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 Proschkinia complanata (Grunow) D.G.Mann Figs 87–90 Ref. illus.: Lobban et al. 2012 , p. 296, pl. 1, figs 4–6 and pl. 53, figs 1–4 [as P. complanatoides (Hustedt) Karayeva ]; Kim et al. 2020 , p. 960, figs 2, S2 Samples: GU44Z-15, GU52Q-10a, GU62A-7, GU66G-5, GU68F-8 Dimensions: Length 32–48 μm, width 6–8 μm; striae 30–32 in 10 μm Comments: Majewska et al. (2019 , p. 625), working on Proschkinia spp. epizoic on sea turtles, described a new species P. torquata Bosak, Van de Vijver & Majewska , which they compared with P. complanatoides . They suggested that our Guam specimens might be a new species because they saw no widening of the central area (GU44Z-15: Fig. 90 ) and the internal fistula was not like P. complanatoides . However, Kim et al. (2020) studied Grunow’s specimens of P. complanata with SEM and showed a fistula matching ours, also matching in the presence of a flap over the external fistula opening ( Figs 87, 88 ) and a raised rib on the raphe internally for some distance from the central nodule ( Fig. 90 ). One short stria on the side with the fistula ( Fig. 88 ), and a silica flap over the fistula opening; central striae on opposite sometimes further apart ( Figs 87, 88 vs. 90). Comparing our specimens to P. torquata , the fistula has a similar series of spheres, and the external opening is also covered by a flap, but P. torquata has longitudinal silica strips over the central part of the valve face and the apices are rounded rather than acute. Kim et al. (2020 , table 4) listed Guam specimens with P. complanata not P. complanatoides and their images of authentic (including type ) material convince us that there are no differences that would warrant a new species. We have seen this species across Micronesia , and it seems so far to be the only species present. We remove P. complanatoides from the Guam flora.