Ventral cephalic structure of <i>Archikainiella</i> (Trilobita, Lichida, Lichakephalidae) from the Cambrian of South China

Abstract The ventral structure of the trilobite family Lichakephalidae has hitherto been mainly inferred. A new discovery of a nearly complete internal mold of Archikainella vomerinus Liu, 1982, from the Sandu Formation (Cambrian, Furongian) of South China, shows its rostral plate and conterminant hypostomal condition. It is the first identified lichakephalid rostral plate. The conterminant hypostomal condition of this lichakephalid specimen is similar to that of the more derived Lichidae and supports the hypothesis that lichakephalid trilobites are a primitive group of lichids.