Data from: Ontogeny of the articulated yiliangellinine trilobite Zhangshania typica from the lower Cambrian (Series 2, Stage 3) of southern China

New discoveries of the early Cambrian yiliangellinine trilobite
Zhangshania typica Li and Zhang in Kunming preserve almost all instars
from early postembryonic (protaspid) to mature (holaspid) phases in
articulated state, in addition to mature specimens with antennae bearing
paired spines on the basal articles. The ontogenetic series shows
protarthrous development with some, but likely not all, early holaspid
instars expressing additional pygidial segments, gradual rearward
migration of the location of the longest pleural spines on the trunk
segments, and striking positive allometry of the genal spines. It also
reveals Parazhangshania sichuanensis Li and Zhang, 1990 to be the holaspid
stage 3 of Z. typica, and therefore its junior synonym. This new find in
the Hongjingshao Formation provides species-based regional correlation
across the South China block and Z. typica may provide an important
biostratigraphic marker for the base of the traditional Tsanglangpuan
Stage.