Surirella cf. fastuosa Ehrenberg

Lobban, Christopher S., 2015, 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), Micronesica 2015 (2), pp. 1-49 : 16

Surirella cf. fastuosa Ehrenberg , sensu Ruck & Kociolek 2004 Figs 146–149

Ref. illus.: Ruck & Kociolek 2004, pl. 11–13

Samples: GU44L-C, GU44AQ-1, GU44AQ-3, GU44AR-1, GU66A-2, GU66C-7, GU66F-4 Dimensions: Length 62–81 µm, width 39–45 µm. Infundibula 2.5 in 10 µm.

Diagnostics: Broadly oval, the sides nearly straight, sometimes very weakly indented; neither the valve margin nor the keel markedly constricted or convex at the center. Lanceolate central area (circlet) with external ribs, but lacking short striae on the perimeter; puncta completely absent on internal side of circlet.

Comments: Plastids: two lobed plates, as in typical Surirella fastuosa ( Fig. 146 ). Larger, more oval, and more symmetrical than S. fastuosa , and without the short striae on the circlet. These specimens match the California sample described by Ruck & Kociolek (2004), except for the complete lack of puncta on the inner face of the circlet here. Ruck & Kociolek identified their material only as comparable to S. fastuosa “until such time as the type material is examined and the variability in morphology documented.” Given this situation, I list this taxon as separate from S. fastuosa .

Amendments and corrections to previous lists

A list of significant corrections to Lobban et al. (2012) was posted on the Micronesica website2 and printed on p. 280 of the hardcopy when that was finally released in October 2013. Of particular note is that Pleurosigma intermedium is for now removed from the flora. Sterrenburg pointed out several ultrastructural features in which our material differs (see Sar et al. 2012); his summary is posted on our ProtistCentral website at http://www.protistcentral.org/Photo/ get/photo_id/2912. We also corrected our error in referring to Mastogloia sergiana Pennesi & Poulin as Mastogloia sergensis . Also, as noted above, I correct the identity of the valve in pl. 68, fig. 4 to Campylodiscus fastuosus and substituted a correct images on the web page for Surirella scalaris .

I correct our name for the record of Nitzschia constricta (Gregory) Grunow to Psammodictyon constrictum (Gregory) D.G. Mann on the basis of the loculate valves.

A nomenclatural change that came to my attention since Lobban et al. (2012) went to press is Reid’s (2012) change of Donkinia minuta to Carinasigma minuta (Donkin) G. Reid. The areolae in our specimens are arranged in transverse and longitudinal rows, consistent with this new genus ( SEM in Jordan et al. 2009 –2015: http://www.protistcentral.org/Photo/get/photo_id/4537). More recently, Lyrella hennedyi var. granulata was promoted to L. granulata (Grunow) Nevrova, Witkowski, Kulikovskiy & Lange-Berthalot ( Nevrova et al. 2014) .

Finally, one taxonomic change affects a species reported from Yap by Navarro & Lobban (2009): Conticribra weissflogii (Grunow) K. Stachura-Suchoples & D.M. Williams is the new name for Thalassiosira weissflogii (Grunow) G. Fryxell & Hasle (Statchura-Suchoples & Williams 2009) .

2 http://micronesica.org/sites/default/files/12_lobban_et_al_2012_errata.pdf

Figures

Figures 139–149. Figs 139–143. Rhoicosigma compactum (GU52N-7). Fig. 139. Three views of a live cell in different orientations (DIC). Figs 140, 141. Acid-cleaned valves showing the two contrasting raphe paths: convex valve nearly straight raphe, concave valve highly sigmoid (DIC). Fig. 142. External detail, convex valve, showing overlapping central raphe endings and pattern of striae (SEM). Fig. 143. Internal surface of concave valve. Figs 144, 145. Seminavis robusta, DIC (GU52Q-1a) and SEM (GU52Q-10a). Figs 146–149. Surirella cf. fastuosa. Fig. 146. Live cell show lobed plastid (GU66C-7). Fig. 147. Valve in DIC (GU44AQ-3) (two stacked images). Figs 148, 149. External and internal views of valve (GU66A-1, GU66A-2) (SEM). Scale bars: Figs 139–141, 143–149 = 10 µm, Figs 142 = 5 µm.