on James Ross Island on the Lagoons Mesa plateau near the ice-free area close to Croft Bay. The largest population was found in the epilithon of a perennial shallow lake with a pH of 7.4, a specific conductance value of 60 ��S/cm and a temperature 6.8 ��C. Dominant species in the sample include Nitzschia gracilis, N. paleacea and N. perminuta. Etymology: ��� permuticopsis refers to the close resemblance to L. muticopsis (per -: Latin for ���quite equally���). Observations: ��� The past few years, a large number of capitate species of Luticola have been separated from Luticola muticopsis s.l. Table 1 includes the main morphological characters of these species, in comparison to L. permuticopsis. Luticola permuticopsis can be separated from L. muticopsis by its typical valve outline: L. muticopsis has one straight and one convex margin, L. permuticopsis always has two convex margins; the apices in L. muticopsis are always more rostrate than capitate, contrary to L. permuticopsis, which has capitate, broadly rounded apices. Another important difference is formed by the areola pattern: in L. permuticopsis the striae are composed of 3���6 moderately large, densely packed areolae, whereas in L. muticopsis, there are only 3���4, more spaced areolae present, a feature easily discernible in LM (Van de Vijver & Mataloni 2008: p. 463, Fig. 77). Finally, the proximal raphe endings in L. permuticopsis are deflected, whereas in L. muticopsis, they are clearly bent. These differences separate the two species. *measurements based on line drawing in original publication Carlson (1913) described Navicula muticopsis f. capitata while Peragallo (1921) described Navicula muticopsis var. capitata ���both separated by their asymmetrical valve outline, with one straight and one convex margin. Both taxa have a strong affinity with L. muticopsis but type material of neither can be investigated due to lack of material. Other similar species are L. austroatlantica, L. palearctica, L. dolia and L. murrayi (West West 1911: 285) D.G.Mann (in Round et al. 1990: 671) sensu Hustedt (1966). Luticola austroatlantica can be separated by its more slender, elongated valve outline and a lower number of areolae per stria [2���3(4) vs. 3���6 in L. permuticopsis] (Esposito et al. 2008). Luticola permuticopsis has a more compact, robust outline. Moreover, near the apices, the areolae in L. permuticopsis continue almost entirely to the end, whereas in L. austroatlantica there is a hyaline zone surrounding the apices. Finally, the distal raphe fissures in L. austroatlantica are shorter than in L. permuticopsis. Luticola palearctica has similar valve dimensions to L. permuticopsis (Hustedt 1966) but a more clearly elliptical valve outline and broadly rounded, large capitate apices, showing little difference between the width of the apices and the width near the central area. In L. permuticopsis the apices are always clearly more narrower than the valve centre. Its discrimination from Luticola murrayi sensu Hustedt (1966) is based on valve outline, with L. murrayi sensu Hustedt (1966) having broadly rounded margins and apices. The latter is currently under revision and will be described as a new species separate from L. murrayi s.s. (Van de Vijver et al., unpubl.). Finally, L. dolia has straighter valve margins and a large axial area with only 1���3 areolae per stria (Esposito et al. 2008 and this paper). It can be separated from two other species present on James Ross Island: Luticola gigamuticopsis is much larger (length 38���46 ��m, width 14���17 ��m vs. 8.5���23.0 ��m and 6.5���8.1 ��m in L. permuticopsis) (Van de Vijver & Mataloni 2008); Luticola gaussii has an almost elliptical valve outline with constricted broadly rounded, large apices., Published as part of Kopalov��, Kate��ina, Nedbalov��, Linda, Haan, Myriam De & Vijver, Bart Van De, 2011, Description of five new species of the diatom genus Luticola (Bacillariophyta, Diadesmidaceae) found in lakes of James Ross Island (Maritime Antarctic Region), pp. 44-60 in Phytotaxa 27 on pages 53-56, DOI: 10.11646/phytotaxa.27.1.5, http://zenodo.org/record/4894204, {"references":["Van de Vijver, B. & Mataloni, G. (2008) New and interesting species in the genus Luticola D. G. Mann (Bacillariophyta) from Deception Island (South Shetland Islands). Phycologia 47: 451 - 467.","Carlson, G. W. F. (1913) Susswasseralgae aus der Antarktis, Sudgeorgien und den Falkland Inseln. Wissenschaftliche Ergebnisse der Schwedischen Sudpolar-Expedition 1901 - 1903, unter leitung von dr. Otto Nordenskjold: 4 (Botanique): 1 - 94.","Peragallo, M. (1921) Diatomees d'eau douce. Premiere partie. Deuxieme Expedition Antarctique Francaise (1908 - 1910) commande par le Dr. J. Charcot. Ouvrage publie sous les auspices du Ministere de l'Institution publique. Masson et cie, Paris, pp. 1 - 38.","West, W. & West, G. S. (1911) Freshwater algae. In: Murray, J. (ed.), Biology, vol. 1. Reports on the Scientific Investigations, British Antarctic Expedition 1907 - 09. Heinemann, London, pp. 263 - 298.","Round, F. E., Crawford, R. M. & Mann, D. G. (1990) The diatoms: Biology and Morphology of the genera. Cambridge, Cambridge University Press, 747 pp.","Hustedt, F. (1966) Die Kieselalgen Deutschlands, Osterreichs und der Schweiz unter Berucksichtigung der ubrigen Lander Europas sowie der angrenzenden Meeresgebiete. In:. Rabenhorst, L. (Ed.), Kryptogamen Flora von Deutschland, Osterreich und der Schweiz. Akademische Verlagsgesellschaft m. b. h. Leipzig 7 (Teil 3, Lief. 4): 557 - 816.","Esposito, R. M. M., Spaulding, S. A., McKnight, D. M., Van de Vijver, B., Kopalova, K., Lubinski, D., Hall, B. & Whittaker, T. (2008) Inland diatoms from the McMurdo Dry Valleys and James Ross Island, Antarctica. Botany 86: 1378 - 1392."]}