FIGURE 6 in Three novel species of Bacillariophyta (Diatoms) belonging to Aulacoseira and Lindavia from the Pliocene Hadar Formation, Afar Depression of Ethiopia

FIGURE 6. Scanning electron micrographs of A. jewsonii. Spatulate linking spines of two internal sister valves (A). Note the doubly punctate areolae that is typical of internal valves (E). Spatulate linking spines are also present on linking valves (B) that sometimes exhibit twisting costae (C). A filament of two frustules, one contains a separation valve (C) (far left), and a linking valve (middle left), the frustules on right contains two linking valves. A well preserved separation valve (D). Sister internal valves held together by spatulate linking spines (E). A single internal valve (F). A single separation valve (G).