Marine benthic diatoms of Guam: new records, Dictyoneis apapae sp. nov., and updates to the checklist Author Lobban, Christopher S. Division of Natural Sciences, University of Guam, Mangilao, GU 96923, USA clobban @ triton. uog. edu clobban@triton.uog.edu Author Witkowski, Andrzej University of Szczecin, Institute of Marine and Environmental Sciences Mickiewicza 16 a, PL 70 - 383 Szczecin, Poland text Micronesica 2023 2024-06-06 2023 2 1 75 journal article 299061 10.5281/zenodo.12118784 2b921c3c-8618-439e-96da-1de9c66a90f9 0026-279X 12118784 Pseudictyota bicornis ( Cleve) P.A.Sims & D.M.Williams Figs 91–93 Ref. illus.: Cleve 1878 , fig. 30; Ashworth et al. 2013 , fig 7b; Sims et al. 2018 , figs 133–138 Sample: GU52U-1 Dimensions: 51 µm long (on the axis with the ocelli), 42 µm wide Diagnostics: Quadrate, false pseudoloculate valve, having two elevations with ocelli and two unelevated points with rimoportulae. Comments: Differing from Pseudictyota dubia (Brightwell) P.A.Sims & D.M.Williams ( Navarro & Lobban 2009 , figs 21–24), which has six angles, three with ocelli and three with rimoportulae; and from P. reticulata (Roper) P.A.Sims & D.M.Williams ( Lobban et al. 2012 , pl. 3, figs 3, 4, as Triceratium dictyotum P.A.Sims & R.Ross ), which is broadly lanceolate with two angles each with both an ocellus and a rimoportula.