Skip to main content
NCBI home page
PhytoKeys logoLink to PhytoKeys
. 2024 Jan 11;237:23–35. doi: 10.3897/phytokeys.237.112939

A new species of genus Crenotia (Bacillariophyta) from Tibet, China

Xinyuan Na 1, Jiaming Liu 1, Ying Zhang 1, John Patrick Kociolek 2, Maxim Kulikovskiy 3, Xinxin Lu 1, Fengyang Sui 1, Huan Zhu 4, Guoxiang Liu 4, Yawen Fan 1,✉, Yan Liu 1,✉
PMCID: PMC10798045  PMID: 38250523

Abstract

During the investigation of the freshwater diatoms from Tibet, a monoraphid species was observed from a hot spring near Anduo County, located on a plateau in the central portion of Tibet. This species shares the diagnostic features of Crenotia, such as the valve bent along the transapical axis, striae uniseriate to biseriate from centre to the apices and areolae with special structures located at the end of each stria. We compared the morphological characters of this new species with the others in this genus and show it to be new; it is named Crenotiatibetiasp. nov. This species has small valves with slightly protracted ends with nearly capitate apices, lanceolate axial area, central area unilaterally expanded to the margin, striae uniseriate to biseriate, but, in some valves, the striae are only uniseriate. Areolae are round small to irregular in shape and, at the end of each stria, there is a horseshoe-shaped areola present. Observations of developing valves show all the striae begin biseriate, then they become covered by silica to form uniseriate striae. Comparisons are made amongst the species in this genus and with genera assigned to the Achnanthidiaceae.

Key words: Freshwater diatoms, hot spring, monoraphid, taxonomy

Introduction

Raphid diatoms that possess a raphe on only one of the valves are very diverse and recent systematic revisions of this group have led to a marked increase in the number of genera, from two (e.g. Hustedt (1930); Patrick and Reimer (1966)) to 27 genera (De Stefano and Marino 2003; Wojtal 2013; Kulikovskiy et al. 2020a; Al-Handal et al. 2021; Ge et al. 2022). Traditionally, these genera have been assigned to one of three families, AchnanthaceaeKützing (1844), CocconeidaceaeKützing (1844) or Achnanthidiaceae Mann in Round et al. (1990). Recent phylogenetic studies have shown these groups to be unrelated, widely dispersed across the raphid diatom tree of life (Thomas et al. 2016; Kulikovskiy et al. 2019). Even genera within the Achnanthidiaceae have been shown to be non-monophyletic (Kociolek et al. 2019; Kulikovskiy et al. 2019).

Crenotia was established in 2013 by Wojtal, when species assigned to it were split from the genus Achnanthidium. The type species of Crenotia, C.thermalis (Rabenhorst) Wojtal, was originally described as a species of Achnanthidium (as A.thermalis Rabenhorst) and then assigned to the genus Achnanthes (as Achnanthesthermalis (Rabenhorst) Schoenfeld). Eight species have been suggested to belong to Crenotia so far. Like other monoraphid diatoms, Crenotia has heterovalvar frustules; however, it is distinguished from other monoraphid genera by lacking a cavum on both valves, having biseriate or uniseriate striae, presence of specialised structures at the end of each stria and no ornamentation on the girdle bands. This genus has been reported to have a worldwide distribution (Rioual et al. 2019), usually being found from benthic or periphytic habitats in lakes, springs and swamps and preferring neutral to alkaline waters (Stockner 1968; Hindáková 2009; Wojtal 2013; Kulikovskiy et al. 2016; Coste et al. 2019; Rioual et al. 2019; Wetzel et al. 2019; Liu et al. 2020).

Tibet is one of the biodiversity hotspots of the world and, in this region, the biodiversity of Crenotia is also relatively high, with five of the eight species of the genus being reported from Tibet. These species include C.gibberula (Grunow) Wojtal, C.grimmei (Krasske) Wojtal, C.hedinii (Hustedt) Rioual, Ector & Wetzel, as well as three species that are endemic to Tibet, namely, C.hedinii (Hustedt) Rioual, C.distincta Liu, Kociolek & Xie and C.oblonga Liu, Kociolek & Xie (Rioual et al. 2019; Liu et al. 2020). During the investigation of freshwater biodiversity of the Tibetan Plateau, samples were collected from a hot spring in Anduo County, specifically, Nagqu City. One species was observed with light microscopy (LM) and scanning electron microscopy (SEM), based on its morphological features, demonstrated to be a new species belonging to the genus Crenotia. Herein we describe this Tibetan diatom as new to science.

Materials and methods

Samples were collected from Tibet, during a biodiversity investigation initiated in 2021. Benthic diatoms were collected from Anduo County, Nagqu City, which is located in about the middle of Tibet. Samples were taken from a hot spring located at 31°40′51.24″N, 91°51′20.52″E and 31°40′52.32″N, 91°51′20.52″E, at an elevation of 4570 m above sea level. At the time of collection, the water temperature was around 20 °C, pH ranged from 6.55 to 7.77, conductivity ranged from 2790 to 3200 μS∙cm-1(determined by YSI 6920 multiparameter probe). This locality has a cold climate, with dry, windy and cold weather and an annual precipitation of only ca. 100–200 mm.

Samples were fixed with 4% formaldehyde in the field. The samples were cleaned with nitric acid (HNO3), then washed and settled using distilled water until the pH was neutral. For LM observations, cleaned diatoms were mounted to make permanent slides with Naphrax. These permanent slides were examined with a Zeiss Imager A2 microscope, equipped with a digital camera (AxioCam MRc 5) and observed with DIC (differential interference contrast) optics (Zeiss, Jena, Germany at Harbin Normal University).

For SEM observations, cleaned material was air-dried and coated with gold-palladium and observations made with a Hitachi S-4800 field emission SEM (Hitachi, Tokyo, Japan at Harbin Normal University) at an operating voltage of 15 kv. Diatom images were compiled with Photoshop 7.0. The holotype slides are deposited in the Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China and isotype slides are kept in the College of Life Science and Technology, Harbin Normal University, Harbin, China. Terminology used in the description were referenced by Round et al. (1990), Kingston (2003) and Kulikovskiy et al. (2022).

Results

. Crenotia tibetia

Liu & Kociolek sp. nov.

F9646BFE-311F-5731-A588-519ACA4C6194

Figs 1 , 2 , 3 , 4 , 5

Figure 1.

Figure 1.

Open in a new tab

Crenotiatibetia sp. nov., LM. Raphe and rapheless valves from the type population. A, A’ illustrations of the holotype. “=” means the raphe valve and rapheless valve are from the same frustule. Scale bar: 10 μm.

Figure 2.

Figure 2.

Open in a new tab

Crenotiatibetia sp. nov. SEM, external view of the raphe valve A external view of the whole valve B, C apices of the valve D magnification of areolae E central area of the valve F girdle view of the valve. Scale bar: 1 μm (A, B, C, E, F); 500 nm (D).

Figure 3.

Figure 3.

Open in a new tab

Crenotiatibetia sp. nov. SEM internal view of the raphe valve A internal view of the whole view B, C apices of the valve D central area of the valve internally E magnification of the areolae, showing the horseshoes areola at the end of striae F internal view of a developing valve. Scale bar: 1 μm (A, B, C, D, F); 500 nm (E).

Figure 4.

Figure 4.

Open in a new tab

Crenotiatibetia sp. nov. SEM external view of the rapheless valve A, B external view of whole valve C, D apices of the valve, showing the areolae. Scale bar: 1 μm.

Figure 5.

Figure 5.

Open in a new tab

Crenotiatibetia sp. nov. SEM internal view of the rapheless valve A internal view of the whole valve B apex of the developing valve C apex of the valve D magnification of the areolae, showing the horseshoe-shaped structure at the end of the areolae. Scale bar: 1 μm.

Holotype.

Slide THXZ2021BYQX1–4#, the holotype specimen circled on the slide, illustrated here as Fig. 1A and 1A’; isotype, slide QX1–4#, illustrated here as Fig. 1C and 1C’.

Type locality.

China. Tibet, Anduo County, Nagqu City, hot spring, periphyton, 31°41'51.24"N, 91°51'20.52"E, 4570 m a.s.l., collected by Huan Zhu, 31 January 2021.

Description.

LM (Fig. 1). Frustule slightly bent along the transapical axis (“V” shaped), monoraphid, with raphe valve concave, rapheless valve convex. Valve lanceolate with slightly protracted ends, slightly asymmetrical to the apical axis, apices nearly capitate. Length 11.8–19.7 μm, breadth 4.1–5.3 μm (n = 30). Raphe valve: straight raphe positioned in the middle of the valve, axial area lanceolate, with asymmetrical, rectangular to rhombic central area. Striae slightly radiating in the centre, becoming parallel towards the apices. Rapheless valve: Axial area lanceolate, central area expanded unilaterally to the margin. Striae 19–21 per 10 μm on both valves.

SEM (Figs 2–5). Raphe valve: Externally, raphe straight, proximal raphe ends slightly deflected to the same side, with distal raphe ends curved to the other side. Axial area lanceolate, nearly 1/3 of the valve width, formed by short striae along the margin. The 3 – 4 striae near the apices are biseriate and become uniseriate towards the valve centre. Areolae openings round to elongate, to irregularly-shaped externally. Internally, proximal raphe ends slightly bent to opposite side, helictoglossae slightly elongated. Areolae covered by hymens, forming two rows of “C”-shaped openings for each stria. Along the axial area, at the end of each stria, there is one horseshoe-shaped structure, open with fine radiating slit-like openings. One developing valve was observed; all the striae were biseriate.

Rapheless valve: Internally, axial area lanceolate, narrow at the apices and becoming wider towards the centre, centre area enlarged unilaterally and reaching the margin. Striae uniseriate to biseriate, mostly biseriate at the apices and becoming uniseriate at the centre. Areolae openings round to irregular in shape. Mantle and girdle bands without ornamentation.

Internally, the axial area is lanceolate, wide in the centre and enlarged at one side extending to the margin. Areolae were occluded by hymens with double rows of “C”-shaped openings; at the end of each stria, there is horseshoe-shaped structure, with fine slit-like openings. A developing valve was observed, all the striae were biseriate, with a “C- shaped structure at the end of each stria.

Etymology.

Named after the type locality from which it was found.

Discussion

Based on the morphological features of the valve and striae structure, this new species appears to be best placed in the genus Crenotia. This small genus currently is known to have nine species, including eight previously-described taxa. The previously-described taxa are: C.angustior (Grunow) Wojtal, C.distincta, C.hedinii, C.oblonga, C.rumrichorum (Lange-Bertalot) Wojtal, C.thermalis, C.gibberula and C.grimmei.

In comparing this new species with other known taxa (Table 1), C.angustior differs by its small frustule and capitate ends. Crenotiahedinii was formally transferred to Crenotia by Rioual et al. (2019); it has more slender valves and more acutely-rounded ends than our new species.

Table 1.

Comparison of morphological characteristics of Crenotiatibetia sp. nov. and closely related taxa.

C.tibetia sp. nov. C.angustior C.distincta C.gibberula C.grimmei C.hedinii C.oblonga C.rumrichorum C.thermalis
Length (μm) 11.8–19.7 10–19.5 14.0–31.5 13.5–39.5 16–24 7–30 8.0–21.0 12–13.4 7–34
Breadth (μm) 4.1–5.3 4.1–5.2 5.0–8.0 3.6–8 3.6–5 3.2–4.6 4.0–6.0 3.4–4 3.3–5.5
Valve shape lanceolate linear to lanceolate lanceolate rhombic-shaped linear lanceolate elliptical-lanceolate narrow lanceolate elliptical-lanceolate or linear
Valve apices capitate small capitate rounded capitate capitate acutely rounded rounded acutely rounded rounded
Striae Slightly radiate to parallel / uni to biseriate Slightly radiate / biseriate Radiate / multiseriate slightly radiate slightly radiate Slightly radiate / uni to biseriate Parallel / bi to triseriate Radiate / uni to biseriate almost parallel / uni to biseriate
Raphe valve
Axial area lanceolate narrow lanceolate very narrow at the apices, broadly lanceolate in shape lanceolate narrow lanceolate narrow lanceolate very narrow at the apices, broadly lanceolate in shape lanceolate, both ends are slightly curved ipsilaterally linear
Central area asymmetrical, rectangular to rhombic small rectangle absent obviously enlarged rectangular small absent small rectangle rectangular
Raphe straight filiform, straight filiform, straight filiform, straight filiform, straight filiform, straight filiform, straight filiform, slightly curved straight, slightly curved at the end
Striae / 10 μm 19–21 12–16 17–18 14–32 20–22 17–25 22–26 25–27 20–26
Rapheless valve
Axial area lanceolate narrow lanceolate broadly lanceolate narrow lanceolate narrow lanceolate broadly lanceolate broadly lanceolate broadly lanceolate needle lanceolate
Central area expanded unilaterally to the margin absent absent absent absent asymmetry absent absent absent
Striae / 10 μm 19–21 14–18 17–19 12–30 18–22 17–25 22–26 25–27 18–20
Open in a new tab

Crenotiagrimmei, C.gibberula and C.rumrichorum, the former two species being designated as synonyms of Achnanthesthermalis (Rabenhorst) Schoenfeld (Krammer and Lange-Bertalot 2004), are the type species of Crenotia. All these three species were transferred to Crenotia by Wojtal (2013) when the genus was established.

Crenotiagrimmei, first reported by Krasske (1925), was originally named Achnanthesgrimmei Krasske; however, Lange-Bertalot and his colleagues rechecked the type and lectotype (Lange-Bertalot and Ruppel (1980), tafel 2, figs 46–50; Lange-Bertalot et al. (1996), tafel 4, figs 8–13) and suggested it is synonymous with A.thermalis. Crenotiagibberula was described originally as Achnanthesgibberula Grunow in Cleve & Grunow. Lange-Bertalot and Ruppel (1980) suggested that A.grimmei and its varieties should be considered synonymous with A.gibberula and illustrated A.gibberula as a morphologically variable taxon (Håkansson 1982). Although Lange-Bertalot and Ruppel (1980) presented the type material of Crenotiagrimmei and C.gibberula, it is hard to suggest that they belong to the same species, at least based on LM morphology. Based on the illustrations of Lange-Bertalot and Ruppel (1980), Lange-Bertalot et al. (1996) and Wojtal (2013), we can separate C.thermalis, C.grimmei and C.gibberula, based on the morphology of the valves. Crenotiathermalis has elliptical-lanceolate or linear valves and the raphe valve face is flat, slightly convex in the central area and the rapheless valves are concave along the apical axis; C.grimmei has linear valves with protracted ends that form capitate apices; C.gibberula has more rhombic-shaped valves and they have capitate apices and the centre of the valves is obviously enlarged.

LM and SEM images were also presented by Håkansson (1982, plate I: 3–6) for A.gibberula, but the striae showed a “macroareolae”-like structure on both valves, similar to those shown in the genus Madinithidium Witkowski, Desrosiers & Riaux-Gobin (Desrosiers et al. 2014) or, probably, similar to developing valves of Achnanthidium species. Okuno (1974, pl. 855–856), also showed a SEM of A.grimmei, but, based on the stria pattern and areola structure, the specimen presented was more similar to Achnanthidium rather than Crenotia.

Compared with the former three species, C.tibetia is morphologically most similar to C.grimmei, but C.tibetia has a more highly deflected frustule about the transapical axis, the raphe valve is more concave and is larger than C.grimmei (Lange-Bertalot et al. (1996) report length 13.0–16.7 μm, breadth 3.6–4.7 μm, striae 16–19/10 μm, for this taxon), striae are denser on both valves, with shorter capitate ends and axial area are wider on the rapheless valves.

Crenotiagrimmei and C.gibberula were also recorded in Tibet by Zhu and Chen (2000), as Achnanthesgrimmei and A.gibberula, respectively, plate 46: 11–14), but, based on the published line drawings, their specimens do not match well either of these species.

The morphology of C.rumrichorum was observed in detail by Hindáková (2009) as Achnanthesthermalisvar.rumrichorum. Based on the structure, this species was found to belong to the genus Crenotia. Crenotiarumrichorum has more acute apices, distinguishing it from C.tibetia.

Within the genus, C.distincta and C.oblonga are endemic to Tibet so far and these two species have chambered and multiseriate striae on both valves, which easily distinguish them from our new species. However, these two species do not share the typical features of Crenotia and the valve structure resembles the genus Haloroundia Diaz & Maidana (2006), a monotypic genus described from Chile. The differences between Crenotia and Haloroundia can be seen in terms of striae structure, raphe system and degree of flexure of the frustules, but further investigations on the relationships between these two genera are warranted.

The work from Lake Baikal (Kulikovskiy et al. 2013, 2020a, b) established many new genera within Achnanthidiaceae. In research on monoraphid diatoms, curvature of the valve, valve shape and raphe system have been considered as critical features used to separate genera within this family (e.g. Yu et al. (2019); You et al. (2021)). However, molecular data showed the raphe number of frustules does not play such an important role in diatom taxonomy and its reduction or loss occurred many times during the evolution of raphid diatoms (Kulikovskiy et al. 2016). Features such as the “cavum” seem to have played important roles in the evolution of this group. Both morphological features and molecular data were used to identify this group and recognise: 1) species with a sinus; 2) species with a cavum; 3) species without these features (Kulikovskiy et al. 2022). Since more and more “intermediate species” between genera have been observed (You et al. 2021), the relationships between some uniseriate genera, such as Achnanthidium, Gomphothidium and Psammothidium (Round et al. 1990; Bukhtiyarova and Round 1996; Kociolek et al. 2021); and multiseriate genera such as Platebaikalia, Lemnicola and Haloroundia (Diaz and Maidana 2006; Kulikovskiy et al. 2020b) and those with macroareolae, such as Scalariella, Madinithidium, Karayevia and Kolbesia (Riaux-Gobin et al. 2012; Desrosiers et al. 2014; Kulikovskiy et al. 2022), appear to be in need of revision. Investigations with formal analyses of both morphological and molecular data may clarify the systematic position and diagnostic features amongst these genera.

Supplementary Material

XML Treatment for Crenotia tibetia

Citation

Na X, Liu J, Zhang Y, Kociolek JP, Kulikovskiy M, Lu X, Sui F, Zhu H, Liu G, Fan Y, Liu Y (2024) A new species of genus Crenotia (Bacillariophyta) from Tibet, China. PhytoKeys 237: 23–35. https://doi.org/10.3897/phytokeys.237.112939

Funding Statement

College of Life Science and Technology, Harbin Normal University, Harbin, China. Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.

Contributor Information

Yawen Fan, Email: fanyaw@163.com.

Yan Liu, Email: yanliuhrb@hotmail.com.

Additional information

Conflict of interest

The authors have declared that no competing interests exist.

Ethical statement

No ethical statement was reported.

Funding

This research was supported by National Science Foundation of China (Grant no. 31970213, 32370215); Natural Science Foundation of Heilongjiang Province for Excellent Young Scholars (Grant no. YQ2020C032) and The Second Tibetan Plateau Scientific Expedition and Research Program (Grant no. 2019QZKK0304).

Author contributions

Validation: John Patrick Kociolek, Maxim Kulikovskiy. Resources: Huan Zhu, Guoxiang Liu. Data Curation: Jiaming Liu, Ying Zhang. Investigation: Xinyuan Na. Writing - Original draft: Xinyuan Na. Writing - Review and Editing: Yawen Fan, Yan Liu. Supervision: Yawen Fan, Yan Liu, Xinxin Lu, Fengyang Sui

Author ORCIDs

Xinyuan Na https://orcid.org/0009-0005-1425-7610

John Patrick Kociolek https://orcid.org/0000-0001-9824-7164

Maxim Kulikovskiy https://orcid.org/0000-0003-0999-9669

Fengyang Sui https://orcid.org/0000-0002-6734-6570

Guoxiang Liu https://orcid.org/0000-0001-8565-2363

Data availability

All of the data that support the findings of this study are available in the main text.

References

  1. Al-Handal AY, Romero OE, Eggers SL, Wulff A. (2021) Navithidium gen. nov., a new monoraphid diatom (Bacillariophyceae) genus based on Achnanthesdelicatissima Simonsen. Diatom Research 36(2): 133–141. 10.1080/0269249X.2021.1921039 [DOI] [Google Scholar]
  2. Bukhtiyarova L, Round FE. (1996) Revision of the genus Achnanthes sensu lato. Psammothidium, a new genus based on A.marginulatum. Diatom Research 11(1): 1–30. 10.1080/0269249X.1996.9705361 [DOI]
  3. Coste M, Riaux-Gobin C, Riaux J, Saenz-Agudelo P, Massuel S, Ector L, Calvez R, Ben AΪssa N. (2019) AΪn Bou Rkhiss and AΪn Kibrit, two springs from the Merguellil Basin (Kairouan, Central Tunisia): diatom assemblages, biological pollusensitivity indices, hydrogeology and societal aspects. Vie et Milieu – life and Environment 69(1): 1–17. [Google Scholar]
  4. De Stefano M, Marino D. (2003) Morphology and taxonomy of Amphicocconeis gen. nov. (Achnanthales, Bacillariophyceae, Bacillariophyta) with considerations on its relationship to other monoraphid diatom genera. European Journal of Phycology 38(4): 361–370. 10.1080/09670260310001612646 [DOI] [Google Scholar]
  5. Desrosiers C, Witkowski A, Riaux-Gobin C, Zglobicka I, Kurzydlowski KJ, Eulin A, Leflaive J, Ten-Hage L. (2014) Madinithidium gen. nov. (Bacillariophyceae), a new monoraphid diatom genus from the tropical marine coastal zone. Phycologia 53(6): 583–592. 10.2216/14-21R2 [DOI] [Google Scholar]
  6. Diaz CA, Maidana NI. (2006) A new monoraphid diatom genus: Haloroundia Diaz & Maidana. Nova Hedwigia. Beiheft 130: 177–184. [Google Scholar]
  7. Ge DY, Zhang SM, Liu HY, Liu Y, Kociolek JP, Zhu H, Liu GX, Fan YW. (2022) One new species of Achnanthidium Kützing (Bacillariophyta, Achnanthidiaceae) from Tibet, China. Phytotaxa 538(4): 268–280. 10.11646/phytotaxa.538.4.1 [DOI] [Google Scholar]
  8. Håkansson H. (1982) Taxonomical discussion on four diatom taxa from an ancient lagoon in Spjälkö, South Sweden. In: Håkansson H (Ed.) Rapport från diatomésymposium i Lund, Maj 1981, University of Lund, Department of Quarternary Geology 22: 65–81.
  9. Hindáková A. (2009) On the occurrence of Achnanthesthermalisvar.rumrichorum (Bacillariophyceae) in Slovakia. Fottea 9(2): 193–198. 10.5507/fot.2009.020 [DOI] [Google Scholar]
  10. Hustedt F. (1930) Die susswasser-Flora Mitteleuropas Heft. Bacillariophyta (diatomeae), Fischer, Jena, Germany, 466 pp. [Google Scholar]
  11. Kingston JC. (2003) Araphid and Monoraphid Diatoms. Freshwater Algae of North America. Ecology and Classification. Elsevier Science, 595–636 10.1016/B978-012741550-5/50017-9 [DOI]
  12. Kociolek JP, Williams DM, Stepanek J, Liu Q, Liu Y, You QM, Karthick B, Kulikovskiy M. (2019) Rampant homoplasy and adaptive radiation in pennate diatoms. Plant Ecology and Evolution 152(2): 131–141. 10.5091/plecevo.2019.1612 [DOI] [Google Scholar]
  13. Kociolek JP, You QM, Li YL, Wang YL, Lowe R, Wang QX. (2021) Description of Gomphothidium gen. nov., with light and scanning electron microscopy: A new freshwater monoraphid diatom genus from Asia. Fottea 21(1): 1–7. 10.5507/fot.2020.011 [DOI] [Google Scholar]
  14. Krammer K, Lange-Bertalot H. (1991b) Suesswasserflora von Mitteleuropa. Bacillariophyceae. 4. Teil: Achnanthaceae, vol. 2/4, Gustav Fischer, Stuttgart, Germany, 437 pp. [Google Scholar]
  15. Krammer K, Lange-Bertalot H. (2004) Bacillariophyceae 4. Teil: Achnanthaceae, Kritische Erganzungen zu Navicula (Lineolatae), Gomphonema Gesamtliteraturverzeichnis [second revised edition] In: Ettl et al. Suesswasserflora von Mitteleuropa. Spektrum Akademischer Verlad Heidelberg, 2, 4, 468 pp. [Google Scholar]
  16. Krasske G. (1925) Die Bacillariaceen-Vegetation Niederhessens. Abhandlungen und Bericht LVI des Vereins für Naturkunde zu Cassel, 84–89 Vereinsjahr 1919–1925, 56: 1–119.
  17. Kulikovskiy M, Andreeva S, Gusev E, Kuznetsova I, Annenkova N. (2016) Molecular phylogeny of monoraphid diatoms and raphe significance in Evolution and taxonomy. Botany 43(5): 398–407. 10.1134/S1062359016050046 [DOI] [PubMed] [Google Scholar]
  18. Kulikovskiy M, Lange-Bertalot H, Witkowski A. (2013) Gliwiczia gen. nov. a new monoraphid diatom genus from Lake Baikal with a description of four species new for science. Phytotaxa 109(1): 1–16. 10.11646/phytotaxa.109.1.1 [DOI] [Google Scholar]
  19. Kulikovskiy M, Glushchenko A, Genkal S, Kuznetsova I. (2016) Identification book of diatoms from Russia. Filigran, Yaroslavl, Russia, 804 pp. [Google Scholar]
  20. Kulikovskiy M, Maltsev Y, Andreeva S, Glushchenko A, Pudonay Y, Ludwig T, Tusset E, Kociolek JP. (2019) Splitting of the diatom genus Naviculasensu lato: Description of Dorofeyukae gen. nov., remarks on the phylogeny of stauroneioid diatoms, and implications for the higher classification of raphid diatoms. Journal of Phycology 55: 173–185. 10.1111/jpy.12810 [DOI] [PubMed] [Google Scholar]
  21. Kulikovskiy M, Glushchenko A, Kuznetsova I, Genkal S, Kociolek JP. (2020a) Gololobovia gen. nov. a new genus from Lake Baikal with comments on pore occlusion in monoraphid diatoms. Phycologia 59(6): 1–18. 10.1080/00318884.2020.1830596 [DOI] [Google Scholar]
  22. Kulikovskiy M, Glushchenko A, Genkal S, Kuznetsova I, Kociolek J. (2020b) Platebaikalia–A new monoraphid diatom genus from ancient Lake Baikal with comments on the genus Platessa. Fottea 2020(20): 58–67. 10.5507/fot.2019.014 [DOI] [Google Scholar]
  23. Kulikovskiy M, Glushchenko A, Kuznetsova I, Kociolek J. (2022) Planoplatessa gen. nov. – A new, neglected monoraphid diatom genus with a cavum. Plants 11(17): 2314. 10.3390/plants11172314 [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Kützing FT. (1844) Die Kieselschaligen. Bacillarien oder Diatomeen. Nordhausen, 152 pp. 10.5962/bhl.title.64360 [DOI]
  25. Lange-Bertalot H, Ruppel M. (1980) A revision of some taxonomically most problematic groups in Achnanthes Bory, important from the ecological point of view. Algological Studies 26: 1–31. [Google Scholar]
  26. Lange-Bertalot H, Külbs K, Lauser T, Nörpel-Schempp M, Willmann M. (1996) Iconographia Diatomologica, Volume 3: Dokumentation und Revision der von Georg Krasske beschriebenen Diatomeen-Taxa. Koeltz Botanical Books, Kapellenbergstr, Germany, 358 pp. [Google Scholar]
  27. Liu Q, Xiang YD, Yu P, Xie SL, Kociolek JP. (2020) New and interesting diatoms from Tibet. II. Description of two new species of monoraphid diatoms. Diatom Research 35(4): 353–361. 10.1080/0269249X.2020.1810781 [DOI] [Google Scholar]
  28. Okuno H. (1974) Freshwater diatoms. In: Helmcke J-G, Krieger W, Gerloff J. (Eds) Diatomeenschalen im elektronenmikroskopischen Bild.Vol. IX, 825–923. [J. Cramer, Vaduz]
  29. Patrick R, Reimer CW. (1966) The diatoms of the United States, exclusive of Alaska and Hawaii. Volume 1. Fragilariaceae, Eunotiaceae, Achnanthaceae, Naviculaceae. The Academy of Natural Sciences of Philadelphia, America, 688 pp. [Google Scholar]
  30. Riaux-Gobin C, Witkowski A, Ruppel M. (2012) Scalariella a new genus of monoraphid diatom (Bacillariophyta) with a bipolar distribution. Fottea 12(1): 13–25. 10.5507/fot.2012.002 [DOI] [Google Scholar]
  31. Rioual P, Ector L, Wetzel CE. (2019) Transfer of Achnantheshedinii Hustedt to the genus Crenotia Wojtal (Achnanthidiaceae, Bacillariophyceae). Notulae Algarum 106: 1–6. 10.5507/fot.2012.002 [DOI] [Google Scholar]
  32. Round FE, Crawford RM, Mann DG. (1990) The Diatoms. Biology and Morphology of the Genera. Cambridge University Press, 747 pp.
  33. Stockner JG. (1968) The ecology of a diatom community in a thermal stream. British Phycological Bulletin 3(3): 501–514. 10.1080/00071616800650101 [DOI] [Google Scholar]
  34. Thomas E, Stepanek J, Kociolek JP. (2016) Historical and current perspectives on the systematics of the ‘Enigmatic’ diatom genus Rhoicosphenia (Bacillariophyta), with single and multi-molecular marker and morphological analyses and discussion on the monophyly of ‘Monoraphid’ Diatoms. PLOS ONE 11(4): e0152797. 10.1371/journal.pone.0152797 [DOI] [PMC free article] [PubMed]
  35. Wetzel CE, Beauger A, Ector L. (2019) Cocconeisrouxii Héribaud & Brun a forgotten, but common benthic diatom species from the Massif Central, France. Botany Letters 166(2): 221–233. 10.1080/23818107.2019.1584865 [DOI] [Google Scholar]
  36. Wojtal AZ. (2013) Bibliotheca Diatomologica, Volume 59: Species composition and distribution of diatom assemblages in spring waters from various geological formation in southern Poland. J. Cramer in Borntraeger Science, Johannesstr, Germany, 436 pp. [Google Scholar]
  37. You QM, Zhao K, Wang YL, Yu P, Kociolek JP, Pang WT, Wang QX. (2021) Four new species of monoraphid diatoms from western sichuan plateau in China. Phytotaxa 479(3): 257–274. 10.11646/phytotaxa.479.3.3 [DOI] [Google Scholar]
  38. Yu P, You QM, Pang WT, Cao Y, Wang QX. (2019) Five new Achnanthidiaceae species (Bacillariophyta) from Jiuzhai Valley, Sichuan Province, Southwestern China. Phytotaxa 405(3): 147–170. 10.11646/phytotaxa.405.3.5 [DOI] [Google Scholar]
  39. Zhu HZ, Chen JY. (2000) Bacillariophyta of the Xizang Plateau. Science Press, Beijing, China, 353 pp. [Google Scholar]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

XML Treatment for Crenotia tibetia
phytokeys.237.112939-treatment1.xml (13.2KB, xml)

Data Availability Statement

All of the data that support the findings of this study are available in the main text.

Articles from PhytoKeys are provided here courtesy of Pensoft Publishers

RESOURCES