Benthic marine diatom flora of Guam: new records, redescription of Psammodictyon pustulatum n. comb., n. stat., and three new species (Colliculoamphora gabgabensis, Lauderia excentrica, and Rhoiconeis pagoensis) Lobban, Christopher S. Micronesica 2015 2015 2 1 49 Ehrenberg Ehrenberg 1845 [232,657,1290,1315] Bacillariophyceae Surirellaceae Campylodiscus GBIF,CoL Chromista Surirellales 2 3 Ochrophyta species fastuosus  Syn:  Campylodiscus thuretiiBrébisson   C. simulansGregory Ref. illus: Peragallo & Peragallo 1897–1908, pl. 57, figs 4–9 (as  C. thuretii); Choi & Noh 1987, figs 73–76; Guettinger 1989 2.09.01-1; López Fuerte et al. 2010, pl. 39, figs 10, 11 (as  C. simulans); Stidolph et al. 2012, pl. 21, fig. 14 and pl. 6, fig. 132 (the latter as  C. thuretii) Samples: GU66F-7A, GU66F-8, GU52Q-10a, GU52Q-2, GY44Y-13 Dimensions: 16–34 µm diam., central striae 14 in10 µm Diagnostics: Circular valves with two parallel lines of short striae along the apical axis. Small valves similar to  Surirella scalarisGiffen(Figs 15, 17) ( Lobban et al. 2012, pl. 68, figs 5, 6; pl. 69, figs 1, 2), but differing in the marked narrowing of the infundibula such that the spaces between them become wider and with a single prominent rib reaching the central area, whereas in  S. scalaristhe infundibula taper only a little and leave a uniform space between them, without a prominent rib. Both have several spiny ridges over the infundibula on both sides of the raphe; those of  C. fastuosusare less spiny in comparison. Comments: The difference is hard to see in small specimens in LM, and we needed complete frustules ( Figs 16, 18) before being sure about  C. fastuosus, which commonly co-occurred with  S. scalarisin these Guamsamples from farmer-fish territories. The LM image published in Lobban et al. 2012, pl. 68, fig. 4 as  Surirella scalarisis in fact  C. fastuosusand a true image is shown here in Fig. 15 for comparison. This has been corrected on the web page. See VanLandingham (1968)for synonymies.