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