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A new species was discovered in Taihang Valley, Shanxi province, China. It shared the typical characteristics of the genus Chamaepinnularia, such as chambered striae, vela-covered areolae and small frustules. Valves of Chamaepinnularia taihangensis sp. nov. are linear-lanceolate with capitate apices. Valve margins showed distinct triple curvatures in light microscopy. Axial area and central area narrow, rhombic. The new species was compared with the four related taxa, C. hassiaca, C. justa, C. krookiformis and C. soehrensis. These species differed from the new species in valve outline, valve size, stria density and the shape of the central area. The details of the valves as shown by light and scanning electron microscopy are described. This new species occurs in benthic and epiphyte habitats. We discuss the ecological breadth and systematic position of the genus Chamaepinnularia.

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.

Navicula fuxianturriformis sp. nov., collected from Lake Fuxian, Yunnan Province, China, is described as a new species based on light and scanning electron microscope observations. N. fuxianturriformis sp. nov. has lineolate areolae closed by hymenes internally and a peculiar structure of the raphe system where the raphe is elevated internally on a thin longitudinal rib that is laterally expanded at the central area; features that assign it to the genus Navicula. The key diagnostic features of this new species include: 1) lanceolate valves with the cuneate to apiculate apices, 2) mostly long, slit-like, partly round-rectangular areolae on the valve exterior and round to rectangular areolae internally, 3) external distal raphe fissures that are hooked opposite one another, and 4) the oval-elliptical central area, with two to five pairs of irregularly shortened striae. This combination of features distinguishes N. fuxianturriformis from congers such as N. turriformis, N. turris, N. reinhardtii, N. hoevsgoelreinhardtii, N. mongolreinhardtii, N. apiculatoreinhardtii or N. apiculatoreinhardtii f. biseriata. A discussion of the morphological features of this taxon and morphologically-similar species is presented. These findings increase our understanding about the morphology and distribution of the genus Navicula in China.

Adlafia kociolekii C.Radhakrishnan, Sudipta K.Das, C.E.Wetzel & B.Karthick sp. nov. (Figs 2–43) Description: —LM (Figs 2–28): Valves lanceolate to linear-lanceolate, elliptical, with acute apices: valve length 16– 53.5 μm, width 6–10.5 μm (n=25). Raphe slightly lateral and straight, inflated proximal ends, very slightly deflected to primary side, distal ends deflected in opposite direction. Striae uniseriate, 26–30 in 10 μm, composed of round areolae, radiate at centre, parallel to convergent near apices. Valves with narrow axial area [sternum], central area broad and elliptical in large valves, narrow, straight in smaller ones. Voigt discontinuity is clearly discernible towards both poles. SEM (Figs 29–43): Externally, the raphe system is narrow and not prominent (Figs 29–30). Proximal raphe ends slightly dilated and teardrop-like (Figs 34–35). Hook-like distal ends bend in the opposite direction (Figs 30–33). Uniseriate striae, areolae mostly covered with hymenes, clearly visible only when thoroughly oxidized (Figs 29–31). The shape of the areolae is round to oval near mantle and oval to elongate near axial area. Areolae more regularly arranged on primary side; less regular on secondary side (Fig. 29). Areolae more elongate near the central area (Fig. 34). Internally, raphe is thin and almost straight and the sternum more elevated (Figs 36–37). Distal raphe ends slightly bent, with long raised helictoglossae (Figs 38, 40–41). Proximal raphe ends are deflected in the opposite direction to the distal ends (Fig. 36). Striae form round to elliptical areolae opening on entire valve (Figs. 42–43). Mantle is deep, a rows of areolae is present near to distal ends and terminating with helictoglossae (Fig. 40). Type locality: Panchgotey, Kyongnosla Alpine Sanctuary, Sikkim, India, 27.3197° N, 88.5455° E, 3888 m a.s.l.; attached to moss (epibryophytic) patches on rocks (Agharkar Herbarium of Maharashtra Association (AHMA) #2421, holotype, an example illustrated in Figure 2; Central National Herbarium (CAL), Isotype no. CAL /ALG.60). Etymology: The species name is in the honour of eminent diatomologist Dr John Patrick Kociolek from CU Museum of Natural History, the University of Colorado at Boulder, USA. Ecology and distribution: The type material was aerial in occurrence. The species was also found epilithic in freshwater and in subaerophytic habitats in northeast India. A small population of the taxon was found epipsammic habitat of a stream near Khamrang, Mizoram. Rare occurrences of the taxa were also noted on wet walls in Angori (Meghalaya) and Keitum (Mizoram). The details of the distributions of the taxon in various parts of northeast India, along with the other diatoms growing in consortium, are presented in Table 1., Published as part of Se. Wetzel & Karthick, Balasubramanian, 2023, Adlafia kociolekii sp. nov. (Bacillariophyceae): a new naviculoid diatom from the Eastern Himalayas, India, pp. 62-72 in Phytotaxa 595 (1) on pages 64-66, DOI: 10.11646/phytotaxa.595.1.4, http://zenodo.org/record/7889438

Se.Wetzel, Karthick, Balasubramanian (2023): Adlafia kociolekii sp. nov. (Bacillariophyceae): a new naviculoid diatom from the Eastern Himalayas, India. Phytotaxa 595 (1): 62-72, DOI: 10.11646/phytotaxa.595.1.4, URL: http://dx.doi.org/10.11646/phytotaxa.595.1.4

Navicula sinicomeniscus Li & Metzeltin sp. nov. (LM: Figs 1–10, SEM: 11–16) LM: Valves linear-lanceolate, with cuneate ends and bluntly rounded apices (also the ends of largest specimens are never protracted). Length 55–75 µm, width 16–18 µm. Length/width ratio 3.3–4.1, median 3.7 (n=30). Raphe filiform, almost straight or weakly curved, and occasionally appears lateral. Central raphe ends expanded and inconspicuously deflected to the secondary side of the valve with drop-like central pores. Terminal raphe fissures rather small and bent towards the same side of the valve. Axial area moderately narrow, linear, slightly expanded proximally. Central area comparatively much less expanded, transversally widened, asymmetrical, shape variable, with one or few obviously irregularly shortened central striae. Striae radiate more strongly towards the center, subapical striae almost parallel, density 7–8 in 10 µm. Voigt faults appear indistinct. Areolae coarse and visible, 22–24 in 10 µm. SEM: External views: Raphe almost straight to slightly undulate with central raphe ends dilated, drop-shaped and slightly inclined to the secondary valve side. The terminal fissures clearly hooked in the same direction. Raphe sternum prominently developed, narrow, raised along the raphe, more obviously towards the center (arrow A in Fig. 11). Areolae slit-like (Figs 12, 13), with one row of apical areolae, arranged horizontally, positioned on the valve apex and mantle (arrow B in Fig. 12). Striae uniseriate, with two obviously shortened striae near the central area (arrows C in Fig. 13) and two occasionally intermittent striae (arrows D in Fig. 13). Internal views: Striae uniseriate, irregularly shortened in central area, composed of round-elliptical, roundrectangular areolae, separated by robust silica ribs. Sternum broad and raised, not interrupted, scarcely expanded in the central pore and inclined to the secondary valve side; lacking central area besides the sternum (black arrows in Figs 14, 16). Raphe continuous, lacking an intermissio. Terminal raphe ends terminate in small and knob-like helictoglossae (Fig. 15). Type: CHINA. Yunnan Province: Fuxian Lake, Fuxian 46–1, 24°24.870′ N, 102°50.590′ E, elevation 1720 m asl, Prof. Yan-Ling Li, 28th March 2005 (holotype Praep. Fuxian 46– 1 in Coll. Yan-Ling Li, Yunnan University, Kunming, China = Fig. 4). Etymology: the epithet refers to the most similar established taxon and the country (China) of the type location. Ecology: Navicula sinicomeniscus was found in a low altitude freshwater lake with moderately alkaline pH (8.71) and very low concentrations of nutrients (TN 0.14 mg ̛L- 1, TP 0.02 mg ̛L- 1). The dominant diatom species discovered in this area include Aulacoseira granulata (Ehrenberg) Simonsen (1979: 58) (1.7 %), Cyclotella rhomboideo-elliptica Skuja (1937: 49) (6.9 %), Cyclotella krammeri Håkansson (1990: 263) (46.4 %), Fragilaria crotonensis Kitton (1869: 110) (7.8 %), Stephanodiscus minutulus (Kützing) Cleve & Möller (1882: 300) (1.1 %), Stephanodiscus hantzschii Grunow (in Cleve & Grunow 1880: 121) (8.6 %), and some unidentified species of Achnanthidium Kützing (1844: 152) (6.7 %) and an Amphora Ehrenberg ex Kützing (Kützing 1844: 107) sp. (4.3 %). These entities comprise more than 83 % of all diatoms enumerated in the samples., Published as part of Xiao, Qiao-Zhi, Guo, Ji-Shu, Tang, Zheng-Bin, Kociolek, John Patrick & Li, Yan-Ling, 2023, Navicula sinicomeniscus sp. nov. (Bacillariophyta; Naviculaceae), a new species from southwestern China, pp. 241-252 in Phytotaxa 591 (4) on page 243, DOI: 10.11646/phytotaxa.591.4.1, http://zenodo.org/record/7835506, {"references":["Simonsen, R. (1979) The diatom system: ideas on phylogeny. Bacillaria 2: 9 - 71.","Skuja, H. (1937) Algae. In: Handel-Mazzetti, H. (Ed.) Symbolae Sinicae - Botanische Ergebnisse der Expedition der Akademie der Wissenschaften in Wien nach Sudwest-China 1914 / 1918. J. Springer, Wien, pp. 1 - 106.","Hakansson, H. (1990) A comparison of Cyclotella krammeri sp. nov. and C. schumannii Hakansson stat. nov. with similar species. Diatom Research 5 (2): 261 - 271. https: // doi. org / 10.1080 / 0269249 X. 1990.9705118","Kitton, F. (1869) Notes on New York diatoms with description of a new species Fragilaria crotonensis. Hardwicke's Science-Gossip 5: 109 - 110.","Cleve, P. T. & Moller, J. D. (1882) Diatoms. Part VI. Esatas Edquists Boktryckeri, Upsala. pp. 277 - 324.","Cleve, P. T. & Grunow, A. (1880) Beitrage zur Kenntniss der Arktischen Diatomeen. Kongliga Svenska-Vetenskaps Akademiens Handlingar 17 (2): 1 - 121."]}

Chamaepinnularia taihangensis N.N. Cui & Q. Liu sp. nov. Figs 2–20 LM (Figs 2–11):— Large specimens, linear-lanceolate valves with capitate apices and margins with distinct triple curvatures (Figs 2–8). Small specimens, valves elliptic-lanceolate with capitate apices and with or without distinct triple curvature (Figs 9–11). Length 10–14 μm, width 3.0–3.5 μm. Axial area narrow, rhombic, widening toward the middle of valve and nearly reaching the valve margins. Central area rhombic. Striae slightly radiate in the central area and convergent toward the ends, 20–21 in 10 μm. Raphe straight, proximal raphe ends expanded and bent slightly to the same side, the terminal raphe fissures deflected to the same direction. SEM (Figs 12–20):— Externally, striae composed of elongated chamber-like areolae and covered by vela (Figs 12–16). Raphe straight and filiform. Proximal raphe ends expanded and unilaterally deflected (Figs 12, 14). Terminal raphe curved to hook-shaped and continuing onto the mantle (Figs 12, 13, 16). Axial area narrow, rhombic. Fascias present, forming rhombic central areas (Fig. 12). Internally, areolae openings interrupted by siliceous bridge that divides striae in two parts (Fig. 17), one small, rounded and located on the valve face-mantle junction, whereas the other elongated and located on the valve face. Proximal raphe ends unilaterally hooked (Fig. 19). Terminal raphe ends weakly deflected and terminated as well-developed helictoglossae (Figs 18, 20). Type:— CHINA. Taihang Valley, Shanxi Province, epiphyton, 35°12’ N, 113°20’ E, 1760 m asl., June 2020 (holotype SXU! slide THS202006086 = Fig. 3, Freshwater Algal Herbarium of Shanxi University, Taiyuan, China; isotype: COLO slide, J.P. Kociolek Collection). Etymology:— Named for the region in which it was found. Ecology and distribution:— C. taihangensis sp. nov. was found in Eight spring gorge, Taihang Valley. Conditions in the type material were as follows: Temperature 17.2 ºC, pH = 8.32, EC = 318.6 µs̽ cm-1, AT = 679.4 mm Hg, dissolved oxygen = 9.57 mg ̽L- 1 and total dissolved solids = 279.50 mg ̽L- 1. Associated diatom species: — The type population of C. taihangensis sp. nov. was found in samples associated with other species. In THS202006086, two dominant species were Achnanthidium minutissimum (Kützing) Czarnecki (1994: 157) (25.8 %) and Delicata sinensis Krammer & Metzeltin (2003: 121) (Krammer 2003) (24.0 %). Diatoma moniliformis (Kützing) D.M. Williams (2012: 260) represented 7.5 % of the community with Cymbopleura kuelbsii (Krammer 2003: 94) (5.8 %), Achnanthidium rivulare Potapova & Ponader (2004: 36) (4.0 %), Achnanthidium pyrenaicum (Hustedt) H.Kobayasi (1997: 148) (3.8 %), Denticula elegans Kützing (1844: 44) (3.0 %), Navicula antonii Lange-Bertalot (2000: 155) (Rumrich, U., Lange-Bertalot, H. & Rumrich, M. 2000) (2.8 %), and Chamaepinnularia taihangensis sp. nov. (2.0 %)., Published as part of Cui, Nini, Liu, Qi, Liu, Xudong, Nan, Fangru, Kociolek, John Patrick & Xie, Shulian, 2023, Chamaepinnularia taihangensis sp. nov. (Bacillariophyceae), a new diatom species from Taihang Valley, Shanxi province, China, pp. 184-192 in Phytotaxa 587 (2) on pages 185-186, DOI: 10.11646/phytotaxa.587.2.7, http://zenodo.org/record/7731953, {"references":["Czarnecki, D. B. (1994) The freshwater diatoms culture collection at Loras College, Dubuque, Iowa. Memoirs of the California Academy of Sciences 17: 155 - 174.","Krammer, K. (2003) Cymbopleura, Delicata, Navicymbula, Gomphocymbellopsis, Afrocymbella. In: Diatoms of Europe, Diatoms of the European Inland waters and comparable habitats. Vol. 4. pp. 1 - 529.","Williams, D. M. (2012) Diatoma moniliforme: Commentary, relationships and an appropriate name. Nova Hedwigia Beiheft 141: 255 - 261.","Potapova, M. G. & Ponader, K. C. (2004) Two common North American diatoms, Achnanthidium rivulare sp. nov. and A. deflexum (Reimer) Kingston: morphology, ecology and comparison with related species. Diatom Research 19 (1): 33 - 57. https: // doi. org / 10.1080 / 0269249 X. 2004.9705606","Kutzing, F. T. (1844) Die Kieselschaligen Bacillarien oder Diatomeen. Nordhausen: zu finden bei W. Kohne, 152 pp. https: // doi. org / 10.5962 / bhl. title. 64360"]}

Brachysira heteropolaris Van de Vijver sp. nov. (Figs 1 –26 LM) Valves heteropolar, clavate. Valve outline lanceolate with convex margins. Apices not protracted, acutely rounded. At footpole slightly more elongated than at headpole. Valve dimensions (n=40): length 18–35 µm, width 6–8 µm, largest width above the valve middle. Axial area very narrow, linear. Two longitudinal ridges bordering the axial area, running from valve apices to central area. Central area usually small, rounded to elliptical, and raised. Occasionally valves with slightly larger central areas observed (see for instance Figs 7, 11). Raphe filiform, raphe branches straight with indistinct, simple central raphe endings. Striae radiate throughout the entire valve length, well discernible in LM, 28–30 in 10 µm. Irregular, short ridges present crossing the striae (e.g. Figs 1, 4, 8 & 14). Type:— UNITED KINGDOM. Loch Canmor 2 (=Loch Kinord), Aberdeenshire 2, Scotland, prep. Weissflog, slide IX-18-A 8 in BR! (holotype slide BR-4777 = Fig. 5). Registration: —http://phycobank.org/103608 Etymology:—The specific epithet “ heteropolaris ” refers to the heteropolar valve outline. Ecology & associated diatom flora:—The Weissflog slide was prepared based on material from Loch Canmor. In the Van Heurck collection in BR (Belgium), several slides from Loch Canmor are conserved, two of them labelled “Loch Canmor 2 – Aberdeenshire – Schottland ” (slides IX-18-A8 &A10). Loch Canmor, nowadays called Loch Kinord is a small, freshwater lake at Muir of Dinnet (Aberdeenshire, Scotland), a few kilometers east of the village of Ballater. This shallow (max. 2m depth) freshwater loch is a part of the Muir of Dinnet National Nature Reserve and an important resting place for wintering birds. The loch is characterised as being oligotrophic and low-alkaline (Bennion et al. 2004, Lang et al. 2012). The diatom flora in the slide is characterised by a high biodiversity. Dominant species include Brachysira follis, B. brebissonii, B. confusa, Encyonema neogracile Krammer (1997a: 177), Encyonopsis cesatii var. geitleri Krammer (1997b: 154), Frustulia saxonica Rabenhorst (1853: 50), Gomphonema coronatum Ehrenberg (1840: 211), G. lagerheimii A. Cleve (1895: 22), Tabellaria fenestrata (Lyngbye 1819: 180) Kützing (1844: 127), and several Eunotia and Pinnularia species. This species composition reflects dystrophic to oligo-trophic, circumneutral to acidic, oligosaprobic conditions (Lange-Bertalot & Moser 1994, Lange-Bertalot et al. 2017). Although most species in the slide are acidophilous, several species preferring calcium-carbonate enriched conditions such as Brachysira styriaca, Eucocconeis flexella (Kützing 1844: 80) F. Meister (1912: 95), and Navicula radiosa Kützing (1844: 91) are present, though in low abundances. Some of these, such as N. radiosa, could, however, also survive in low-alkaline conditions, though not in high abundances (Lange-Bertalot 2001)., Published as part of Vijver, Bart Van De, 2023, Brachysira heteropolaris, a new diatom (Brachysiraceae, Bacillariophyta) species observed in an historic Weissflog slide from Scotland (UK), pp. 47-52 in Phytotaxa 587 (1) on pages 48-49, DOI: 10.11646/phytotaxa.587.1.6, http://zenodo.org/record/7710708, {"references":["Bennion, H., Fluin, J. & Simpson, G. L. (2004) Assessing eutrophication and reference conditions for Scottish freshwater lochs using subfossil diatoms. Journal of Applied Ecology 41: 124 - 138. https: // doi. org / 10.1111 / j. 1365 - 2664.2004.00874. x","Lang, P., Krokowski, J., Ross, N. & Doughty, R. (2012) The rare green alga Pediastrum privum (Chlorophyta, Sphaeropleales) in a Scottish kettle loch: new to British freshwaters. The Glasgow Naturalist 25: 139 - 142.","Krammer, K. (1997 a) Die cymbelloiden Diatomeen. Eine Monographie der weltweit bekannten Taxa. Teil 1. Allgemeines und Encyonema Part. Bibliotheca Diatomologica 36: 1 - 382.","Krammer, K. (1997 b) Die cymbelloiden Diatomeen. Eine Monographie der weltweit bekannten Taxa. Teil 2. Encyonema Part., Encyonopsis und Cymbellopsis. Bibliotheca Diatomologica 37: 1 - 469.","Rabenhorst, L. (1853) Die Susswasser-Diatomaceen (Bacillarien.): fur Freunde der Mikroskopie. pp. 1 - 72. https: // doi. org / 10.5962 / bhl. title. 8348","Ehrenberg, C. G. (1840) Characteristik von 274 neuenArten von Infusorien. Bericht uber die zur Bekanntmachung geeigneten Verhandlungen der Koniglich-Preussischen Akademie der Wissenschaften zu Berlin 1840: 197 - 219.","Cleve, A. (1895) On recent freshwater diatoms from Lule Lappmark in Sweden. Bihang till Kongliga Svenska Vetenskaps-Akademiens Handlingar 21 (Afh. III, 2): 1 - 44.","Lyngbye, H. C. (1819) Tentamen hydrophytologiae danicae continens omnia hydrophyta cryptogama Daniae, Holsatiae, Faeroae, Islandiae, Groenlandiae hucusque cognita, systematice disposita, descripta et iconibus illustrata, adjectis simul speciebus norvegicis. pp. [i] - xxxii, [1] - 248, 70 pls. Hafniae [Copenhagen]: typis Schultzianis, in commissis Librariae Gyldendaliae. https: // doi. org / 10.5962 / bhl. title. 6079","Kutzing, F. T. (1844) Die Kieselschaligen Bacillarien oder Diatomeen. Nordhausen. pp. 1 - 152. https: // doi. org / 10.5962 / bhl. title. 64360","Lange-Bertalot, H. & Moser, G. (1994) Brachysira. Monographie der Gattung und Naviculadicta nov. gen. Bibliotheca Diatomologica 29: 1 - 212.","Lange-Bertalot, H., Hofmann, G., Werum, M. & Cantonati, M. (2017) Freshwater benthic diatoms of Central Europe: over 800 common species used in ecological assessment. English edition with updated taxonomy and added species. Schmitten-Oberreifenberg: Koeltz Botanical Books; p. 1 - 942.","Meister, F. (1912) Die Kieselalgen der Schweiz. Beitrage zur Kryptogamenflora der Schweiz. Materiaux pour la flore cryptogamique suisse. Vol. IV, fasc. 1. pp. [i] - vi, [1] - 254.","Lange-Bertalot, H. (2001) Navicula sensu stricto. 10 Genera separated from Navicula sensu lato. Frustulia. Diatoms of Europe 2: 1 - 526."]}

We present light and scanning electron microscopical observations on two new species of Navicula Bory sensu stricto from Southeast Asia. Navicula winoniformis Chudaev, Glushchenko, Kulikovskiy & Kociolek, sp. nov. differs from taxa with similar outline and size by the combination of simple drop-like external raphe endings deflected to the primary valve side, presence of well-developed external longitudinal grooves and relatively low lineolae density. Navicula sparsilineolata Chudaev, Glushchenko, Kulikovskiy & Kociolek, sp. nov. can be discriminated from the taxa of similar valve shape and size by consistently lower lineolae density, and from the majority of them also by the structure of external proximal raphe endings with small projections in proximal parts and larger triangular insertions in distal parts. Some remarks on Navicula species diversity and its distribution in the Southeast Asia are given.

During the analysis of an historic slide of Loch Canmor, Aberdeenshire (Scotland, UK) prepared by Eugene Weissflog and conserved in the Van Heurck collection (BR, Belgium), an unknown, heteropolar Brachysira taxon was observed that could not be identified using the currently available literature. The new species, described as Brachysira heteropolaris sp. nov., is characterised in having a strictly heteropolar, broadly lanceolate valve outline with non-protracted, acutely rounded apices. The new species was observed in a dystrophic-oligotrophic, weakly acidic lake, based on the analysis of the composing diatom flora, dominated by several Brachysira species, Gomphonema coronatum and Encyonopsis cesatii var. geitleri.

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)., 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 page 12, DOI: 10.11646/phytotaxa.572.1.1, http://zenodo.org/record/7305672, {"references":["Peragallo, M. (1921) Diatomees d'eau douce et diatomees d'eau salee. In: Deuxieme Expedition Antarctique Francaise (1908 - 1910) commandee par le Dr. Jean Charcot. Sciences Naturelles, Documents Scientifiques, Botanique, Masson et Cie, pp. 96 + Pl. https: // doi. org / 10.5962 / bhl. title. 64272","Williams, D. M. (1988) Tabulariopsis, a new genus of marine araphid diatom, with notes on the taxonomy of Tabularia Williams et Round. Nova Hedwigia 47: 247 - 254.","Frenguelli, J. & Orlando, H. A. (1958) Diatomeas y silicoflagelados del sector Antartico Sudamericano. Instituto Antartico Argentino Publicacion No. 5: 1 - 191.","Fernandes, L. F. & Sar, E. A. (2009) Fine morphology of Gomphonema margaritae Frenguelli & Orlando and its validation and transfer to Tripterion Holmes, Nagasawa & Takano. Diatom Research 24: 63 - 78. https: // doi. org / 10.1080 / 0269249 X. 2009.9705783"]}

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).

Placoneis asymmetricus Glushchenko, Kezlya, Kulikovskiy & Kociolek, sp. nov. (Figs 2-4) HOLOTYPE. — Vietnam. Đồng Nai Province, Cát Tiên National Park, from soil sampled at Đồng Nai riverside, 11°26’05.6”N, 107°25’44.8”E, 03.VI.2019, E.S. Gusev & E.M. Kezlya, slide no. 06728 (oxidized material of cultured strain VP57). Deposited in the collection of Maxim Kulikovskiy at the Herbarium of the Institute of Plant Physiology, Russian Academy of Science, Moscow, Russia (Fig. 2P). ISOTYPE. — Same data as holotype, slide no. 06728a. Deposited in the collection of the Main Botanical Garden of the Russian Academy of Science, Moscow, Russia (MHA). TYPE LOCALITY. — Vietnam. Đồng Nai Province, Cát Tiên National Park, Đồng Nai riverside, 11°26’05.6”N, 107°25’44.8”E. ETYMOLOGY. — The specific epithet refers to the typical asymmetry of the valves of this species. SEQUENCE DATA. — Nuclear-encoded SSU rDNA partial sequence (GenBank accession: MW 979509), plastid gene rbc L partial sequence (GenBank accession: MW 987572). DISTRIBUTION. — So far only known from the type locality. DESCRIPTION LM (Fig. 2) Cells solitary, rectangular in girdle view, with a single chloroplast with medially positioned centre and lobes beneath both valves (Fig. 2 A-I). Chloroplasts share the characteristic organization typical for the genus (Mereschkowsky 1903; Cox 1987, 2003). The chloroplast is single, large, and extends along the inner surface of the cell. The central column (isthmus) is offset to one side from the central axis and forms a slight bend. Libroplast is missing or represented by only one granule (Fig. 2A, F). The chloroplast has four irregular outgrowths (similar to petals) extending from the isthmus. Valve are linear-elliptical, slightly asymmetric along the longitudinal axis (Fig. 2 J-Z). Apices are bluntly rostrate, often asymmetric, breadth 1.3-2.0 µm. Valve length 10.3- 15.4 µm, valve width 6.0-6.8 µm. Axial area narrow, almost linear, very slightly wided towards the valve middle. Central area is absent. Raphe filiform, straight, central pores are small. The structure of distal raphe ends not discernible in the LM. Striae radiate, 17-21 in 10 µm, in the valve middle 2-3 irregularly shortened striae are present on each side. Areolae not resolvable in LM. SEM external views (Fig. 3) Valve face is flat. Raphe narrow, linear (Fig. 3A). Proximal raphe ends straight, small, slightly expanded (Fig. 3B). Distal raphe ends hook-shaped, extending to the valve mantle and unilaterally bent (Fig. 3A, C). Striae composed of 3-11 rounded or weakly elongated areolae, continuing onto the valve mantle. Areolae 45-50 in 10 µm. Stigma is absent. SEM internal views (Fig. 4) The raphe is straight (Fig. 4A). Proximal raphe ends are hooked-shaped and deflected to one side (Fig. 4B). Distal ends terminating on small helictoglossae and may be slightly deflected to opposite sides (Fig. 4A, C). The striae are bordered by broad interstriae (virgae) (Fig. 4C). Areolae small, square or round.Two isolated areolae are present at the apices (Fig. 4C). Volate occlusions were not preserved during the material treatment., Published as part of Kezlya, Elena, Glushchenko, Anton, Kociolek, John Patrick, Maltsev, Yevhen, Genkal, Sergey & Kulikovskiy, Maxim, 2022, A new species of Placoneis Mereschkowsky (Bacillariophyceae: Cymbellales) from wet soils in southern Vietnam, pp. 177-188 in Cryptogamie, Algologie 20 (11) on pages 180-181, DOI: 10.5252/cryptogamie-algologie2022v43a11, http://zenodo.org/record/7829344, {"references":["MERESCHKOWSKY C. 1903. - Uber Placoneis, ein neues Diatomeen- Genus. Beihefte zum Botanischen Centralblatt 15 (1): 1 - 30.","COX E. J. 1987. - Placoneis Mereschkowsky: the re-evaluation of a diatom genus originally characterized by its chloroplast type. Diatom Research 2 (2): 145 - 157. https: // doi. org / 10.1080 / 0269 249 X. 1987.9704994","COX E. J. 2003. - Placoneis Mereschkowsky revisited: resolution of several typification and nomenclatural problems, including the generitype. Botanical Journal of the Linnean Society 141 (1): 53 - 83. https: // doi. org / 10.1046 / j. 1095 - 8339.2003.00115. x"]}

Kezlya, Elena, Glushchenko, Anton, Kociolek, John Patrick, Maltsev, Yevhen, Genkal, Sergey, Kulikovskiy, Maxim (2022): A new species of Placoneis Mereschkowsky (Bacillariophyceae: Cymbellales) from wet soils in southern Vietnam. Cryptogamie, Algologie 20 (11): 177-188, DOI: 10.5252/cryptogamie-algologie2022v43a11, URL: http://dx.doi.org/10.5252/cryptogamie-algologie2022v43a11

Hippodonta mudumalaiensis A.Vigneshwaran & B.Karthick sp. nov. (Figs 2–39, Fig. 22 represents the holotype) Description:— LM (Figs 2–29): Cells solitary, valves narrow-lanceolate to rhombic-lanceolate with broadly rounded apices. Valve length 13.0–20.0 μm, width 5.0–6.2 μm (n=67). Axial area narrow-linear, tilted, slightly asymmetric to the apical axis. Central area broadened with short single striae, shorter striae present at any one side; Striae radiate near centre and parallel near apices; no fascia is formed. Raphe linear-filiform, weakly pronounced, small teardrop-shaped and closely spaced central endings. Distal ends of raphe discernible in LM, equally pronounced as central endings, teardrop-shaped. Raphe distal ends positioned before terminal area or weakly advancing into slightly curved towards valve side. Terminal area distinguishable in LM, narrow, lunate and cap-like. Striae coarse, evenly spaced throughout valve, weakly to moderately radiate in the middle, becoming parallel or weakly convergent towards ends, 10–12/10 μm. Lineolae not discernible in LM. SEM (Figs 30–39): Externally (Figs 30–34), valves with flat face and slightly convex central area (Figs 30–32). Axial area slightly asymmetric (Fig. 30). Proximal raphe endings strongly pronounced, teardrop-shaped and bent towards same side as distal ends (Figs 31, 32). Terminal pores of raphe distinct, advancing towards the terminal area and deflected towards one valve side (Figs 33, 34). Terminal septa clearly developed and bordered by semi circumpolar (Figs 33, 34). Slit-like elongated areolae positioned on apical valve mantle, 40–50 in 10 μm. Striae uniseriate throughout valve, simple apically elongated lineolate, 50–60/10 μm. Rarely near central area transapically elongated lineolate areolae (Fig. 32). Striae in the central area clearly shortened, one side longer than the other side (Figs 30, 32). Prominent hyaline area present throughout the valve mantle (Fig. 31). Internally (Figs 35–39), striae placed in shallow linear depressions. Areolae covered by hymens. Central raphe endings simple, linear and gradually disappear (Fig. 38). Small wedge-shaped hyaline area present at centre. Distal raphe endings terminate on small defused helictoglossae (Figs 35, 36, 39). Terminal area internally prominent and bordered by hymenated linear depressions (Fig. 39). Type:— INDIA. Masinagudi, Nilgiris, Tamil Nadu. Stream, 11°33’14.8” N, 76°37’21.6” E, altitude 940 m asl, was collected by Mr. Kannan Govindarajan. (holotype AHMA! Slide #1752 = Fig. 22). Type material AHMA #1752. Habitat:— Epilithic, submerged stones in the stream. Water chemistry measurements includes pH of 7.35, nitrate (low range, NO 3 –) 0.03 mg ∙L- 1; dissolved oxygen (DO) 6.84 mg ∙L- 1; conductivity: 635 μS∙ cm-1; water temperature: 23.6 °C, total dissolved solids (TDS) 276 mg ∙L- 1. Etymology:— The specific epithet “ mudumalaiensis ” refers to the name of the location from which this new taxon is identified., Published as part of Vigneshwaran, Anbukkarasu, Wadmare, Neha & Karthick, Balasubramanian, 2022, A new species of Hippodonta Lange-Bertalot, Metzeltin & Witkowski (Bacillariophyceae, Naviculales) from the Western Ghats, India, pp. 219-228 in Phytotaxa 558 (2) on pages 222-223, DOI: 10.11646/phytotaxa.558.2.5, http://zenodo.org/record/7002983

Vigneshwaran, Anbukkarasu, Wadmare, Neha, Karthick, Balasubramanian (2022): A new species of Hippodonta Lange-Bertalot, Metzeltin & Witkowski (Bacillariophyceae, Naviculales) from the Western Ghats, India. Phytotaxa 558 (2): 219-228, DOI: 10.11646/phytotaxa.558.2.5, URL: http://dx.doi.org/10.11646/phytotaxa.558.2.5

Key to species of the genus Fogedia 1a Cells are heterovalvate.............................................................................................................................................. F. heterovalvata 1b Cells are not heterovalvate.................................................................................................................................................................2 2a Valves with lateral area.......................................................................................................................................................................3 2a Valves without lateral area..................................................................................................................................................................9 3a Central area with stauros-like transverse expansion..........................................................................................................................4 3b Central area without transverse expansion.........................................................................................................................................5 4a Striae 16-18 in 10 μm............................................................................................................................................................. F. acuta 4b Striae 9-13, Areolae 35-40 in 10 μm............................................................................................................................. F. finmarchica 4c Striae 10-12, Areolae 26-29 in 10 μm.............................................................................................................................. F. krammeri 5a External terminal raphe fissure hooked..............................................................................................................................................6 5b External terminal raphe fissure simple or slightly bent......................................................................................................................8 6a Areolae 26-29 in 10 μm............................................................................................................................................................. F. lyra 6b Areolae 35-40 in 10 μm......................................................................................................................................................................7 7a Valves 15.5-18.5 μm long, 6.5-7 μm wide.................................................................................................................. F. christensenii 7b Valves 26-37 μm long, 8-9 μm wide............................................................................................................................... F. giffeniana 8a Striae parallel in the middle of the valve................................................................................................ F. giffeniana var. yemenitica 8b Striae radiate in the middle of the valve.......................................................................................................................... F. geisslerae 9a Valves elliptic with broad apices........................................................................................................................................ F. elliptica 9b Valves with distinctively protracted apices......................................................................................................................................10 10a Striae parallel in the middle of the valve.......................................................................................................................... F. orientalis 10b Striae radiate in the middle of the valve...........................................................................................................................................11 11a Striae 12-14, Areolae 15 in 10 μm...................................................................................................................................... F. coreana 11b Striae 18-21, Areolae 21-24 in 10 μm.................................................................................................................................... F. densa

The genus Fogedia was first established in 1997 based on Navicula giffeniana as a type species. The important features of the genus were the presence of lateral area, the location of the internal raphe fissure, and the simple apical raphe endings. Later, the generic description of Fogedia has been emended with the reports of four new species to the science having the genus to include twelve members in total. A thirteenth member of the genus has been observed in tidal flats of the Yellow Sea, and here we describe the species as Fogedia orientalis sp. nov. based on observations with the light (LM) and scanning electron microscope (SEM). Regional distribution of the species in the Northeast Asia is also discussed. The new Fogedia species is morphologically similar to F. densa in terms of small cell size as wells as the absence of a lateral area, however, the density and pattern of striae are clearly different from each other. Morphological characteristics and global occurrences of the thirteen Fogedia species has been provided.

Fogedia orientalis Kim, Khim, Witkowski and Park, sp. nov. (Figs 2–15) LM observations (Figs 2–9): Valves are elliptic-lanceolate to lanceolate, with acutely-rounded protracted apices, 11.5–21 μm in length and 5.5–6.5 μm in width. External central raphe endings are punctiform, while external apical raphe endings are slightly bent to the same direction. Axial area is very narrow and linear throughout. Central area is small and square in shape, formed by two shortened striae one on each side. Typical lateral area is absent in the valve. Transapical striae parallel in the middle of the valve then becoming slightly radiate towards apices, 15–18 in 10 μm. Voigt discordance is barely discernible with LM. SEM observations (Figs 10–15): External valve face is flat with an abrupt transition to the valve mantle. Axial area is straight and symmetrical with very narrow raphe-sternum (Fig. 10). External central raphe endings are slightly expanded (Figs 10–11). The areolae and transapical striae are evenly spaced. Certain areolae near the central area exhibit different shape compared to other areolae, often being circular in shape. The raphe slit runs relatively straight from the central area to the helictoglossa which is relatively simple and small without twist (Figs 13, 15). Areolae are internally occluded by thin hymenes. Type:— Gyehwa tidal flat (35°46’ N, 126°36’ E; KO-GY), Korea. Type material collected on 6 August 2003 by Dr J. Ryu. Holotype slide deposited in MABIK (MABIK D10042862). Etymology:—The species name ‘ orientalis ’ is derived from the Latin ‘oriental’ meaning east, because the species is widely distributed in Northeast Asia. Distribution:—The species was also observed from various tidal flats on the Korean coast (a mudflat at Gyeonggi Bay, a sandflat in Saemangeum, and a mixed flat near Lake Shihwa) and Chinese coast (three sandflats at Qinhuangdao and Yingkou, in a mixed flat at Yingkou, and in a mudflat at Yancheng) of the Yellow Sea. The species was also found in a sandflat at Minamiarao in the Ariake Sea, Japan. Thus F. orientalis is probably widespread along the coast of the Yellow Sea. Differential diagnosis:—The species is similar to Fogedia densa in its valve outline, small cell size, and the absence of a lateral area. However, the pattern of striae in F. orientalis is parallel in the middle of the valve, while F. densa has a distinctively radiate striae pattern, thus the two species are readily discernable. Stria density is also much sparser in F. orientalis compared to F. densa., Published as part of Kim, Hyesuk, Khim, Jong Seong, Witkowski, Andrzej & Park, Jinsoon, 2022, A new species of Fogedia (Bacillariophyceae) from tidal flats of Northeast Asia, pp. 77-84 in Phytotaxa 554 (1) on pages 79-80, DOI: 10.11646/phytotaxa.554.1.6, http://zenodo.org/record/6809823

Key to species of the genus Fogedia 1a Cells are heterovalvate.............................................................................................................................................. F. heterovalvata 1b Cells are not heterovalvate.................................................................................................................................................................2 2a Valves with lateral area.......................................................................................................................................................................3 2a Valves without lateral area..................................................................................................................................................................9 3a Central area with stauros-like transverse expansion..........................................................................................................................4 3b Central area without transverse expansion.........................................................................................................................................5 4a Striae 16-18 in 10 μm............................................................................................................................................................. F. acuta 4b Striae 9-13, Areolae 35-40 in 10 μm............................................................................................................................. F. finmarchica 4c Striae 10-12, Areolae 26-29 in 10 μm.............................................................................................................................. F. krammeri 5a External terminal raphe fissure hooked..............................................................................................................................................6 5b External terminal raphe fissure simple or slightly bent......................................................................................................................8 6a Areolae 26-29 in 10 μm............................................................................................................................................................. F. lyra 6b Areolae 35-40 in 10 μm......................................................................................................................................................................7 7a Valves 15.5-18.5 μm long, 6.5-7 μm wide.................................................................................................................. F. christensenii 7b Valves 26-37 μm long, 8-9 μm wide............................................................................................................................... F. giffeniana 8a Striae parallel in the middle of the valve................................................................................................ F. giffeniana var. yemenitica 8b Striae radiate in the middle of the valve.......................................................................................................................... F. geisslerae 9a Valves elliptic with broad apices........................................................................................................................................ F. elliptica 9b Valves with distinctively protracted apices......................................................................................................................................10 10a Striae parallel in the middle of the valve.......................................................................................................................... F. orientalis 10b Striae radiate in the middle of the valve...........................................................................................................................................11 11a Striae 12-14, Areolae 15 in 10 μm...................................................................................................................................... F. coreana 11b Striae 18-21, Areolae 21-24 in 10 μm.................................................................................................................................... F. densa, Published as part of Kim, Hyesuk, Khim, Jong Seong, Witkowski, Andrzej & Park, Jinsoon, 2022, A new species of Fogedia (Bacillariophyceae) from tidal flats of Northeast Asia, pp. 77-84 in Phytotaxa 554 (1) on pages 82-83, DOI: 10.11646/phytotaxa.554.1.6, http://zenodo.org/record/6809823

During a survey of benthic diatoms from the Bulgarian Black Sea coast near the historic town of Sozopol, we found a high diversity of Amphora sensu lato taxa at a single site and on a single type of artificial substratum. A total of 40 taxa from the current genera Amphora, Halamphora, Seminavis and Tetramphora were recognized during light microscopy (LM) and scanning electron microscopy (SEM) observations. We were able to identify with a high degree of certainty only 6 taxa based on the literature, whereas for 19 taxa (or almost 50% of all taxa) we could not find even sufficiently similar species, and they remained unidentified to species level. Many of the species had small valve dimensions. The paper presents all taxa with short morphometric data and microphotographs under LM and SEM, where possible. All taxa are discussed and compared with similar known taxa. The illustrative materials in earlier works from the Black Sea and species descriptions, where such were available, were also consulted. Diversity of Amphora sensu lato in the Black Sea coastal waters seems to be underestimated, whereas some of the past records are uncertain. A discussion on the current state of knowledge of Amphora sensu lato species from the Black Sea is given.

figs 2A–C & 8D: Amphora cf. proteus W.Gregory Morphometric data:— L: 40.7–52.5 µm; W: 8.5–9.8 µm; DS: 11–13; VS: 10–12 (n=5). Notes:— These valves do not fit entirely A. proteus since they usually have a single elongated areola on the ventral side, and not two rows of areolae as in A. proteus (Schoeman & Archibald 1986, Levkov 2009), although a very short second row could be present (figs 2B–C), as in some of the valves of A. proteus in Levkov (2009, Pl. 248: 6). Valves are also slightly smaller than those of the original A. proteus (length> 50 µm, width> 9 µm, Schoeman & Archibald 1986, Levkov 2009). However, the only valve we were able to find under SEM (fig. 8D) showed the presence of dimple-like depressions internally near the elongated central nodule, as in A. proteus (Levkov 2009, Pl. 248: 6). Another similar taxon in both dimensions and striation pattern, A. proteoides f. varians Proshkina-Lavrenko, was described from the Black Sea (Proshkina-Lavrenko 1963). Unfortunately, it is only known from her description and drawings (Proshkina-Lavrenko 1963, Pl. IX: 1–4), presenting insufficient details for species separation nowadays., Published as part of Zidarova, Ralitsa, Ivanov, Plamen, Hristova, Ognyana, Dzhurova, Boryana & Hineva, Elitsa, 2022, The unexpected diversity in Amphora sensu lato (Bacillariophyta) at Sozopol Bay, the western Black Sea, pp. 103-127 in Phytotaxa 544 (2) on page 106, DOI: 10.11646/phytotaxa.544.2.1, http://zenodo.org/record/6503793, {"references":["Schoeman, F. R. & Archibald, R. E. M. (1986) Observations on Amphora species (Bacillariophyceae) in the British Museum (Natural History). V. Some species from the subgenus Amphora. Journal of South African Botany 52: 425 - 437. https: // doi. org / 10.1016 / S 0254 - 6299 (16) 31507 - 1","Levkov, Z. (2009) Amphora sensu lato. Diatoms of Europe 5: 1 - 916.","Proshkina-Lavrenko, A. I. (1963) Diatoms from the Black Sea benthos. Akademii Nauk USSR, Moscow-Leningrad, 243 pp. [in Russian]"]}

Navicula fuxianturriformis Y.-L. Li, J.-S. Guo & Kociolek, sp. nov. (Figs 1–19) LM (Figs 1–13): Valves lanceolate with cuneate to apiculate apices, nearly symmetrical about the apical axis, with a moderately inflated central portion gradually tapering to the ends. Length 33.5–47.0 µm, width 10.5–12.0 μm, length/width ratio 3.2–3.8, median 3.5 (n = 30). Raphe filiform to slightly lateral. External central raphe ends expanded, appearing as tear drop-like central pores. External terminal raphe fissures short. Axial area narrow-linear, not or slightly expanded proximally. Central area weekly expanded transapically, barely symmetrical, oval-elliptical, with two to five pairs of irregularly shortened striae proximally. Striae nearly parallel at the poles, becoming slightly radiate towards the valve centre, 9–12 in 10 μm. Areolae visible, 36–40 in 10 μm. SEM: Valve exterior (Figs 14–16): the central raphe ends almost straight with simple drop-like, expanded central pores (Fig. 16). The terminal fissures appear undulate, hooked in opposite directions from one another (Figs 14–15). Striae uniseriate (Figs 14–15). Areolae mostly slit-like, partly round-rectangular around central area (Figs 15–16). Areolae may contain small occlusions (Fig. 16). Valve interior (Figs 17–19): striae uniseriate, formed by round to rectangular areolae, separated by robust silica ribs (Figs 18–19). Terminal raphe ends offset slightly and terminate in small, knob-like helictoglossae (Fig. 18). Helictoglossae terminate on a small, inwardly projected platform at each apex. Apical areolae rectangular, arranged horizontally and raphe-sternum slightly elevated above the rest of valve (Fig. 19). Type:— CHINA. Yunnan Province: Fuxian Lake, FXH1, 24°24.870′ N, 102°50.590′ E, elevation 1720 m asl., samples collected by Prof. Yan-Ling Li, 28th March 2005. Holotype FXH200532801 in surficial sediments. Yan-Ling Li, Yunnan University, Kunming, China. Figure 4 is of the holotype. Etymology:— Specific epithet is compound name referring to the relation of this species to N. turriformis and its type locality in Lake Fuxian. Ecology:— Navicula fuxianturriformis is known from the surficial sediments, situated at 1720 m a.s.l. At this site, diatom assemblages were dominated by Cyclotella krammeri Håkansson (1990: 261–271), Stephanodiscus hantzschii Grunow (in Cleve et Grunow 1880: 121), Fragilaria crotonensis Kitton (1869: 109–110), Cyclotella rhomboideo - elliptica Skuja (1937: 1–106), Aulacoseira granulata (Ehrenberg) Simonsen (1979: 9–71), Stephanodiscus minutulus (Kützing) Cleve et Möller (1882: 277–324), and several at present unidentified species of Achnanthes Bory de St. - Vincent (1822b) and Amphora Ehrenberg ex Kützing (Kützing 1844: 152)., Published as part of Zhang, Yu, Guo, Ji-Shu, Kociolek, John Patrick & Li, Yan-Ling, 2022, Navicula fuxianturriformis sp. nov. (Bacillariophyceae), a new species from southwest China, pp. 141-152 in Phytotaxa 541 (2) on pages 143-144, DOI: 10.11646/phytotaxa.541.2.4, http://zenodo.org/record/6388702, {"references":["Hakansson, H. (1990) A comparison of Cyclotella krammeri sp. nov. and C. schumannii Hakansson stat. nov. with similar species. Diatom Research 5 (2): 261 - 271. https: // doi. org / 10.1080 / 0269249 X. 1990.9705118","Cleve, P. T. & Grunow, A. (1880) Beitrage zur Kenntniss der Arktischen Diatomeen. Kongliga Svenska-Vetenskaps Akademiens Handlingar 17 (2): 1 - 121.","Kitton, F. (1869) Notes on New York diatoms with description of a new species Fragilaria crotonensis. Hardwicke's Science-Gossip 5: 109 - 110.","Skuja, H. (1937) Algae. In: Handel-Mazzetti, H. (Ed.) Symbolae Sinicae - Botanische Ergebnisse der Expedition der Akademie der Wissenschaften in Wien nach Sudwest-China 1914 / 1918. J. Springer, Wien, pp. 1 - 106.","Simonsen, R. (1979) The diatom system: ideas on phylogeny. Bacillaria 2: 9 - 71.","Cleve, P. T. & Moller, J. D. (1882) Diatoms. Esatas Edquists Boktryckeri, Upsala. part VI: 277 - 324.","Kutzing, F. T. (1844) Die Kieselschaligen. Bacillarien oder Diatomeen, Nordhausen, 152 pp, 30 pls. https: // doi. org / 10.5962 / bhl. title. 64360"]}

54. Seminavis cf. pusilla (Grunow) Cox & Reid (Figs 126, 127) Basionym: Cymbella pusilla Grunow. Synonym: Navicymbula pusilla (Grunow) Krammer. Type locality: Kunsee; Bayonne. References: Cox & Reid 2004, p. 60; Cavalcante et al. 2014, p. 258, figs 1, 2; Donadel 2018, p. 14, figs 3m, 14a–g. Morphometrics: Valves 17–22 (22–30) μm long, 5–7 (5–7) μm wide, transapical striae 18–19 (17–19) in 10 μm in dorsal side, 16 (15–17) in 10 μm in ventral side. Remarks: Specimens collected in local areas exhibit lower valve length and width. Seminavis pusilla has been reported in a lagoon of the Galapagos Islands (Seddon et al. 2011), coastal Mediterranean Spanish lakes (Antón-Garrido et al 2013), lagoons of the southern Brazil (Donadel 2018), and southern Everglades of Florida (Mazzei et al. 2018). The brackish species inhabits saline lakes in the desert of Inner Mongolia, China (Rioual et al. 2014). Further, the species has been reported in freshwater with a high mineral content throughout the United States as Navicymbula pusilla (Potapova 2011), and in a river of Northeast Brazil as Seminavis pusilla (Cavalcante et al. 2014). Despite the unusual distribution, it has been reported in tropical or subtropical coasts. In South Korea, it was encountered rarely in reed marsh in the lagoon of the Seogwipo coast in Jeju Island, and represents a new record for South Korea.

55. Trachyneis velata (A. Schmidt) Cleve (Figs 116, 117) Basionym: Navicula velata A. Schmidt. Type locality: Sandwich Island (Hawaiian Islands). References: Witkowski et al. 2000, p. 356, pl. 159, figs 7, 8; Lobban et al. 2012, p. 293, pl. 49, figs 1, 2. Morphometrics: Valves 82–150 (70–130) μm long, 23–27 (20–22) μm wide, transapical striae 10–13 (15–16) in 10 μm. Remarks: The transapical striae of the local specimens are denser than those of the type ones, and the valves are much wider. Trachyneis velata has been found in False Bay of South Africa (Giffen 1971), the Indian Ocean (Giffen 1980), the Caribbean Sea (Foged 1984, Lobban et al. 2012), and the Pacific Ocean (Foged 1987, Witkowski et al. 2000, Lobban et al. 2012, Park et al. 2018), and frequently reported from mangrove lagoon of the Baja California Peninsula, Mexico (Siqueiros-Beltrones & López-Fuerte 2006, López-Fuerte et al. 2010, Siqueiros-Beltrones et al. 2017), and the southern coast of Wellington, New Zealand (Harper & Harper 2010). It is mentioned on the algal checklist of Hawaii (MacCaughey 1918). In South Korea, it was encountered frequently as an epiphyte on seaweeds along the Seogwipo coast in Jeju Island., Published as part of Joh, Gyeongje, 2021, Distribution and frequent occurrence of diatom taxa (Bacillariophyta) inhabiting warmer oceans in Seogwipo coast of Jeju Island, southernmost Korea, pp. 1-67 in Phytotaxa 517 (1) on page 35, DOI: 10.11646/phytotaxa.517.1.1, http://zenodo.org/record/8061058, {"references":["Witkowski, A., Lange-Bertalot, H. & Metzeltin, D. (2000) Diatom flora of marine coasts I. Iconographia Diatomologica. Vol. 7. A. R. G. Ganter Verlag K. G., Ruggell, 925 pp.","Lobban, C. S., Schefter, M., Jordan, R. W., Arai, Y., Sasaki, A., Theriot, E. C., Ashworth, M., Ruck, E. C. & Pennesi, C. (2012) Coral-reef diatoms (Bacillariophyta) from Guam: new records and preliminary checklist, with emphasis on epiphytic species from farmer-fish territories. Micronesica 43: 237 - 479.","Giffen, M. H. (1971) Marine littoral diatoms from the Gordon's bay region of False Bay, Cape Province, South Africa. Botanica Marina 14: 1 - 16. https: // doi. org / 10.1515 / botm. 1971.14. s 1.1","Giffen, M. H. (1980) A checklist of marine littoral diatoms from Mahe, Seychelles Islands. Bacillaria 3: 129 - 159.","Foged, N. (1984) Freshwater and littoral diatoms from Cuba. Bibliotheca Diatomologica. Vol. 5. J. Cramer, Germany, 121 pp.","Foged, N. (1987) Diatoms from Viti Levu, Fiji Islands. Bibliotheca Diatomologica Vol. 14. J. Cramer, Berlin, 128 pp.","Park, J. S., Lobban, C. S. & Lee, K. W. (2018) Diatoms associated with seaweeds from Moen Island in Chuuk Lagoon, Micronesia. Phytotaxa 351: 101 - 140. https: // doi. org / 10.11646 / phytotaxa. 351.2.1","Siqueiros-Beltrones, D. A. & Lopez-Fuerte, F. O. (2006) Epiphytic diatoms associated with red mangrove (Rhizophora mangle) prop roots in Bahia Magdalena, Baja California Sur, Mexico. Revista de Biologia Tropical 54: 287 - 297. https: // doi. org / 10.15517 / rbt. v 54 i 2.13869","Lopez-Fuerte, F. O., Siqueiros-Beltrones, D. A. & Navarro, J. N. (2010) Benthic diatoms associated with mangrove environments in the Northwest region of Mexico. CONABIO, Gobierno Federal Mexicano, Mexico City, 206 pp.","Harper, M. A. & Harper, J. F. (2010) Otari and Taputeranga bioblitzes: diatoms-microscopic algae. Wellington Botanical Society Bulletin 52: 53 - 63.","MacCaughey, V. (1918) Algae of the Hawaiian archipelago. II. Botanical Gazette 65: 121 - 149."]}

52. Navicula zostereti Grunow (Figs 97, 98, 195–197, 200, 201) Type locality: Adriatic Sea. References: Peragallo & Peragallo 1897–1908, p. 91, pl. 12, fig. 7; Takano 1962, p. 33, fig. 8; Moreira-Filho & de Oliveira-Filho 1976, p. 65, pl. 4, fig. 14; Foged 1987, p. 81, pl. 20, fig. 8. Morphometrics: Valves 75–91 (65–140) μm long, 15 (11–22) μm wide, transapical striae 7–8 (6–7) in 10 μm, and lineolae distinct, 24–26 in 10 μm. Remarks: Navicula zostereti is closely similar to Navicula longa var. irregularis Hustedt in valve morphology, but wider in valve breadth (14.5–15.3 vs 9–14 μm) and denser in lineolae on a stria (24–26 vs 16–18 in 10 μm), indicating a large difference in the lineola density on a stria. This species may be mistaken as Navicula longa var. irregularis, (e.g., Witkowski et al. 2000), from many places in the Caribbean Sea, the Indian Ocean, and the Pacific Ocean. This taxon has been reported from Katsuura and Miyazaki of Japan (Takano 1962), Brazil (Moreira-Filho & de Oliveira-Filho 1976), Cuba (Foged 1984), Viti Levu Island (Fiji) in the southwestern Pacific Ocean (Foged 1987), Palawan of Philippines (Podzorski & Håkansson 1987), the eastern coast of India (Gouda & Panigraphy 1989), and Guadalupe Island of the Baja California Peninsula, Mexico (López-Fuerte et al. 2015). It is a diatom taxon inhabiting warmer oceans. It was encountered frequently as an epiphyte along the Seogwipo coast in Jeju Island, and represents a new record for South Korea., Published as part of Joh, Gyeongje, 2021, Distribution and frequent occurrence of diatom taxa (Bacillariophyta) inhabiting warmer oceans in Seogwipo coast of Jeju Island, southernmost Korea, pp. 1-67 in Phytotaxa 517 (1) on pages 34-35, DOI: 10.11646/phytotaxa.517.1.1, http://zenodo.org/record/8061058, {"references":["Takano, H. (1962) Notes on epiphytic diatoms upon sea-weeds from Japan. Journal of the Oceanographical Society of Japan 18: 29 - 33. https: // doi. org / 10.5928 / kaiyou 1942.18.29","Moreira-Filho, H. & de Oliveira-Filho, E. C. (1976) Diatomaceas epifitas em duas populacies de Sargassum cymosum C. Ag. Acta Biologica Paranaense 5: 53 - 75. [in Portuguese] https: // doi. org / 10.5380 / abpr. v 5 i 0.911","Foged, N. (1987) Diatoms from Viti Levu, Fiji Islands. Bibliotheca Diatomologica Vol. 14. J. Cramer, Berlin, 128 pp.","Witkowski, A., Lange-Bertalot, H. & Metzeltin, D. (2000) Diatom flora of marine coasts I. Iconographia Diatomologica. Vol. 7. A. R. G. Ganter Verlag K. G., Ruggell, 925 pp.","Foged, N. (1984) Freshwater and littoral diatoms from Cuba. Bibliotheca Diatomologica. Vol. 5. J. Cramer, Germany, 121 pp.","Podzorski, A. C. & Hakansson, H. (1987) Freshwater and marine diatoms from Palawan (a Philippine island). Bibliotheca Diatomologica Vol. 13. J. Cramer, Berlin, 245 pp.","Gouda, R. & Panigraphy, R. C. (1989) Diurnal variation of phytoplankton in Rushikulya estuary, east coast of India. Indian Journal of Geo-Marine Sciences 18: 246 - 250.","Lopez-Fuerte, F. O., Siqueiros-Beltrones, D. A. & Yabur, R. (2015) First record of benthic diatoms (Bacillariophyceae and Fragilariophyceae) from Isla Guadalupe, Baja California, Mexico. Revista Mexicana de Biodiversida 86: 281 - 292. https: // doi. org / 10.1016 / j. rmb. 2015.04.016"]}

The epiphytic diatoms attached to seaweeds and benthic diatom assemblages, have been collected along the Seogwipo coast in Jeju Island, South Korea. In the last three-year survey, 80 diatom taxa inhabiting warmer oceans have been found, including those in the tropical and subtropical regions such as the Pacific Ocean, the Caribbean Sea, the western Indian Ocean, and other warmer regions. These diatom flora shows a worldwide pattern that concentrated around the Tropic of Cancer. This survey of local areas reveals the existence of many rare or retrieved taxa that were not well known until recently. Furthermore, some of them, including Aulacodiscus affinis, Leudugeria janischii, Hyalosynedra lanceolata, Trachyneis velata var. ornata, Lyrella concilians have been reported for the first time since the first entry or haven been reported only once. Of the diatom flora described here, 48 taxa are new to South Korea and previously unrecorded in the local area.

39. Caloneis cf. excentrica (Grunow) Boyer (Figs 118, 119) Basionym: Navicula excentrica Grunow. Synonym: Caloneis liber var. excentrica (Grunow) Cleve; Navicula maxima var. excentrica (Grunow) Peragallo & Peragallo; Navicula liber var. excentrica (Grunow) Fricke. Type locality: Adriatic Sea; Corsica. References: Peragallo and Peragallo 1897–1908, p. 73, pl. 9, fig. 18; Navarro 1982b, p. 323, figs 38–43; Witkowski et al. 2000, pl. 151, figs 5, 6. Morphometrics: Valves 55–74 (81–140) μm long, 14–17 (14–23) μm wide, and transapical striae 22–26 (18–22) in 10 μm. Remarks: The local specimens are small in valve length and width, and transapical striae denser than some of the referred specimens. It is distributed in Colón of Panama and Guadalope in Spain (Boyer 1927), and has been reported from Puerto Rico (Navarro 1982b), the southern Gulf of Mexico (López–Fuerte et al. 2013), Hainan Islands in the southern coast of China (Cheng & Gao 2013), the Caribbean Sea and the Campeche Bay of the Gulf of Mexico (Witkowski et al. 2000), and the Bahamas (Hein et al. 2008). It is found in the Mediterranean Sea and in warmer coasts as a tropical taxon. It is rarely found as an epiphyte on seaweeds and diatoms in the Seogwipo coast, and is new to South Korea., Published as part of Joh, Gyeongje, 2021, Distribution and frequent occurrence of diatom taxa (Bacillariophyta) inhabiting warmer oceans in Seogwipo coast of Jeju Island, southernmost Korea, pp. 1-67 in Phytotaxa 517 (1) on page 29, DOI: 10.11646/phytotaxa.517.1.1, http://zenodo.org/record/8061058, {"references":["Navarro, J. N. (1982 b) A survey of the marine diatoms of Puerto Rico. V. Suborder Raphidineae: Families Achnanthaceae and Naviculaceae (excluding Navicula and Mastogloia). Botanica Marina 25: 321 - 338. https: // doi. org / 10.1515 / botm. 1982.25.7.321","Witkowski, A., Lange-Bertalot, H. & Metzeltin, D. (2000) Diatom flora of marine coasts I. Iconographia Diatomologica. Vol. 7. A. R. G. Ganter Verlag K. G., Ruggell, 925 pp.","Boyer, C. S. (1927) Synopsis of North American diatomaceae, supplement, part 2. Naviculatae, Surirellatae. Proceedings of the Academy of Natural Sciences of Philadelphia 79: 229 - 583. [https: // www. jstor. org / stable / 4064028]","Cheng, Z. & Gao, Y. (2013) Flora algarum marinarum sinicarum. Tomus V. Bacillariophyta No. III. Pennatae II. Naviculales Naviculaceae Cymbellaceae Auriculaceae Gomphonemataceae. Science Press, Beijing, 183 pp, 80 pls.","Hein, M. K., Winsborough, B. M. & Sullivan, M. J. (2008) Bacillariophyta (diatoms) of the Bahamas. Iconographia Diatomologica Vol. 19. Gantner Publishing, Ruggell, Germany, 303 pp."]}

53. Seminavis latior (A. Schmidt) Danielidis & D.G. Mann (Figs 131, 132) Basionym: Amphora cymbelloides var. latior A. Schmidt. Type locality: Java. References: Danielidis & Mann 2003, p. 34, figs 35–41; Wachnicka & Gaiser 2007, p. 442, figs 226, 227. Morphometrics: Valves 52–73 (35–67) μm long, 12–15 (10–13) μm wide, and transapical striae in dorsal side 12–16 (13–15) in 10 μm, in ventral side 12–17 (13–15) in 10 μm. Remarks: Seminavis latior was reported previously in the lagoon of the Seogwipo coast, Jeju Island of South Korea (Park et al. 2017), and in Chuuk Lagoon of Micronesia (Park et al. 2018). This taxon appears to exist in three locations, including the type locality, Java. It was collected previously from the lagoon of the Seogwipo coast in 2016 (Park et al. 2017), and in this survey, was found rarely on the rock pools.

60. Amphora cingulata Cleve (Figs 142, 143, 213–215) Synonym: Amphora ocellata var. cingulata Cleve. Type locality: G. v. Mexico References: Peragallo and Peragallo 1897–1908, p. 219, pl. 48, fig. 3, pl. 49, figs 5–7; Wachnicka & Gaiser 2007, p. 436, fig. 189; Stidolph et al. 2012, pl. 2, figs 53, 54. Morphometrics: Valves 74–77 (70–87) μm long, 13–14.9 (11.5–12.5) μm wide, and transapical striae 23–25 (22–24) in 10 μm. Remarks: This taxon is similar to Amphora ocellata Donkin in valve morphology, but A. cingulata has a more arcuate dorsal margin and more distinct puncta. In addition, it also resembles A. obtusa Gregory and A. arenaria Donkin in valve outlines but it differs from them by having several widely spaced striae at the central portion of the dorsal side of the valve like a kind of stauros (Wachnicka & Gaiser 2007). Amphora cingulata was reported in the coasts of France (Peragallo & Peragallo1897–1908), Palawan of Philippines (Podzorski and Håkansson 1987), Baja California Sur of Mexico (Siqueiros-Beltrones et al. 2005), the Cape Verde in the Atlantic Ocean off the North Africa (Wachnicka and Gaiser 2007). There are not many cases reported worldwide, but it is mainly distributed in the warmer waters such as tropical regions. It was found very rare in Seogwipo coast, and is a new report in South Korea., Published as part of Joh, Gyeongje, 2021, Distribution and frequent occurrence of diatom taxa (Bacillariophyta) inhabiting warmer oceans in Seogwipo coast of Jeju Island, southernmost Korea, pp. 1-67 in Phytotaxa 517 (1) on page 38, DOI: 10.11646/phytotaxa.517.1.1, http://zenodo.org/record/8061058, {"references":["Wachnicka, A. H. & Gaiser, E. E. (2007) Characterization of Amphora and Seminavis from South Florida, U. S. A. Diatom Research 22: 387 - 455, 240 figs, 4 tables. https: // doi. org / 10.1080 / 0269249 X. 2007.9705722","Stidolph, S. R., Sterrenburg, F. A. S., Smith, K. E. L. & Kraberg, A. (2012) Stuart R. Stidolph diatom atlas. U. S. Department of the Interior and U. S. Geological Survey. USGS Open-File Report 2012 - 1163. https: // doi. org / 10.3133 / ofr 20121163","Podzorski, A. C. & Hakansson, H. (1987) Freshwater and marine diatoms from Palawan (a Philippine island). Bibliotheca Diatomologica Vol. 13. J. Cramer, Berlin, 245 pp.","Siqueiros-Beltrones, D., Lopez-Fuerte, F. O. & Garate-Lizarraga, I. (2005) Structure of Diatom Assemblages Living on Prop Roots of the Red Mangrove (Rhizophora mangle) from the West Coast of Baja California Sur, Mexico 1. Pacific Science 59: 79 - 96. https: // doi. org / 10.1353 / psc. 2005.0014"]}

56. Trachyneis velata var. ornata Meister (Figs 114, 115) References: Meister 1937, p. 272, pl. 10, fig. 10; Podzorski & Håkansson 1987, p. 91, pl. 34, fig. 2. Type locality: Nagasaki. Morphometrics: Valves 35–46 (27–44) μm long, 12–13 (11–15) μm wide, transapical striae 17–19 (19–20) in 10 μm. Remarks: The striae on valves are composed of more or less elongated areolae. Six to seven very long areolae surround the central area, which is significantly smaller than that of the nominate variety, Trachyneis velata. This taxon was first discovered in Nagasaki of Japan, and described by Meister (1937). It has been reported from Palawan of Philippines by Podzorski & Håkansson (1987). Until now, only two locations have been reported, but the taxon appears to grow in the warmer marine waters of Asia. However, it is possible that it may have been considered as small forms of the nominate variety, due to similar valve morphology. It was found rarely in rock pools and pseudo-lagoons along the Seogwipo coast in Jeju Island, and thus represents a new record for South Korea., Published as part of Joh, Gyeongje, 2021, Distribution and frequent occurrence of diatom taxa (Bacillariophyta) inhabiting warmer oceans in Seogwipo coast of Jeju Island, southernmost Korea, pp. 1-67 in Phytotaxa 517 (1) on page 36, DOI: 10.11646/phytotaxa.517.1.1, http://zenodo.org/record/8061058, {"references":["Meister, F. (1937) Seltene und neue Kieselalgen. II. Berichte der Schweizerischen Botanischen Gesellschaft 47: 258 - 276; pls. 3 - 13.","Podzorski, A. C. & Hakansson, H. (1987) Freshwater and marine diatoms from Palawan (a Philippine island). Bibliotheca Diatomologica Vol. 13. J. Cramer, Berlin, 245 pp."]}

45. Cymatoneis circumvallata Cleve (Figs 104) Synonym: Navicula circumvallata (Cleve) Schmidt. References: Peragallo & Peragallo 1897–1908, p. 107, pl. 13, fig. 28; Giffen 1976, p. 384, figs 44, 45; Podzorski & Håkansson 1987, p. 56, pl. 18, figs 6, 9, 11, 12. Type locality: Balearic Island; Ceylon; Labuan; Japan. Morphometrics: Valves 28–38 (27–52) μm long, 13–14 (10–13) μm wide, transapical striae 10–11 (9–12) in 10 μm. Remarks: This taxon has been reported from a few localitions: Saldanha Bay lagoon of South Africa (Giffen 1976), Palawan of Philippines (Podzorski & Håkansson 1987), and the mangrove coast of the Baja California Peninsula of Mexico (Siqueiros-Beltrones et al. 2011). It has been reported rarely, but can be assigned to a typical tropical taxon based on the earliest type locality and subsequent discovery areas. It was found rarely in rock pools along the Seogwipo coast in Jeju Island, and is herein newly reported in South Korea, Published as part of Joh, Gyeongje, 2021, Distribution and frequent occurrence of diatom taxa (Bacillariophyta) inhabiting warmer oceans in Seogwipo coast of Jeju Island, southernmost Korea, pp. 1-67 in Phytotaxa 517 (1) on page 33, DOI: 10.11646/phytotaxa.517.1.1, http://zenodo.org/record/8061058, {"references":["Giffen, M. H. (1976) Further account of the marine littoral diatoms of the Saldanha Bay Lagoon, Cape province, South Africa. Botanica Marina 19: 379 - 394. https: // doi. org / 10.1515 / botm. 1976.19.6.379","Podzorski, A. C. & Hakansson, H. (1987) Freshwater and marine diatoms from Palawan (a Philippine island). Bibliotheca Diatomologica Vol. 13. J. Cramer, Berlin, 245 pp.","Siqueiros-Beltrones, D. A., Lopez-Fuerte, F. O., Hernandez-Almeida, O. U. & Argumedo-Hernandez, U. (2011) Microalgae associated to mangrove systems. In: Felix-Pico, E. F. Zaragoza, E. S., Rodriguez, R. R. & Luz, J. L. L. de L. (Eds.) Los Manglares de la Peninsula de Baja California. pp. 155 - 180. [in Spanish]"]}

61. Amphora staurohyalina Podzorski & Håkansson (Figs 123, 124, 203–206) Type locality: Philippines: Palawan: Malapakan Cove, Langen (Malapakan) Island, Taytay. Reference: Podzorski & Håkansson 1987, p. 52, pl. 15, fig. 11, pl. 51, figs 4–6. Morphometrics: Valves 25–32 (33) μm long, 4 (5) μm wide, and transapical striae unresolved in LM, 34 in 10 μm in SEM. Remarks: The characteristic morphological features include a narrow hyaline stauros in the central area dorsally and double rows of striae. Amphora staurohyalina is a tropical taxon found in warmer coasts, and has not been reported in any other location except the type locality, Palawan of Philippines. It was more or less frequently encountered as an epiphyte along the Seogwipo coast in Jeju Island, and represents a new record for South Korea., Published as part of Joh, Gyeongje, 2021, Distribution and frequent occurrence of diatom taxa (Bacillariophyta) inhabiting warmer oceans in Seogwipo coast of Jeju Island, southernmost Korea, pp. 1-67 in Phytotaxa 517 (1) on page 38, DOI: 10.11646/phytotaxa.517.1.1, http://zenodo.org/record/8061058, {"references":["Podzorski, A. C. & Hakansson, H. (1987) Freshwater and marine diatoms from Palawan (a Philippine island). Bibliotheca Diatomologica Vol. 13. J. Cramer, Berlin, 245 pp."]}

59. Amphora bigibba var. interrupta (Grunow) Cleve (Figs 121, 122) Basionym: Amphora binodis var. interrupta Grunow. Type locality: Campeche Bank. References: Witkowski et al. 2000, p. 131, pl. 163, figs 27–30; Wachnicka & Gaiser 2007, p. 414, figs 84, 95. Morphometrics: Valves 28–40 (20–46) μm long, 5–6 (5–7) μm wide, and transapical striae 20–22 (21–25) in 10 μm. Remarks: No transapical striae exist on valve in the middle dorsally. Amphora bigibba var. interrupta is widespread along the coasts of warmer oceans (Witkowski et al. 2000), the Florida Bay (Wachnicka & Gaiser 2007), the Bahamas (Hein et al. 2008), the coast of Thailand (Kokociński et al. 2009), and the coast of Baja California Peninsula of Mexico (Siqueiros-Beltrones & Argumedo-Hernández 2015). This taxon is also a subtropical taxon found in the warmer oceans as the nominate variety, Amphora bigibba. It was rarely epiphytic along the Seogwipo coast in Jeju Island, and represents a new record for South Korea., Published as part of Joh, Gyeongje, 2021, Distribution and frequent occurrence of diatom taxa (Bacillariophyta) inhabiting warmer oceans in Seogwipo coast of Jeju Island, southernmost Korea, pp. 1-67 in Phytotaxa 517 (1) on pages 36-38, DOI: 10.11646/phytotaxa.517.1.1, http://zenodo.org/record/8061058, {"references":["Witkowski, A., Lange-Bertalot, H. & Metzeltin, D. (2000) Diatom flora of marine coasts I. Iconographia Diatomologica. Vol. 7. A. R. G. Ganter Verlag K. G., Ruggell, 925 pp.","Wachnicka, A. H. & Gaiser, E. E. (2007) Characterization of Amphora and Seminavis from South Florida, U. S. A. Diatom Research 22: 387 - 455, 240 figs, 4 tables. https: // doi. org / 10.1080 / 0269249 X. 2007.9705722","Hein, M. K., Winsborough, B. M. & Sullivan, M. J. (2008) Bacillariophyta (diatoms) of the Bahamas. Iconographia Diatomologica Vol. 19. Gantner Publishing, Ruggell, Germany, 303 pp.","Kokocinski, M., Szczucinski, W., Zgrundo, A. & Ibragimow, A. (2009) Diatom assemblages in 26 December 2004 tsunami deposits from coastal zone of Thailand as sediment provenance indicators. Polish Journal of Environmental Studies 18: 93 - 101.","Siqueiros-Beltrones, D. A. & Argumedo-Hernandez, U. (2015) Epiphytic diatoms grazed by adult abalone (Haliotis spp.) in Baja California Sur, Mexico. Revista Mexicana de Biodiversidad 86: 111 - 122. https: // doi. org / 10.7550 / rmb. 47977"]}

34. Cocconeiopsis orthoneoides (Hustedt) Witkowski, Lange-Bertalot & Metzeltin (Fig. 78) Basionym: Navicula orthoneoides Hustedt. Type locality: Beaufort, North Carolina. References: Hustedt 1961–1966, p. 345, fig. 1455; Witkowski et al. 2000, p. 174, pl. 67, figs 1, 2, pl. 68, fig. 1; Garcia & Dutra 2013, p. 217, figs 1–10. Morphometrics: Valves 26–29 (23–37, 43) μm long, 18–20 (16–27) μm wide, transapical striae 17–20 (13–22) in 10 μm, puncta on a stria 14–16 in 10 μm. Remarks: Cocconeiopsis orthoneoides is distributed in marine littoral zones, frequently along the coasts of warmer oceans, especially Indian Ocean and Thailand (Witkowski et al. 2000). It has been reported from mangrove lagoons of the Baja California Peninsula in Mexico (Lopez-Fuerte et al. 2010; Siqueiros-Beltrones et al. 2011), and the coasts of southern Brazil (Garcia & Dutra 2013). Although rarely reported, it is a taxon that grows in warmer oceans. It was found less frequently on the sandy beaches of the Seogwipo coast, and is new to South Korea., Published as part of Joh, Gyeongje, 2021, Distribution and frequent occurrence of diatom taxa (Bacillariophyta) inhabiting warmer oceans in Seogwipo coast of Jeju Island, southernmost Korea, pp. 1-67 in Phytotaxa 517 (1) on page 25, DOI: 10.11646/phytotaxa.517.1.1, http://zenodo.org/record/8061058, {"references":["Witkowski, A., Lange-Bertalot, H. & Metzeltin, D. (2000) Diatom flora of marine coasts I. Iconographia Diatomologica. Vol. 7. A. R. G. Ganter Verlag K. G., Ruggell, 925 pp.","Garcia, M. & Dutra, D. B. (2013) Morphology and distribution of Cocconeiopsis Witkowski, Lange-Bertalot and Metzeltin from Santa Catarina state littoral, Brazil. Iheringia Serie Botanica 68: 215 - 224. [in Portuguese]","Lopez-Fuerte, F. O., Siqueiros-Beltrones, D. A. & Navarro, J. N. (2010) Benthic diatoms associated with mangrove environments in the Northwest region of Mexico. CONABIO, Gobierno Federal Mexicano, Mexico City, 206 pp.","Siqueiros-Beltrones, D. A., Lopez-Fuerte, F. O., Hernandez-Almeida, O. U. & Argumedo-Hernandez, U. (2011) Microalgae associated to mangrove systems. In: Felix-Pico, E. F. Zaragoza, E. S., Rodriguez, R. R. & Luz, J. L. L. de L. (Eds.) Los Manglares de la Peninsula de Baja California. pp. 155 - 180. [in Spanish]"]}

46. Cymatoneis margarita Witkowski (Fig. 105) Type locality: Orum Beach, Oman. References: Witkowski et al. 2000. p. 179, pl. 109, figs 9–17. Morphometrics: Valves 16–17 (13.5–18) μm long, 6–6.3 (5–6) μm wide, and transapical striae 18–19 (18–20) in 10 μm. Remarks: This species differs from other Cymatoneis in smaller size and lanceolate to elliptic-lanceolate valve outline (Witkowski et al. 2000). Cymatoneis margarita is distributed in Oman as type locality, the Mississippi Delta and Borneo (Witkowski et al. 2000). Since then, it has been reported off the coasts of Guinea, West Africa (Compère and Riaux-Gobin 2009). Although the species have been reported in a few areas, it seems to be pantropical taxon in warmer ocean. This taxon has been found a few times in sand beaches of the Seogwipo coast, representing a new report to South Korea., Published as part of Joh, Gyeongje, 2021, Distribution and frequent occurrence of diatom taxa (Bacillariophyta) inhabiting warmer oceans in Seogwipo coast of Jeju Island, southernmost Korea, pp. 1-67 in Phytotaxa 517 (1) on page 33, DOI: 10.11646/phytotaxa.517.1.1, http://zenodo.org/record/8061058, {"references":["Witkowski, A., Lange-Bertalot, H. & Metzeltin, D. (2000) Diatom flora of marine coasts I. Iconographia Diatomologica. Vol. 7. A. R. G. Ganter Verlag K. G., Ruggell, 925 pp.","Compere, P. & Riaux-Gobin, C. (2009) Diatoms from some marine, brackish and freshwater biotopes of Guinea (West Africa). Systematics and Geography of Plants 79: 33 - 66."]}

30. Lyrella concilians (Cleve) D.G. Mann (Fig. 120) Basionym: Navicula concilians Cleve. Synonym: Navicula bialbata H. Peragallo & M. Peragallo. Type locality: Honolulu, USA. References: Peragallo and Peragallo 1897–1908, p. 144, pl. 28, fig. 1; Hustedt 1961–1966, p. 519, fig. 1559. Morphometrics: Valves 62 (45–77) μm long, 27 (21–26) μm wide, transapical striae 11 (11–14) in 10 μm, and puncta in a stria 13 (13–16) in 10 μm. Remarks: Lyrella concilians is distributed in the western Pacific Ocean: Honolulu, Samoa, and China (Hustedt 1961–1966). This taxon was reported from Villefranche of the Mediterranean (Peragallo & Peragallo 1897–1908), and rarely from the other areas except the type locality. It was found twice in salt marshes of the Seogwipo coast in Jeju Island, representing a new record for South Korea., Published as part of Joh, Gyeongje, 2021, Distribution and frequent occurrence of diatom taxa (Bacillariophyta) inhabiting warmer oceans in Seogwipo coast of Jeju Island, southernmost Korea, pp. 1-67 in Phytotaxa 517 (1) on page 24, DOI: 10.11646/phytotaxa.517.1.1, http://zenodo.org/record/8061058

47. Navicula hochstetteri Grunow (Figs 93, 94) Type locality: Nicobar Islands (in the eastern sea of Bay of Bengal, India). Reference: Hustedt 1961–1966, p. 663, fig. 1664. Morphometrics: Valves 24–58 (27–57) μm long, 15–34 (13–32) μm wide, transapical striae of the central parts 11–14 (14–20) in 10 μm, of the terminal parts 18–20 in 10 μm, with puncta on a stria 14–19 (14–17) in 10 μm. Remarks: Navicula hochstetteri is distributed along the coastal areas of warmer oceans, but is not common (Hustedt 1961–1966), and was rarely found in other regions except the type locality. This taxon was reported from Brazil (Kutner 1961), and from Lakes Entrance of Australia (Foged 1978), and is mentioned on the checklist of biota of Chinese Seas (Liu 2008) and the inventory of biodiversity of New Zealand (Harper et al. 2012). It is a tropical taxon in warmer coasts, despite limited distribution. This taxon was rarely encountered as an epiphyte along the Seogwipo coast in Jeju Island, and represents a new record for South Korea., Published as part of Joh, Gyeongje, 2021, Distribution and frequent occurrence of diatom taxa (Bacillariophyta) inhabiting warmer oceans in Seogwipo coast of Jeju Island, southernmost Korea, pp. 1-67 in Phytotaxa 517 (1) on page 33, DOI: 10.11646/phytotaxa.517.1.1, http://zenodo.org/record/8061058, {"references":["Kutner, M. B. (1961) Algumas diatomaceas encontradas sobre algas superiores. Boletim do Instituto Oceanografico 11: 3 - 15. [in Portuguese] https: // doi. org / 10.1590 / s 0373 - 55241961000200001","Foged, N. (1978) Diatoms in eastern Australia. Bibliotheca Phycologica. Vol. 41. 148 pp., 48 pls.","Liu, R. (2008) Checklist of marine biota of China Seas. Diatoms, pp. 49 - 90. Science Press, Academia Sinica, Beijing. 1267 pp.","Harper, M. A., Cassie Cooper, V., Chang, F. H., Nelson, W. A. & Broady, P. A. (2012) Phylum Ochrophyta: brown and golden-brown algae, diatoms, silicioflagellates, and kin. In: New Zealand inventory of biodiversity. Volume Three. Kingdoms Bacteria, Protozoa, Chromista, Plantae, Fungi. (Gordon, D. P. eds), pp. 114 - 163. Christchurch: Canterbury University Press."]}

51. Navicula semiarea Meister (Fig. 79) Type locality: Nagasaki, Japan. References: Hustedt 1961–1966, p. 655, fig. 1655; Suzuki et al. 1999, p. 154, pl. 5, figs 5–8. Morphometrics: Valves 34–40 (33–47) μm long, 20–21 (21–27) μm wide, transapical striae 15–16 (15) in 10 μm, puncta on a stria 16–17 (16–18) in 10 μm. Remarks: Navicula semiarea is distributed in the marine waters of East Asia (Hustedt 1961–1966), and was reported only from Japan, Nagasaki and Niijima Island (Suzuki et al. 1999). This taxon is probably distributed in the coastal regions of oceans in Northeast Asia. It was found twice in the salt marshes of the Seogwipo coast in Jeju Island, and represents a new taxon for South Korea., Published as part of Joh, Gyeongje, 2021, Distribution and frequent occurrence of diatom taxa (Bacillariophyta) inhabiting warmer oceans in Seogwipo coast of Jeju Island, southernmost Korea, pp. 1-67 in Phytotaxa 517 (1) on page 34, DOI: 10.11646/phytotaxa.517.1.1, http://zenodo.org/record/8061058, {"references":["Suzuki, H., Tanaka, J. & Nagumo, T. (1999) Epiphytic diatoms on a red algae Plocamium telfairiae (Hooker et Harvey) Harvey in Shikine Island, the Izu Island. Japanese Bulletin of the Nippon Dental University, General Education 28: 147 - 160. [in Japanese]"]}

58. Amphora bigibba Grunow (Figs 135–137) Type locality: Celebes. Reference: Navarro 1982b, p. 322, fig. 17. Morphometrics: Valves 25 (25–39) μm long, 4 (4–7) μm wide, transapical striae 18 (18–20) in 10 μm. Remarks: Amphora bigibba has been reported along the Brazilian coasts (Andrade & Teixeira 1957, Procopiak et al. 2006), and in Puerto Rico (Navarro 1982b), in Fiji (Foged 1987), Palawan of Philippines (Podzorski & Håkansson 1987), the Gulf of Mexico (Krayesky et al. 2009), Yap and Guam (Navarro & Lobban 2009), and Cape Verde Islands in the Atlantic Ocean off the western Africa (Stidolph et al. 2012). In South Korea, it is rare in the Seogwipo coastal area in Jeju Island., Published as part of Joh, Gyeongje, 2021, Distribution and frequent occurrence of diatom taxa (Bacillariophyta) inhabiting warmer oceans in Seogwipo coast of Jeju Island, southernmost Korea, pp. 1-67 in Phytotaxa 517 (1) on page 36, DOI: 10.11646/phytotaxa.517.1.1, http://zenodo.org/record/8061058, {"references":["Navarro, J. N. (1982 b) A survey of the marine diatoms of Puerto Rico. V. Suborder Raphidineae: Families Achnanthaceae and Naviculaceae (excluding Navicula and Mastogloia). Botanica Marina 25: 321 - 338. https: // doi. org / 10.1515 / botm. 1982.25.7.321","Andrade, M. D. A. & Teixeira, C. (1957) Contribuic \" o para o conhecimento das diatomaceas do Brasil: generos Amphora, Cymatoneis, Diploneis, Gyrosigma, Mastogloia, Navicula, Oestrupia e Pleurosigma. Boletim do Instituto Oceanografico 8: 171 - 215. [in Portuguese] https: // doi. org / 10.1590 / S 0373 - 55241957000100005","Procopiak, L. K., Fernandes, L. F. & Moreira-Filho, H. (2006) Diatomaceas (Bacillariophyta) marinhas e estuarinas do Parana, Sul do Brasil: lista de especies com enfase em especies nocivas. Biota Neotropica 6: 1 - 28. [in Portuguese] https: // doi. org / 10.1590 / S 1676 - 06032006000300013","Foged, N. (1987) Diatoms from Viti Levu, Fiji Islands. Bibliotheca Diatomologica Vol. 14. J. Cramer, Berlin, 128 pp.","Podzorski, A. C. & Hakansson, H. (1987) Freshwater and marine diatoms from Palawan (a Philippine island). Bibliotheca Diatomologica Vol. 13. J. Cramer, Berlin, 245 pp.","Krayesky, D. M., Meave del Castillo, E., Zamudio, E., Norris, J. N., Fredericq, S., Tunnell Jr, J., Felder, D. & Earle, S. (2009) Diatoms (Bacillariophyta) of the Gulf of Mexico. In: Felder, D. L. & Camp, D. K. (Eds.) Gulf of Mexico: Origin, Waters, and Biota. Vol. 1. Biodiversity. pp. 155 - 186.","Navarro, J. N. & Lobban, C. S. (2009) Freshwater and marine diatoms from the western Pacific islands of Yap and Guam, with notes on some diatoms in damselfish territories. Diatom Research 24: 123 - 157. https: // doi. org / 10.1080 / 0269249 X. 2009.9705787","Stidolph, S. R., Sterrenburg, F. A. S., Smith, K. E. L. & Kraberg, A. (2012) Stuart R. Stidolph diatom atlas. U. S. Department of the Interior and U. S. Geological Survey. USGS Open-File Report 2012 - 1163. https: // doi. org / 10.3133 / ofr 20121163"]}

50. Navicula plicatula Grunow (Figs 99, 100) Type locality: Gulf of Naples; Balearic Islands; Madagascar; Seychelles; Japan. Reference: Lobban et al. 2012. p. 293, pl. 48, figs 1–3. Morphometrics: Valves 66–81 (49–64) μm long, 24–26 (15–18) μm wide, and transapical striae 18 (15–24) in 10 μm. Remarks: Navicula plicatula contains not only sinuous raphe, but also raised raphe fissures, and is distinguished from others. This taxon was reported from Balearic Island and Naples in the Mediteranean (Peragallo & Peragallo 1897–1908), Philippines (Mann 1925), Guam and Society Islands of the Pacific Ocean and the Caribbean Sea (Lobban et al. 2012), and is also indicated on the check-list of Chinese marine diatoms (Liu 2008). It was encountered rarely along the Seogwipo coast in Jeju Island, and represents a new record for South Korea., Published as part of Joh, Gyeongje, 2021, Distribution and frequent occurrence of diatom taxa (Bacillariophyta) inhabiting warmer oceans in Seogwipo coast of Jeju Island, southernmost Korea, pp. 1-67 in Phytotaxa 517 (1) on page 34, DOI: 10.11646/phytotaxa.517.1.1, http://zenodo.org/record/8061058, {"references":["Lobban, C. S., Schefter, M., Jordan, R. W., Arai, Y., Sasaki, A., Theriot, E. C., Ashworth, M., Ruck, E. C. & Pennesi, C. (2012) Coral-reef diatoms (Bacillariophyta) from Guam: new records and preliminary checklist, with emphasis on epiphytic species from farmer-fish territories. Micronesica 43: 237 - 479.","Mann, A. (1925) Marine diatoms of the Philippine Islands. Smithsonian Institution United States National Museum Bulletin 100: 1 - 182, pls. 154.","Liu, R. (2008) Checklist of marine biota of China Seas. Diatoms, pp. 49 - 90. Science Press, Academia Sinica, Beijing. 1267 pp."]}

49. Navicula platyventris Meister (Figs 95, 96) Type locality: Honduras. References: Meister 1935, p. 95, fig. 33; Podzorski & Håkansson 1987, p. 81, pl. 32, fig. 3; Al-Yamani & Daburova 2011, p. 110, pl. 86, figs a–e. Witkowski et al., 2000, p. 299, pl. 143, figs 16–19 Morphometrics: Valves 10–11 (11–13) μm long, 5–6 (5–7) μm wide, transapical striae 14–15 (12–15) in 10 μm. Remarks: This taxon was found in many warmer coasts, the southwestern Atlantic Ocean of Brazil (Fernandes et al. 1999, Fernandes et al. 2002), the Seto Inland Sea of Japan (Takai et al. 2004), the mangroves of Fujian in China (Chang-Ping et al. 2005), and the Baja California Peninsula, Mexico (Siqueiros-Beltrones & López-Fuerte 2006). The specimens collected from Kenia, Fiji Islands, South Africa and the Caribbean Sea are illustrated in Witkowski et al. (2000). It is rarely epiphytic in the pseudo-lagoons of the Seogwipo coast in Jeju Island, represents a new record for South Korea., Published as part of Joh, Gyeongje, 2021, Distribution and frequent occurrence of diatom taxa (Bacillariophyta) inhabiting warmer oceans in Seogwipo coast of Jeju Island, southernmost Korea, pp. 1-67 in Phytotaxa 517 (1) on page 34, DOI: 10.11646/phytotaxa.517.1.1, http://zenodo.org/record/8061058, {"references":["Meister, F. (1935) Seltene und neue Kieselalgen. I. Berichte der Schweizerischen Botanischen Gesellschaft 44: 87 - 108.","Podzorski, A. C. & Hakansson, H. (1987) Freshwater and marine diatoms from Palawan (a Philippine island). Bibliotheca Diatomologica Vol. 13. J. Cramer, Berlin, 245 pp.","Al-Yamani, F. Y. & Daburova, M. A. (2011) Illustrated guide on the benthic diatoms of Kuwait's marine environment. Kuwait Institute for Scientific Research, 364 pp.","Witkowski, A., Lange-Bertalot, H. & Metzeltin, D. (2000) Diatom flora of marine coasts I. Iconographia Diatomologica. Vol. 7. A. R. G. Ganter Verlag K. G., Ruggell, 925 pp.","Fernandes, L. F., Brandini, F. P., Gutseit, K. S., Fonseca, A. L. D. O. & Pellizzari, F. M. (1999) Benthic diatoms growing on glass slides in the Paranagua Bay, Southern Brazil: taxonomic structure and seasonal variation. INSULA Revista de Botanica 28: 53 - 100.","Fernandes, L. F., Eskinazi-Leca, E., Moura, Moura, A. do N. & de Oliveira, G. G. (2002) The occurrence of Nitzschia martiana (C. A. Agardh) Van Heurck (Nitzschiaceae-Bacillariophyta) in the southwestern Atlantic Ocean. Hoehnea 29: 119 - 131.","Takai, N., Yorozu, A., Tanimoto, T., Hoshika, A. & Yoshihara, K. (2004) Transport pathways of microphytobenthos-originating organic carbon in the food web of an exposed hard bottom shore in the Seto Inland Sea, Japan. Marine Ecology Progress Series 284: 97 - 108. https: // doi. org / 10.3354 / meps 284097","Chang-Ping, C. H. E. N., Ya-Hui, G. A. O. & Peng, L. I. N. (2005) Four newly recorded species of Bacillariophyta from the mangroves in China. Journal of Systematics and Evolution 44: 95 - 99. https: // doi. org / 10.1360 / aps 040085","Siqueiros-Beltrones, D. A. & Lopez-Fuerte, F. O. (2006) Epiphytic diatoms associated with red mangrove (Rhizophora mangle) prop roots in Bahia Magdalena, Baja California Sur, Mexico. Revista de Biologia Tropical 54: 287 - 297. https: // doi. org / 10.15517 / rbt. v 54 i 2.13869"]}

48. Navicula perrhombus Hustedt (Figs 102, 103) Type locality: Borneo: Miang Besar. References: Simonsen 1987, p. 163, pl. 262, figs 7–12; Witkowski et al. 2000, p. 298, pl. 141, figs 24–26; Al-Yamani & Daburova 2011, p. 110, pl. 86, figs f–i. Morphometrics: Valves 17–27 (16–25) μm long, 8–11 (7–8) μm wide, transapical striae 8–10 (10–12) in 10 μm. Remarks: This species occurred in Tahiti (Ricard 1977), the Penghu Islands of Taiwan (Li 1978), Kuwait coast (Al-Yamani & Daburova 2011) and sandflats of the Nakdong River estuary of Korea (Joh 2013). The specimens collected from the Red Sea near Eilat and Réunion Islands of the western Indean Ocean are illustrated in Witkowski et al. (2000), and it is on the check-list of epiphytic diatoms in Florida Bay compiled by Frankovich & Wachnicka (2015). In the Seogwipo coast in Jeju Island, this taxon was rarely found in the benthic sediments and seaweeds in the lagoon and pseudo-lagoons., Published as part of Joh, Gyeongje, 2021, Distribution and frequent occurrence of diatom taxa (Bacillariophyta) inhabiting warmer oceans in Seogwipo coast of Jeju Island, southernmost Korea, pp. 1-67 in Phytotaxa 517 (1) on pages 33-34, DOI: 10.11646/phytotaxa.517.1.1, http://zenodo.org/record/8061058, {"references":["Simonsen, R. (1987) Atlas and catalogue of the diatom types of Friedrich Hustedt. Vol. 1. Catalogue, 525 pp. Vol. 2. Atlas, Plates 1 - 395, Vol. 3. Atlas, Plates 396 - 772. [J. Cramer, Berlin]","Witkowski, A., Lange-Bertalot, H. & Metzeltin, D. (2000) Diatom flora of marine coasts I. Iconographia Diatomologica. Vol. 7. A. R. G. Ganter Verlag K. G., Ruggell, 925 pp.","Al-Yamani, F. Y. & Daburova, M. A. (2011) Illustrated guide on the benthic diatoms of Kuwait's marine environment. Kuwait Institute for Scientific Research, 364 pp.","Ricard, M. (1977) Ecology of diatoms from two Polynesian lagoons. Nova Hedwigia 54: 389 - 405.","Li, C. W. (1978) Notes on marine littoral diatoms of Taiwan I. Some diatoms of Pescadores. Nova Hedwigia 29: 787 - 812.","Joh, G. (2013) Species diversity of the old genus Navicula Bory (Bacillariophyta) on intertidal sand-flats in the Nakdong River estuary, Korea. Journal of ecology and environment 36: 371 - 390. https: // doi. org / 10.5141 / ecoenv. 2013.371","Frankovich, T. A. & Wachnicka, A. (2015) Epiphytic diatoms along phosphorus and salinity gradients in Florida Bay (Florida, USA), an illustrated guide and annotated checklist. In: Entry, J. A., Gottlieb, A. D., Jayachandran, K. and Ogram, A. (Eds.) Microbiology of the Everglades ecosystem. CRC Press, Boca Raton, Florida, pp. 241 - 288. https: // doi. org / 10.1201 / b 18253 - 15"]}

57. Amphora arenaria Donkin (Figs 101, 110, 207–210) Synonym: Amphora arenaria var. typica Cleve. Type locality: Along the southern portion of Northumberland shore, England. References: Witkowski et al. 2000, p. 130, pl. 168, fig. 14; Wachnicka & Gaiser 2007, p. 435, fig. 188; Hein et al. 2008, p. 41, pl. 19, figs 1, 2; Lobban et al. 2012, p. 297, pl. 53, figs 5, 6, pl. 54, figs 1, 2. Morphometrics: Valves 84–95 (52–118) μm long, 17–24 (8–18) μm wide, and transapical striae 22–23 (20–26) in 10 μm. Remarks: Amphora arenaria is very close to A. obtusa Gregory in morphology and dimensions, but the former lacks intercalary bands in the girdle and carries a narrow girdle band, in addition to a slightly sinuate ventral margin, whereas the latter contains has straight margins (Wachnicka & Gaiser 2007, Lobban et al. 2012). The two species exhibit a large difference in strial density, but broadly overlap in the range of 21–28 in 10 μm. However, it is difficult to distinguish according to strial density (Lobban et al. 2012). This taxon is widespread on the coasts of European Atlantic Ocean (Witkowski et al. 2000), and is frequently found in warmer oceans: Sesoko Island of Okinawa, Japan (Nagumo & Mayama 2000), the Florida Bay (Wachnicka & Gaiser 2007), the Bahamas of the southeastern Florida (Hein et al. 2008), and Guam and Chuuk Lagoon of the western Pacific Ocean (Lobban et al. 2012, Park et al. 2018). It is distributed along the tropical and subtropical coasts. In South Korea, it is rarely epiphytic on seaweeds along the Seogwipo coast in Jeju Island., Published as part of Joh, Gyeongje, 2021, Distribution and frequent occurrence of diatom taxa (Bacillariophyta) inhabiting warmer oceans in Seogwipo coast of Jeju Island, southernmost Korea, pp. 1-67 in Phytotaxa 517 (1) on page 36, DOI: 10.11646/phytotaxa.517.1.1, http://zenodo.org/record/8061058, {"references":["Witkowski, A., Lange-Bertalot, H. & Metzeltin, D. (2000) Diatom flora of marine coasts I. Iconographia Diatomologica. Vol. 7. A. R. G. Ganter Verlag K. G., Ruggell, 925 pp.","Wachnicka, A. H. & Gaiser, E. E. (2007) Characterization of Amphora and Seminavis from South Florida, U. S. A. Diatom Research 22: 387 - 455, 240 figs, 4 tables. https: // doi. org / 10.1080 / 0269249 X. 2007.9705722","Hein, M. K., Winsborough, B. M. & Sullivan, M. J. (2008) Bacillariophyta (diatoms) of the Bahamas. Iconographia Diatomologica Vol. 19. Gantner Publishing, Ruggell, Germany, 303 pp.","Lobban, C. S., Schefter, M., Jordan, R. W., Arai, Y., Sasaki, A., Theriot, E. C., Ashworth, M., Ruck, E. C. & Pennesi, C. (2012) Coral-reef diatoms (Bacillariophyta) from Guam: new records and preliminary checklist, with emphasis on epiphytic species from farmer-fish territories. Micronesica 43: 237 - 479.","Nagumo, T. & Mayama, S. (2000) Marine coastal diatoms of Sesoko Island, Okinawa Prefecture, Japan. Diatom 16: 11 - 17. https: // doi. org / 10.11464 / diatom 1985.16.0 _ 11","Park, J. S., Lobban, C. S. & Lee, K. W. (2018) Diatoms associated with seaweeds from Moen Island in Chuuk Lagoon, Micronesia. Phytotaxa 351: 101 - 140. https: // doi. org / 10.11646 / phytotaxa. 351.2.1"]}

53. Seminavis latior (A. Schmidt) Danielidis & D.G. Mann (Figs 131, 132) Basionym: Amphora cymbelloides var. latior A. Schmidt. Type locality: Java. References: Danielidis & Mann 2003, p. 34, figs 35–41; Wachnicka & Gaiser 2007, p. 442, figs 226, 227. Morphometrics: Valves 52–73 (35–67) μm long, 12–15 (10–13) μm wide, and transapical striae in dorsal side 12–16 (13–15) in 10 μm, in ventral side 12–17 (13–15) in 10 μm. Remarks: Seminavis latior was reported previously in the lagoon of the Seogwipo coast, Jeju Island of South Korea (Park et al. 2017), and in Chuuk Lagoon of Micronesia (Park et al. 2018). This taxon appears to exist in three locations, including the type locality, Java. It was collected previously from the lagoon of the Seogwipo coast in 2016 (Park et al. 2017), and in this survey, was found rarely on the rock pools., Published as part of Joh, Gyeongje, 2021, Distribution and frequent occurrence of diatom taxa (Bacillariophyta) inhabiting warmer oceans in Seogwipo coast of Jeju Island, southernmost Korea, pp. 1-67 in Phytotaxa 517 (1) on page 35, DOI: 10.11646/phytotaxa.517.1.1, http://zenodo.org/record/8061058, {"references":["Danielidis, D. B. & Mann, D. G. (2003) New species and new combinations in the genus Seminavis (Bacillariophyta). Diatom Research 18: 21 - 39. https: // doi. org / 10.1080 / 0269249 X. 2003.9705570","Wachnicka, A. H. & Gaiser, E. E. (2007) Characterization of Amphora and Seminavis from South Florida, U. S. A. Diatom Research 22: 387 - 455, 240 figs, 4 tables. https: // doi. org / 10.1080 / 0269249 X. 2007.9705722","Park, J. S., Yun, S. M., Lee, S. D., Lee, J. B. & Lee, J. H. (2017) New records of the diatoms (Bacillariophyta) in the brackish and coastal waters of Korea. Korean Journal of Environmental Biology 35: 215 - 226. https: // doi. org / 10.11626 / KJEB. 2017.35.3.215","Park, J. S., Lobban, C. S. & Lee, K. W. (2018) Diatoms associated with seaweeds from Moen Island in Chuuk Lagoon, Micronesia. Phytotaxa 351: 101 - 140. https: // doi. org / 10.11646 / phytotaxa. 351.2.1"]}

In the course of preparation of a major checklist for Yap and ongoing investigations into the benthic marine diatom flora of Micronesia, thirteen new araphid and raphid pennate diatom species have been recognized and are described here. Plagiogramma subatomus is even smaller than P. atomus and the pseudoseptum forms a box with only a small opening toward the cell interior. Licmophora romuli is similar in size and spathulate shape to L. remulus, but the majority of the striae in the lamina lack vimines. L. graphis is exceedingly delicate, pencil-shaped, with apical striae 60–70 in 10 µm. Divergita biformis and D. decipiens are straight species with striae biseriate on the margin, uniseriate on the valve face, differing in the shape and prominence of the sternum and the shape of the valve-face areolae. D. macinnisii (from Marshall Islands, but included here for comparison) is curved, again with the decussate areolar pattern on the mantle, but with single extended areolae along each side of the linear sternum. These characters slightly amend the diagnosis of the genus. Thalassionema baculum is a very short member of the genus, linear and isopolar. Climaconeis tarangensis is curved and differs from C. riddleae in stria density and areola shape; C. minaegensis is straight, without a stauros or craticular bars, of intermediate length, 228–247 µm. First SEM observations of Climaconeis lorenzii are presented and an updated key to Climaconeis is appended. Parlibellus paschalis is a tube-dwelling species differing from P. delognei is lacking cuniculi and pores in the central area. P. waabensis is a relatively large species, possibly tube-dwelling, that differs from P. delognei in shape and spacing of central striae and from P. berkeleyi in width and stria density. Pleurosigma simulacrum differs in ultrastructural details from P. intermedium. Lastly, Nitzschia tarangensis is a conopeate species, spathulate in profile with ribs along the edge of the valve depression and bordering the raphe, and with pores in the peri-raphe zone.

Parlibellus paschalis Lobban, sp. nov. Figs 70–78. Diagnosis:— Differing from P. delognei (Van Heurck 1880: pl. 11) E.J. Cox 1988: 19 in lacking the cuniculus and pores in the central area and smaller size, and from P. berkeleyi (Kützing 1849: 106) E.J. Cox 1988: 21 in width and stria density. Description:— Tube-dwelling cells with plastids reminiscent of a hot cross bun in valve view, a butterfly in girdle view (Figs 70–72). Frustules, often remaining together after acid cleaning (Fig. 73), with numerous copulae (Fig. 74). Valves elliptico-lanceolate, 28–35 µm long, 10.5–12.5 µm wide (Figs 75–78). Striae 25–26 in 10 µm except slightly more distant (21 in 10 µm) in those adjacent to central area, weakly radiate in the central area, otherwise parallel, continuing around the apices (Figs 75–78). Striae punctate, the external areolae openings circular to transapically elongate, internally circular. Areolae closest to the raphe sternum somewhat more prominent (Fig. 77, arrow). Central area lacking isolated pores. External central raphe endings 4–6 striae apart, straight, extending into the narrowly oval central area, which as defined by the line of areolae is 11–12 striae long. External terminal raphe endings subapical (ca. 5 striae short of apex) with a small hook into a small hyaline area 1–2 striae wide. Internal raphe endings straight, a small helictoglossa at each terminus; no cuniculi at the central endings. Holotype hic designatus:— specimen at 16.1 mm E and 9.7 mm S of the mark on slide 192, deposited at ANSP, accession # ANSP-GC20094. Fig. 75. Registration: http://phycobank.org/102762. Type locality:— GUAM: Apra Harbor, GabGab reef, 13.443 N, 144.643 E, farmer fish (Plectroglyphidodon lacrimatus) territory 7–8 m depth, sample GU44L-C. C.S. Lobban and M. Schefter, 2 March 2008. Etymology:— paschalis, L. adjective referring to Easter, with reference to the resemblance of the live cells in valve view to the Eastertime bakery item, hot cross buns. Additional Records:— GUAM: GabGab reef, Apra Harbor, GU44I-2!, GU44K-6!. Comments:— This species is most like P. delognei f. elliptica (Lobban 1983: 287) Cox 1988: 21 but differs in lacking the cuniculus that is characteristic of both forms of delognei, along with associated pores in the central area. [A cuniculus (Ross et al. 1979, Cox 1978) “comprises a simple pore in the external central area connecting with an elongate perforate raised structure terminating the internal raphe fissures in the central area.”] It is also shorter and narrower than that form, though wider than P. berkeleyi. The colony structure is similar to the narrow threads of the nominate variety of P. delognei but much different from the large, cold-water colonies of var. elliptica (Cox 1988, Lobban 1983). The stria density is higher than other similar species (Table 2), including P. berkeleyi (16–18 in 10 µm)., Published as part of Lobban, Christopher S., 2021, New species of benthic marine diatoms (Bacillariophyta) from the Western Pacific islands of Guam and Yap, pp. 235-265 in Phytotaxa 508 (3) on pages 251-252, DOI: 10.11646/phytotaxa.508.3.1, http://zenodo.org/record/5425968, {"references":["Van Heurck, H. (1880) Synopsis des Diatomees de Belgique Atlas. Anvers: Ducaju et Cie. pls I - XXX [pls 1 - 30].","Cox, E. J. (1988) Taxonomic studies on the diatom genus Navicula. V. The establishment of Parlibellus gen. nov. for some members of Navicula sect. Microstigmaticae. Diatom Research 3: 9 - 38. https: // doi. org / 10.1080 / 0269249 X. 1988.9705014","Kutzing, F. T. (1849) Species algarum. pp. [i] - vi, [1] - 922. Lipsiae [Leipzig]: F. A. Brockhaus.","Lobban, C. S. (1983) Colony and frustule morphology of three tube-dwelling diatoms from eastern Canada. Journal of Phycology 19: 281 - 289. https: // doi. org / 10.1111 / j. 0022 - 3646.1983.00281. x","Ross, R., Cox, E. J., Karayeva, N. I., Mann, D. G., Paddock, T. B. B., Simonsen, R. & Sims, P. A. (1979) An amended terminology for the siliceous components of the diatom cell. Nova Hedwigia Beihefte 64: 513 - 533.","Cox, E. J. (1978) Taxonomic studies on the diatom genus Navicula Bory. Navicula grevillii (C. A. Ag.) Heiberg and N. comoides (Dillwyn) H. & M. Peragallo. Botanical Journal of the Linnaean Society 76: 127 - 143. https: // doi. org / 10.1111 / j. 1095 - 8339.1978. tb 01502. x"]}

Climaconeis tarangensis Lobban, sp. nov. Figs 45–49. Diagnosis:— Curved species without craticular bars or stauros, differing from Climaconeis riddleae A.K.S.K. Prasad 2003: 14 in its lower stria density (20 vs 24–27 in 10 µm) and regular apically rectangular areolae. Description:— Living cells not observed. Valves arcuate, 121–124 µm long, 4.5 µm wide at center, gradually tapering to 3.0 µm just before the weakly capitate apices, 3.5 µm wide (Fig. 45). Striae 20–21 in 10 µm, parallel except convergent near apices and radiating around the apex; areolae apically rectangular (Figs 46–49). Raphe biarcuate (Fig. 45), the raphe slit partially covered by an irregular flap along the ventral side (Figs 46, 47). External central raphe endings turned slightly ventral, terminal endings nearly straight. Internal raphe with a rib along one side, helictoglossa at the apex (Figs. 48, 49). Copulae with two rows of apically-oriented pores similar to those on the valve (Figs 46, 47). Holotype hic designatus:— Specimen at 9.0 mm E, 6.4 mm S of the mark on slide 512, deposited at ANSP, accession # ANSP-GC20095. Fig. 45. Registration: http://phycobank.org/102760. Type locality:— F.S.M. Yap State: Tarang (“ O’Keefe’s Island ”), 9.525 N, 138.132 E; subtidal sediments from 15 m depth, sample Y26 C. C.S. Lobban and M. Schefter, 25 September 1988 . Etymology:— Named for the type locality. Comments:— This species is very similar to C. riddleae, which has been recorded from Guam (Lobban et al. 2011) and Chuuk (Park et al. in prep.), but Prasad (2003) described the areolae of that species thus: “squarish or subrectangular poroids… [sometimes] slightly apically elongated, especially at the apices.” In C. tarangensis the areolae are distinctly apically elongate even in the central part of the cell. Prasad’s images show a row of somewhat larger, square areolae along the ventral side of the raphe sternum (the same side that bears the silica flaps). While the differences in stria density and areola shape are small, it has become clear in this genus that such details must be taken into account in discriminating species [e.g., in distinguishing C. mabikii J.Park, Khim & J.H.Lee 2016: 592 from C. undulata (Meister 1932: 41) Lobban, Ashworth & E.C.Theriot 2010: 295 – Park et al. 2016]. For C. tarangensis, with C. riddleae known from the region, it is especially clear that the differences cannot be dismissed as geographic variation between Atlantic and Pacific Ocean basins., Published as part of Lobban, Christopher S., 2021, New species of benthic marine diatoms (Bacillariophyta) from the Western Pacific islands of Guam and Yap, pp. 235-265 in Phytotaxa 508 (3) on page 246, DOI: 10.11646/phytotaxa.508.3.1, http://zenodo.org/record/5425968, {"references":["Prasad, A. K. S. K. (2003) Fine structure and taxonomy of two species of the marine diatom genus Climaconeis (Berkeleyaceae, Bacillariophyta): C. silvae sp. nov. and C. riddleae sp. nov. from the Caribbean Sea and Florida Bay, U. S. A. Hidrobiologica 13: 9 - 22. [http: // www. scielo. org. mx / scielo. php? script = sci _ arttext & pid = S 0188 - 88972003000100002]","Lobban, C. S., Schefter, M. & Ruck, E. C. (2011) Licmophora flucticulata sp. nov. (Licmophoraceae, Bacillariophyceae), an unusual flabellate species from Guam and Palau. Phycologia 50: 11 - 22. https: // doi. org / 10.2216 / 09 - 85.1","Meister, F. (1932) Kieselalgen aus Asien. Berlin: Gebruder Bornetraeger.","Park, J., Lee, J. H. & Khim, J. S. (2016) The identity of ' Berkeleya scopulorum ' from northeast Asia: report on Climaconeis mabikii sp. nov. from temperate marine waters with notes on biogeography of the genus. Ocean Science Journal 51: 591 - 598. https: // doi. org / 10.1007 / s 12601 - 016 - 0059 - z"]}

Navicula pseudocryptofallax sp. nov. Description: —LM (Figs 21–36): Valves lanceolate with protracted rostrate to subcapitate ends, length 17.5–29.5 µm, width 5.0–6.0 µm. Axial area narrow, slightly widening towards valve centre; central area very small, irregular or indistinct. Striae strongly radiate, arched, becoming convergent towards the poles, 15.0– 16.5 in 10 µm, in valve centre long and short striae alternate. Areolae not discernible in LM. Raphe filiform, straight; terminal fissures indistinct; central pores straight, positioned close to each other. SEM external valve surface (Figs 37–39): Areolae apically elongate, areola openings at same level as valve surface. At valve apex two isolated areolae present with openings oriented approximately parallel to valve margin. Areola density 40–45 in 10 µm. Raphe sternum slightly elevated and widened at valve centre. Raphe branches straight. Central raphe endings clearly hooked to secondary valve side. Terminal fissures curved to secondary valve side. SEM internal valve surface (Fig. 40): Striae lie in shallow transapical depressions, striae wider than virgae. Areolae occluded by hymenes, two isolated areolae present at valve apex. Raphe opens obliquely to secondary valve side, raphe sternum slightly widened at centre. Accessory rib absent. Central raphe endings simple, straight, separated. Distal raphe terminates in well developed helictoglossae. Type: — RUSSIA. Krasnodar Territory: vicinity of Afonka Khutor, small, intermittent pool in the riverbed of a tributary to the Adegoy River on its northern side, on filamentous algae and silt, 44.72635°N, 37.93951°E, 179 m asl, D.A. Chudaev, 29th May 2016 (Holotype: MW-D! slide # 509s1 = Fig. 22; isotype: slide LE A0000281). Etymology: —The specific epithet reflects the similarity with N. cryptofallax Lange-Bertalot & Hofmann in Lange-Bertalot (1993: 103). Distribution and ecology: —The species is so far only known from the River Adegoy and its tributaries (samples 501, 502, 506, 507, 508, 509, 510). In the type material, where it occurs at a relative abundance of 7.5%, it is associated with the following Navicula taxa: N. adegoyensis sp. nov., N. antonii Lange-Bertalot in Rumrich et al. (2000: 155), N. avenacea, N. capitatoradiata, N. cryptotenella, N. gregaria, N. metareichardtiana, N. novaesiberica, N. oblonga (Kützing 1833: 548) Kützing (1844: 97), N. radiosa, N. tripunctata, N. trivialis Lange-Bertalot (1980: 31) (all occur at Encyonopsis spp. (48.6%) and Achnanthidium spp. (19.3%).