TABLE 1. Comparison of Actinocyclus ferrarioae (Frenguelli) Lameiro, Vouilloud & Cefarelli nom. nov. with allied taxa. TaxaValveNº ofRP inAreolaeStriae in 10ValveHyaline rays lengthFasciculationEnvironmentReferencesDiameterFascicles100 µmin 10 µmµmface featurespattern(µm)Actinocyclus39–576–74.1–7*5–6*8 (center)Flat with convexLong (cosmiodiscoid);Parallel*MarineFrenguelli (1928)ferrarioae12 (margins)edgesnot so definedRecentas CoscinodiscusLameiro, Vouilloud(actinocycloid)variabilis& Cefarelli29–596–144.8–8.28–108–10 (center)Flat o almostComplete, incompleteParallelThis study(44.1)8–12 (v.flat; with central(¾ to ⅓ of the valvemargin)depressions,face), not clearlycurving towardsdefinedthe mantleA. asteriscus20–753–4 to 163.6–4.9*7–1018–19Dome-shapedComplete*ParallelMarineWu et al.(Barron) Wu,(center)Fossil(2022)Williams, Pheng &9–13Cheng(margin)A. kanitzii50–10013–15*10.4–7–914*FlatIncomplete (¾ to ⅓ ofRadialLacustrineBradbury & Krebs(Pantocsek11.1*the valve face)*Fossil(1995)& Grunow)SchaudernaA. ingens var.40–8610*7*3–66*(valveFlat with centralIncomplete (half of theParallelMarineDesikachary &indica Desikacharycenter)depression andvalve face)*ExtantPrema (1987)& Prema10*(valverounded margins*margin)A. nipponicus15–736 to 205.7–8.3*10–1214–18*Almost entirelyComplete, incompleteRadial–Subparallel–LacustrineHayashi et al.Hayashi, Saito-flat with inclined(¾ to ⅓ of the valveParallel (accordingFossil(2012)Kato & Tanimuramantleface), not clearlyto valve size)defined*A. nigriniae Barron15–703–157–8.75*8 (center)11–12*Flat or domedIncompleteParallelMarineBarron12(¾ to ⅓ of the valveFossil(2005)(margin)face)*A. podolicus35–5711*5.8–15–1714–16*Flat with slightlyIncomplete (¾ of theParallelBrackish-Ognjanova &(Missuna)11.9*raised centervalve face)*MarineBuczkoKoryzenkoFossil(2015)A. claviolus17–606–8*6.4–7.3*13–1420*nearly flat withNot clearly defined *Radial andLacustrineBradbury & KrebsBradbury & Krebs(27–30)raised or depressedSubparallelFossil(1995)centerA. tenellus56–708–9*3.6–4.5*618Nearly flatNot clearly defined*ParallelMarineAndrews(Brèbisson)Fossil(1976)Andrews *Measured on the figures in the publications

Published as part of Lameiro, Rubén A., Cefarelli, Adrián O. & Vouilloud, Amelia A., 2023, Taxonomic revision of Coscinodiscus variabilis (Bacillariophyta): analysis of type material, lectotypification and transfer to the genus Actinocyclus, pp. 275 in Phytotaxa 626 (4) on page 275, DOI: 10.11646/phytotaxa.626.4.4, http://zenodo.org/record/10212960