Conodonts

        Conodonts are small tooth-like, phosphatic structures that until recently were of uncertain affinity.  However, recent finds of conodont animals with soft parts preserved  indicate that the conodont animals were in fact primitive chordates, and possible vertebrates (see Donaghue et al., 1998, for a discussion). 

        Conodonts come in a wide variety of forms and they are widespread (though generally dispersed) in Paleozoic marine sedimentary deposits, including deposits which are otherwise unfossiliferous in terms of macrofossils.  As such they have proven useful for stategraphic correlation over very wide geographical areas. 

        The North Evans Limestone, a thin lag bed deposit at the base of the Upper Devonian in western New York State, is an exceptionally concentrated deposit of conodonts and other microfossils.   The conodonts shown below were recovered from the North Evans Ls. exposed at the former Penn-Dixie Cement quarry in Hamburg, NY, using dilute acetic acid dissolution of the matrix.

Conodont species (*) :

Polygnathus caelatus Bryant

Polygnathus foliatus
Bryant

Polygnathus linguiformus Hinde 

Polygnathus pennatus
Hinde

Polygnathus rotundilobus
Bryant

Prioniodus alatus
Hinde

Prioniodus colligatus
Bryant

Prioniodus erraticus
Hinde

Prioniodus radiatus
Hinde

Prioniodus recedens
Hinde

Prioniodus sp.
Fragments

Unknown


*
Nomenclature is that of Bryant (1921)

References:

Bryant, W.L. (1921) The Genesee Conodonts.  Bull. Buffalo Soc. Nat. Sci. 13, 1-59.

Donoghue, P.C.J., Purnell, M.A., and Aldridge, R.J. (1998) Conodont Anatomy, Chordate Phylogeny and Vertebrate Classification.  Lethaia   35, 211-219.

Page last revised June 17, 2000