Agnostida

Corrugatagnostus jiangshanensis

Order Agnostida / Suborder Agnostina / Superfamily Agnostoidea / Family Metagnostidae

Ordovician, Late Ordovician KatianZhejiang, Jiangsu, Hunan, Yunnan
Corrugatagnostus jiangshanensis — photo 1
Photo 1 · Type specimens (Zhejiang; Lu Yanhao Reconstruction (Zhou Zhiyi Complete dorsal shield without et al. 1964) 1987) 'reticulation' (Zhejiang; Guodong) Complete Complete dorsal shield Complete dorsal shield dorsal shield (Yunnan; Baishui) (Yunnan; Tang (Yunnan; Guodong) Shi)
Corrugatagnostus jiangshanensis — photo 2
Photo 2 · Type specimens (Zhejiang; Lu Yanhao Reconstruction (Zhou Zhiyi Complete dorsal shield without et al. 1964) 1987) 'reticulation' (Zhejiang; Guodong) Complete Complete dorsal shield Complete dorsal shield dorsal shield (Yunnan; Baishui) (Yunnan; Tang (Yunnan; Guodong) Shi)
Corrugatagnostus jiangshanensis — photo 3
Photo 3 · Type specimens (Zhejiang; Lu Yanhao Reconstruction (Zhou Zhiyi Complete dorsal shield without et al. 1964) 1987) 'reticulation' (Zhejiang; Guodong) Complete Complete dorsal shield Complete dorsal shield dorsal shield (Yunnan; Baishui) (Yunnan; Tang (Yunnan; Guodong) Shi)
Corrugatagnostus jiangshanensis — photo 4
Photo 4 · Type specimens (Zhejiang; Lu Yanhao Reconstruction (Zhou Zhiyi Complete dorsal shield without et al. 1964) 1987) 'reticulation' (Zhejiang; Guodong) Complete Complete dorsal shield Complete dorsal shield dorsal shield (Yunnan; Baishui) (Yunnan; Tang (Yunnan; Guodong) Shi)
Corrugatagnostus jiangshanensis — photo 5
Photo 5 · Type specimens (Zhejiang; Lu Yanhao Reconstruction (Zhou Zhiyi Complete dorsal shield without et al. 1964) 1987) 'reticulation' (Zhejiang; Guodong) Complete Complete dorsal shield Complete dorsal shield dorsal shield (Yunnan; Baishui) (Yunnan; Tang (Yunnan; Guodong) Shi)
Corrugatagnostus jiangshanensis — photo 6
Photo 6 · Type specimens (Zhejiang; Lu Yanhao Reconstruction (Zhou Zhiyi Complete dorsal shield without et al. 1964) 1987) 'reticulation' (Zhejiang; Guodong) Complete Complete dorsal shield Complete dorsal shield dorsal shield (Yunnan; Baishui) (Yunnan; Tang (Yunnan; Guodong) Shi)
Corrugatagnostus jiangshanensis — photo 7
Photo 7 · Type specimens (Zhejiang; Lu Yanhao Reconstruction (Zhou Zhiyi Complete dorsal shield without et al. 1964) 1987) 'reticulation' (Zhejiang; Guodong) Complete Complete dorsal shield Complete dorsal shield dorsal shield (Yunnan; Baishui) (Yunnan; Tang (Yunnan; Guodong) Shi)
Classification
Order Agnostida / Suborder Agnostina / Superfamily Agnostoidea / Family Metagnostidae
Genus
Corrugatagnostus Kobayashi, 1939
Genus author
Kobayashi T.
Genus etymology
corrugat-, Latin, wrinkled; Agnostus, a trilobite genus name.
Species
C. jiangshanensis Lu in Wang et al., 1964
Species author
Lu Yanhao
Species etymology
Jiangshan, the type locality, Jiangshan, Zhejiang.
Age
Ordovician, Late Ordovician Katian
Distribution
Zhejiang, Jiangsu, Hunan, Yunnan
Synonyms
Geragnostus sinensis; Corrugatagnostus chekiangensis; Girvanagnostus sinensis; Corrugatagnostus carinatus
Diagnosis
Cephalon and pygidium subsquare, cheek and pleural regions with radiating depressions or none. Cephalon widening forward; glabella convex, slightly constricted forward, anterior margin rounded; glabellar transverse the furrow forming a forward obtuse angle at the longitudinal midline; frontal lobe semicircular-oval; posterior lobe subpentagonal, with a small node against the transverse furrow in front; basal lobe short and broad, triangular; border furrow deep; border narrow. Pygidium widening slightly backward; axis stout and short, tapering backward, divided into three rectangular rings, terminal end nearly straight, with a small node-like spine medially; median node huge, longitudinally Crossing anterior two segments; Border narrow; Border furrow deep; A pair of marginal spines projecting from posterolateral corner.
Remarks
Typical body length about 0.2-1.2 cm; both 'reticulate' and 'non-reticulate' forms occur.