Agnostida

Ptychagnostus praecurrens

Order Agnostida / Suborder Agnostina / Superfamily Agnostoidea / Family Ptychagnostidae

Cambrian, Miaolingian, WuliuanSweden, Canada

Ptychagnostus praecurrens — photo 1 — Photo 1 · Cephalon is the holotype Illustrated specimens (Sweden; Weidner et al., SGC611 2014) (Sweden; left: Westergård 1936; right: Weidner et al., 2014) Specimen with appendages preserved (Canada; Moysiuk USNM 116212 (Canada; SNMNH) Complete dorsal shield (Canada; et al., 2019) Zhonghouzhengzhi)

Ptychagnostus praecurrens — photo 2 — Photo 2 · Cephalon is the holotype Illustrated specimens (Sweden; Weidner et al., SGC611 2014) (Sweden; left: Westergård 1936; right: Weidner et al., 2014) Specimen with appendages preserved (Canada; Moysiuk USNM 116212 (Canada; SNMNH) Complete dorsal shield (Canada; et al., 2019) Zhonghouzhengzhi)

Ptychagnostus praecurrens — photo 3 — Photo 3 · Cephalon is the holotype Illustrated specimens (Sweden; Weidner et al., SGC611 2014) (Sweden; left: Westergård 1936; right: Weidner et al., 2014) Specimen with appendages preserved (Canada; Moysiuk USNM 116212 (Canada; SNMNH) Complete dorsal shield (Canada; et al., 2019) Zhonghouzhengzhi)

Ptychagnostus praecurrens — photo 4 — Photo 4 · Cephalon is the holotype Illustrated specimens (Sweden; Weidner et al., SGC611 2014) (Sweden; left: Westergård 1936; right: Weidner et al., 2014) Specimen with appendages preserved (Canada; Moysiuk USNM 116212 (Canada; SNMNH) Complete dorsal shield (Canada; et al., 2019) Zhonghouzhengzhi)

Ptychagnostus praecurrens — photo 5 — Photo 5 · Cephalon is the holotype Illustrated specimens (Sweden; Weidner et al., SGC611 2014) (Sweden; left: Westergård 1936; right: Weidner et al., 2014) Specimen with appendages preserved (Canada; Moysiuk USNM 116212 (Canada; SNMNH) Complete dorsal shield (Canada; et al., 2019) Zhonghouzhengzhi)

Ptychagnostus praecurrens — photo 6 — Photo 6 · Cephalon is the holotype Illustrated specimens (Sweden; Weidner et al., SGC611 2014) (Sweden; left: Westergård 1936; right: Weidner et al., 2014) Specimen with appendages preserved (Canada; Moysiuk USNM 116212 (Canada; SNMNH) Complete dorsal shield (Canada; et al., 2019) Zhonghouzhengzhi)

Classification

Order Agnostida / Suborder Agnostina / Superfamily Agnostoidea / Family Ptychagnostidae

Genus

Ptychagnostus Jaekel, 1909

Genus author

Jaekel O.

Genus etymology

ptych-, Greek, fold; Agnostus, a trilobite genus name.

Species

P. praecurrens (Westergård, 1936)

Species author

Westerg å rd A. H.

Species etymology

prae-, Latin, before; currens, Latin, running. Describing the early appearance of this species in the strata.

Age

Cambrian, Miaolingian, Wuliuan

Distribution

Sweden, Canada

Synonyms

Agnostus gibbus praecurrens; Ptychagnostus (Triplagnostus) praecurrens; Triplagnostus burgessensis; Triplagnostus praecurrens; Triplagnostus ademptus; Pentagnostus veles; Pentagnostus rallus; Pentagnostus praecurrens

Diagnosis

Compared with the type species Ptychagnostus punctuosus, the surface lacks nodes and the glabellar posterior lobe is cylindrical rather than trapezoidal.

Remarks

This species may be the earliest member of Ptychagnostus.