Prioniodinidae Bassler, 1925

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 Prioniodinidae Bassler, 1925 Genus Ligonodina Bassler, 1925

Type species: L. pectinata Bassler, 1925 .

Emended diagnosis.—The anteriormost element of the apparatus (ne) with a wide and flat cusp.

Nomenclatorial comment.—No doubt that Ligonodina , Lonchodina , and Hibbardella are closely related. Jeppson (1969), while proposing the first apparatus restoration of a prioniodinid, made choice of Ligonodina as the generic name and this has to be followed, contrary to later choices of Hibbardella ( Clark et al. 1981) and Prioniodina ( Sparling 1981) . Delotaxis Klapper and Philip, 1971 should not be used for Devonian species because its type species, the Silurian D. elegans (Walliser, 1964) is of a very primitive aspect. Its biramous S 0 (tr) element, weakly asymmetric S 2 (pl) elements, and M (ne) elements with short processes and a slightly basally bent cusp resemble rather the Ordovician Oulodus Branson and Mehl, 1933 . Oulodus differs from Delotaxis only in having even more primitive M (ne) elements with radiating denticles, not parallel to the cusp as is the case in virtually all the post−Ordovician ozarkodinids.