Species/Feature;"A. qingxiensis sp. nov.";"A. sublanceolatum Yu, You & Wang";"A. linannulumm Karthick, Taylor & Hamilton";"A. sinense Liu & Blanco";"A. gracillimum (Meister) Mayama";"A. chitrakootense Wojtal" "Valve length (μm)";22.5–28;18–35;15.5–32.5;17.5–31.7;19–31.5;13–42 "Valve width (μm)";3.8–4.6;4–4.5;2.5–4.5;4.1–6.0;3–4;3.4–4.2 "Valve outline";Linear-lanceolate;Linear-lanceolate;"Linear elliptical to lanceolate";"Narrow lanceolate";"Elliptical to lanceolate";"Linear to linear-elliptical" "Valve apices";Rounded;"Rounded or weakly protracted";"Rounded or slightly protacted";"Not protracted, acute round";"Narrowly rostrate to subcapitate";"Subcapitate to rounded" "Raphe valve" "Axial area";"Narrow, linear-lanceolate";"Narrow, linear-lanceolate";Lanceolate;"Narrow lanceolate";Linear;linear-lanceolate "Central area";Absent;Absent;"Indistinct to weakly expanded";Rhombic-lanceolate;Asymmetrical;"Indistinct to weakly expanded" Raphe;"Slightly undulate, distal raphe ends deflected towards the same side, internally proximal raphe endings weakly deflected in opposite directions";"Distal raphe fissures deflected to the same side, internally proximal raphe fissures weakly deflected in opposite direction";"Distal fissures deflected to the same side at an ange of 80–90°, internally proximal ends curved in opposite directions";"Raphe distal raphe ends curved to the same side, internally proximal raphe endings curved towards opposite side";"Distal raphe fissures are sharply bent, internally central raphe ends curve to opposite sides";"Distal raphe ends strongly curved to the same side, proximal raphe ends with slightly defl ected to opposite sides" "Density of striae (10 μm)";"21–25 (middle), 42–44 (apices)";"20–23 (middle), 34–42 (apices)";"24–27 (middle), 32–34 (apices)";"21–28 (middle), 40 (apices)";"22 (middle), 36 (apices)";26–30 "Number of areolae per stria";"5–8 (middle), 1–3 (apices)";"3–4 (middle), 1–2 (apices)";2–3;"5–6 (middle), 1–3 (apices)";"4–5 (middle), 1–2 (apices)";"2–4 (middle), 1–3 (apices)" "Rapheless valve" "Axial area";Linear;"Narrow linear-lanceolate";"Narrow lanceolate";Linear;Linear;Linear "Central area";Absent;Absent;"Weakly expanded to absent";Absent;"Weakly expanded to absent";Absent "Density of striae (10 μm)";"20–24 (middle), 32–34 (apices)";"21–24 (middle), 30–36 (apices)";"24–26 (middle), 28–30 (apices)";"21–27 (middle), 34 (apices)";"22 (middle), 36 (apices)";26–30 "Number of areolae per stria";"5–10 (middle), 1–4 (apices)";"2–5 (middle), 1–2 (apices)";2–4;"6–7 (middle), 1–3 (apices)";"4–5 (middle), 1–3 (apices)";"4–5 (middle), 2–4 (apices)" References;"Current study";"Yu et al. (2019a)";"Karthick et al. (2017)";"Liu et al. (2016)";"Kobayasi et al. (2006)";"Wojtal et al. (2010)"