thickening of silica in the central area of a valve, found only in the genus Stauroneis.
Some references consider a fascia and a stauros to be equivalent structures, but recent work (Cox 1999, 2001, 2012) has shown that the stauros has a distinct pattern of development. During valve formation in Stauroneis, a transverse strip of silica develops from each side of the central nodule.
Cox, E.J. (1999). Craspedostauros gen. nov., a new diatom genus for some unusual marine raphid diatoms previously placed in Stauroneis Ehrenberg and Stauronella Mereschkowsky (Bacillariophyta) . European Journal of Phycology 34: 131–47.
Cox, E.J. (2001). What constitutes a stauros? A morphogenetic perspective . In Jahn, R., Witkowski, A. & Compe`re, P. [Eds.] Festschrift füe H. Lange-Bertalot. A.R.G. Gantner Verlag K.G, Ruggell, Liechtenstein, pp. 303–16.
Cox, E.J. (2012). Ontogeny, homology, and terminology - wall morphogenesis as an aid to character recognition and character state definition for pennate diatom systematics. Journal of Phycology 48: 1–31. 10.1111/j.1529-8817.2011.01081.x