taxonID	type	description	language	source
5D089C6DC82A6464FF474494F72FF777.taxon	materials_examined	Holotype. Slide no. kam 288 (08120), in collection of Maxim Kulikovskiy, Institute of Plant Physiology, Russian Academy of Sciences, Russia, represented here by Figure 4. Reference strain. kam 288, isolated from sample 116. Type locality. Russia, Greshnaya river, sample 116, sand and detritus (N 55.923. 778 E 158.701.194), 15.07.2021.	en	Tseplik, Natalia, Maltsev, Yevhen, Glushchenko, Anton, Genkal, Sergey, Mironova, Elina, Kulikovskiy, Maxim (2024): New cavum-bearing Planothidium (Achnanthidiaceae, Bacillariophyceae) species from the Kamchatka Peninsula, Russia. Phytotaxa 665 (3): 271-281, DOI: 10.11646/phytotaxa.665.3.9, URL: https://doi.org/10.11646/phytotaxa.665.3.9
5D089C6DC82A6464FF474494F72FF777.taxon	description	Description. LM. Valves small, elliptic-lanceolate, with protracted and rounded ends. Length 11.0 – 13.5 μm, width 4.5 – 5.5 μm. Raphe straight, filiform, with expanded central ends and distal ends turned to one side. Axial area on the raphe valve narrow linear, central area rectangular, formed by 2 – 3 shortened striae on each side of the valve. Axial area on the rapheless valve narrow linear. A cavum is present on one side of the rapheless valve; 3 – 4 striae are shortened on the other side, forming a small semicircular central area. Striae on both valves almost parallel in the centre, becoming distinctly radiate on the ends of the valves. Striae density 15 – 19 in 10 μm on the raphe valve, 15 – 17 in 10 μm on the rapheless valve. SEM. External central raphe ends straight, expanded, distal ends turned to one side and extended onto the mantle. Internal central raphe ends slightly turned to opposite sides, distal ends terminate in faint helictoglossae. Striae multiseriate, consisting of 3 – 4 rows of small round areolae on both valves. Rapheless valve is faintly ornamented with small round depressions along the axial area. Internally, the interstriae are distinctly raised. The cavum is elongated, with a moderately wide opening. Sequence data. Partial 18 S rDNA gene sequence comprising V 4 domain sequence (GenBank accession number PP 965379) and partial rbc L sequence (GenBank accession number PP 965730) for the strain kam 288.	en	Tseplik, Natalia, Maltsev, Yevhen, Glushchenko, Anton, Genkal, Sergey, Mironova, Elina, Kulikovskiy, Maxim (2024): New cavum-bearing Planothidium (Achnanthidiaceae, Bacillariophyceae) species from the Kamchatka Peninsula, Russia. Phytotaxa 665 (3): 271-281, DOI: 10.11646/phytotaxa.665.3.9, URL: https://doi.org/10.11646/phytotaxa.665.3.9
5D089C6DC82A6464FF474494F72FF777.taxon	etymology	Etymology. The name of this species is dedicated to Vladimir Nikolaevich Tyushov, a prominent Russian naturalist and researcher of Kamchatka nature. He was a doctor in the Petropavlovsk region and took part in an expedition organized by the Russian Geographical Society. His achievements include the study of glaciers in the Klyuchyevskaya volcanic group, the establishment of the first hospital in Petropavlovsk, and the publication of the book On the West Coast of Kamchatka.	en	Tseplik, Natalia, Maltsev, Yevhen, Glushchenko, Anton, Genkal, Sergey, Mironova, Elina, Kulikovskiy, Maxim (2024): New cavum-bearing Planothidium (Achnanthidiaceae, Bacillariophyceae) species from the Kamchatka Peninsula, Russia. Phytotaxa 665 (3): 271-281, DOI: 10.11646/phytotaxa.665.3.9, URL: https://doi.org/10.11646/phytotaxa.665.3.9
5D089C6DC82A6464FF474494F72FF777.taxon	distribution	Distribution. As yet known only from type locality.	en	Tseplik, Natalia, Maltsev, Yevhen, Glushchenko, Anton, Genkal, Sergey, Mironova, Elina, Kulikovskiy, Maxim (2024): New cavum-bearing Planothidium (Achnanthidiaceae, Bacillariophyceae) species from the Kamchatka Peninsula, Russia. Phytotaxa 665 (3): 271-281, DOI: 10.11646/phytotaxa.665.3.9, URL: https://doi.org/10.11646/phytotaxa.665.3.9
5D089C6DC8296465FF4745F9F72FF7E7.taxon	materials_examined	Holotype. Slide no. kam 373 (08205), in collection of Maxim Kulikovskiy, Institute of Plant Physiology, Russian Academy of Sciences, Russia, represented here by Figure 24. Reference strain. kam 373, isolated from sample 219. Type locality. Russia, Dachnye hot springs, sample 219, detritus, sand and clay (N 52.530. 139 E 158.191.755), 18.07.2021.	en	Tseplik, Natalia, Maltsev, Yevhen, Glushchenko, Anton, Genkal, Sergey, Mironova, Elina, Kulikovskiy, Maxim (2024): New cavum-bearing Planothidium (Achnanthidiaceae, Bacillariophyceae) species from the Kamchatka Peninsula, Russia. Phytotaxa 665 (3): 271-281, DOI: 10.11646/phytotaxa.665.3.9, URL: https://doi.org/10.11646/phytotaxa.665.3.9
5D089C6DC8296465FF4745F9F72FF7E7.taxon	description	Description. LM. Valves lanceolate, with rounded or slightly protracted ends. Length 12.0 – 14.0 μm, width 5.0 – 5.5 μm. Raphe straight, filiform, with expanded central ends and distal ends turned to one side. Axial area on the raphe valve narrow, linear, central area elliptical or roundish, formed by 2 – 3 striae shortened on each side. Axial area on the rapheless valve narrow, linear. A large elongated cavum is present on one side of the valve; 2 – 3 striae are shortened on the other side and form a small semicircular central area. Striae on both valves almost parallel at the centre of the valve, radiate at the ends, 14 – 16 in 10 μm. SEM. External central raphe ends straight, slightly expanded; distal ends turned to one side and extended onto the mantle. Internal central raphe ends slightly turned to opposite sides; distal ends terminate in faint helictoglossae. Striae multiseriate on both valves, consisting of 2 – 4 rows of areolae on the raphe valve and 3 – 4 rows on the rapheless valve. Areolae small, circular. The rapheless valve is ornamented with small round depressions along the axial area. Internally the interstriae are slightly raised. The cavum is large, elongated, with a relatively small opening. Sequence data. Partial 18 S rDNA gene sequence comprising V 4 domain sequence (GenBank accession number PP 965380) and partial rbc L sequence (GenBank accession number PP 965731) for the strain kam 373.	en	Tseplik, Natalia, Maltsev, Yevhen, Glushchenko, Anton, Genkal, Sergey, Mironova, Elina, Kulikovskiy, Maxim (2024): New cavum-bearing Planothidium (Achnanthidiaceae, Bacillariophyceae) species from the Kamchatka Peninsula, Russia. Phytotaxa 665 (3): 271-281, DOI: 10.11646/phytotaxa.665.3.9, URL: https://doi.org/10.11646/phytotaxa.665.3.9
5D089C6DC8296465FF4745F9F72FF7E7.taxon	etymology	Etymology. This species is named after Pavel Nikolaevich Dyakonov, a renowned Russian expert in forestry and forest conservation. He authored the book Forests of Kamchatka and was known for his poetry and photographs of Kamchatkan landscapes. Dyakonov actively promoted nature conservation among the local population and was involved in the activities of the Soviet Geographical Society.	en	Tseplik, Natalia, Maltsev, Yevhen, Glushchenko, Anton, Genkal, Sergey, Mironova, Elina, Kulikovskiy, Maxim (2024): New cavum-bearing Planothidium (Achnanthidiaceae, Bacillariophyceae) species from the Kamchatka Peninsula, Russia. Phytotaxa 665 (3): 271-281, DOI: 10.11646/phytotaxa.665.3.9, URL: https://doi.org/10.11646/phytotaxa.665.3.9
5D089C6DC8296465FF4745F9F72FF7E7.taxon	distribution	Distribution. As yet known only from type locality.	en	Tseplik, Natalia, Maltsev, Yevhen, Glushchenko, Anton, Genkal, Sergey, Mironova, Elina, Kulikovskiy, Maxim (2024): New cavum-bearing Planothidium (Achnanthidiaceae, Bacillariophyceae) species from the Kamchatka Peninsula, Russia. Phytotaxa 665 (3): 271-281, DOI: 10.11646/phytotaxa.665.3.9, URL: https://doi.org/10.11646/phytotaxa.665.3.9
