PBDB Taxon

Basic info	Taxonomic history	Classification	Included Taxa
Morphology	Ecology and taphonomy	External Literature Search	Age range and collections

Ptychagnostus richmondensis

Artiopoda - Agnostida - Ptychagnostidae

Taxonomy

Agnostus richmondensis was named by Walcott (1884).

It was recombined as Ptychagnostus richmondensis by Palmer (1954).

Sister species lacking formal opinion data

P. atavus, P. burgessensis, P. ciceroides, P. coartatus, P. davidis, P. granulatum, P. hybridus, P. idmon, P. mesostatus, P. triangulatus, P. puncturosus, P. vinicensis

Synonymy list

Year	Name and author
1884	Agnostus richmondensis Walcott pp. 24 - 25 figs. Pl. 9, Fig. 10
1954	Ptychagnostus richmondensis Palmer p. 61 figs. Plate 13, figures 4, 5

Is something missing? Join the Paleobiology Database and enter the data

Rank	Name	Author
kingdom	Animalia	()
—	Bilateria
—	Eubilateria	Ax 1987
—	Protostomia
—	Ecdysozoa	Aguinaldo et al. 1997
—	Panarthropoda
phylum	Arthropoda	Gravenhorst 1843

Rank	Name	Author
class	Artiopoda	Hou and Bergstrom
order	Agnostida	Salter 1864
suborder	Agnostina	Salter 1864
superfamily	Condylopygoidea	Raymond 1913
family	Ptychagnostidae	Kobayashi 1939
genus	Ptychagnostus	Jaekel 1909
species	richmondensis	()

If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.

†Ptychagnostus richmondensis Walcott 1884

show all | hide all

Diagnosis

Reference	Diagnosis
A. R. Palmer 1954	Cephalon with cheeks scrobiculate; basal glabellar lobes divided; long posterolaterally curved postcephalic spines present. Pygidium with axial lobe bluntly pointed posteriorly, reaching nearly to border; width about equal to that of pleural lobes; posterolateral marginal spines absent.