taxonID	type	description	language	source
039287B99D26FF9DFCBCF9EB56BCB129.taxon	materials_examined	Type: Russia, Shikotan Island, Tymovo Distr., vicinity of Malokurilskoe Village, 43.88292 ° N, 146.83257 ° E, 230 m alt. In shaded niche of rock outcrops. 7 August 2021, coll. Fedosov V. E. & Shkurko A. V. (holotype MW).	en	Fedosov, V. E., Ignatova, E. A., Fedorova, A. V., Kucera, J. (2021): Microamblystegium - a new genus of Amblystegiaceae from Shikotan Island (South Kurils, Russian Far East). Arctoa 30 (2): 417-424, DOI: 10.15298/arctoa.30.27, URL: https://doi.org/10.15298/arctoa.30.27
039287B99D26FF9DFCBCF9EB56BCB129.taxon	etymology	Etymology: The generic name originates from Amblystegium (a genus of mosses) and refers to its small size. The specific epithet refers to the habitat where it was discovered.	en	Fedosov, V. E., Ignatova, E. A., Fedorova, A. V., Kucera, J. (2021): Microamblystegium - a new genus of Amblystegiaceae from Shikotan Island (South Kurils, Russian Far East). Arctoa 30 (2): 417-424, DOI: 10.15298/arctoa.30.27, URL: https://doi.org/10.15298/arctoa.30.27
039287B99D26FF9DFCBCF9EB56BCB129.taxon	diagnosis	Diagnosis: Microamblystegium differs from most oth- er genera of pleurocarpous mosses in combination of minute size of plants; stem not differentiated internally, composed of thin-walled cells; a weak single costa reaching above mid-leaf at least in several leaves; short and wide rhomboidal, smooth laminal cells and scarcely differentiated alar cells. It differs from the similar Arvernella pisarenkoi, Amblystegium fauriei and Platydictya hattorii in a longer single vs. forked costa, somewhat shorter leaf cells and scarcely developed groups of quadrate cells in leaf angles. Sequences: Plastid, trn S- trn F OL 689422; atp B- rbc L OL 689420; nr ITS OL 689127.	en	Fedosov, V. E., Ignatova, E. A., Fedorova, A. V., Kucera, J. (2021): Microamblystegium - a new genus of Amblystegiaceae from Shikotan Island (South Kurils, Russian Far East). Arctoa 30 (2): 417-424, DOI: 10.15298/arctoa.30.27, URL: https://doi.org/10.15298/arctoa.30.27
039287B99D26FF9DFCBCF9EB56BCB129.taxon	description	Description. Plants small, in moderately dense, delicate mats, green, yellowish or olivaceous green. Shoots creeping, to 10 mm long, with terete foliation, loosely irregularly branched, stem in transverse section composed of homogeneous thin-walled cells, without central strand and sclerodermis, outermost cells somewhat smaller, with slightly thicker outer walls than cells inwards; paraphyllia absent. Axillary hairs few, pellucid, 3 – 4 - celled, 30 × 6 µm, apical cell 10 µm long; proximal branch leaves of branch primordia variable in size, lanceolate or triangular. Leaves appressed when dry, spreading when moist, (0.22 –) 0.27 – 0.35 (– 0.40) × 0.10 – 0.13 (– 0.16) mm, from ovate base gradually narrowed into lanceolate or narrowly triangular acumen, apex acute to subobtuse, some leaves with weak shoulders, slightly narrowed to base, not or shortly decurrent, concave; costa single, to 0.3 – 0.7 of leaf length, occasionally geniculate, gradually disappearing distally; margins plane, uneven to obtusely serrulate at shoulders; laminal cells rhomboidal or elongate-rhomboidal, (9 –) 15 – 17 (– 25) × 5 – 6 (– 7) µm, with length to width ratio 1.5 – 2.5 (– 3): 1, moderately thick-walled, smooth; cells along margin in 1 – 2 rows subquadrate to short-rectangular, 9 – 18 × 4 – 6 µm, alar cells not or weakly differentiated, subquadrate, transition to adjacent laminal cells gradual. Branch leaves somewhat smaller and narrower than stem leaves. Sexual condition, reproductive structures, and sporophytes unknown. Differentiation. Microamblystegium saxicola resembles Arvernella pisarenkoi in its combination of small size, sparse branching, not differentiated stem cells in transverse section, rather weak costae, short leaf cells, and saxicolous habitat. It differs from it in single, somewhat longer costae, which typically reach mid-leaf or higher vs. usually forked costae extending to 0.2 – 0.4 the leaf length; leaves often with shoulders and narrower acumina vs. gradually tapered into wider acumina, and shorter cells with length / width ratio up to 2.5 (– 3): 1 vs. usually 3 – 4: 1 in A. pisarenkoi. Microamblystegium saxicola also resembles the insufficiently known Japanese species Amblystegium fauriei, as illustrated by Kanda (1976) from type material, in its stem not differentiated in transverse section, but that species differs in having elongate, thick-walled, prorate laminal cells and subquadrate cells along basal leaf margin in 2 – 3 rows (in 1 row in Microamblystegium saxicola). The likewise saxicolous Serpoleskea confervoides also lacks a central strand, but has a well-developed sclerodermis. Another minute saxicolous Far Eastern pleurocarpous species, Ignatovia microphylla, differs from Microamblystegium saxicola in having a strong costa nearly reaching the leaf apex, and smaller, rounded, thick-walled laminal cells. The insufficiently known Japanese species Hygroamblystegium calcareum Kanda resembles Microamblystegium saxicola in having a small size, a rather long single costa and weakly differentiated alar cells. However, H. calcareum has a stem with a differentiated sclerodermis and a central strand that differentiate it from M. saxicola. Anoth- er small and poorly known amblystegiaceous moss, which likely represents the C 2 Amblystegiaceae clade (cf. Kučera & Hedenäs, 2020), Cratoneuron tenerrimum Kanda, according to illustration in Kanda (1976), also has a well differentiated sclerodermis and central strand in the stem, and its alar group is remarkably differentiat- ed, composed of strongly inflated cells.	en	Fedosov, V. E., Ignatova, E. A., Fedorova, A. V., Kucera, J. (2021): Microamblystegium - a new genus of Amblystegiaceae from Shikotan Island (South Kurils, Russian Far East). Arctoa 30 (2): 417-424, DOI: 10.15298/arctoa.30.27, URL: https://doi.org/10.15298/arctoa.30.27
039287B99D26FF9DFCBCF9EB56BCB129.taxon	biology_ecology	Ecology and distribution. The new species is at the moment known from a single locality in the northern part of Shikotan Island. Shikotan differs from all other areas of Russia in a very mild and humid climate. The specimen was collected from shaded humid niche of an acidic rock, where it formed a pure mat. Among other epilithic species growing there, Bryoxiphium japonicum (Berggr.) E. Britton, Calohypnum plumiforme (Wilson) Jan Kučera & Ignatov, Dozya japonica Sande Lac., and Forsstroemia yezoana (Besch.) S. Olsson, Enroth & D. Quandt are the most common ones.	en	Fedosov, V. E., Ignatova, E. A., Fedorova, A. V., Kucera, J. (2021): Microamblystegium - a new genus of Amblystegiaceae from Shikotan Island (South Kurils, Russian Far East). Arctoa 30 (2): 417-424, DOI: 10.15298/arctoa.30.27, URL: https://doi.org/10.15298/arctoa.30.27
039287B99D25FF9FFF42FF38571EB203.taxon	description	Campylophyllopsis sommerfeltii 1 Hedenäs, S B 175748 MH 613368 MH 613594 MH 613502 Campylophyllopsis sommerfeltii 2 Ca 2020, Czechia, Salajka, OL 740036 OL 792052 OL 792050 25. IX. 2019 Mikulaskova, CBFS 22454 Campylophyllum halleri Kučera 18388 MK 327293 MK 313975 MK 313887 Cratoneuron curvicaule Kučera 15725, CBFS MN 646798 MN 635410 MN 635403 Cratoneuron filicinum 1 Kučera 18759, CBFS MN 646797 MN 635411 MN 635404 Cratoneuron filicinum 2 Lewis 87262 AF 168155 AY 009817 AF 322332 Cratoneuropsis relaxa Streimann 49394 FJ 535787 FJ 535748 FJ 535768 Drepanium fastigiatum 1 Kučera 12468 MH 613449 MH 613674 MH 613552 Drepanium fastigiatum 2 Kučera 18282 MK 327338 MK 314022 MK 313936 Drepanocladus aduncus S B 1047 EU 216317 EU 216109 FJ 535761 Drepanocladus trifarius S B 73402 KC 601928 FJ 535737 FJ 535756 Hamatocaulis vernicosus S B 1068 AY 625994 AY 626012 AY 625976 Helodium blandowii Schofield 108637 AY 009803 AY 009852 AF 322313 Hygroamblystegium fluviatile Vanderpoorten 3739 AF 464979 AF 465000 AF 464956 Hygrohypnella bestii Schofield S B 81888 AY 857598 AY 857555 AY 857576 species voucher / isolate ITS trnL-trnF AtpB-rbcL Hygrohypnella ochracea S B 818976 AY 857605 AY 857563 AY 857584 Hygrohypnum luridum 1 Kučera 18482 CBFS MH 613385 MH 613611 MH 613512 Hygrohypnum luridum 2 S B 81975 AY 857601 AY 857559 AY 857580 Hygrohypnum styriacum 1 CBFS 18850 MH 613386 MH 613612 MH 613513 Hygrohypnum styriacum 2 S B 81902 AY 857608 AY 857566 AY 857587 Hypnobartlettia fontana isolate Hypno. 1477 AY 242368 AY 242376 HQ 268437 Kandaea elodes Kučera 20960 CBFS MN 646796 MN 635412 MN 635405 Leptodictyum riparium 1 Kučera 17055 MH 613473 MH 613698 MH 613564 Leptodictyum riparium 2 LF 1, Russia, Vladimir Province, MW 6046724 OL 6891231 OL 689427 – Leptodictyum riparium 3 LF 5, Russia, Tatarstan Republic, MW 9046928 OL 6891230 OL 689426 – Leptodictyum riparium 4 LF 8, Russia, Volgograd Province, MW 9046941 OL 689129 OL 689425 – Lindbergia sinensis Jiangsu KF 770668 KF 770506 KF 770614 Microhypnum sauteri Kučera 16814 MH 613460 MH 613684 MH 613558 Myrinia pulvinata 1 Chernyadyeva 3. VII. 2015 MK 327351 MK 314034 MK 313949 Myrinia pulvinata 2 ThF 11, Russia, Nenets autonomous Distr., OL 689128 OL 689424 OL 689421 MHA 9024223 Palustriella commutata Kučera 20946 CBFS MN 646799 MN 635409 MN 635402 Palustriella decipiens 1 Kučera 20956 CBFS MN 646800 MN 635408 MN 635401 Palustriella decipiens 2 MACB 90037 AY 857615 AY 857572 AY 857594 Palustriella falcata S B 61810 GU 237137 AY 626006 AY 625966 Platyhypnum alpestre S B 81980 AY 857596 AY 857553 AY 857574 Platyhypnum cochlearifolium S B 81890 AY 857599 AY 857556 AY 857577 Platyhypnum duriusculum Kučera 10940 MH 613476 MH 613701 – Platyhypnum norvegicum S B 81898 AY 857604 AY 857562 AY 857583 Platyhypnum smithii Schofield 104556 AY 857607 AY 857565 AY 857586 Pseudoamblystegium subtile Kučera 16368 MH 613478 MH 613703 MH 613566 Pseudocampylium radicale Kučera 18708 MH 613480 MH 613705 MH 613568 Rhytidium rugosum Kučera 12871 MK 327361 MK 314044 MK 313960 Sanionia uncinata S B 96458 GQ 849964 GQ 849841 AF 322321 Scorpidium scorpioides S B 61836 AY 625995 AY 626014 AY 625977 Serpoleskea confervoides Kučera 14744 MH 613488 MH 613713 MH 613573 Thuidium cf. assimile Yunnan KF 770638 KF 770476 KF 770584 Tomentypnum nitens Schofield 103470 AF 168161 AY 009854 AF 322352 Vittia pachyloma 1 Goffinet 5605 AY 062886 AY 062889 AY 062883 Vittia pachyloma 2 isolate Vittia 1303 AY 242367 AY 242375 AY 242358 Vittia salina isolate Vittia 1466 AY 242370 AY 242378 AY 24236	en	Fedosov, V. E., Ignatova, E. A., Fedorova, A. V., Kucera, J. (2021): Microamblystegium - a new genus of Amblystegiaceae from Shikotan Island (South Kurils, Russian Far East). Arctoa 30 (2): 417-424, DOI: 10.15298/arctoa.30.27, URL: https://doi.org/10.15298/arctoa.30.27
