Members of the Lyttoniidae Waagen, 1883 (Lyttonioidea Waagen, 1883, Brachiopoda) are characterized by numerous peculiarities, including their disproportionately inequivalve, rudimentary articulatory apparatus and asymmetrically developed muscle scars. The ventral valve of lyttonioids usually possesses a posterior flap and complementary septal apparatus and the dorsal valve has corresponding lobes and slits to fit around the ventral septa (Noetling, 1905; Fredericks, 1926; Wanner, 1935; Williams, 1953; Grant, 1976; Williams et al., 2000). Externally, the Lyttoniidae have been previously described as being smooth or having some growth banding, lines, or disturbances only (Cooper and...

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