Asaphida

Heterocyclopyge obsoleta

Order Asaphida / Superfamily Cyclopygoidea / Family Cyclopygidae

Sandbian to Katian (Late Ordovician)Shaanxi

Heterocyclopyge obsoleta — photo 1 — Photo 1 · Liwen Holotype NIGP16803 (Shaanxi; photograph courtesy of Prof. Zhou Zhiqiang) Cranidium and pygidium specimens (Shaanxi; Zhou Zhiqiang et al. 2016)

Heterocyclopyge obsoleta — photo 2 — Photo 2 · Liwen Holotype NIGP16803 (Shaanxi; photograph courtesy of Prof. Zhou Zhiqiang) Cranidium and pygidium specimens (Shaanxi; Zhou Zhiqiang et al. 2016)

Classification

Order Asaphida / Superfamily Cyclopygoidea / Family Cyclopygidae

Genus

Heterocyclopyge Marek, 1961

Genus author

Marek L.

Genus etymology

hetero-, different, other; Cyclopyge, a trilobite genus name

Species

H. obsoleta Zhou, Zhou & Xiang, 2016

Species author

Zhou Zhiqiang, Zhou Zhiyi, Xiang

Species etymology

obsoleta, obsolete, undeveloped

Age

Sandbian to Katian (Late Ordovician)

Distribution

Shaanxi

Diagnosis

Dorsal shield ornamented with faint ridges. Cephalon subsemi-elliptical; glabella subparabolic, sides converging forward, anterior part strongly bent downward, median node prominent; dorsal furrows and palpebral lobes extremely narrow; eyes elongate, ovate in outline, narrowing forward, strongly bent downward externally, separated anteriorly by the glabella, each eye of about 370 polygonal lenses, which make up most of the librigenae; lateral borders of librigenae very narrow. Thorax of five segments; axis tapering slowly backward; dorsal furrows deep; pleural furrows deep, extremely wide adaxially, narrowing rapidly outward. Pygidium semi-elliptical with squarish-rounded posterior margin; axis narrow and short, moderately convex; border furrow shown only on the anterior lateral parts of the pygidium; border very wide.