Pleurosigma rigidum W. Smith, 1853

Park, Joon Sang, Lobban, Christopher S. & Lee, Kyun-Woo, 2018, Diatoms associated with seaweeds from Moen Island in Chuuk Lagoon, Micronesia, Phytotaxa 351 (2), pp. 101-140 : 125

101. Pleurosigma rigidum W. Smith Fig. 121

References: Giffen (1971), p. 11; Navarro (1982a), p. 325, fig. 100; Sterrenburg (2001), p. 124, figs 7–10, 19–22; Al-Handal et al. (2016), p. 31, pl. 9, fig. 1.

Samples: Moen1_ Padina

Dimensions: 215.6 μm long, 29.8 μm wide; transverse striae 19 in 10 μm, diagonal striae 20 in 10 μm; raphe angle +3°.

Diagnostics: Valve vaulted with obtuse apices. Areolae fine. Raphe nearly straight.

Comments: The vaulted valve with obtuse apices and minimal sigmoid raphe sternum of the specimen match the type material of P. rigidum examined by Sterrenburg (2001).

Figures

FIGURES 120–123. Four Pleurosigma species. Fig. 120. P. formosum. Fig. 121. P. rigidum. Fig. 122. Pleurosigma sp. 1. Fig. 123. Pleurosigma sp. 2. Scale bar = 10 μm.