Asaphida

Nileus walcotti

Order Asaphida / Superfamily Cyclopygoidea / Family Nileidae

Dapingian to Darriwilian (Middle Ordovician)Shaanxi, Xinjiang, Hubei

Nileus walcotti — photo 1 — Photo 1 · Holotype USNM 83770 (Shaanxi; Endo Type specimens of the former Nileus liangshanensis (Shaanxi; Lu Yanhao 1975) 1932) Literature specimen (Xinjiang; Zhou et al., 1998) Enrolled specimen preserving the hypostome (Shaanxi; Baishui)

Nileus walcotti — photo 2 — Photo 2 · Holotype USNM 83770 (Shaanxi; Endo Type specimens of the former Nileus liangshanensis (Shaanxi; Lu Yanhao 1975) 1932) Literature specimen (Xinjiang; Zhou et al., 1998) Enrolled specimen preserving the hypostome (Shaanxi; Baishui)

Nileus walcotti — photo 3 — Photo 3 · Holotype USNM 83770 (Shaanxi; Endo Type specimens of the former Nileus liangshanensis (Shaanxi; Lu Yanhao 1975) 1932) Literature specimen (Xinjiang; Zhou et al., 1998) Enrolled specimen preserving the hypostome (Shaanxi; Baishui)

Nileus walcotti — photo 4 — Photo 4 · Holotype USNM 83770 (Shaanxi; Endo Type specimens of the former Nileus liangshanensis (Shaanxi; Lu Yanhao 1975) 1932) Literature specimen (Xinjiang; Zhou et al., 1998) Enrolled specimen preserving the hypostome (Shaanxi; Baishui)

Nileus walcotti — photo 5 — Photo 5 · Holotype USNM 83770 (Shaanxi; Endo Type specimens of the former Nileus liangshanensis (Shaanxi; Lu Yanhao 1975) 1932) Literature specimen (Xinjiang; Zhou et al., 1998) Enrolled specimen preserving the hypostome (Shaanxi; Baishui)

Classification

Order Asaphida / Superfamily Cyclopygoidea / Family Nileidae

Genus

Nileus Dalman, 1827

Genus author

Dalman J. W.

Genus etymology

Possibly from Latin nilio-, gem

Species

N. walcotti Endo, 1932

Species author

Endo R.

Species etymology

In honour of the American palaeontologist C. D. Walcott, an early researcher of Chinese trilobites

Age

Dapingian to Darriwilian (Middle Ordovician)

Distribution

Shaanxi, Xinjiang, Hubei

Synonyms

Nileus liangshanensis; Nileus shibingensis

Diagnosis

Dorsal shield long-ovate. Cephalon long-semi-elliptical, strongly bent downward forward and anterolaterally; glabella distinctly convex, longer than wide, narrowest in front of the eyes; dorsal furrows shallow; eyes large; librigenae wider posteriorly with rounded genal angles. Thorax of 8 segments; axis convex and extremely wide; pleural ends rounded, pleural spines absent. Pygidium subsemicircular, rather convex; axis indistinct; border wide and flat.