Article: The trilobite Clavagnostus Howell from the Cambrian of Tasmania
Two new species of Clavagnostus, C. milli and C. burnsi, are described from the late Middle and early Upper Cambrian sequences of Tasmania. A third new species, Clavagnostus(?) rawlingi is questionably assigned to Clavagnostus. The genus Clavagnostus is reviewed. It is shown that the known species of Clavagnostus can be placed into three groups: (1) the C. repandus group which is characterized by a rounded glabellar front, no preglabellar median furrow, and a blunt pygidial axis which reaches the posterior border; (2) the C. burnsi group which is characterized by an angular glabellar front, a preglabellar median furrow, and a blunt pygidial axis which reaches the posterior border; and (3) the C.sulcatus group which is characterised by a preglabellar median furrow and a pointed pygidial axis.It is shown that four and probably five different species of Clavagnostus have been included in C. repandus. The pygidium figured by Poulsen (1960) as the holotype of Peronupsis ultima is shown to be a cephalon of a species of Clavagnostus, probably that of C. chipiquensis (Rusconi).