Morphology of possible lattice organs in SEM
Left: Covers an oval area of 140 × 80 µm (Fig. 3A). A club-shaped trench or depression of 90 µm length is laterally surrounded by two longitudinally running ridges. Small lines demarcate the periphery outside of the ridges. The distance between the tops of the two ridges is 40–60 µm, being widest near the anterior end. From each ridge a steep but not vertical slope leads toward the more or less flat-bottomed trench. Anteriorly the floor of the trench is 15 µm wide, narrowing down to 5 µm posteriorly.
Right: Covers approximately 140 × 70 µm. Its outline resembles the previous. Less pronounced ridges surround the ~ 100 µm long depression, which has a wider anterior part and a more narrow and shallow posterior part. The floor of the anterior part is cast into a few distinct, mainly longitudinal folds.
Left: Dimensions 150 × 80 µm (Fig. 3B). Apparently the depression falls in several different parts. Anteriorly there seems to be a short shallow terrace with a bump-like short fold. This is followed by a deep, only 40 µm long part of the trench that extends into the 60 µm more shallow posterior region. The width narrows from 15 µm to 10 µm. Weak folding of the floor occurs in both the deep part of the trench and the more shallow part. A groove is observed near the anterior margin.
Right: A 125 µm long trench area surrounded by diminutive ridges (Fig 3C). The floor of the up to 20 µm wide trench shows some folding anteriorly, but a grainy substance obscures most of this territory especially towards the 5 µm wide posterior end.
Left: Covers an oval area of 130 × 80 µm. The ridges surround an at least 90 µm long club-shaped trench that preserves traces of folds anteriorly. Near the anterior margin there is a diminutive indentation that could represent a pore.
Right: A 130 × 60 mm long structure in which the median ridge is practically absent. Nevertheless, the remaining slopes delimit a trench of the usual shape. A short depression occurs near the 20 µm wide anterior margin followed by a raised area that may correspond to the short folds mentioned above. The posterior part of the trench is somewhat obscured by sediment and presents little evidence for the presence of a pore.
Left: Covers an area of 120 × 50 µm. Not as clearly defined as previous due to sediment, but it includes ridges and a club-shaped trench.
Right: The general outline is the usual, but sediment obscures details.