Playfordiidae, Dzik, 2002

Dzik, Jerzy, 2002, Emergence and collapse of the Frasnian conodont and ammonoid communities in the Holy Cross Mountains, Poland, Acta Palaeontologica Polonica 47 (4), pp. 565-650 : 598

Family Playfordiidae nov.

Diagnosis.—Elements of the apparatus with very thin, finely denticulated blades and very wide basal cavity; little shape differentiation within the apparatus.

Remark.—Despite its originally suggested icriodontid affinities, the apparatus of Playfordia primitiva ( Bischoff and Ziegler, 1957) is basically different from those of the icriodontids in not showing distinction between the platform series and the symmetry transition series elements, as discussed above ( Fig. 15). Some remote similarities to the Early Carboniferous Eotaphrus can be traced, but there is too long time hiatus separating these genera. Symmetrical elements of Playfordia resemble superficially Ancyrognathus ancyrognathoideus ( Ziegler, 1958) (see Wang 1994: pl. 10: 1) but to make them homologous would require to assume that the basal cone of Playfordia is an extremely thin platform derived from that of Ancyrognathus . They also differ in surface ornamentation (see Figs. 15B and 28), which in the ancyrognathids, as well as in Dinodus , is covered with cell imprints and not finely tuberculated. Moreover, the stratigraphic occurrence of Playfordia makes it derivation from Ancyrognathus unlikely.

Genera included.—Only Playfordia Glenister and Klapper, 1966 .