Agnostida
Ammagnostus laiwuensis
Order Agnostida / Suborder Agnostina / Superfamily Agnostoidea / Family Ammagnostidae
Cambrian, Miaolingian Drumian to GuzhangianShandong, Hunan, Qinghai, and other areas of North China
Classification
Order Agnostida / Suborder Agnostina / Superfamily Agnostoidea / Family Ammagnostidae
Genus
Ammagnostus
Genus author
Ö pik A. A.
Genus etymology
amm-, Greek, a knob; Agnostus, a trilobite genus name. The name is derived from the sand-grain-like
Species
A. laiwuensis (Lorenz, 1906)
Species author
Lorenz T.
Species etymology
Laiwu, Laiwu, Shandong, the type locality.
Age
Cambrian, Miaolingian Drumian to Guzhangian
Distribution
Shandong, Hunan, Qinghai, and other areas of North China
Synonyms
incertus; P. gullini; P. ozakii; P. comes; P. ekip; P. shandongensis P. cylindrata; P. quadratiformis; P. grossus; Hypagnostus latelimbatus; Ammagnostus quadratiformis; A. shandongensis; Iniospheniscus nodai; I. walcotti; Pseudoperonopsis ozakii P. rakuroensis; P. elengans; Baltagnostus yaojiayuensis; Utagnostus sulcatus; Homagnostus incertus; Kormagnostus?copelandi; Ammagnostus quadratiformis; Ammagnostus shandongensis
Diagnosis
Cephalon subsquare, moderately convex; glabella cylindrical-conical, divided into two segments, frontal segment subsemicircular, posterior segment slightly constricted laterally, with small glabellar median node at the center; basal lobe small, subtriangular; cephalic border narrow, border furrow narrow and deep. Thorax of two segments. Pygidium moderately convex, nearly square; pygidial axis broad and long, gradually tapering backward medially, posterior margin rounded, almost in contact with the border furrow; axial ring node of the pygidium oval, on the second axial ring; pygidial border narrow to moderately broad, border furrow narrow, widening and deepening posterolaterally; with a pair of short lateral spines.
Remarks
Typical body length about 0.2-1.2 cm.