The apparatus structure of the latest Silurian to Early Devonian conodont Icriodus woschmidti hesperius from sequences in north Queensland, Australia, consists of Pa, Pb and M elements with a symmetry transition series of distinct, but variable, coniform elements. A similar complex of cones was recovered from Ludlow (siluricus Zone) strata; although the apparatus structure is incomplete, the results indicate the existence of a likely ancestral form of the genus Icriodus. The cryptic origin of the genus is discussed in general terms. A distomodontid or icriodellid origin is considered possible. The former is supported by some morphological similarities of the symmetry transition series and stratigraphic considerations. The documentation of a Pa element with morphology apparently transitional between Icriodella and Icriodus supports the second possibility.
|Title of host publication||Proceedings of the sixth European Conodont Symposium (ECOS VI)|
|Place of Publication||Warsaw|
|Number of pages||17|
|Publication status||Published - 1998|