One new species of Achnanthidium Kützing (Bacillariophyta, Achnanthidiaceae) from Tibet, China Author Ge, Danyang 0000-0003-2904-0260 College of Life Science and Technology, Harbin Normal University, Harbin, 150025, China & gdy 18846166215 @ 163. com; https: // orcid. org / 0000 - 0003 - 2904 - 0260 Author Zhang, Simeng 0000-0001-9461-2646 College of Life Science and Technology, Harbin Normal University, Harbin, 150025, China & zhangsm 147 @ 163. com; https: // orcid. org / 0000 - 0001 - 9461 - 2646 Author Liu, Hongyan 0000-0003-1960-6806 College of Life Science and Technology, Harbin Normal University, Harbin, 150025, China & tgzy 1632021 @ 163. com; https: // orcid. org / 0000 - 0003 - 1960 - 6806 Author Liu, Yan 0000-0001-8556-5040 College of Life Science and Technology, Harbin Normal University, Harbin, 150025, China & yanliuhrb @ hotmail. com; https: // orcid. org / 0000 - 0001 - 8556 - 5040 yanliuhrb@hotmail.com Author Kociolek, Patrick John 0000-0001-8556-5040 Museum of Natural History and Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309, U. S. A. Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China & patrick. kociolek @ colorado. edu; https: // orcid. org / 0000 - 0001 - 8556 - 5040 patrick.kociolek@colorado.edu Author Zhu, Huan 0000-0002-8531-2067 huanzhu @ ihb. ac. cn; https: // orcid. org / 0000 - 0002 - 8531 - 2067 huanzhu@ihb.ac.cn Author Liu, Guoxiang 0000-0001-8565-2363 liugx @ ihb. ac. cn; https: // orcid. org / 0000 - 0001 - 8565 - 2363 liugx@ihb.ac.cn Author Fan, Yawen 0000-0001-9969-5428 College of Life Science and Technology, Harbin Normal University, Harbin, 150025, China & fanyaw @ 163. com; https: // orcid. org / 0000 - 0001 - 9969 - 5428 text Phytotaxa 2022 2022-03-09 538 4 268 280 journal article 10.11646/phytotaxa.538.4.1 82dc7ea9-e911-4675-8c59-797222354a47 1179-3163 6340368

TABLE 3. Comparison of Achnanthidium tibeticum sp. nov. and its similar taxa.

	Achnanthidium	A. zhakovschikovii	A. atomoides	A. atomus	A. nanum	A. delmontii	A. lineare	A. straubianum	A. japonicum	A. convergens
	tibeticum sp.
	nov.
Frustule	raphe valve	raphe valve	slightly bent,	slightly bent,	slightly arched,	slightly arched,	raphe valve	raphe valve	slightly bent,	slightly bent,
	slightly convex,	concave, rapheless	raphe valve	raphe valve	raphe valve	raphe valve	slightly concave;	slightly concave;	raphe valve	raphe valve
	rapheless valve	valve convex	concave,	concave,	slightly concave,	slightly concave,	raphelss valve	raphelss valve	concave,	concave,
	slightly concave		rapheless valve	rapheless valve	rapheless valve	rapheless valve	slightly conve	slightly convex	rapheless valve	rapheless valve
			convex	convex	slightly convex	slightly convex			convex	convex
Valve outline	linear to elliptic,	broadly linear to	linear to elliptic	linear elliptic	linear to linear-	linear with	linear to	elliptic to	linear to elliptical	linear lanceolate
	with round apices	elliptical			elliptic, broadly	rounded apices	narrowly	narrowly elliptic,
					rounded apices,		lanceolate,	with broadly
					non protracted		parallel margins	rounded apices
					or slightly		and broadly
					subrostrate		rounded non
							protracted ends
Length (μm)	7.9̀–13.6	9.1–-14.8	4.3–11.6	6.6–13.4	5.0–12.3	7.3–21.4	9.0–13.5	6.5–8.5	9–10	10–25
Width (μm)	2.9–3.9	2.9–4.0	2.2–3.2	2.7–3.7	1.9–2.9	3.3–5.1	2.2–2.8	2.6–3.5	4.0–4.5	4.0–4.5
Raphe valve
Axial area	narrow and linear	linear-lanceolate	narrow, linear	narrow, linear	narrow, linear	narrow	narrow, linear,	narrowly	linear-lanceolate	narrow, linear to
							gradually but	lanceolate		lanceolate
							weakly widening
							towards the
							central area
Central area	inconspicuous	rectangular,	bow-tie shape	bow-tie shape	inconspicuous	rectangular fascia	broad rectangular	small lanceolate,	small, lanceolate	inconspicuous
		asymmetrical				with shortened	fascia	formed by two	to round
						stria present on		shorter striae in
						one margin		the middle
Proximal	slightly	external:	external: slightly	external: slightly	external: slightly	external: droplet-	external: drop-	external:	external: slightly	external: laterally
raphe ends	expanded, tear	teardrop-shaped;	expanded,	expanded,	expanded,	like, internal:	like straight;	simple or drop-	expanded;	expanded;
	drop-shaped		internal: short,	internal: short,	straight;	deflected to	internal: slightly	like;	internal: curved	internal:
			and slightly	and slightly	internal: short,	opposite sides	curved to	internal:	to opposite sides	deflected
			curved to	curved to	and curved to		opposite sides			to opposite
			opposite sides	opposite sides	opposite sides					directions
Distal raphe	“?”shaped,	hooked to same	straight	straight	straight	deflected to same	small drop-like,	simple or drop-	curved to same	bend to same
ends	curved to the	direction				sides	straight	like	sides	sides
	same directions