Ptychagnostus sinicus

Order Agnostida / Suborder Agnostina / Superfamily Agnostoidea / Family Ptychagnostidae

ptych-, Greek, fold; Agnostus, a trilobite genus name.

sin-, Greek, China, Chinese, referring to its occurrence in China.

Ptychagnostus (Ptychagnostus) idmon; Ptychagnostus (Ptychagnostus) scarifatus; Zeteagnostus scarifatus; Ptychagnostus (Acidusus) sinicus

Cephalon nearly round; glabella conical, frontal segment triangular; posterior segment convex, median node on the posterior part of the posterior segment; basal lobe small, triangular; with preglabellar median furrow; cheek with radiating furrows, with a pair of crescentic small furrows beside the frontal lobe; border narrow. Pygidial axis relatively broad, divided into three rings; first transverse furrow slightly curved forward; anterior ring short, second ring broad, with a node at its end; Posterior axial ring longer than the sum of the anterior two rings, tapering smoothly backward; a shallow median furrow behind the pygidial axis; pleural region smooth; border broad, without marginal spines.

Typical body length about 0.2-1 cm.