Cocconeis ornata W. Gregory

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 : 4

Cocconeis ornata W. Gregory Figs 22–26

Ref. illus.: Gregory 1857, pl. IX (1), fig. 24; Peragallo & Peragallo 1897 –1908, pl. 4, figs 13–15; Montgomery 1978, pl. 61, figs A–D; Riaux-Gobin et al. 2014, figs 9–14

Samples: GU44AU-2

Dimensions: Length 19 µm, width 15 µm, striae ca 10 in 10 µm

Diagnostics: SV: striae coarsely uniseriate but sometimes branching towards the margin, striae interrupted by a longitudinal hyaline line; margin with parallel rows of papillae. RV not seen.

Comments: A few specimens in this sample. Gregory (1857) was charmed by the “rich ornate aspect” of this “beautiful” species, which does indeed appear ornate, especially in SEM ( Fig. 27 ). The original drawing did not do it justice.

Figures

Figures 22–40. Figs 22–26. Cocconeis ornata, two valves at two focal planes each in DIC and external view in SEM (GU44AU-2). Figs 27–32. Cocconeis subtilissima. Figs 27, 28. Frustules in LM (GU44I-2, GU44Z-15) (DIC). Figs 29, 30. RV external and internal with valvocopula (GU44AQ-1). Figs 31, 32. SV external (whole mount, GU44AC-4), showing the alveolae at the fracture (arrow), and internal (GU44AQ-1). Figs 33–40. Colliculoamphora gabgabensis. Fig. 33. Holotype specimen (GU44AK-6) (DIC). Fig. 34. Paratype specimen (GU44I-1) (DIC). Fig. 35. Specimen showing deeper indentation (GU44AK-6). Figs 36–38. External views, showing the eunotid position of the raphe; arrows on Fig. 37 indicate short striae; Fig. 38 shows girdle bands (GU44AK-6, GU44Z-15, GU52Q-10a, respectively) (SEM). Figs 39, 40. Internal views (GU44W- 10, GU44K-6) (SEM). Scale bars: Figs 22–36 = 5 µm, Figs 37, 38 = 2.5 µm, Figs 39, 40 = 2 µm.