Agnostida

Oidalagnostus changi

Order Agnostida / Suborder Agnostina / Superfamily Agnostoidea / Family Diplagnostidae

Cambrian, Miaolingian, GuzhangianZhejiang, Hunan; Australia

Oidalagnostus changi — photo 1 — Photo 1 · Holotype specimen Illustrated specimens NIGP 124021, 124023, 124029, 124300 NIGP 23718, external mould and rubber cast (Hunan; Peng Shanchi 2020) (Zhejiang; Lu Yanhao et al. 1974, 1989) Complete dorsal shield (Zhejiang; Baishui)

Oidalagnostus changi — photo 2 — Photo 2 · Holotype specimen Illustrated specimens NIGP 124021, 124023, 124029, 124300 NIGP 23718, external mould and rubber cast (Hunan; Peng Shanchi 2020) (Zhejiang; Lu Yanhao et al. 1974, 1989) Complete dorsal shield (Zhejiang; Baishui)

Oidalagnostus changi — photo 3 — Photo 3 · Holotype specimen Illustrated specimens NIGP 124021, 124023, 124029, 124300 NIGP 23718, external mould and rubber cast (Hunan; Peng Shanchi 2020) (Zhejiang; Lu Yanhao et al. 1974, 1989) Complete dorsal shield (Zhejiang; Baishui)

Oidalagnostus changi — photo 4 — Photo 4 · Holotype specimen Illustrated specimens NIGP 124021, 124023, 124029, 124300 NIGP 23718, external mould and rubber cast (Hunan; Peng Shanchi 2020) (Zhejiang; Lu Yanhao et al. 1974, 1989) Complete dorsal shield (Zhejiang; Baishui)

Classification

Order Agnostida / Suborder Agnostina / Superfamily Agnostoidea / Family Diplagnostidae

Genus

Oidalagnostus

Genus author

Westerg å rd A. H.

Genus etymology

oid-, Greek, swelling; Agnostus, a trilobite genus name.

Species

O. changi Lu, 1964

Species author

Lu Yanhao

Species etymology

Chang, a surname, Zhang; the source literature does not specify the reference.

Age

Cambrian, Miaolingian, Guzhangian

Distribution

Zhejiang, Hunan; Australia

Synonyms

Oidalagnostus personatus; O. eximius; Ovalagnostus personatus; O. changi; O. bispiniformis Oidalagnostus bispiniformis

Diagnosis

Cephalon subovate, glabella subrectangular, divided into two segments, anterior part of posterior segment with a narrow, long median node. Thoracic axis divided into three lobes. Pygidial axis narrower in front, broader behind, divided into four rings; first two rings with ridge-like axial node; third ring with small axial node; posterior axial ring broad, raised, nearly rectangular; posterior border broad, with a crescentic depression on it and an undulating transverse ridge dividing the depression separated from the axis; posterolateral corner with a pair of small marginal spines. The cheek of the cephalon and the pleural lobes of the pygidium have pits or short furrows.

Remarks

Typical body length about 0.2-1.2 cm.