Ptychodus polygyrus Agassiz, 1839

Remarks

• Collector:    Brent Buemi

• Formation:  Eagle Ford Group, Kamp Ranch Limestone

• Location:     Dallas County, Texas

General Info

Synonyms (older names and misidentifications in the literature)

• extinct shell–crushing shark
• 1839 Ptychodus polygyrus Agassiz
• 1900 Ptychodus polygyrus Agassiz; Williston
• 1970 Ptychodus polygyrus Agassiz; Applegate
• 1993 Ptychodus polygyrus Agassiz; Welton & Farish

Stratigraphic Occurrence

• Upper Eagle Ford Group, Kamp Ranch Member of the Arcadia Park Formation, North Texas
• Possibly from the overlying Arcadia Park as well
• Benton Group, Carlile Formation (Fairport Member (?)) of Kansas
• Selma Group, Mooreville Chalk of Alabama
• Possibly from the Mancos Shale of northeastern Arizona
• Upper Cretaceous rocks of Belgium
• Upper Cretaceous rocks of Kent, England

Age

• Ptychodus polygyrus Agassiz occurs at from about the Collignoniceras woollgari (Mantell) zone to roughly the Peroniceras (Peroniceras) westphalicum (Schlüter) zone, from middle Turonian to middle Coniacian time (~92–88 mya).  The teeth from the North American Upper Cretaceous appear to be restricted to the Turonian, while this guy ranges into the Coniacian in Europe.

Geographic Occurrence (not an all-inclusive list)

• AL
• Possibly from Coconino and Navajo Counties, AZ
• Belgium
• Dallas County, TX
• KS (County ?)
• Kent, England

Remarks

         For identification and descriptions, see:

• Welton, B. J; Farish, R. F.  1993.  The  Collector’s  Guide  to  Fossil  Sharks  and  Rays  from  the  Cretaceous  of  Texas.  Lewisville:  Before Time.