Articulated lepidocoleid machaeridians from the Silurian of Gotland, Sweden

Machaeridians, enigmatic Palaeozoic metazoans have a dorsal scleritome comp osed of two or four longitudinal series of calcitic sclerites. Though rarel y found complete, articulated specimens are an important source of informat ion concerning form and function of the machaeridian scleritome. Here seven articulated specimens from the Silurian of Gotland are described and refer red to five species of lepid-ocoleid machaeridians. The specimens show sign s of a terminal growth pattern (crowding of rugae near the accreting margin ), extreme dorsoventral elongation of sclerites, reflected by varying densi ties of rugae. Narrow dorsal depressions which may limit the amount of scle rite rotation, and possibly affecting the opening process of the scleritome .