Adlafia sinensis B. Liu & Williams

Tusset, Eduardo A., Tremarin, Priscila I., Straube, Arielli & Ludwig, Thelma A. V., 2017, Morphology of Adlafia taxa (Bacillariophyta, Cymbellaceae), with proposition of two new species from Brazil, Phytotaxa 306 (4), pp. 259-274 : 268

Adlafia sinensis B. Liu & Williams in Liu et al., Phytotaxa 298(1): 43‒54, 2017.

Figs 71‒80

Valves elliptic-lanceolate with subcapitate apices, 11.8‒15.2 μm in long, 3.3‒4.2 μm in wide (n=11). Raphe sternum linear and narrow. Central area absent or reduced. Raphe filiform, distal raphe ends unilaterally bent and internally terminate in a small helictoglossa; proximal raphe ends slightly curved and internally deflected to the primary side of valve. Terminal nodule transversally expanded in t-shaped in inner view. Striae uniseriate, 30‒32 in 10 μm, curve-radiate along the valve to abruptly convergent near the apices, running continuously onto the mantle; one or more shortened striae in the median portion of valve. Valve apex with two rows of small areolae on the mantle. Areolae rounded, ca. 55–60 in 10 μm, externally occluded by hymenes, inconspicuous at light microscopy.

Occurrence in samples: UPCB 72982, 72989, 72997.

Adlafia sinensis was recently proposed by Liu et al. (2017) from China. This species resembles A. submuscora Van de Vijver, Kopalová, Zidarova & Cox (2013: 191) in the valve shape, but the latter taxon presents narrower valves (2.5‒3.1 μm), higher striae density (40‒45 in 10 μm), and subrostrate apices (Van de Vijver et al. 2013). Adlafia sinensis is also similar to A. multnomahii Morales & Le (2005: 151) and to A. muscora . However, A. multnomahii has larger valves with lanceolate contour and higher striae density (37‒45 in 10 μm) ( Morales & Le 2005), and Adlafia muscora has linear-lanceolate valves and lower striae density (23‒26 in 10 μm in the median region of valve) ( Kociolek & Reviers 1996, Moser et al. 1998).

In China, A. sinensis was found on stones in alkaline waters with moderate electrolyte content ( Liu et al. 2017). However, in Brazilian samples this species occurred on macrophytes in neutral waters (pH 6.9‒7.2) with low conductivity (21.1‒39.4 μS/cm).

Figures

FIGURES 71‒80. Adlafia sinensis Figs 71‒75. Valve view, LM. Scale bar= 10 μm. Fig. 76. External valve view, SEM. Scale bar = 2 μm. Fig. 77. Internal view of valve apex showing helictoglossa, SEM. Scale bar = 1 μm. Fig. 78. Internal valve view, SEM. Scale bar = 2 μm. Fig. 79. Median region of valve showing the proximal raphe ends in external view, SEM. Scale bar = 1 μm. Fig. 80. External view of distal raphe end, SEM. Scale bar = 1 μm.