Eoisotelus orientalis

Order Asaphida / Superfamily Asaphoidea / Family Asaphidae

eo-, Greek, dawn, beginning; Isotelus, a trilobite genus name

orientalis, Latin, oriental, referring to the Chinese locality

Eoisotelus mathieui; Eoisotelus suni

Dorsal shield long-ovate. Cephalon semicircular; glabella moderately convex, extending forward to the cranidial margin, hourglass-shaped, strongly constricted at the level of the palpebral lobes with a pointed front; occipital furrow shallow; palpebral lobes small, semicircular; librigenae wide with short, wide genal spines. Thorax of 8 segments; axis subequal in width to pleurae; pleural furrows deep, situated on the upper part of the pleurae. Pygidium semi-elliptical; axis long, moderately convex, not reaching the border furrow posteriorly, axial rings faint or absent in large specimens; border wide and flat, border furrow wide and shallow in large specimens.

This species is the type species of the genus Eoisotelus and is among the largest Chinese trilobites. Mr. Zhang Wentang recorded a specimen of about 35 cm in his article "Reminiscences of Prof. Sun Yunchu".