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Ptychagnostus
Taxonomy
Ptychagnostus was named by Jaekel (1909) [Sepkoski's age data: Cm uMid-m].
It was reranked as Agnostus (Ptychagnostus) by Kobayashi (1935).
It was assigned to Agnostus by Kobayashi (1935); to Agnostinae by Palmer (1954); to Ptychagnostidae by Westrop et al. (1996) and Whittington et al. (1997); and to Agnostida by Sepkoski (2002).
It was reranked as Agnostus (Ptychagnostus) by Kobayashi (1935).
It was assigned to Agnostus by Kobayashi (1935); to Agnostinae by Palmer (1954); to Ptychagnostidae by Westrop et al. (1996) and Whittington et al. (1997); and to Agnostida by Sepkoski (2002).
Species
P. (Acidusus), P. (Ptychagnostus), P. acidusus, P. affinis, P. akanthodes, P. aksayensis, P. atavus, P. convexus, P. cuyanus, P. intermedius, P. karatauensis, P. punctuosus, P. richmondensis, P. seminula, P. sinicus, P. spinosus, Triplagnostus (Aristarius) aristarius, Zeteagnostus incautus, Zeteagnostus scarifatus
Synonyms
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Synonymy list
| Year | Name and author |
|---|---|
| 1909 | Ptychagnostus Jaekel |
| 1935 | Agnostus (Ptychagnostus) Kobayashi |
| 1951 | Canotagnostus Rusconi |
| 1954 | Ptychagnostus Palmer p. 60 |
| 1979 | Zeteagnostus Opik |
| 1979 | Triplagnostus (Aristarius) Öpik p. 125 |
| 1996 | Ptychagnostus Westrop et al. p. 816 |
| 1997 | Ptychagnostus Whittington et al. p. 350 |
| 2002 | Ptychagnostus Sepkoski |
| 2002 | Zeteagnostus Sepkoski |
| 2008 | Zeteagnostus Ergaliev and Ergaliev |
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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.
G. †Ptychagnostus Jaekel 1909
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Subg. †Ptychagnostus (Ptychagnostus) Jaekel 1909
†Ptychagnostus acidusus Opik 1979
†Ptychagnostus affinis Brøgger 1878
†Ptychagnostus akanthodes Robison 1964
†Ptychagnostus aksayensis Ergaliev and Ergaliev 2008
†Ptychagnostus atavus Tullberg 1880
†Ptychagnostus convexus Westergard 1946
†Ptychagnostus cuyanus Rusconi 1948
†Ptychagnostus intermedius Tullberg 1880
†Ptychagnostus karatauensis Ergaliev 1980
†Ptychagnostus punctuosus Angelin 1851
†Ptychagnostus richmondensis Walcott 1884
†Ptychagnostus seminula Whitehouse 1939
†Ptychagnostus sinicus Lu 1957
†Ptychagnostus spinosus Ergaliev 1980
Invalid names: Aristarius Öpik 1979 [synonym], Canotagnostus Rusconi 1951 [synonym], Zeteagnostus Opik 1979 [synonym]
Diagnosis
| Reference | Diagnosis | |
|---|---|---|
| A. R. Palmer 1954 | Cephalon with glabella bilobed, tapered forward; median longitudinal preglabellar furrow pres- ent; basal glabellar lobes simple or divided. Pygidium with axial lobe usually bluntly pointed posteriorly; anterior third separated from posterior portion and subequally divided by distinct transverse furrows; margin usually without posterolateral spines. |