This study considers [delta][.sup.13][C.sub.org] values and their variations in conodont elements of the latest Famennian-Tournaisian species Polygnathus parapetus Druce.
The P1 elements of the long-lived conodont species Polygnathus parapetus Druce (Fig.
The miospores belong to the Emphanisporites annulatus--Camarozonotriletes sextantii Assemblage Zone (Richardson and McGregor 1986), which corresponds approximately to the Polygnathus
dehiscens to Polygnathus
serotinus conodont zones of early Emsian to early late Emsian age (Blieck and Cloutier 2000).
The genus Polygnathus evolved during the Pragian (early Pragian in traditional sense, Valenzuela-Rios, 1997) from the Eognathodus group (Klapper and Philip, 1972; Cooper, 1973; Klapper and Johnson, 1975).
This study has yielded a significant assemblage of conodont faunas, which allows the recognition of an important Polygnathus radiation in the region, with the presence of different cosmopolitan and endemic species.
The conodont association of the studied section consists of Polygnathus parapetus Druce (dominates), P.
Koos kirjeldatud uue liigiga leitud konodondid Hindeodus cristulus (Youngquist & Miller), Bispathodus stabilis (Branson & Mehl), Polygnathus longiposticus Branson & Mehl ja Pseudopolygnathus nodomarginatus (Branson) naitavad, et tegemist on Hilis-Tournai vanusega kihtidega (vastavad Alumisele Siphonodella crenulata Tsoonile).
Miospores in the Campbellton Formation place it in the Emphanisporites annulatus-Camarozonotriletes sextantii Assemblage Zone which corresponds approximately to the Polygnathus
dehiscens to Polygnathus
serotinus conodont zones of early Emsian to early late Emsian age (Richardson and McGregor 1986).
According to this, the boundaries and biozones of the Emsian Stage are based essentially upon the successive occurrence of, phylogenetically related, species of the genus Polygnathus (see for example Klapper and Johnson, 1975; Klapper, 1977; Weddige and Ziegler, 1977; Lane and Ormiston, 1979; Yolkin et al., 1994; Bardashev et al., 2002).
This zone was subsequently subdivided into the Lower and Upper gronbergi subzones by Bultynck (1989), according to the polygnathid succession found in the La Grange Limestone of the Armorican Massif (north-western France), identifying the lower boundary of the Upper gronbergi subzone with the first occurrence of a new species, Polygnathus catherinae.
According to Valiukevicius & Ovnatanova (1993), the conodont assemblage consists of Icriodus struvei Weddige, Polygnathus
linguiformis linguiformis Hinde, P.
All these forms, originally described either as Neospathodus, Pseudofurnishius, Polygnathus
, Gondolella, Metapolygnathus, Epigondolella, Tardogondonella, Carinella, Sephardiella and Budurovignathus, belong into the new subfamily Sephardiellinae.