Solenopora sp. (Jurassic). Bar seem to represent true red algae (Aguirre and Barattolo, 2001), whereas others, again, are interpreted as chaetetid sponges today (Riding, 2004). The cells of Solenomeris are polygonal in outline, with those of adjacent rows forming a zigzag configuration. Formerly considered to be a red alga, today Solenomeris belongs with the incrusting foraminifera (Bassi, 2003). Marinella lugeoni (Late Jurassic-Oligocene) was originally described as a cyanobacterium but has more recently been included in the Codiaceae (Chlorophyta) and the Solenoporaceae. This organism forms either encrusting thalli, several centimeters in diameter, or erect, digitiform, and branching thalli with branches up to 9 mm high that are

FIGURE 4.50 Graticula gotandica framestone from Gotland with laterally linked red algal pillars (Silurian). Bar = 2 cm (Courtesy M. Nose.)

attached to the substrate by a narrow base. The internal tissue is composed of radially oriented and densely packed filaments. Specimens of M. lugeoni from the Upper Jurassic of Portugal imply a close relationship with the corallinaceans, but structural similarities to the solenoporaceans have also been noted (Leinfelder and Werner, 1993). What were initially thought to be oval, aggregate reproductive structures in the

Miocene genus Neosolenopora (Mastrorilli, 1955) have been reinterpreted as an unusual bryozoan (Tillier, 1975). Several other genera traditionally referred to the Solenoporaceae, such as Metasolenopora, Petrophyton, and Solenoporella may belong, or be related to the Corallinaceae (Riding, 2004). The identification of various organisms traditionally included in the Solenoporaceae has been useful in understanding how skeletal organisms and microbes interacted to produce certain reef limestones (Adachi et al., 2007).

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