FIGURES 43–52 in Achnanthidium lucectorii sp. nov. and A. enigmaticum sp. nov., novel diatoms (Bacillariophyta, Achnanthidiaceae) from Texas, U.S.A.

FIGURES 43–52. Achnanthidium enigmaticum sp. nov. (LM) from type material. 43–54. RV arranged in size diminution series, Figures 53 and 54 correspond to the same frustule, 54 being a SV; Figure 48 corresponds to the holotype. 55–59. SV arranged in increasing size order. Notice axial area expanded in central area and clearly observable areolae along striae. Scale bar = 10 µm.