First complete specimens of Karslanus (Trilobita, Dameselloidea) from Longha Formation (Cambrian: Guzhangian), Yunnan, South China

The trilobite Karslanus Özdikmen, 2009 (replacement name for Ariaspis Wolfart, 1974, preoccupied) is a presumed dameselloid genus reported from Afghanistan and South China. Until now, it has been known only from fragmentary material. A new species, Karslanus leishuae, from the Fulu Biota in the Longha Formation (Cambrian: Guzhangian) of Yunnan, South China, is represented by complete exoskeletons, the first such material recovered for the genus. Karslanus is unusual among dameselloids in having an holaspid thorax of 10 segments; it is also characterized by a pygidium with the pleurae extended into marginal spines that decrease in length rearward and a natant hypostome. This discovery adds to growing evidence that both conterminant and natant hypostomal conditions are represented among taxa in the superfamily Dameselloidea.